Add staticcheck tool

Makefile

@@ -8,14 +8,15 @@ GOVET       := go vet
 GOIMPORTS   := go tool goimports
 DEADCODE    := go tool deadcode
 GOVULNCHECK := go tool govulncheck
+STATICCHECK := go tool staticcheck
 BIOME       := biome
 
 BUILDFLAGS := -buildvcs=true
 PLATFORMS  := linux/amd64
 
 .PHONY: all build build-all buildinfo check clean deadcode deps fmt help \
-        imports install lint run test tidy tools uninstall verify vet \
+        imports install lint run staticcheck test tidy tools uninstall \
-	vulncheck $(CMDS)
+	verify vet vulncheck $(CMDS)
 
 ## Build all binaries (default target)
 all: build
@@ -67,7 +68,7 @@ test:
 	$(GO) test -cover -race ./...
 
 ## Run all linters (fmt, vet, imports, deadcode, vulncheck)
-lint: fmt vet imports deadcode vulncheck biome
+lint: fmt vet imports deadcode vulncheck staticcheck biome
 
 ## Format code using go fmt
 fmt:
@@ -75,7 +76,8 @@ fmt:
 
 ## Fix imports and format using goimports
 imports:
-	$(GOIMPORTS) -w -local "$(MODULE)" .
+	find . -type f -name '*.go' -not -path './vendor/*' | \
+	xargs $(GOIMPORTS) -w -local "$(MODULE)"
 
 ## Run go vet
 vet:
@@ -96,6 +98,10 @@ check: lint
 tidy:
 	$(GO) mod tidy
 
+## Run staticcheck
+staticcheck:
+	$(STATICCHECK) ./...
+
 ## Download dependencies
 deps:
 	$(GO) mod download
@@ -109,6 +115,7 @@ tools:
 	go get -tool golang.org/x/tools/cmd/deadcode@latest
 	go get -tool golang.org/x/tools/cmd/goimports@latest
 	go get -tool golang.org/x/vuln/cmd/govulncheck@latest
+	go get -tool honnef.co/go/tools/cmd/staticcheck@latest
 
 ## Run the specified CMD binary (use ARGS="..." to pass arguments)
 # trap '' INT prevents colorize-logs from exiting immediately on Ctrl-C,

go.mod

@@ -6,6 +6,7 @@ tool (
 	golang.org/x/tools/cmd/deadcode
 	golang.org/x/tools/cmd/goimports
 	golang.org/x/vuln/cmd/govulncheck
+	honnef.co/go/tools/cmd/staticcheck
 )
 
 require (
@@ -16,10 +17,13 @@ require (
 )
 
 require (
+	github.com/BurntSushi/toml v1.4.1-0.20240526193622-a339e1f7089c // indirect
+	golang.org/x/exp/typeparams v0.0.0-20231108232855-2478ac86f678 // indirect
 	golang.org/x/mod v0.36.0 // indirect
 	golang.org/x/sync v0.20.0 // indirect
 	golang.org/x/sys v0.44.0 // indirect
 	golang.org/x/telemetry v0.0.0-20260508192327-42602be52be6 // indirect
 	golang.org/x/tools v0.45.0 // indirect
 	golang.org/x/vuln v1.3.0 // indirect
+	honnef.co/go/tools v0.7.0 // indirect
 )

go.sum

@@ -1,3 +1,5 @@
+github.com/BurntSushi/toml v1.4.1-0.20240526193622-a339e1f7089c h1:pxW6RcqyfI9/kWtOwnv/G+AzdKuy2ZrqINhenH4HyNs=
+github.com/BurntSushi/toml v1.4.1-0.20240526193622-a339e1f7089c/go.mod h1:ukJfTF/6rtPPRCnwkur4qwRxa8vTRFBF0uk2lLoLwho=
 github.com/google/go-cmdtest v0.4.1-0.20220921163831-55ab3332a786 h1:rcv+Ippz6RAtvaGgKxc+8FQIpxHgsF+HBzPyYL2cyVU=
 github.com/google/go-cmdtest v0.4.1-0.20220921163831-55ab3332a786/go.mod h1:apVn/GCasLZUVpAJ6oWAuyP7Ne7CEsQbTnc0plM3m+o=
 github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
@@ -10,6 +12,8 @@ github.com/robfig/cron/v3 v3.0.1 h1:WdRxkvbJztn8LMz/QEvLN5sBU+xKpSqwwUO1Pjr4qDs=
 github.com/robfig/cron/v3 v3.0.1/go.mod h1:eQICP3HwyT7UooqI/z+Ov+PtYAWygg1TEWWzGIFLtro=
 github.com/sashabaranov/go-openai v1.41.2 h1:vfPRBZNMpnqu8ELsclWcAvF19lDNgh1t6TVfFFOPiSM=
 github.com/sashabaranov/go-openai v1.41.2/go.mod h1:lj5b/K+zjTSFxVLijLSTDZuP7adOgerWeFyZLUhAKRg=
+golang.org/x/exp/typeparams v0.0.0-20231108232855-2478ac86f678 h1:1P7xPZEwZMoBoz0Yze5Nx2/4pxj6nw9ZqHWXqP0iRgQ=
+golang.org/x/exp/typeparams v0.0.0-20231108232855-2478ac86f678/go.mod h1:AbB0pIl9nAr9wVwH+Z2ZpaocVmF5I4GyWCDIsVjR0bk=
 golang.org/x/mod v0.36.0 h1:JJjpVx6myfUsUdAzZuOSTTmRE0PfZeNWzzvKrP7amb4=
 golang.org/x/mod v0.36.0/go.mod h1:moc6ELqsWcOw5Ef3xVprK5ul/MvtVvkIXLziUOICjUQ=
 golang.org/x/sync v0.20.0 h1:e0PTpb7pjO8GAtTs2dQ6jYa5BWYlMuX047Dco/pItO4=
@@ -30,3 +34,5 @@ gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+honnef.co/go/tools v0.7.0 h1:w6WUp1VbkqPEgLz4rkBzH/CSU6HkoqNLp6GstyTx3lU=
+honnef.co/go/tools v0.7.0/go.mod h1:pm29oPxeP3P82ISxZDgIYeOaf9ta6Pi0EWvCFoLG2vc=

vendor/github.com/BurntSushi/toml/.gitignore

@@ -0,0 +1,2 @@
+/toml.test
+/toml-test

vendor/github.com/BurntSushi/toml/COPYING

@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2013 TOML authors
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.

vendor/github.com/BurntSushi/toml/README.md

@@ -0,0 +1,120 @@
+TOML stands for Tom's Obvious, Minimal Language. This Go package provides a
+reflection interface similar to Go's standard library `json` and `xml` packages.
+
+Compatible with TOML version [v1.0.0](https://toml.io/en/v1.0.0).
+
+Documentation: https://godocs.io/github.com/BurntSushi/toml
+
+See the [releases page](https://github.com/BurntSushi/toml/releases) for a
+changelog; this information is also in the git tag annotations (e.g. `git show
+v0.4.0`).
+
+This library requires Go 1.18 or newer; add it to your go.mod with:
+
+    % go get github.com/BurntSushi/toml@latest
+
+It also comes with a TOML validator CLI tool:
+
+    % go install github.com/BurntSushi/toml/cmd/tomlv@latest
+    % tomlv some-toml-file.toml
+
+### Examples
+For the simplest example, consider some TOML file as just a list of keys and
+values:
+
+```toml
+Age = 25
+Cats = [ "Cauchy", "Plato" ]
+Pi = 3.14
+Perfection = [ 6, 28, 496, 8128 ]
+DOB = 1987-07-05T05:45:00Z
+```
+
+Which can be decoded with:
+
+```go
+type Config struct {
+	Age        int
+	Cats       []string
+	Pi         float64
+	Perfection []int
+	DOB        time.Time
+}
+
+var conf Config
+_, err := toml.Decode(tomlData, &conf)
+```
+
+You can also use struct tags if your struct field name doesn't map to a TOML key
+value directly:
+
+```toml
+some_key_NAME = "wat"
+```
+
+```go
+type TOML struct {
+    ObscureKey string `toml:"some_key_NAME"`
+}
+```
+
+Beware that like other decoders **only exported fields** are considered when
+encoding and decoding; private fields are silently ignored.
+
+### Using the `Marshaler` and `encoding.TextUnmarshaler` interfaces
+Here's an example that automatically parses values in a `mail.Address`:
+
+```toml
+contacts = [
+    "Donald Duck <donald@duckburg.com>",
+    "Scrooge McDuck <scrooge@duckburg.com>",
+]
+```
+
+Can be decoded with:
+
+```go
+// Create address type which satisfies the encoding.TextUnmarshaler interface.
+type address struct {
+	*mail.Address
+}
+
+func (a *address) UnmarshalText(text []byte) error {
+	var err error
+	a.Address, err = mail.ParseAddress(string(text))
+	return err
+}
+
+// Decode it.
+func decode() {
+	blob := `
+		contacts = [
+			"Donald Duck <donald@duckburg.com>",
+			"Scrooge McDuck <scrooge@duckburg.com>",
+		]
+	`
+
+	var contacts struct {
+		Contacts []address
+	}
+
+	_, err := toml.Decode(blob, &contacts)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	for _, c := range contacts.Contacts {
+		fmt.Printf("%#v\n", c.Address)
+	}
+
+	// Output:
+	// &mail.Address{Name:"Donald Duck", Address:"donald@duckburg.com"}
+	// &mail.Address{Name:"Scrooge McDuck", Address:"scrooge@duckburg.com"}
+}
+```
+
+To target TOML specifically you can implement `UnmarshalTOML` TOML interface in
+a similar way.
+
+### More complex usage
+See the [`_example/`](/_example) directory for a more complex example.

vendor/github.com/BurntSushi/toml/decode.go

@@ -0,0 +1,615 @@
+package toml
+
+import (
+	"bytes"
+	"encoding"
+	"encoding/json"
+	"fmt"
+	"io"
+	"io/fs"
+	"math"
+	"os"
+	"reflect"
+	"strconv"
+	"strings"
+	"time"
+)
+
+// Unmarshaler is the interface implemented by objects that can unmarshal a
+// TOML description of themselves.
+type Unmarshaler interface {
+	UnmarshalTOML(any) error
+}
+
+// Unmarshal decodes the contents of data in TOML format into a pointer v.
+//
+// See [Decoder] for a description of the decoding process.
+func Unmarshal(data []byte, v any) error {
+	_, err := NewDecoder(bytes.NewReader(data)).Decode(v)
+	return err
+}
+
+// Decode the TOML data in to the pointer v.
+//
+// See [Decoder] for a description of the decoding process.
+func Decode(data string, v any) (MetaData, error) {
+	return NewDecoder(strings.NewReader(data)).Decode(v)
+}
+
+// DecodeFile reads the contents of a file and decodes it with [Decode].
+func DecodeFile(path string, v any) (MetaData, error) {
+	fp, err := os.Open(path)
+	if err != nil {
+		return MetaData{}, err
+	}
+	defer fp.Close()
+	return NewDecoder(fp).Decode(v)
+}
+
+// DecodeFS reads the contents of a file from [fs.FS] and decodes it with
+// [Decode].
+func DecodeFS(fsys fs.FS, path string, v any) (MetaData, error) {
+	fp, err := fsys.Open(path)
+	if err != nil {
+		return MetaData{}, err
+	}
+	defer fp.Close()
+	return NewDecoder(fp).Decode(v)
+}
+
+// Primitive is a TOML value that hasn't been decoded into a Go value.
+//
+// This type can be used for any value, which will cause decoding to be delayed.
+// You can use [PrimitiveDecode] to "manually" decode these values.
+//
+// NOTE: The underlying representation of a `Primitive` value is subject to
+// change. Do not rely on it.
+//
+// NOTE: Primitive values are still parsed, so using them will only avoid the
+// overhead of reflection. They can be useful when you don't know the exact type
+// of TOML data until runtime.
+type Primitive struct {
+	undecoded any
+	context   Key
+}
+
+// The significand precision for float32 and float64 is 24 and 53 bits; this is
+// the range a natural number can be stored in a float without loss of data.
+const (
+	maxSafeFloat32Int = 16777215                // 2^24-1
+	maxSafeFloat64Int = int64(9007199254740991) // 2^53-1
+)
+
+// Decoder decodes TOML data.
+//
+// TOML tables correspond to Go structs or maps; they can be used
+// interchangeably, but structs offer better type safety.
+//
+// TOML table arrays correspond to either a slice of structs or a slice of maps.
+//
+// TOML datetimes correspond to [time.Time]. Local datetimes are parsed in the
+// local timezone.
+//
+// [time.Duration] types are treated as nanoseconds if the TOML value is an
+// integer, or they're parsed with time.ParseDuration() if they're strings.
+//
+// All other TOML types (float, string, int, bool and array) correspond to the
+// obvious Go types.
+//
+// An exception to the above rules is if a type implements the TextUnmarshaler
+// interface, in which case any primitive TOML value (floats, strings, integers,
+// booleans, datetimes) will be converted to a []byte and given to the value's
+// UnmarshalText method. See the Unmarshaler example for a demonstration with
+// email addresses.
+//
+// # Key mapping
+//
+// TOML keys can map to either keys in a Go map or field names in a Go struct.
+// The special `toml` struct tag can be used to map TOML keys to struct fields
+// that don't match the key name exactly (see the example). A case insensitive
+// match to struct names will be tried if an exact match can't be found.
+//
+// The mapping between TOML values and Go values is loose. That is, there may
+// exist TOML values that cannot be placed into your representation, and there
+// may be parts of your representation that do not correspond to TOML values.
+// This loose mapping can be made stricter by using the IsDefined and/or
+// Undecoded methods on the MetaData returned.
+//
+// This decoder does not handle cyclic types. Decode will not terminate if a
+// cyclic type is passed.
+type Decoder struct {
+	r io.Reader
+}
+
+// NewDecoder creates a new Decoder.
+func NewDecoder(r io.Reader) *Decoder {
+	return &Decoder{r: r}
+}
+
+var (
+	unmarshalToml = reflect.TypeOf((*Unmarshaler)(nil)).Elem()
+	unmarshalText = reflect.TypeOf((*encoding.TextUnmarshaler)(nil)).Elem()
+	primitiveType = reflect.TypeOf((*Primitive)(nil)).Elem()
+)
+
+// Decode TOML data in to the pointer `v`.
+func (dec *Decoder) Decode(v any) (MetaData, error) {
+	rv := reflect.ValueOf(v)
+	if rv.Kind() != reflect.Ptr {
+		s := "%q"
+		if reflect.TypeOf(v) == nil {
+			s = "%v"
+		}
+
+		return MetaData{}, fmt.Errorf("toml: cannot decode to non-pointer "+s, reflect.TypeOf(v))
+	}
+	if rv.IsNil() {
+		return MetaData{}, fmt.Errorf("toml: cannot decode to nil value of %q", reflect.TypeOf(v))
+	}
+
+	// Check if this is a supported type: struct, map, any, or something that
+	// implements UnmarshalTOML or UnmarshalText.
+	rv = indirect(rv)
+	rt := rv.Type()
+	if rv.Kind() != reflect.Struct && rv.Kind() != reflect.Map &&
+		!(rv.Kind() == reflect.Interface && rv.NumMethod() == 0) &&
+		!rt.Implements(unmarshalToml) && !rt.Implements(unmarshalText) {
+		return MetaData{}, fmt.Errorf("toml: cannot decode to type %s", rt)
+	}
+
+	// TODO: parser should read from io.Reader? Or at the very least, make it
+	// read from []byte rather than string
+	data, err := io.ReadAll(dec.r)
+	if err != nil {
+		return MetaData{}, err
+	}
+
+	p, err := parse(string(data))
+	if err != nil {
+		return MetaData{}, err
+	}
+
+	md := MetaData{
+		mapping: p.mapping,
+		keyInfo: p.keyInfo,
+		keys:    p.ordered,
+		decoded: make(map[string]struct{}, len(p.ordered)),
+		context: nil,
+		data:    data,
+	}
+	return md, md.unify(p.mapping, rv)
+}
+
+// PrimitiveDecode is just like the other Decode* functions, except it decodes a
+// TOML value that has already been parsed. Valid primitive values can *only* be
+// obtained from values filled by the decoder functions, including this method.
+// (i.e., v may contain more [Primitive] values.)
+//
+// Meta data for primitive values is included in the meta data returned by the
+// Decode* functions with one exception: keys returned by the Undecoded method
+// will only reflect keys that were decoded. Namely, any keys hidden behind a
+// Primitive will be considered undecoded. Executing this method will update the
+// undecoded keys in the meta data. (See the example.)
+func (md *MetaData) PrimitiveDecode(primValue Primitive, v any) error {
+	md.context = primValue.context
+	defer func() { md.context = nil }()
+	return md.unify(primValue.undecoded, rvalue(v))
+}
+
+// unify performs a sort of type unification based on the structure of `rv`,
+// which is the client representation.
+//
+// Any type mismatch produces an error. Finding a type that we don't know
+// how to handle produces an unsupported type error.
+func (md *MetaData) unify(data any, rv reflect.Value) error {
+	// Special case. Look for a `Primitive` value.
+	// TODO: #76 would make this superfluous after implemented.
+	if rv.Type() == primitiveType {
+		// Save the undecoded data and the key context into the primitive
+		// value.
+		context := make(Key, len(md.context))
+		copy(context, md.context)
+		rv.Set(reflect.ValueOf(Primitive{
+			undecoded: data,
+			context:   context,
+		}))
+		return nil
+	}
+
+	rvi := rv.Interface()
+	if v, ok := rvi.(Unmarshaler); ok {
+		err := v.UnmarshalTOML(data)
+		if err != nil {
+			return md.parseErr(err)
+		}
+		return nil
+	}
+	if v, ok := rvi.(encoding.TextUnmarshaler); ok {
+		return md.unifyText(data, v)
+	}
+
+	// TODO:
+	// The behavior here is incorrect whenever a Go type satisfies the
+	// encoding.TextUnmarshaler interface but also corresponds to a TOML hash or
+	// array. In particular, the unmarshaler should only be applied to primitive
+	// TOML values. But at this point, it will be applied to all kinds of values
+	// and produce an incorrect error whenever those values are hashes or arrays
+	// (including arrays of tables).
+
+	k := rv.Kind()
+
+	if k >= reflect.Int && k <= reflect.Uint64 {
+		return md.unifyInt(data, rv)
+	}
+	switch k {
+	case reflect.Struct:
+		return md.unifyStruct(data, rv)
+	case reflect.Map:
+		return md.unifyMap(data, rv)
+	case reflect.Array:
+		return md.unifyArray(data, rv)
+	case reflect.Slice:
+		return md.unifySlice(data, rv)
+	case reflect.String:
+		return md.unifyString(data, rv)
+	case reflect.Bool:
+		return md.unifyBool(data, rv)
+	case reflect.Interface:
+		if rv.NumMethod() > 0 { /// Only empty interfaces are supported.
+			return md.e("unsupported type %s", rv.Type())
+		}
+		return md.unifyAnything(data, rv)
+	case reflect.Float32, reflect.Float64:
+		return md.unifyFloat64(data, rv)
+	}
+	return md.e("unsupported type %s", rv.Kind())
+}
+
+func (md *MetaData) unifyStruct(mapping any, rv reflect.Value) error {
+	tmap, ok := mapping.(map[string]any)
+	if !ok {
+		if mapping == nil {
+			return nil
+		}
+		return md.e("type mismatch for %s: expected table but found %s", rv.Type().String(), fmtType(mapping))
+	}
+
+	for key, datum := range tmap {
+		var f *field
+		fields := cachedTypeFields(rv.Type())
+		for i := range fields {
+			ff := &fields[i]
+			if ff.name == key {
+				f = ff
+				break
+			}
+			if f == nil && strings.EqualFold(ff.name, key) {
+				f = ff
+			}
+		}
+		if f != nil {
+			subv := rv
+			for _, i := range f.index {
+				subv = indirect(subv.Field(i))
+			}
+
+			if isUnifiable(subv) {
+				md.decoded[md.context.add(key).String()] = struct{}{}
+				md.context = append(md.context, key)
+
+				err := md.unify(datum, subv)
+				if err != nil {
+					return err
+				}
+				md.context = md.context[0 : len(md.context)-1]
+			} else if f.name != "" {
+				return md.e("cannot write unexported field %s.%s", rv.Type().String(), f.name)
+			}
+		}
+	}
+	return nil
+}
+
+func (md *MetaData) unifyMap(mapping any, rv reflect.Value) error {
+	keyType := rv.Type().Key().Kind()
+	if keyType != reflect.String && keyType != reflect.Interface {
+		return fmt.Errorf("toml: cannot decode to a map with non-string key type (%s in %q)",
+			keyType, rv.Type())
+	}
+
+	tmap, ok := mapping.(map[string]any)
+	if !ok {
+		if tmap == nil {
+			return nil
+		}
+		return md.badtype("map", mapping)
+	}
+	if rv.IsNil() {
+		rv.Set(reflect.MakeMap(rv.Type()))
+	}
+	for k, v := range tmap {
+		md.decoded[md.context.add(k).String()] = struct{}{}
+		md.context = append(md.context, k)
+
+		rvval := reflect.Indirect(reflect.New(rv.Type().Elem()))
+
+		err := md.unify(v, indirect(rvval))
+		if err != nil {
+			return err
+		}
+		md.context = md.context[0 : len(md.context)-1]
+
+		rvkey := indirect(reflect.New(rv.Type().Key()))
+
+		switch keyType {
+		case reflect.Interface:
+			rvkey.Set(reflect.ValueOf(k))
+		case reflect.String:
+			rvkey.SetString(k)
+		}
+
+		rv.SetMapIndex(rvkey, rvval)
+	}
+	return nil
+}
+
+func (md *MetaData) unifyArray(data any, rv reflect.Value) error {
+	datav := reflect.ValueOf(data)
+	if datav.Kind() != reflect.Slice {
+		if !datav.IsValid() {
+			return nil
+		}
+		return md.badtype("slice", data)
+	}
+	if l := datav.Len(); l != rv.Len() {
+		return md.e("expected array length %d; got TOML array of length %d", rv.Len(), l)
+	}
+	return md.unifySliceArray(datav, rv)
+}
+
+func (md *MetaData) unifySlice(data any, rv reflect.Value) error {
+	datav := reflect.ValueOf(data)
+	if datav.Kind() != reflect.Slice {
+		if !datav.IsValid() {
+			return nil
+		}
+		return md.badtype("slice", data)
+	}
+	n := datav.Len()
+	if rv.IsNil() || rv.Cap() < n {
+		rv.Set(reflect.MakeSlice(rv.Type(), n, n))
+	}
+	rv.SetLen(n)
+	return md.unifySliceArray(datav, rv)
+}
+
+func (md *MetaData) unifySliceArray(data, rv reflect.Value) error {
+	l := data.Len()
+	for i := 0; i < l; i++ {
+		err := md.unify(data.Index(i).Interface(), indirect(rv.Index(i)))
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func (md *MetaData) unifyString(data any, rv reflect.Value) error {
+	_, ok := rv.Interface().(json.Number)
+	if ok {
+		if i, ok := data.(int64); ok {
+			rv.SetString(strconv.FormatInt(i, 10))
+		} else if f, ok := data.(float64); ok {
+			rv.SetString(strconv.FormatFloat(f, 'f', -1, 64))
+		} else {
+			return md.badtype("string", data)
+		}
+		return nil
+	}
+
+	if s, ok := data.(string); ok {
+		rv.SetString(s)
+		return nil
+	}
+	return md.badtype("string", data)
+}
+
+func (md *MetaData) unifyFloat64(data any, rv reflect.Value) error {
+	rvk := rv.Kind()
+
+	if num, ok := data.(float64); ok {
+		switch rvk {
+		case reflect.Float32:
+			if num < -math.MaxFloat32 || num > math.MaxFloat32 {
+				return md.parseErr(errParseRange{i: num, size: rvk.String()})
+			}
+			fallthrough
+		case reflect.Float64:
+			rv.SetFloat(num)
+		default:
+			panic("bug")
+		}
+		return nil
+	}
+
+	if num, ok := data.(int64); ok {
+		if (rvk == reflect.Float32 && (num < -maxSafeFloat32Int || num > maxSafeFloat32Int)) ||
+			(rvk == reflect.Float64 && (num < -maxSafeFloat64Int || num > maxSafeFloat64Int)) {
+			return md.parseErr(errUnsafeFloat{i: num, size: rvk.String()})
+		}
+		rv.SetFloat(float64(num))
+		return nil
+	}
+
+	return md.badtype("float", data)
+}
+
+func (md *MetaData) unifyInt(data any, rv reflect.Value) error {
+	_, ok := rv.Interface().(time.Duration)
+	if ok {
+		// Parse as string duration, and fall back to regular integer parsing
+		// (as nanosecond) if this is not a string.
+		if s, ok := data.(string); ok {
+			dur, err := time.ParseDuration(s)
+			if err != nil {
+				return md.parseErr(errParseDuration{s})
+			}
+			rv.SetInt(int64(dur))
+			return nil
+		}
+	}
+
+	num, ok := data.(int64)
+	if !ok {
+		return md.badtype("integer", data)
+	}
+
+	rvk := rv.Kind()
+	switch {
+	case rvk >= reflect.Int && rvk <= reflect.Int64:
+		if (rvk == reflect.Int8 && (num < math.MinInt8 || num > math.MaxInt8)) ||
+			(rvk == reflect.Int16 && (num < math.MinInt16 || num > math.MaxInt16)) ||
+			(rvk == reflect.Int32 && (num < math.MinInt32 || num > math.MaxInt32)) {
+			return md.parseErr(errParseRange{i: num, size: rvk.String()})
+		}
+		rv.SetInt(num)
+	case rvk >= reflect.Uint && rvk <= reflect.Uint64:
+		unum := uint64(num)
+		if rvk == reflect.Uint8 && (num < 0 || unum > math.MaxUint8) ||
+			rvk == reflect.Uint16 && (num < 0 || unum > math.MaxUint16) ||
+			rvk == reflect.Uint32 && (num < 0 || unum > math.MaxUint32) {
+			return md.parseErr(errParseRange{i: num, size: rvk.String()})
+		}
+		rv.SetUint(unum)
+	default:
+		panic("unreachable")
+	}
+	return nil
+}
+
+func (md *MetaData) unifyBool(data any, rv reflect.Value) error {
+	if b, ok := data.(bool); ok {
+		rv.SetBool(b)
+		return nil
+	}
+	return md.badtype("boolean", data)
+}
+
+func (md *MetaData) unifyAnything(data any, rv reflect.Value) error {
+	rv.Set(reflect.ValueOf(data))
+	return nil
+}
+
+func (md *MetaData) unifyText(data any, v encoding.TextUnmarshaler) error {
+	var s string
+	switch sdata := data.(type) {
+	case Marshaler:
+		text, err := sdata.MarshalTOML()
+		if err != nil {
+			return err
+		}
+		s = string(text)
+	case encoding.TextMarshaler:
+		text, err := sdata.MarshalText()
+		if err != nil {
+			return err
+		}
+		s = string(text)
+	case fmt.Stringer:
+		s = sdata.String()
+	case string:
+		s = sdata
+	case bool:
+		s = fmt.Sprintf("%v", sdata)
+	case int64:
+		s = fmt.Sprintf("%d", sdata)
+	case float64:
+		s = fmt.Sprintf("%f", sdata)
+	default:
+		return md.badtype("primitive (string-like)", data)
+	}
+	if err := v.UnmarshalText([]byte(s)); err != nil {
+		return md.parseErr(err)
+	}
+	return nil
+}
+
+func (md *MetaData) badtype(dst string, data any) error {
+	return md.e("incompatible types: TOML value has type %s; destination has type %s", fmtType(data), dst)
+}
+
+func (md *MetaData) parseErr(err error) error {
+	k := md.context.String()
+	d := string(md.data)
+	return ParseError{
+		Message:  err.Error(),
+		err:      err,
+		LastKey:  k,
+		Position: md.keyInfo[k].pos.withCol(d),
+		Line:     md.keyInfo[k].pos.Line,
+		input:    d,
+	}
+}
+
+func (md *MetaData) e(format string, args ...any) error {
+	f := "toml: "
+	if len(md.context) > 0 {
+		f = fmt.Sprintf("toml: (last key %q): ", md.context)
+		p := md.keyInfo[md.context.String()].pos
+		if p.Line > 0 {
+			f = fmt.Sprintf("toml: line %d (last key %q): ", p.Line, md.context)
+		}
+	}
+	return fmt.Errorf(f+format, args...)
+}
+
+// rvalue returns a reflect.Value of `v`. All pointers are resolved.
+func rvalue(v any) reflect.Value {
+	return indirect(reflect.ValueOf(v))
+}
+
+// indirect returns the value pointed to by a pointer.
+//
+// Pointers are followed until the value is not a pointer. New values are
+// allocated for each nil pointer.
+//
+// An exception to this rule is if the value satisfies an interface of interest
+// to us (like encoding.TextUnmarshaler).
+func indirect(v reflect.Value) reflect.Value {
+	if v.Kind() != reflect.Ptr {
+		if v.CanSet() {
+			pv := v.Addr()
+			pvi := pv.Interface()
+			if _, ok := pvi.(encoding.TextUnmarshaler); ok {
+				return pv
+			}
+			if _, ok := pvi.(Unmarshaler); ok {
+				return pv
+			}
+		}
+		return v
+	}
+	if v.IsNil() {
+		v.Set(reflect.New(v.Type().Elem()))
+	}
+	return indirect(reflect.Indirect(v))
+}
+
+func isUnifiable(rv reflect.Value) bool {
+	if rv.CanSet() {
+		return true
+	}
+	rvi := rv.Interface()
+	if _, ok := rvi.(encoding.TextUnmarshaler); ok {
+		return true
+	}
+	if _, ok := rvi.(Unmarshaler); ok {
+		return true
+	}
+	return false
+}
+
+// fmt %T with "interface {}" replaced with "any", which is far more readable.
+func fmtType(t any) string {
+	return strings.ReplaceAll(fmt.Sprintf("%T", t), "interface {}", "any")
+}

vendor/github.com/BurntSushi/toml/deprecated.go

@@ -0,0 +1,29 @@
+package toml
+
+import (
+	"encoding"
+	"io"
+)
+
+// TextMarshaler is an alias for encoding.TextMarshaler.
+//
+// Deprecated: use encoding.TextMarshaler
+type TextMarshaler encoding.TextMarshaler
+
+// TextUnmarshaler is an alias for encoding.TextUnmarshaler.
+//
+// Deprecated: use encoding.TextUnmarshaler
+type TextUnmarshaler encoding.TextUnmarshaler
+
+// DecodeReader is an alias for NewDecoder(r).Decode(v).
+//
+// Deprecated: use NewDecoder(reader).Decode(&value).
+func DecodeReader(r io.Reader, v any) (MetaData, error) { return NewDecoder(r).Decode(v) }
+
+// PrimitiveDecode is an alias for MetaData.PrimitiveDecode().
+//
+// Deprecated: use MetaData.PrimitiveDecode.
+func PrimitiveDecode(primValue Primitive, v any) error {
+	md := MetaData{decoded: make(map[string]struct{})}
+	return md.unify(primValue.undecoded, rvalue(v))
+}

vendor/github.com/BurntSushi/toml/doc.go

@@ -0,0 +1,8 @@
+// Package toml implements decoding and encoding of TOML files.
+//
+// This package supports TOML v1.0.0, as specified at https://toml.io
+//
+// The github.com/BurntSushi/toml/cmd/tomlv package implements a TOML validator,
+// and can be used to verify if TOML document is valid. It can also be used to
+// print the type of each key.
+package toml

vendor/github.com/BurntSushi/toml/encode.go

@@ -0,0 +1,778 @@
+package toml
+
+import (
+	"bufio"
+	"bytes"
+	"encoding"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"math"
+	"reflect"
+	"sort"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/BurntSushi/toml/internal"
+)
+
+type tomlEncodeError struct{ error }
+
+var (
+	errArrayNilElement = errors.New("toml: cannot encode array with nil element")
+	errNonString       = errors.New("toml: cannot encode a map with non-string key type")
+	errNoKey           = errors.New("toml: top-level values must be Go maps or structs")
+	errAnything        = errors.New("") // used in testing
+)
+
+var dblQuotedReplacer = strings.NewReplacer(
+	"\"", "\\\"",
+	"\\", "\\\\",
+	"\x00", `\u0000`,
+	"\x01", `\u0001`,
+	"\x02", `\u0002`,
+	"\x03", `\u0003`,
+	"\x04", `\u0004`,
+	"\x05", `\u0005`,
+	"\x06", `\u0006`,
+	"\x07", `\u0007`,
+	"\b", `\b`,
+	"\t", `\t`,
+	"\n", `\n`,
+	"\x0b", `\u000b`,
+	"\f", `\f`,
+	"\r", `\r`,
+	"\x0e", `\u000e`,
+	"\x0f", `\u000f`,
+	"\x10", `\u0010`,
+	"\x11", `\u0011`,
+	"\x12", `\u0012`,
+	"\x13", `\u0013`,
+	"\x14", `\u0014`,
+	"\x15", `\u0015`,
+	"\x16", `\u0016`,
+	"\x17", `\u0017`,
+	"\x18", `\u0018`,
+	"\x19", `\u0019`,
+	"\x1a", `\u001a`,
+	"\x1b", `\u001b`,
+	"\x1c", `\u001c`,
+	"\x1d", `\u001d`,
+	"\x1e", `\u001e`,
+	"\x1f", `\u001f`,
+	"\x7f", `\u007f`,
+)
+
+var (
+	marshalToml = reflect.TypeOf((*Marshaler)(nil)).Elem()
+	marshalText = reflect.TypeOf((*encoding.TextMarshaler)(nil)).Elem()
+	timeType    = reflect.TypeOf((*time.Time)(nil)).Elem()
+)
+
+// Marshaler is the interface implemented by types that can marshal themselves
+// into valid TOML.
+type Marshaler interface {
+	MarshalTOML() ([]byte, error)
+}
+
+// Marshal returns a TOML representation of the Go value.
+//
+// See [Encoder] for a description of the encoding process.
+func Marshal(v any) ([]byte, error) {
+	buff := new(bytes.Buffer)
+	if err := NewEncoder(buff).Encode(v); err != nil {
+		return nil, err
+	}
+	return buff.Bytes(), nil
+}
+
+// Encoder encodes a Go to a TOML document.
+//
+// The mapping between Go values and TOML values should be precisely the same as
+// for [Decode].
+//
+// time.Time is encoded as a RFC 3339 string, and time.Duration as its string
+// representation.
+//
+// The [Marshaler] and [encoding.TextMarshaler] interfaces are supported to
+// encoding the value as custom TOML.
+//
+// If you want to write arbitrary binary data then you will need to use
+// something like base64 since TOML does not have any binary types.
+//
+// When encoding TOML hashes (Go maps or structs), keys without any sub-hashes
+// are encoded first.
+//
+// Go maps will be sorted alphabetically by key for deterministic output.
+//
+// The toml struct tag can be used to provide the key name; if omitted the
+// struct field name will be used. If the "omitempty" option is present the
+// following value will be skipped:
+//
+//   - arrays, slices, maps, and string with len of 0
+//   - struct with all zero values
+//   - bool false
+//
+// If omitzero is given all int and float types with a value of 0 will be
+// skipped.
+//
+// Encoding Go values without a corresponding TOML representation will return an
+// error. Examples of this includes maps with non-string keys, slices with nil
+// elements, embedded non-struct types, and nested slices containing maps or
+// structs. (e.g. [][]map[string]string is not allowed but []map[string]string
+// is okay, as is []map[string][]string).
+//
+// NOTE: only exported keys are encoded due to the use of reflection. Unexported
+// keys are silently discarded.
+type Encoder struct {
+	Indent     string // string for a single indentation level; default is two spaces.
+	hasWritten bool   // written any output to w yet?
+	w          *bufio.Writer
+}
+
+// NewEncoder create a new Encoder.
+func NewEncoder(w io.Writer) *Encoder {
+	return &Encoder{w: bufio.NewWriter(w), Indent: "  "}
+}
+
+// Encode writes a TOML representation of the Go value to the [Encoder]'s writer.
+//
+// An error is returned if the value given cannot be encoded to a valid TOML
+// document.
+func (enc *Encoder) Encode(v any) error {
+	rv := eindirect(reflect.ValueOf(v))
+	err := enc.safeEncode(Key([]string{}), rv)
+	if err != nil {
+		return err
+	}
+	return enc.w.Flush()
+}
+
+func (enc *Encoder) safeEncode(key Key, rv reflect.Value) (err error) {
+	defer func() {
+		if r := recover(); r != nil {
+			if terr, ok := r.(tomlEncodeError); ok {
+				err = terr.error
+				return
+			}
+			panic(r)
+		}
+	}()
+	enc.encode(key, rv)
+	return nil
+}
+
+func (enc *Encoder) encode(key Key, rv reflect.Value) {
+	// If we can marshal the type to text, then we use that. This prevents the
+	// encoder for handling these types as generic structs (or whatever the
+	// underlying type of a TextMarshaler is).
+	switch {
+	case isMarshaler(rv):
+		enc.writeKeyValue(key, rv, false)
+		return
+	case rv.Type() == primitiveType: // TODO: #76 would make this superfluous after implemented.
+		enc.encode(key, reflect.ValueOf(rv.Interface().(Primitive).undecoded))
+		return
+	}
+
+	k := rv.Kind()
+	switch k {
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32,
+		reflect.Int64,
+		reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32,
+		reflect.Uint64,
+		reflect.Float32, reflect.Float64, reflect.String, reflect.Bool:
+		enc.writeKeyValue(key, rv, false)
+	case reflect.Array, reflect.Slice:
+		if typeEqual(tomlArrayHash, tomlTypeOfGo(rv)) {
+			enc.eArrayOfTables(key, rv)
+		} else {
+			enc.writeKeyValue(key, rv, false)
+		}
+	case reflect.Interface:
+		if rv.IsNil() {
+			return
+		}
+		enc.encode(key, rv.Elem())
+	case reflect.Map:
+		if rv.IsNil() {
+			return
+		}
+		enc.eTable(key, rv)
+	case reflect.Ptr:
+		if rv.IsNil() {
+			return
+		}
+		enc.encode(key, rv.Elem())
+	case reflect.Struct:
+		enc.eTable(key, rv)
+	default:
+		encPanic(fmt.Errorf("unsupported type for key '%s': %s", key, k))
+	}
+}
+
+// eElement encodes any value that can be an array element.
+func (enc *Encoder) eElement(rv reflect.Value) {
+	switch v := rv.Interface().(type) {
+	case time.Time: // Using TextMarshaler adds extra quotes, which we don't want.
+		format := time.RFC3339Nano
+		switch v.Location() {
+		case internal.LocalDatetime:
+			format = "2006-01-02T15:04:05.999999999"
+		case internal.LocalDate:
+			format = "2006-01-02"
+		case internal.LocalTime:
+			format = "15:04:05.999999999"
+		}
+		switch v.Location() {
+		default:
+			enc.wf(v.Format(format))
+		case internal.LocalDatetime, internal.LocalDate, internal.LocalTime:
+			enc.wf(v.In(time.UTC).Format(format))
+		}
+		return
+	case Marshaler:
+		s, err := v.MarshalTOML()
+		if err != nil {
+			encPanic(err)
+		}
+		if s == nil {
+			encPanic(errors.New("MarshalTOML returned nil and no error"))
+		}
+		enc.w.Write(s)
+		return
+	case encoding.TextMarshaler:
+		s, err := v.MarshalText()
+		if err != nil {
+			encPanic(err)
+		}
+		if s == nil {
+			encPanic(errors.New("MarshalText returned nil and no error"))
+		}
+		enc.writeQuoted(string(s))
+		return
+	case time.Duration:
+		enc.writeQuoted(v.String())
+		return
+	case json.Number:
+		n, _ := rv.Interface().(json.Number)
+
+		if n == "" { /// Useful zero value.
+			enc.w.WriteByte('0')
+			return
+		} else if v, err := n.Int64(); err == nil {
+			enc.eElement(reflect.ValueOf(v))
+			return
+		} else if v, err := n.Float64(); err == nil {
+			enc.eElement(reflect.ValueOf(v))
+			return
+		}
+		encPanic(fmt.Errorf("unable to convert %q to int64 or float64", n))
+	}
+
+	switch rv.Kind() {
+	case reflect.Ptr:
+		enc.eElement(rv.Elem())
+		return
+	case reflect.String:
+		enc.writeQuoted(rv.String())
+	case reflect.Bool:
+		enc.wf(strconv.FormatBool(rv.Bool()))
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		enc.wf(strconv.FormatInt(rv.Int(), 10))
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
+		enc.wf(strconv.FormatUint(rv.Uint(), 10))
+	case reflect.Float32:
+		f := rv.Float()
+		if math.IsNaN(f) {
+			if math.Signbit(f) {
+				enc.wf("-")
+			}
+			enc.wf("nan")
+		} else if math.IsInf(f, 0) {
+			if math.Signbit(f) {
+				enc.wf("-")
+			}
+			enc.wf("inf")
+		} else {
+			enc.wf(floatAddDecimal(strconv.FormatFloat(f, 'f', -1, 32)))
+		}
+	case reflect.Float64:
+		f := rv.Float()
+		if math.IsNaN(f) {
+			if math.Signbit(f) {
+				enc.wf("-")
+			}
+			enc.wf("nan")
+		} else if math.IsInf(f, 0) {
+			if math.Signbit(f) {
+				enc.wf("-")
+			}
+			enc.wf("inf")
+		} else {
+			enc.wf(floatAddDecimal(strconv.FormatFloat(f, 'f', -1, 64)))
+		}
+	case reflect.Array, reflect.Slice:
+		enc.eArrayOrSliceElement(rv)
+	case reflect.Struct:
+		enc.eStruct(nil, rv, true)
+	case reflect.Map:
+		enc.eMap(nil, rv, true)
+	case reflect.Interface:
+		enc.eElement(rv.Elem())
+	default:
+		encPanic(fmt.Errorf("unexpected type: %s", fmtType(rv.Interface())))
+	}
+}
+
+// By the TOML spec, all floats must have a decimal with at least one number on
+// either side.
+func floatAddDecimal(fstr string) string {
+	if !strings.Contains(fstr, ".") {
+		return fstr + ".0"
+	}
+	return fstr
+}
+
+func (enc *Encoder) writeQuoted(s string) {
+	enc.wf("\"%s\"", dblQuotedReplacer.Replace(s))
+}
+
+func (enc *Encoder) eArrayOrSliceElement(rv reflect.Value) {
+	length := rv.Len()
+	enc.wf("[")
+	for i := 0; i < length; i++ {
+		elem := eindirect(rv.Index(i))
+		enc.eElement(elem)
+		if i != length-1 {
+			enc.wf(", ")
+		}
+	}
+	enc.wf("]")
+}
+
+func (enc *Encoder) eArrayOfTables(key Key, rv reflect.Value) {
+	if len(key) == 0 {
+		encPanic(errNoKey)
+	}
+	for i := 0; i < rv.Len(); i++ {
+		trv := eindirect(rv.Index(i))
+		if isNil(trv) {
+			continue
+		}
+		enc.newline()
+		enc.wf("%s[[%s]]", enc.indentStr(key), key)
+		enc.newline()
+		enc.eMapOrStruct(key, trv, false)
+	}
+}
+
+func (enc *Encoder) eTable(key Key, rv reflect.Value) {
+	if len(key) == 1 {
+		// Output an extra newline between top-level tables.
+		// (The newline isn't written if nothing else has been written though.)
+		enc.newline()
+	}
+	if len(key) > 0 {
+		enc.wf("%s[%s]", enc.indentStr(key), key)
+		enc.newline()
+	}
+	enc.eMapOrStruct(key, rv, false)
+}
+
+func (enc *Encoder) eMapOrStruct(key Key, rv reflect.Value, inline bool) {
+	switch rv.Kind() {
+	case reflect.Map:
+		enc.eMap(key, rv, inline)
+	case reflect.Struct:
+		enc.eStruct(key, rv, inline)
+	default:
+		// Should never happen?
+		panic("eTable: unhandled reflect.Value Kind: " + rv.Kind().String())
+	}
+}
+
+func (enc *Encoder) eMap(key Key, rv reflect.Value, inline bool) {
+	rt := rv.Type()
+	if rt.Key().Kind() != reflect.String {
+		encPanic(errNonString)
+	}
+
+	// Sort keys so that we have deterministic output. And write keys directly
+	// underneath this key first, before writing sub-structs or sub-maps.
+	var mapKeysDirect, mapKeysSub []string
+	for _, mapKey := range rv.MapKeys() {
+		k := mapKey.String()
+		if typeIsTable(tomlTypeOfGo(eindirect(rv.MapIndex(mapKey)))) {
+			mapKeysSub = append(mapKeysSub, k)
+		} else {
+			mapKeysDirect = append(mapKeysDirect, k)
+		}
+	}
+
+	var writeMapKeys = func(mapKeys []string, trailC bool) {
+		sort.Strings(mapKeys)
+		for i, mapKey := range mapKeys {
+			val := eindirect(rv.MapIndex(reflect.ValueOf(mapKey)))
+			if isNil(val) {
+				continue
+			}
+
+			if inline {
+				enc.writeKeyValue(Key{mapKey}, val, true)
+				if trailC || i != len(mapKeys)-1 {
+					enc.wf(", ")
+				}
+			} else {
+				enc.encode(key.add(mapKey), val)
+			}
+		}
+	}
+
+	if inline {
+		enc.wf("{")
+	}
+	writeMapKeys(mapKeysDirect, len(mapKeysSub) > 0)
+	writeMapKeys(mapKeysSub, false)
+	if inline {
+		enc.wf("}")
+	}
+}
+
+const is32Bit = (32 << (^uint(0) >> 63)) == 32
+
+func pointerTo(t reflect.Type) reflect.Type {
+	if t.Kind() == reflect.Ptr {
+		return pointerTo(t.Elem())
+	}
+	return t
+}
+
+func (enc *Encoder) eStruct(key Key, rv reflect.Value, inline bool) {
+	// Write keys for fields directly under this key first, because if we write
+	// a field that creates a new table then all keys under it will be in that
+	// table (not the one we're writing here).
+	//
+	// Fields is a [][]int: for fieldsDirect this always has one entry (the
+	// struct index). For fieldsSub it contains two entries: the parent field
+	// index from tv, and the field indexes for the fields of the sub.
+	var (
+		rt                      = rv.Type()
+		fieldsDirect, fieldsSub [][]int
+		addFields               func(rt reflect.Type, rv reflect.Value, start []int)
+	)
+	addFields = func(rt reflect.Type, rv reflect.Value, start []int) {
+		for i := 0; i < rt.NumField(); i++ {
+			f := rt.Field(i)
+			isEmbed := f.Anonymous && pointerTo(f.Type).Kind() == reflect.Struct
+			if f.PkgPath != "" && !isEmbed { /// Skip unexported fields.
+				continue
+			}
+			opts := getOptions(f.Tag)
+			if opts.skip {
+				continue
+			}
+
+			frv := eindirect(rv.Field(i))
+
+			if is32Bit {
+				// Copy so it works correct on 32bit archs; not clear why this
+				// is needed. See #314, and https://www.reddit.com/r/golang/comments/pnx8v4
+				// This also works fine on 64bit, but 32bit archs are somewhat
+				// rare and this is a wee bit faster.
+				copyStart := make([]int, len(start))
+				copy(copyStart, start)
+				start = copyStart
+			}
+
+			// Treat anonymous struct fields with tag names as though they are
+			// not anonymous, like encoding/json does.
+			//
+			// Non-struct anonymous fields use the normal encoding logic.
+			if isEmbed {
+				if getOptions(f.Tag).name == "" && frv.Kind() == reflect.Struct {
+					addFields(frv.Type(), frv, append(start, f.Index...))
+					continue
+				}
+			}
+
+			if typeIsTable(tomlTypeOfGo(frv)) {
+				fieldsSub = append(fieldsSub, append(start, f.Index...))
+			} else {
+				fieldsDirect = append(fieldsDirect, append(start, f.Index...))
+			}
+		}
+	}
+	addFields(rt, rv, nil)
+
+	writeFields := func(fields [][]int) {
+		for _, fieldIndex := range fields {
+			fieldType := rt.FieldByIndex(fieldIndex)
+			fieldVal := rv.FieldByIndex(fieldIndex)
+
+			opts := getOptions(fieldType.Tag)
+			if opts.skip {
+				continue
+			}
+			if opts.omitempty && isEmpty(fieldVal) {
+				continue
+			}
+
+			fieldVal = eindirect(fieldVal)
+
+			if isNil(fieldVal) { /// Don't write anything for nil fields.
+				continue
+			}
+
+			keyName := fieldType.Name
+			if opts.name != "" {
+				keyName = opts.name
+			}
+
+			if opts.omitzero && isZero(fieldVal) {
+				continue
+			}
+
+			if inline {
+				enc.writeKeyValue(Key{keyName}, fieldVal, true)
+				if fieldIndex[0] != len(fields)-1 {
+					enc.wf(", ")
+				}
+			} else {
+				enc.encode(key.add(keyName), fieldVal)
+			}
+		}
+	}
+
+	if inline {
+		enc.wf("{")
+	}
+	writeFields(fieldsDirect)
+	writeFields(fieldsSub)
+	if inline {
+		enc.wf("}")
+	}
+}
+
+// tomlTypeOfGo returns the TOML type name of the Go value's type.
+//
+// It is used to determine whether the types of array elements are mixed (which
+// is forbidden). If the Go value is nil, then it is illegal for it to be an
+// array element, and valueIsNil is returned as true.
+//
+// The type may be `nil`, which means no concrete TOML type could be found.
+func tomlTypeOfGo(rv reflect.Value) tomlType {
+	if isNil(rv) || !rv.IsValid() {
+		return nil
+	}
+
+	if rv.Kind() == reflect.Struct {
+		if rv.Type() == timeType {
+			return tomlDatetime
+		}
+		if isMarshaler(rv) {
+			return tomlString
+		}
+		return tomlHash
+	}
+
+	if isMarshaler(rv) {
+		return tomlString
+	}
+
+	switch rv.Kind() {
+	case reflect.Bool:
+		return tomlBool
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32,
+		reflect.Int64,
+		reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32,
+		reflect.Uint64:
+		return tomlInteger
+	case reflect.Float32, reflect.Float64:
+		return tomlFloat
+	case reflect.Array, reflect.Slice:
+		if isTableArray(rv) {
+			return tomlArrayHash
+		}
+		return tomlArray
+	case reflect.Ptr, reflect.Interface:
+		return tomlTypeOfGo(rv.Elem())
+	case reflect.String:
+		return tomlString
+	case reflect.Map:
+		return tomlHash
+	default:
+		encPanic(errors.New("unsupported type: " + rv.Kind().String()))
+		panic("unreachable")
+	}
+}
+
+func isMarshaler(rv reflect.Value) bool {
+	return rv.Type().Implements(marshalText) || rv.Type().Implements(marshalToml)
+}
+
+// isTableArray reports if all entries in the array or slice are a table.
+func isTableArray(arr reflect.Value) bool {
+	if isNil(arr) || !arr.IsValid() || arr.Len() == 0 {
+		return false
+	}
+
+	ret := true
+	for i := 0; i < arr.Len(); i++ {
+		tt := tomlTypeOfGo(eindirect(arr.Index(i)))
+		// Don't allow nil.
+		if tt == nil {
+			encPanic(errArrayNilElement)
+		}
+
+		if ret && !typeEqual(tomlHash, tt) {
+			ret = false
+		}
+	}
+	return ret
+}
+
+type tagOptions struct {
+	skip      bool // "-"
+	name      string
+	omitempty bool
+	omitzero  bool
+}
+
+func getOptions(tag reflect.StructTag) tagOptions {
+	t := tag.Get("toml")
+	if t == "-" {
+		return tagOptions{skip: true}
+	}
+	var opts tagOptions
+	parts := strings.Split(t, ",")
+	opts.name = parts[0]
+	for _, s := range parts[1:] {
+		switch s {
+		case "omitempty":
+			opts.omitempty = true
+		case "omitzero":
+			opts.omitzero = true
+		}
+	}
+	return opts
+}
+
+func isZero(rv reflect.Value) bool {
+	switch rv.Kind() {
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return rv.Int() == 0
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
+		return rv.Uint() == 0
+	case reflect.Float32, reflect.Float64:
+		return rv.Float() == 0.0
+	}
+	return false
+}
+
+func isEmpty(rv reflect.Value) bool {
+	switch rv.Kind() {
+	case reflect.Array, reflect.Slice, reflect.Map, reflect.String:
+		return rv.Len() == 0
+	case reflect.Struct:
+		if rv.Type().Comparable() {
+			return reflect.Zero(rv.Type()).Interface() == rv.Interface()
+		}
+		// Need to also check if all the fields are empty, otherwise something
+		// like this with uncomparable types will always return true:
+		//
+		//   type a struct{ field b }
+		//   type b struct{ s []string }
+		//   s := a{field: b{s: []string{"AAA"}}}
+		for i := 0; i < rv.NumField(); i++ {
+			if !isEmpty(rv.Field(i)) {
+				return false
+			}
+		}
+		return true
+	case reflect.Bool:
+		return !rv.Bool()
+	case reflect.Ptr:
+		return rv.IsNil()
+	}
+	return false
+}
+
+func (enc *Encoder) newline() {
+	if enc.hasWritten {
+		enc.wf("\n")
+	}
+}
+
+// Write a key/value pair:
+//
+//	key = <any value>
+//
+// This is also used for "k = v" in inline tables; so something like this will
+// be written in three calls:
+//
+//	┌───────────────────┐
+//	│      ┌───┐  ┌────┐│
+//	v      v   v  v    vv
+//	key = {k = 1, k2 = 2}
+func (enc *Encoder) writeKeyValue(key Key, val reflect.Value, inline bool) {
+	/// Marshaler used on top-level document; call eElement() to just call
+	/// Marshal{TOML,Text}.
+	if len(key) == 0 {
+		enc.eElement(val)
+		return
+	}
+	enc.wf("%s%s = ", enc.indentStr(key), key.maybeQuoted(len(key)-1))
+	enc.eElement(val)
+	if !inline {
+		enc.newline()
+	}
+}
+
+func (enc *Encoder) wf(format string, v ...any) {
+	_, err := fmt.Fprintf(enc.w, format, v...)
+	if err != nil {
+		encPanic(err)
+	}
+	enc.hasWritten = true
+}
+
+func (enc *Encoder) indentStr(key Key) string {
+	return strings.Repeat(enc.Indent, len(key)-1)
+}
+
+func encPanic(err error) {
+	panic(tomlEncodeError{err})
+}
+
+// Resolve any level of pointers to the actual value (e.g. **string → string).
+func eindirect(v reflect.Value) reflect.Value {
+	if v.Kind() != reflect.Ptr && v.Kind() != reflect.Interface {
+		if isMarshaler(v) {
+			return v
+		}
+		if v.CanAddr() { /// Special case for marshalers; see #358.
+			if pv := v.Addr(); isMarshaler(pv) {
+				return pv
+			}
+		}
+		return v
+	}
+
+	if v.IsNil() {
+		return v
+	}
+
+	return eindirect(v.Elem())
+}
+
+func isNil(rv reflect.Value) bool {
+	switch rv.Kind() {
+	case reflect.Interface, reflect.Map, reflect.Ptr, reflect.Slice:
+		return rv.IsNil()
+	default:
+		return false
+	}
+}

vendor/github.com/BurntSushi/toml/error.go

@@ -0,0 +1,347 @@
+package toml
+
+import (
+	"fmt"
+	"strings"
+)
+
+// ParseError is returned when there is an error parsing the TOML syntax such as
+// invalid syntax, duplicate keys, etc.
+//
+// In addition to the error message itself, you can also print detailed location
+// information with context by using [ErrorWithPosition]:
+//
+//	toml: error: Key 'fruit' was already created and cannot be used as an array.
+//
+//	At line 4, column 2-7:
+//
+//	      2 | fruit = []
+//	      3 |
+//	      4 | [[fruit]] # Not allowed
+//	            ^^^^^
+//
+// [ErrorWithUsage] can be used to print the above with some more detailed usage
+// guidance:
+//
+//	toml: error: newlines not allowed within inline tables
+//
+//	At line 1, column 18:
+//
+//	      1 | x = [{ key = 42 #
+//	                           ^
+//
+//	Error help:
+//
+//	  Inline tables must always be on a single line:
+//
+//	      table = {key = 42, second = 43}
+//
+//	  It is invalid to split them over multiple lines like so:
+//
+//	      # INVALID
+//	      table = {
+//	          key    = 42,
+//	          second = 43
+//	      }
+//
+//	  Use regular for this:
+//
+//	      [table]
+//	      key    = 42
+//	      second = 43
+type ParseError struct {
+	Message  string   // Short technical message.
+	Usage    string   // Longer message with usage guidance; may be blank.
+	Position Position // Position of the error
+	LastKey  string   // Last parsed key, may be blank.
+
+	// Line the error occurred.
+	//
+	// Deprecated: use [Position].
+	Line int
+
+	err   error
+	input string
+}
+
+// Position of an error.
+type Position struct {
+	Line  int // Line number, starting at 1.
+	Col   int // Error column, starting at 1.
+	Start int // Start of error, as byte offset starting at 0.
+	Len   int // Lenght of the error in bytes.
+}
+
+func (p Position) withCol(tomlFile string) Position {
+	var (
+		pos   int
+		lines = strings.Split(tomlFile, "\n")
+	)
+	for i := range lines {
+		ll := len(lines[i]) + 1 // +1 for the removed newline
+		if pos+ll >= p.Start {
+			p.Col = p.Start - pos + 1
+			if p.Col < 1 { // Should never happen, but just in case.
+				p.Col = 1
+			}
+			break
+		}
+		pos += ll
+	}
+	return p
+}
+
+func (pe ParseError) Error() string {
+	if pe.LastKey == "" {
+		return fmt.Sprintf("toml: line %d: %s", pe.Position.Line, pe.Message)
+	}
+	return fmt.Sprintf("toml: line %d (last key %q): %s",
+		pe.Position.Line, pe.LastKey, pe.Message)
+}
+
+// ErrorWithPosition returns the error with detailed location context.
+//
+// See the documentation on [ParseError].
+func (pe ParseError) ErrorWithPosition() string {
+	if pe.input == "" { // Should never happen, but just in case.
+		return pe.Error()
+	}
+
+	// TODO: don't show control characters as literals? This may not show up
+	// well everywhere.
+
+	var (
+		lines = strings.Split(pe.input, "\n")
+		b     = new(strings.Builder)
+	)
+	if pe.Position.Len == 1 {
+		fmt.Fprintf(b, "toml: error: %s\n\nAt line %d, column %d:\n\n",
+			pe.Message, pe.Position.Line, pe.Position.Col)
+	} else {
+		fmt.Fprintf(b, "toml: error: %s\n\nAt line %d, column %d-%d:\n\n",
+			pe.Message, pe.Position.Line, pe.Position.Col, pe.Position.Col+pe.Position.Len-1)
+	}
+	if pe.Position.Line > 2 {
+		fmt.Fprintf(b, "% 7d | %s\n", pe.Position.Line-2, expandTab(lines[pe.Position.Line-3]))
+	}
+	if pe.Position.Line > 1 {
+		fmt.Fprintf(b, "% 7d | %s\n", pe.Position.Line-1, expandTab(lines[pe.Position.Line-2]))
+	}
+
+	/// Expand tabs, so that the ^^^s are at the correct position, but leave
+	/// "column 10-13" intact. Adjusting this to the visual column would be
+	/// better, but we don't know the tabsize of the user in their editor, which
+	/// can be 8, 4, 2, or something else. We can't know. So leaving it as the
+	/// character index is probably the "most correct".
+	expanded := expandTab(lines[pe.Position.Line-1])
+	diff := len(expanded) - len(lines[pe.Position.Line-1])
+
+	fmt.Fprintf(b, "% 7d | %s\n", pe.Position.Line, expanded)
+	fmt.Fprintf(b, "% 10s%s%s\n", "", strings.Repeat(" ", pe.Position.Col-1+diff), strings.Repeat("^", pe.Position.Len))
+	return b.String()
+}
+
+// ErrorWithUsage returns the error with detailed location context and usage
+// guidance.
+//
+// See the documentation on [ParseError].
+func (pe ParseError) ErrorWithUsage() string {
+	m := pe.ErrorWithPosition()
+	if u, ok := pe.err.(interface{ Usage() string }); ok && u.Usage() != "" {
+		lines := strings.Split(strings.TrimSpace(u.Usage()), "\n")
+		for i := range lines {
+			if lines[i] != "" {
+				lines[i] = "    " + lines[i]
+			}
+		}
+		return m + "Error help:\n\n" + strings.Join(lines, "\n") + "\n"
+	}
+	return m
+}
+
+func expandTab(s string) string {
+	var (
+		b    strings.Builder
+		l    int
+		fill = func(n int) string {
+			b := make([]byte, n)
+			for i := range b {
+				b[i] = ' '
+			}
+			return string(b)
+		}
+	)
+	b.Grow(len(s))
+	for _, r := range s {
+		switch r {
+		case '\t':
+			tw := 8 - l%8
+			b.WriteString(fill(tw))
+			l += tw
+		default:
+			b.WriteRune(r)
+			l += 1
+		}
+	}
+	return b.String()
+}
+
+type (
+	errLexControl       struct{ r rune }
+	errLexEscape        struct{ r rune }
+	errLexUTF8          struct{ b byte }
+	errParseDate        struct{ v string }
+	errLexInlineTableNL struct{}
+	errLexStringNL      struct{}
+	errParseRange       struct {
+		i    any    // int or float
+		size string // "int64", "uint16", etc.
+	}
+	errUnsafeFloat struct {
+		i    interface{} // float32 or float64
+		size string      // "float32" or "float64"
+	}
+	errParseDuration struct{ d string }
+)
+
+func (e errLexControl) Error() string {
+	return fmt.Sprintf("TOML files cannot contain control characters: '0x%02x'", e.r)
+}
+func (e errLexControl) Usage() string { return "" }
+
+func (e errLexEscape) Error() string        { return fmt.Sprintf(`invalid escape in string '\%c'`, e.r) }
+func (e errLexEscape) Usage() string        { return usageEscape }
+func (e errLexUTF8) Error() string          { return fmt.Sprintf("invalid UTF-8 byte: 0x%02x", e.b) }
+func (e errLexUTF8) Usage() string          { return "" }
+func (e errParseDate) Error() string        { return fmt.Sprintf("invalid datetime: %q", e.v) }
+func (e errParseDate) Usage() string        { return usageDate }
+func (e errLexInlineTableNL) Error() string { return "newlines not allowed within inline tables" }
+func (e errLexInlineTableNL) Usage() string { return usageInlineNewline }
+func (e errLexStringNL) Error() string      { return "strings cannot contain newlines" }
+func (e errLexStringNL) Usage() string      { return usageStringNewline }
+func (e errParseRange) Error() string       { return fmt.Sprintf("%v is out of range for %s", e.i, e.size) }
+func (e errParseRange) Usage() string       { return usageIntOverflow }
+func (e errUnsafeFloat) Error() string {
+	return fmt.Sprintf("%v is out of the safe %s range", e.i, e.size)
+}
+func (e errUnsafeFloat) Usage() string   { return usageUnsafeFloat }
+func (e errParseDuration) Error() string { return fmt.Sprintf("invalid duration: %q", e.d) }
+func (e errParseDuration) Usage() string { return usageDuration }
+
+const usageEscape = `
+A '\' inside a "-delimited string is interpreted as an escape character.
+
+The following escape sequences are supported:
+\b, \t, \n, \f, \r, \", \\, \uXXXX, and \UXXXXXXXX
+
+To prevent a '\' from being recognized as an escape character, use either:
+
+- a ' or '''-delimited string; escape characters aren't processed in them; or
+- write two backslashes to get a single backslash: '\\'.
+
+If you're trying to add a Windows path (e.g. "C:\Users\martin") then using '/'
+instead of '\' will usually also work: "C:/Users/martin".
+`
+
+const usageInlineNewline = `
+Inline tables must always be on a single line:
+
+    table = {key = 42, second = 43}
+
+It is invalid to split them over multiple lines like so:
+
+    # INVALID
+    table = {
+        key    = 42,
+        second = 43
+    }
+
+Use regular for this:
+
+    [table]
+    key    = 42
+    second = 43
+`
+
+const usageStringNewline = `
+Strings must always be on a single line, and cannot span more than one line:
+
+    # INVALID
+    string = "Hello,
+    world!"
+
+Instead use """ or ''' to split strings over multiple lines:
+
+    string = """Hello,
+    world!"""
+`
+
+const usageIntOverflow = `
+This number is too large; this may be an error in the TOML, but it can also be a
+bug in the program that uses too small of an integer.
+
+The maximum and minimum values are:
+
+    size   │ lowest         │ highest
+    ───────┼────────────────┼──────────────
+    int8   │ -128           │ 127
+    int16  │ -32,768        │ 32,767
+    int32  │ -2,147,483,648 │ 2,147,483,647
+    int64  │ -9.2 × 10¹⁷    │ 9.2 × 10¹⁷
+    uint8  │ 0              │ 255
+    uint16 │ 0              │ 65,535
+    uint32 │ 0              │ 4,294,967,295
+    uint64 │ 0              │ 1.8 × 10¹⁸
+
+int refers to int32 on 32-bit systems and int64 on 64-bit systems.
+`
+
+const usageUnsafeFloat = `
+This number is outside of the "safe" range for floating point numbers; whole
+(non-fractional) numbers outside the below range can not always be represented
+accurately in a float, leading to some loss of accuracy.
+
+Explicitly mark a number as a fractional unit by adding ".0", which will incur
+some loss of accuracy; for example:
+
+	f = 2_000_000_000.0
+
+Accuracy ranges:
+
+	float32 =            16,777,215
+	float64 = 9,007,199,254,740,991
+`
+
+const usageDuration = `
+A duration must be as "number<unit>", without any spaces. Valid units are:
+
+    ns         nanoseconds (billionth of a second)
+    us, µs     microseconds (millionth of a second)
+    ms         milliseconds (thousands of a second)
+    s          seconds
+    m          minutes
+    h          hours
+
+You can combine multiple units; for example "5m10s" for 5 minutes and 10
+seconds.
+`
+
+const usageDate = `
+A TOML datetime must be in one of the following formats:
+
+    2006-01-02T15:04:05Z07:00   Date and time, with timezone.
+    2006-01-02T15:04:05         Date and time, but without timezone.
+    2006-01-02                  Date without a time or timezone.
+    15:04:05                    Just a time, without any timezone.
+
+Seconds may optionally have a fraction, up to nanosecond precision:
+
+    15:04:05.123
+    15:04:05.856018510
+`
+
+// TOML 1.1:
+// The seconds part in times is optional, and may be omitted:
+//     2006-01-02T15:04Z07:00
+//     2006-01-02T15:04
+//     15:04

vendor/github.com/BurntSushi/toml/internal/tz.go

@@ -0,0 +1,36 @@
+package internal
+
+import "time"
+
+// Timezones used for local datetime, date, and time TOML types.
+//
+// The exact way times and dates without a timezone should be interpreted is not
+// well-defined in the TOML specification and left to the implementation. These
+// defaults to current local timezone offset of the computer, but this can be
+// changed by changing these variables before decoding.
+//
+// TODO:
+// Ideally we'd like to offer people the ability to configure the used timezone
+// by setting Decoder.Timezone and Encoder.Timezone; however, this is a bit
+// tricky: the reason we use three different variables for this is to support
+// round-tripping – without these specific TZ names we wouldn't know which
+// format to use.
+//
+// There isn't a good way to encode this right now though, and passing this sort
+// of information also ties in to various related issues such as string format
+// encoding, encoding of comments, etc.
+//
+// So, for the time being, just put this in internal until we can write a good
+// comprehensive API for doing all of this.
+//
+// The reason they're exported is because they're referred from in e.g.
+// internal/tag.
+//
+// Note that this behaviour is valid according to the TOML spec as the exact
+// behaviour is left up to implementations.
+var (
+	localOffset   = func() int { _, o := time.Now().Zone(); return o }()
+	LocalDatetime = time.FixedZone("datetime-local", localOffset)
+	LocalDate     = time.FixedZone("date-local", localOffset)
+	LocalTime     = time.FixedZone("time-local", localOffset)
+)

vendor/github.com/BurntSushi/toml/meta.go

@@ -0,0 +1,148 @@
+package toml
+
+import (
+	"strings"
+)
+
+// MetaData allows access to meta information about TOML data that's not
+// accessible otherwise.
+//
+// It allows checking if a key is defined in the TOML data, whether any keys
+// were undecoded, and the TOML type of a key.
+type MetaData struct {
+	context Key // Used only during decoding.
+
+	keyInfo map[string]keyInfo
+	mapping map[string]any
+	keys    []Key
+	decoded map[string]struct{}
+	data    []byte // Input file; for errors.
+}
+
+// IsDefined reports if the key exists in the TOML data.
+//
+// The key should be specified hierarchically, for example to access the TOML
+// key "a.b.c" you would use IsDefined("a", "b", "c"). Keys are case sensitive.
+//
+// Returns false for an empty key.
+func (md *MetaData) IsDefined(key ...string) bool {
+	if len(key) == 0 {
+		return false
+	}
+
+	var (
+		hash      map[string]any
+		ok        bool
+		hashOrVal any = md.mapping
+	)
+	for _, k := range key {
+		if hash, ok = hashOrVal.(map[string]any); !ok {
+			return false
+		}
+		if hashOrVal, ok = hash[k]; !ok {
+			return false
+		}
+	}
+	return true
+}
+
+// Type returns a string representation of the type of the key specified.
+//
+// Type will return the empty string if given an empty key or a key that does
+// not exist. Keys are case sensitive.
+func (md *MetaData) Type(key ...string) string {
+	if ki, ok := md.keyInfo[Key(key).String()]; ok {
+		return ki.tomlType.typeString()
+	}
+	return ""
+}
+
+// Keys returns a slice of every key in the TOML data, including key groups.
+//
+// Each key is itself a slice, where the first element is the top of the
+// hierarchy and the last is the most specific. The list will have the same
+// order as the keys appeared in the TOML data.
+//
+// All keys returned are non-empty.
+func (md *MetaData) Keys() []Key {
+	return md.keys
+}
+
+// Undecoded returns all keys that have not been decoded in the order in which
+// they appear in the original TOML document.
+//
+// This includes keys that haven't been decoded because of a [Primitive] value.
+// Once the Primitive value is decoded, the keys will be considered decoded.
+//
+// Also note that decoding into an empty interface will result in no decoding,
+// and so no keys will be considered decoded.
+//
+// In this sense, the Undecoded keys correspond to keys in the TOML document
+// that do not have a concrete type in your representation.
+func (md *MetaData) Undecoded() []Key {
+	undecoded := make([]Key, 0, len(md.keys))
+	for _, key := range md.keys {
+		if _, ok := md.decoded[key.String()]; !ok {
+			undecoded = append(undecoded, key)
+		}
+	}
+	return undecoded
+}
+
+// Key represents any TOML key, including key groups. Use [MetaData.Keys] to get
+// values of this type.
+type Key []string
+
+func (k Key) String() string {
+	// This is called quite often, so it's a bit funky to make it faster.
+	var b strings.Builder
+	b.Grow(len(k) * 25)
+outer:
+	for i, kk := range k {
+		if i > 0 {
+			b.WriteByte('.')
+		}
+		if kk == "" {
+			b.WriteString(`""`)
+		} else {
+			for _, r := range kk {
+				// "Inline" isBareKeyChar
+				if !((r >= 'A' && r <= 'Z') || (r >= 'a' && r <= 'z') || (r >= '0' && r <= '9') || r == '_' || r == '-') {
+					b.WriteByte('"')
+					b.WriteString(dblQuotedReplacer.Replace(kk))
+					b.WriteByte('"')
+					continue outer
+				}
+			}
+			b.WriteString(kk)
+		}
+	}
+	return b.String()
+}
+
+func (k Key) maybeQuoted(i int) string {
+	if k[i] == "" {
+		return `""`
+	}
+	for _, r := range k[i] {
+		if (r >= 'A' && r <= 'Z') || (r >= 'a' && r <= 'z') || (r >= '0' && r <= '9') || r == '_' || r == '-' {
+			continue
+		}
+		return `"` + dblQuotedReplacer.Replace(k[i]) + `"`
+	}
+	return k[i]
+}
+
+// Like append(), but only increase the cap by 1.
+func (k Key) add(piece string) Key {
+	if cap(k) > len(k) {
+		return append(k, piece)
+	}
+	newKey := make(Key, len(k)+1)
+	copy(newKey, k)
+	newKey[len(k)] = piece
+	return newKey
+}
+
+func (k Key) parent() Key  { return k[:len(k)-1] } // all except the last piece.
+func (k Key) last() string { return k[len(k)-1] }  // last piece of this key.

vendor/github.com/BurntSushi/toml/parse.go

@@ -0,0 +1,846 @@
+package toml
+
+import (
+	"fmt"
+	"math"
+	"os"
+	"strconv"
+	"strings"
+	"time"
+	"unicode/utf8"
+
+	"github.com/BurntSushi/toml/internal"
+)
+
+type parser struct {
+	lx         *lexer
+	context    Key      // Full key for the current hash in scope.
+	currentKey string   // Base key name for everything except hashes.
+	pos        Position // Current position in the TOML file.
+	tomlNext   bool
+
+	ordered []Key // List of keys in the order that they appear in the TOML data.
+
+	keyInfo   map[string]keyInfo  // Map keyname → info about the TOML key.
+	mapping   map[string]any      // Map keyname → key value.
+	implicits map[string]struct{} // Record implicit keys (e.g. "key.group.names").
+}
+
+type keyInfo struct {
+	pos      Position
+	tomlType tomlType
+}
+
+func parse(data string) (p *parser, err error) {
+	_, tomlNext := os.LookupEnv("BURNTSUSHI_TOML_110")
+
+	defer func() {
+		if r := recover(); r != nil {
+			if pErr, ok := r.(ParseError); ok {
+				pErr.input = data
+				err = pErr
+				return
+			}
+			panic(r)
+		}
+	}()
+
+	// Read over BOM; do this here as the lexer calls utf8.DecodeRuneInString()
+	// which mangles stuff. UTF-16 BOM isn't strictly valid, but some tools add
+	// it anyway.
+	if strings.HasPrefix(data, "\xff\xfe") || strings.HasPrefix(data, "\xfe\xff") { // UTF-16
+		data = data[2:]
+		//lint:ignore S1017 https://github.com/dominikh/go-tools/issues/1447
+	} else if strings.HasPrefix(data, "\xef\xbb\xbf") { // UTF-8
+		data = data[3:]
+	}
+
+	// Examine first few bytes for NULL bytes; this probably means it's a UTF-16
+	// file (second byte in surrogate pair being NULL). Again, do this here to
+	// avoid having to deal with UTF-8/16 stuff in the lexer.
+	ex := 6
+	if len(data) < 6 {
+		ex = len(data)
+	}
+	if i := strings.IndexRune(data[:ex], 0); i > -1 {
+		return nil, ParseError{
+			Message:  "files cannot contain NULL bytes; probably using UTF-16; TOML files must be UTF-8",
+			Position: Position{Line: 1, Col: 1, Start: i, Len: 1},
+			Line:     1,
+			input:    data,
+		}
+	}
+
+	p = &parser{
+		keyInfo:   make(map[string]keyInfo),
+		mapping:   make(map[string]any),
+		lx:        lex(data, tomlNext),
+		ordered:   make([]Key, 0),
+		implicits: make(map[string]struct{}),
+		tomlNext:  tomlNext,
+	}
+	for {
+		item := p.next()
+		if item.typ == itemEOF {
+			break
+		}
+		p.topLevel(item)
+	}
+
+	return p, nil
+}
+
+func (p *parser) panicErr(it item, err error) {
+	panic(ParseError{
+		Message:  err.Error(),
+		err:      err,
+		Position: it.pos.withCol(p.lx.input),
+		Line:     it.pos.Len,
+		LastKey:  p.current(),
+	})
+}
+
+func (p *parser) panicItemf(it item, format string, v ...any) {
+	panic(ParseError{
+		Message:  fmt.Sprintf(format, v...),
+		Position: it.pos.withCol(p.lx.input),
+		Line:     it.pos.Len,
+		LastKey:  p.current(),
+	})
+}
+
+func (p *parser) panicf(format string, v ...any) {
+	panic(ParseError{
+		Message:  fmt.Sprintf(format, v...),
+		Position: p.pos.withCol(p.lx.input),
+		Line:     p.pos.Line,
+		LastKey:  p.current(),
+	})
+}
+
+func (p *parser) next() item {
+	it := p.lx.nextItem()
+	//fmt.Printf("ITEM %-18s line %-3d │ %q\n", it.typ, it.pos.Line, it.val)
+	if it.typ == itemError {
+		if it.err != nil {
+			panic(ParseError{
+				Message:  it.err.Error(),
+				err:      it.err,
+				Position: it.pos.withCol(p.lx.input),
+				Line:     it.pos.Line,
+				LastKey:  p.current(),
+			})
+		}
+
+		p.panicItemf(it, "%s", it.val)
+	}
+	return it
+}
+
+func (p *parser) nextPos() item {
+	it := p.next()
+	p.pos = it.pos
+	return it
+}
+
+func (p *parser) bug(format string, v ...any) {
+	panic(fmt.Sprintf("BUG: "+format+"\n\n", v...))
+}
+
+func (p *parser) expect(typ itemType) item {
+	it := p.next()
+	p.assertEqual(typ, it.typ)
+	return it
+}
+
+func (p *parser) assertEqual(expected, got itemType) {
+	if expected != got {
+		p.bug("Expected '%s' but got '%s'.", expected, got)
+	}
+}
+
+func (p *parser) topLevel(item item) {
+	switch item.typ {
+	case itemCommentStart: // # ..
+		p.expect(itemText)
+	case itemTableStart: // [ .. ]
+		name := p.nextPos()
+
+		var key Key
+		for ; name.typ != itemTableEnd && name.typ != itemEOF; name = p.next() {
+			key = append(key, p.keyString(name))
+		}
+		p.assertEqual(itemTableEnd, name.typ)
+
+		p.addContext(key, false)
+		p.setType("", tomlHash, item.pos)
+		p.ordered = append(p.ordered, key)
+	case itemArrayTableStart: // [[ .. ]]
+		name := p.nextPos()
+
+		var key Key
+		for ; name.typ != itemArrayTableEnd && name.typ != itemEOF; name = p.next() {
+			key = append(key, p.keyString(name))
+		}
+		p.assertEqual(itemArrayTableEnd, name.typ)
+
+		p.addContext(key, true)
+		p.setType("", tomlArrayHash, item.pos)
+		p.ordered = append(p.ordered, key)
+	case itemKeyStart: // key = ..
+		outerContext := p.context
+		/// Read all the key parts (e.g. 'a' and 'b' in 'a.b')
+		k := p.nextPos()
+		var key Key
+		for ; k.typ != itemKeyEnd && k.typ != itemEOF; k = p.next() {
+			key = append(key, p.keyString(k))
+		}
+		p.assertEqual(itemKeyEnd, k.typ)
+
+		/// The current key is the last part.
+		p.currentKey = key.last()
+
+		/// All the other parts (if any) are the context; need to set each part
+		/// as implicit.
+		context := key.parent()
+		for i := range context {
+			p.addImplicitContext(append(p.context, context[i:i+1]...))
+		}
+		p.ordered = append(p.ordered, p.context.add(p.currentKey))
+
+		/// Set value.
+		vItem := p.next()
+		val, typ := p.value(vItem, false)
+		p.setValue(p.currentKey, val)
+		p.setType(p.currentKey, typ, vItem.pos)
+
+		/// Remove the context we added (preserving any context from [tbl] lines).
+		p.context = outerContext
+		p.currentKey = ""
+	default:
+		p.bug("Unexpected type at top level: %s", item.typ)
+	}
+}
+
+// Gets a string for a key (or part of a key in a table name).
+func (p *parser) keyString(it item) string {
+	switch it.typ {
+	case itemText:
+		return it.val
+	case itemString, itemStringEsc, itemMultilineString,
+		itemRawString, itemRawMultilineString:
+		s, _ := p.value(it, false)
+		return s.(string)
+	default:
+		p.bug("Unexpected key type: %s", it.typ)
+	}
+	panic("unreachable")
+}
+
+var datetimeRepl = strings.NewReplacer(
+	"z", "Z",
+	"t", "T",
+	" ", "T")
+
+// value translates an expected value from the lexer into a Go value wrapped
+// as an empty interface.
+func (p *parser) value(it item, parentIsArray bool) (any, tomlType) {
+	switch it.typ {
+	case itemString:
+		return it.val, p.typeOfPrimitive(it)
+	case itemStringEsc:
+		return p.replaceEscapes(it, it.val), p.typeOfPrimitive(it)
+	case itemMultilineString:
+		return p.replaceEscapes(it, p.stripEscapedNewlines(stripFirstNewline(it.val))), p.typeOfPrimitive(it)
+	case itemRawString:
+		return it.val, p.typeOfPrimitive(it)
+	case itemRawMultilineString:
+		return stripFirstNewline(it.val), p.typeOfPrimitive(it)
+	case itemInteger:
+		return p.valueInteger(it)
+	case itemFloat:
+		return p.valueFloat(it)
+	case itemBool:
+		switch it.val {
+		case "true":
+			return true, p.typeOfPrimitive(it)
+		case "false":
+			return false, p.typeOfPrimitive(it)
+		default:
+			p.bug("Expected boolean value, but got '%s'.", it.val)
+		}
+	case itemDatetime:
+		return p.valueDatetime(it)
+	case itemArray:
+		return p.valueArray(it)
+	case itemInlineTableStart:
+		return p.valueInlineTable(it, parentIsArray)
+	default:
+		p.bug("Unexpected value type: %s", it.typ)
+	}
+	panic("unreachable")
+}
+
+func (p *parser) valueInteger(it item) (any, tomlType) {
+	if !numUnderscoresOK(it.val) {
+		p.panicItemf(it, "Invalid integer %q: underscores must be surrounded by digits", it.val)
+	}
+	if numHasLeadingZero(it.val) {
+		p.panicItemf(it, "Invalid integer %q: cannot have leading zeroes", it.val)
+	}
+
+	num, err := strconv.ParseInt(it.val, 0, 64)
+	if err != nil {
+		// Distinguish integer values. Normally, it'd be a bug if the lexer
+		// provides an invalid integer, but it's possible that the number is
+		// out of range of valid values (which the lexer cannot determine).
+		// So mark the former as a bug but the latter as a legitimate user
+		// error.
+		if e, ok := err.(*strconv.NumError); ok && e.Err == strconv.ErrRange {
+			p.panicErr(it, errParseRange{i: it.val, size: "int64"})
+		} else {
+			p.bug("Expected integer value, but got '%s'.", it.val)
+		}
+	}
+	return num, p.typeOfPrimitive(it)
+}
+
+func (p *parser) valueFloat(it item) (any, tomlType) {
+	parts := strings.FieldsFunc(it.val, func(r rune) bool {
+		switch r {
+		case '.', 'e', 'E':
+			return true
+		}
+		return false
+	})
+	for _, part := range parts {
+		if !numUnderscoresOK(part) {
+			p.panicItemf(it, "Invalid float %q: underscores must be surrounded by digits", it.val)
+		}
+	}
+	if len(parts) > 0 && numHasLeadingZero(parts[0]) {
+		p.panicItemf(it, "Invalid float %q: cannot have leading zeroes", it.val)
+	}
+	if !numPeriodsOK(it.val) {
+		// As a special case, numbers like '123.' or '1.e2',
+		// which are valid as far as Go/strconv are concerned,
+		// must be rejected because TOML says that a fractional
+		// part consists of '.' followed by 1+ digits.
+		p.panicItemf(it, "Invalid float %q: '.' must be followed by one or more digits", it.val)
+	}
+	val := strings.Replace(it.val, "_", "", -1)
+	signbit := false
+	if val == "+nan" || val == "-nan" {
+		signbit = val == "-nan"
+		val = "nan"
+	}
+	num, err := strconv.ParseFloat(val, 64)
+	if err != nil {
+		if e, ok := err.(*strconv.NumError); ok && e.Err == strconv.ErrRange {
+			p.panicErr(it, errParseRange{i: it.val, size: "float64"})
+		} else {
+			p.panicItemf(it, "Invalid float value: %q", it.val)
+		}
+	}
+	if signbit {
+		num = math.Copysign(num, -1)
+	}
+	return num, p.typeOfPrimitive(it)
+}
+
+var dtTypes = []struct {
+	fmt  string
+	zone *time.Location
+	next bool
+}{
+	{time.RFC3339Nano, time.Local, false},
+	{"2006-01-02T15:04:05.999999999", internal.LocalDatetime, false},
+	{"2006-01-02", internal.LocalDate, false},
+	{"15:04:05.999999999", internal.LocalTime, false},
+
+	// tomlNext
+	{"2006-01-02T15:04Z07:00", time.Local, true},
+	{"2006-01-02T15:04", internal.LocalDatetime, true},
+	{"15:04", internal.LocalTime, true},
+}
+
+func (p *parser) valueDatetime(it item) (any, tomlType) {
+	it.val = datetimeRepl.Replace(it.val)
+	var (
+		t   time.Time
+		ok  bool
+		err error
+	)
+	for _, dt := range dtTypes {
+		if dt.next && !p.tomlNext {
+			continue
+		}
+		t, err = time.ParseInLocation(dt.fmt, it.val, dt.zone)
+		if err == nil {
+			if missingLeadingZero(it.val, dt.fmt) {
+				p.panicErr(it, errParseDate{it.val})
+			}
+			ok = true
+			break
+		}
+	}
+	if !ok {
+		p.panicErr(it, errParseDate{it.val})
+	}
+	return t, p.typeOfPrimitive(it)
+}
+
+// Go's time.Parse() will accept numbers without a leading zero; there isn't any
+// way to require it. https://github.com/golang/go/issues/29911
+//
+// Depend on the fact that the separators (- and :) should always be at the same
+// location.
+func missingLeadingZero(d, l string) bool {
+	for i, c := range []byte(l) {
+		if c == '.' || c == 'Z' {
+			return false
+		}
+		if (c < '0' || c > '9') && d[i] != c {
+			return true
+		}
+	}
+	return false
+}
+
+func (p *parser) valueArray(it item) (any, tomlType) {
+	p.setType(p.currentKey, tomlArray, it.pos)
+
+	var (
+		// Initialize to a non-nil slice to make it consistent with how S = []
+		// decodes into a non-nil slice inside something like struct { S
+		// []string }. See #338
+		array = make([]any, 0, 2)
+	)
+	for it = p.next(); it.typ != itemArrayEnd; it = p.next() {
+		if it.typ == itemCommentStart {
+			p.expect(itemText)
+			continue
+		}
+
+		val, typ := p.value(it, true)
+		array = append(array, val)
+
+		// XXX: type isn't used here, we need it to record the accurate type
+		// information.
+		//
+		// Not entirely sure how to best store this; could use "key[0]",
+		// "key[1]" notation, or maybe store it on the Array type?
+		_ = typ
+	}
+	return array, tomlArray
+}
+
+func (p *parser) valueInlineTable(it item, parentIsArray bool) (any, tomlType) {
+	var (
+		topHash      = make(map[string]any)
+		outerContext = p.context
+		outerKey     = p.currentKey
+	)
+
+	p.context = append(p.context, p.currentKey)
+	prevContext := p.context
+	p.currentKey = ""
+
+	p.addImplicit(p.context)
+	p.addContext(p.context, parentIsArray)
+
+	/// Loop over all table key/value pairs.
+	for it := p.next(); it.typ != itemInlineTableEnd; it = p.next() {
+		if it.typ == itemCommentStart {
+			p.expect(itemText)
+			continue
+		}
+
+		/// Read all key parts.
+		k := p.nextPos()
+		var key Key
+		for ; k.typ != itemKeyEnd && k.typ != itemEOF; k = p.next() {
+			key = append(key, p.keyString(k))
+		}
+		p.assertEqual(itemKeyEnd, k.typ)
+
+		/// The current key is the last part.
+		p.currentKey = key.last()
+
+		/// All the other parts (if any) are the context; need to set each part
+		/// as implicit.
+		context := key.parent()
+		for i := range context {
+			p.addImplicitContext(append(p.context, context[i:i+1]...))
+		}
+		p.ordered = append(p.ordered, p.context.add(p.currentKey))
+
+		/// Set the value.
+		val, typ := p.value(p.next(), false)
+		p.setValue(p.currentKey, val)
+		p.setType(p.currentKey, typ, it.pos)
+
+		hash := topHash
+		for _, c := range context {
+			h, ok := hash[c]
+			if !ok {
+				h = make(map[string]any)
+				hash[c] = h
+			}
+			hash, ok = h.(map[string]any)
+			if !ok {
+				p.panicf("%q is not a table", p.context)
+			}
+		}
+		hash[p.currentKey] = val
+
+		/// Restore context.
+		p.context = prevContext
+	}
+	p.context = outerContext
+	p.currentKey = outerKey
+	return topHash, tomlHash
+}
+
+// numHasLeadingZero checks if this number has leading zeroes, allowing for '0',
+// +/- signs, and base prefixes.
+func numHasLeadingZero(s string) bool {
+	if len(s) > 1 && s[0] == '0' && !(s[1] == 'b' || s[1] == 'o' || s[1] == 'x') { // Allow 0b, 0o, 0x
+		return true
+	}
+	if len(s) > 2 && (s[0] == '-' || s[0] == '+') && s[1] == '0' {
+		return true
+	}
+	return false
+}
+
+// numUnderscoresOK checks whether each underscore in s is surrounded by
+// characters that are not underscores.
+func numUnderscoresOK(s string) bool {
+	switch s {
+	case "nan", "+nan", "-nan", "inf", "-inf", "+inf":
+		return true
+	}
+	accept := false
+	for _, r := range s {
+		if r == '_' {
+			if !accept {
+				return false
+			}
+		}
+
+		// isHexis a superset of all the permissable characters surrounding an
+		// underscore.
+		accept = isHex(r)
+	}
+	return accept
+}
+
+// numPeriodsOK checks whether every period in s is followed by a digit.
+func numPeriodsOK(s string) bool {
+	period := false
+	for _, r := range s {
+		if period && !isDigit(r) {
+			return false
+		}
+		period = r == '.'
+	}
+	return !period
+}
+
+// Set the current context of the parser, where the context is either a hash or
+// an array of hashes, depending on the value of the `array` parameter.
+//
+// Establishing the context also makes sure that the key isn't a duplicate, and
+// will create implicit hashes automatically.
+func (p *parser) addContext(key Key, array bool) {
+	/// Always start at the top level and drill down for our context.
+	hashContext := p.mapping
+	keyContext := make(Key, 0, len(key)-1)
+
+	/// We only need implicit hashes for the parents.
+	for _, k := range key.parent() {
+		_, ok := hashContext[k]
+		keyContext = append(keyContext, k)
+
+		// No key? Make an implicit hash and move on.
+		if !ok {
+			p.addImplicit(keyContext)
+			hashContext[k] = make(map[string]any)
+		}
+
+		// If the hash context is actually an array of tables, then set
+		// the hash context to the last element in that array.
+		//
+		// Otherwise, it better be a table, since this MUST be a key group (by
+		// virtue of it not being the last element in a key).
+		switch t := hashContext[k].(type) {
+		case []map[string]any:
+			hashContext = t[len(t)-1]
+		case map[string]any:
+			hashContext = t
+		default:
+			p.panicf("Key '%s' was already created as a hash.", keyContext)
+		}
+	}
+
+	p.context = keyContext
+	if array {
+		// If this is the first element for this array, then allocate a new
+		// list of tables for it.
+		k := key.last()
+		if _, ok := hashContext[k]; !ok {
+			hashContext[k] = make([]map[string]any, 0, 4)
+		}
+
+		// Add a new table. But make sure the key hasn't already been used
+		// for something else.
+		if hash, ok := hashContext[k].([]map[string]any); ok {
+			hashContext[k] = append(hash, make(map[string]any))
+		} else {
+			p.panicf("Key '%s' was already created and cannot be used as an array.", key)
+		}
+	} else {
+		p.setValue(key.last(), make(map[string]any))
+	}
+	p.context = append(p.context, key.last())
+}
+
+// setValue sets the given key to the given value in the current context.
+// It will make sure that the key hasn't already been defined, account for
+// implicit key groups.
+func (p *parser) setValue(key string, value any) {
+	var (
+		tmpHash    any
+		ok         bool
+		hash       = p.mapping
+		keyContext = make(Key, 0, len(p.context)+1)
+	)
+	for _, k := range p.context {
+		keyContext = append(keyContext, k)
+		if tmpHash, ok = hash[k]; !ok {
+			p.bug("Context for key '%s' has not been established.", keyContext)
+		}
+		switch t := tmpHash.(type) {
+		case []map[string]any:
+			// The context is a table of hashes. Pick the most recent table
+			// defined as the current hash.
+			hash = t[len(t)-1]
+		case map[string]any:
+			hash = t
+		default:
+			p.panicf("Key '%s' has already been defined.", keyContext)
+		}
+	}
+	keyContext = append(keyContext, key)
+
+	if _, ok := hash[key]; ok {
+		// Normally redefining keys isn't allowed, but the key could have been
+		// defined implicitly and it's allowed to be redefined concretely. (See
+		// the `valid/implicit-and-explicit-after.toml` in toml-test)
+		//
+		// But we have to make sure to stop marking it as an implicit. (So that
+		// another redefinition provokes an error.)
+		//
+		// Note that since it has already been defined (as a hash), we don't
+		// want to overwrite it. So our business is done.
+		if p.isArray(keyContext) {
+			p.removeImplicit(keyContext)
+			hash[key] = value
+			return
+		}
+		if p.isImplicit(keyContext) {
+			p.removeImplicit(keyContext)
+			return
+		}
+		// Otherwise, we have a concrete key trying to override a previous key,
+		// which is *always* wrong.
+		p.panicf("Key '%s' has already been defined.", keyContext)
+	}
+
+	hash[key] = value
+}
+
+// setType sets the type of a particular value at a given key. It should be
+// called immediately AFTER setValue.
+//
+// Note that if `key` is empty, then the type given will be applied to the
+// current context (which is either a table or an array of tables).
+func (p *parser) setType(key string, typ tomlType, pos Position) {
+	keyContext := make(Key, 0, len(p.context)+1)
+	keyContext = append(keyContext, p.context...)
+	if len(key) > 0 { // allow type setting for hashes
+		keyContext = append(keyContext, key)
+	}
+	// Special case to make empty keys ("" = 1) work.
+	// Without it it will set "" rather than `""`.
+	// TODO: why is this needed? And why is this only needed here?
+	if len(keyContext) == 0 {
+		keyContext = Key{""}
+	}
+	p.keyInfo[keyContext.String()] = keyInfo{tomlType: typ, pos: pos}
+}
+
+// Implicit keys need to be created when tables are implied in "a.b.c.d = 1" and
+// "[a.b.c]" (the "a", "b", and "c" hashes are never created explicitly).
+func (p *parser) addImplicit(key Key)        { p.implicits[key.String()] = struct{}{} }
+func (p *parser) removeImplicit(key Key)     { delete(p.implicits, key.String()) }
+func (p *parser) isImplicit(key Key) bool    { _, ok := p.implicits[key.String()]; return ok }
+func (p *parser) isArray(key Key) bool       { return p.keyInfo[key.String()].tomlType == tomlArray }
+func (p *parser) addImplicitContext(key Key) { p.addImplicit(key); p.addContext(key, false) }
+
+// current returns the full key name of the current context.
+func (p *parser) current() string {
+	if len(p.currentKey) == 0 {
+		return p.context.String()
+	}
+	if len(p.context) == 0 {
+		return p.currentKey
+	}
+	return fmt.Sprintf("%s.%s", p.context, p.currentKey)
+}
+
+func stripFirstNewline(s string) string {
+	if len(s) > 0 && s[0] == '\n' {
+		return s[1:]
+	}
+	if len(s) > 1 && s[0] == '\r' && s[1] == '\n' {
+		return s[2:]
+	}
+	return s
+}
+
+// stripEscapedNewlines removes whitespace after line-ending backslashes in
+// multiline strings.
+//
+// A line-ending backslash is an unescaped \ followed only by whitespace until
+// the next newline. After a line-ending backslash, all whitespace is removed
+// until the next non-whitespace character.
+func (p *parser) stripEscapedNewlines(s string) string {
+	var (
+		b strings.Builder
+		i int
+	)
+	b.Grow(len(s))
+	for {
+		ix := strings.Index(s[i:], `\`)
+		if ix < 0 {
+			b.WriteString(s)
+			return b.String()
+		}
+		i += ix
+
+		if len(s) > i+1 && s[i+1] == '\\' {
+			// Escaped backslash.
+			i += 2
+			continue
+		}
+		// Scan until the next non-whitespace.
+		j := i + 1
+	whitespaceLoop:
+		for ; j < len(s); j++ {
+			switch s[j] {
+			case ' ', '\t', '\r', '\n':
+			default:
+				break whitespaceLoop
+			}
+		}
+		if j == i+1 {
+			// Not a whitespace escape.
+			i++
+			continue
+		}
+		if !strings.Contains(s[i:j], "\n") {
+			// This is not a line-ending backslash. (It's a bad escape sequence,
+			// but we can let replaceEscapes catch it.)
+			i++
+			continue
+		}
+		b.WriteString(s[:i])
+		s = s[j:]
+		i = 0
+	}
+}
+
+func (p *parser) replaceEscapes(it item, str string) string {
+	var (
+		b    strings.Builder
+		skip = 0
+	)
+	b.Grow(len(str))
+	for i, c := range str {
+		if skip > 0 {
+			skip--
+			continue
+		}
+		if c != '\\' {
+			b.WriteRune(c)
+			continue
+		}
+
+		if i >= len(str) {
+			p.bug("Escape sequence at end of string.")
+			return ""
+		}
+		switch str[i+1] {
+		default:
+			p.bug("Expected valid escape code after \\, but got %q.", str[i+1])
+		case ' ', '\t':
+			p.panicItemf(it, "invalid escape: '\\%c'", str[i+1])
+		case 'b':
+			b.WriteByte(0x08)
+			skip = 1
+		case 't':
+			b.WriteByte(0x09)
+			skip = 1
+		case 'n':
+			b.WriteByte(0x0a)
+			skip = 1
+		case 'f':
+			b.WriteByte(0x0c)
+			skip = 1
+		case 'r':
+			b.WriteByte(0x0d)
+			skip = 1
+		case 'e':
+			if p.tomlNext {
+				b.WriteByte(0x1b)
+				skip = 1
+			}
+		case '"':
+			b.WriteByte(0x22)
+			skip = 1
+		case '\\':
+			b.WriteByte(0x5c)
+			skip = 1
+		// The lexer guarantees the correct number of characters are present;
+		// don't need to check here.
+		case 'x':
+			if p.tomlNext {
+				escaped := p.asciiEscapeToUnicode(it, str[i+2:i+4])
+				b.WriteRune(escaped)
+				skip = 3
+			}
+		case 'u':
+			escaped := p.asciiEscapeToUnicode(it, str[i+2:i+6])
+			b.WriteRune(escaped)
+			skip = 5
+		case 'U':
+			escaped := p.asciiEscapeToUnicode(it, str[i+2:i+10])
+			b.WriteRune(escaped)
+			skip = 9
+		}
+	}
+	return b.String()
+}
+
+func (p *parser) asciiEscapeToUnicode(it item, s string) rune {
+	hex, err := strconv.ParseUint(strings.ToLower(s), 16, 32)
+	if err != nil {
+		p.bug("Could not parse '%s' as a hexadecimal number, but the lexer claims it's OK: %s", s, err)
+	}
+	if !utf8.ValidRune(rune(hex)) {
+		p.panicItemf(it, "Escaped character '\\u%s' is not valid UTF-8.", s)
+	}
+	return rune(hex)
+}

vendor/github.com/BurntSushi/toml/type_fields.go

@@ -0,0 +1,238 @@
+package toml
+
+// Struct field handling is adapted from code in encoding/json:
+//
+// Copyright 2010 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the Go distribution.
+
+import (
+	"reflect"
+	"sort"
+	"sync"
+)
+
+// A field represents a single field found in a struct.
+type field struct {
+	name  string       // the name of the field (`toml` tag included)
+	tag   bool         // whether field has a `toml` tag
+	index []int        // represents the depth of an anonymous field
+	typ   reflect.Type // the type of the field
+}
+
+// byName sorts field by name, breaking ties with depth,
+// then breaking ties with "name came from toml tag", then
+// breaking ties with index sequence.
+type byName []field
+
+func (x byName) Len() int      { return len(x) }
+func (x byName) Swap(i, j int) { x[i], x[j] = x[j], x[i] }
+func (x byName) Less(i, j int) bool {
+	if x[i].name != x[j].name {
+		return x[i].name < x[j].name
+	}
+	if len(x[i].index) != len(x[j].index) {
+		return len(x[i].index) < len(x[j].index)
+	}
+	if x[i].tag != x[j].tag {
+		return x[i].tag
+	}
+	return byIndex(x).Less(i, j)
+}
+
+// byIndex sorts field by index sequence.
+type byIndex []field
+
+func (x byIndex) Len() int      { return len(x) }
+func (x byIndex) Swap(i, j int) { x[i], x[j] = x[j], x[i] }
+func (x byIndex) Less(i, j int) bool {
+	for k, xik := range x[i].index {
+		if k >= len(x[j].index) {
+			return false
+		}
+		if xik != x[j].index[k] {
+			return xik < x[j].index[k]
+		}
+	}
+	return len(x[i].index) < len(x[j].index)
+}
+
+// typeFields returns a list of fields that TOML should recognize for the given
+// type. The algorithm is breadth-first search over the set of structs to
+// include - the top struct and then any reachable anonymous structs.
+func typeFields(t reflect.Type) []field {
+	// Anonymous fields to explore at the current level and the next.
+	current := []field{}
+	next := []field{{typ: t}}
+
+	// Count of queued names for current level and the next.
+	var count map[reflect.Type]int
+	var nextCount map[reflect.Type]int
+
+	// Types already visited at an earlier level.
+	visited := map[reflect.Type]bool{}
+
+	// Fields found.
+	var fields []field
+
+	for len(next) > 0 {
+		current, next = next, current[:0]
+		count, nextCount = nextCount, map[reflect.Type]int{}
+
+		for _, f := range current {
+			if visited[f.typ] {
+				continue
+			}
+			visited[f.typ] = true
+
+			// Scan f.typ for fields to include.
+			for i := 0; i < f.typ.NumField(); i++ {
+				sf := f.typ.Field(i)
+				if sf.PkgPath != "" && !sf.Anonymous { // unexported
+					continue
+				}
+				opts := getOptions(sf.Tag)
+				if opts.skip {
+					continue
+				}
+				index := make([]int, len(f.index)+1)
+				copy(index, f.index)
+				index[len(f.index)] = i
+
+				ft := sf.Type
+				if ft.Name() == "" && ft.Kind() == reflect.Ptr {
+					// Follow pointer.
+					ft = ft.Elem()
+				}
+
+				// Record found field and index sequence.
+				if opts.name != "" || !sf.Anonymous || ft.Kind() != reflect.Struct {
+					tagged := opts.name != ""
+					name := opts.name
+					if name == "" {
+						name = sf.Name
+					}
+					fields = append(fields, field{name, tagged, index, ft})
+					if count[f.typ] > 1 {
+						// If there were multiple instances, add a second,
+						// so that the annihilation code will see a duplicate.
+						// It only cares about the distinction between 1 or 2,
+						// so don't bother generating any more copies.
+						fields = append(fields, fields[len(fields)-1])
+					}
+					continue
+				}
+
+				// Record new anonymous struct to explore in next round.
+				nextCount[ft]++
+				if nextCount[ft] == 1 {
+					f := field{name: ft.Name(), index: index, typ: ft}
+					next = append(next, f)
+				}
+			}
+		}
+	}
+
+	sort.Sort(byName(fields))
+
+	// Delete all fields that are hidden by the Go rules for embedded fields,
+	// except that fields with TOML tags are promoted.
+
+	// The fields are sorted in primary order of name, secondary order
+	// of field index length. Loop over names; for each name, delete
+	// hidden fields by choosing the one dominant field that survives.
+	out := fields[:0]
+	for advance, i := 0, 0; i < len(fields); i += advance {
+		// One iteration per name.
+		// Find the sequence of fields with the name of this first field.
+		fi := fields[i]
+		name := fi.name
+		for advance = 1; i+advance < len(fields); advance++ {
+			fj := fields[i+advance]
+			if fj.name != name {
+				break
+			}
+		}
+		if advance == 1 { // Only one field with this name
+			out = append(out, fi)
+			continue
+		}
+		dominant, ok := dominantField(fields[i : i+advance])
+		if ok {
+			out = append(out, dominant)
+		}
+	}
+
+	fields = out
+	sort.Sort(byIndex(fields))
+
+	return fields
+}
+
+// dominantField looks through the fields, all of which are known to
+// have the same name, to find the single field that dominates the
+// others using Go's embedding rules, modified by the presence of
+// TOML tags. If there are multiple top-level fields, the boolean
+// will be false: This condition is an error in Go and we skip all
+// the fields.
+func dominantField(fields []field) (field, bool) {
+	// The fields are sorted in increasing index-length order. The winner
+	// must therefore be one with the shortest index length. Drop all
+	// longer entries, which is easy: just truncate the slice.
+	length := len(fields[0].index)
+	tagged := -1 // Index of first tagged field.
+	for i, f := range fields {
+		if len(f.index) > length {
+			fields = fields[:i]
+			break
+		}
+		if f.tag {
+			if tagged >= 0 {
+				// Multiple tagged fields at the same level: conflict.
+				// Return no field.
+				return field{}, false
+			}
+			tagged = i
+		}
+	}
+	if tagged >= 0 {
+		return fields[tagged], true
+	}
+	// All remaining fields have the same length. If there's more than one,
+	// we have a conflict (two fields named "X" at the same level) and we
+	// return no field.
+	if len(fields) > 1 {
+		return field{}, false
+	}
+	return fields[0], true
+}
+
+var fieldCache struct {
+	sync.RWMutex
+	m map[reflect.Type][]field
+}
+
+// cachedTypeFields is like typeFields but uses a cache to avoid repeated work.
+func cachedTypeFields(t reflect.Type) []field {
+	fieldCache.RLock()
+	f := fieldCache.m[t]
+	fieldCache.RUnlock()
+	if f != nil {
+		return f
+	}
+
+	// Compute fields without lock.
+	// Might duplicate effort but won't hold other computations back.
+	f = typeFields(t)
+	if f == nil {
+		f = []field{}
+	}
+
+	fieldCache.Lock()
+	if fieldCache.m == nil {
+		fieldCache.m = map[reflect.Type][]field{}
+	}
+	fieldCache.m[t] = f
+	fieldCache.Unlock()
+	return f
+}

vendor/github.com/BurntSushi/toml/type_toml.go

@@ -0,0 +1,65 @@
+package toml
+
+// tomlType represents any Go type that corresponds to a TOML type.
+// While the first draft of the TOML spec has a simplistic type system that
+// probably doesn't need this level of sophistication, we seem to be militating
+// toward adding real composite types.
+type tomlType interface {
+	typeString() string
+}
+
+// typeEqual accepts any two types and returns true if they are equal.
+func typeEqual(t1, t2 tomlType) bool {
+	if t1 == nil || t2 == nil {
+		return false
+	}
+	return t1.typeString() == t2.typeString()
+}
+
+func typeIsTable(t tomlType) bool {
+	return typeEqual(t, tomlHash) || typeEqual(t, tomlArrayHash)
+}
+
+type tomlBaseType string
+
+func (btype tomlBaseType) typeString() string { return string(btype) }
+func (btype tomlBaseType) String() string     { return btype.typeString() }
+
+var (
+	tomlInteger   tomlBaseType = "Integer"
+	tomlFloat     tomlBaseType = "Float"
+	tomlDatetime  tomlBaseType = "Datetime"
+	tomlString    tomlBaseType = "String"
+	tomlBool      tomlBaseType = "Bool"
+	tomlArray     tomlBaseType = "Array"
+	tomlHash      tomlBaseType = "Hash"
+	tomlArrayHash tomlBaseType = "ArrayHash"
+)
+
+// typeOfPrimitive returns a tomlType of any primitive value in TOML.
+// Primitive values are: Integer, Float, Datetime, String and Bool.
+//
+// Passing a lexer item other than the following will cause a BUG message
+// to occur: itemString, itemBool, itemInteger, itemFloat, itemDatetime.
+func (p *parser) typeOfPrimitive(lexItem item) tomlType {
+	switch lexItem.typ {
+	case itemInteger:
+		return tomlInteger
+	case itemFloat:
+		return tomlFloat
+	case itemDatetime:
+		return tomlDatetime
+	case itemString, itemStringEsc:
+		return tomlString
+	case itemMultilineString:
+		return tomlString
+	case itemRawString:
+		return tomlString
+	case itemRawMultilineString:
+		return tomlString
+	case itemBool:
+		return tomlBool
+	}
+	p.bug("Cannot infer primitive type of lex item '%s'.", lexItem)
+	panic("unreachable")
+}

vendor/golang.org/x/exp/typeparams/LICENSE

@@ -0,0 +1,27 @@
+Copyright (c) 2009 The Go Authors. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+   * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+   * Neither the name of Google Inc. nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

vendor/golang.org/x/exp/typeparams/common.go

@@ -0,0 +1,182 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package typeparams contains common utilities for writing tools that interact
+// with generic Go code, as introduced with Go 1.18.
+//
+// Many of the types and functions in this package are proxies for the new APIs
+// introduced in the standard library with Go 1.18. For example, the
+// typeparams.Union type is an alias for go/types.Union, and the ForTypeSpec
+// function returns the value of the go/ast.TypeSpec.TypeParams field. At Go
+// versions older than 1.18 these helpers are implemented as stubs, allowing
+// users of this package to write code that handles generic constructs inline,
+// even if the Go version being used to compile does not support generics.
+//
+// Additionally, this package contains common utilities for working with the
+// new generic constructs, to supplement the standard library APIs. Notably,
+// the NormalTerms API computes a minimal representation of the structural
+// restrictions on a type parameter. In the future, these supplemental APIs may
+// be available in the standard library..
+package typeparams
+
+import (
+	"go/ast"
+	"go/token"
+	"go/types"
+)
+
+// Enabled reports whether type parameters are enabled in the current build
+// environment.
+func Enabled() bool {
+	return enabled
+}
+
+// UnpackIndexExpr extracts data from AST nodes that represent index
+// expressions.
+//
+// For an ast.IndexExpr, the resulting indices slice will contain exactly one
+// index expression. For an ast.IndexListExpr (go1.18+), it may have a variable
+// number of index expressions.
+//
+// For nodes that don't represent index expressions, the first return value of
+// UnpackIndexExpr will be nil.
+func UnpackIndexExpr(n ast.Node) (x ast.Expr, lbrack token.Pos, indices []ast.Expr, rbrack token.Pos) {
+	switch e := n.(type) {
+	case *ast.IndexExpr:
+		return e.X, e.Lbrack, []ast.Expr{e.Index}, e.Rbrack
+	case *IndexListExpr:
+		return e.X, e.Lbrack, e.Indices, e.Rbrack
+	}
+	return nil, token.NoPos, nil, token.NoPos
+}
+
+// PackIndexExpr returns an *ast.IndexExpr or *ast.IndexListExpr, depending on
+// the cardinality of indices. Calling PackIndexExpr with len(indices) == 0
+// will panic.
+func PackIndexExpr(x ast.Expr, lbrack token.Pos, indices []ast.Expr, rbrack token.Pos) ast.Expr {
+	switch len(indices) {
+	case 0:
+		panic("empty indices")
+	case 1:
+		return &ast.IndexExpr{
+			X:      x,
+			Lbrack: lbrack,
+			Index:  indices[0],
+			Rbrack: rbrack,
+		}
+	default:
+		return &IndexListExpr{
+			X:       x,
+			Lbrack:  lbrack,
+			Indices: indices,
+			Rbrack:  rbrack,
+		}
+	}
+}
+
+// IsTypeParam reports whether t is a type parameter.
+func IsTypeParam(t types.Type) bool {
+	_, ok := t.(*TypeParam)
+	return ok
+}
+
+// OriginMethod returns the origin method associated with the method fn. For
+// methods on a non-generic receiver base type, this is just fn. However, for
+// methods with a generic receiver, OriginMethod returns the corresponding
+// method in the method set of the origin type.
+//
+// As a special case, if fn is not a method (has no receiver), OriginMethod
+// returns fn.
+func OriginMethod(fn *types.Func) *types.Func {
+	recv := fn.Type().(*types.Signature).Recv()
+	if recv == nil {
+		return fn
+	}
+	base := recv.Type()
+	p, isPtr := base.(*types.Pointer)
+	if isPtr {
+		base = p.Elem()
+	}
+	named, isNamed := base.(*types.Named)
+	if !isNamed {
+		// Receiver is a *types.Interface.
+		return fn
+	}
+	if ForNamed(named).Len() == 0 {
+		// Receiver base has no type parameters, so we can avoid the lookup below.
+		return fn
+	}
+	orig := NamedTypeOrigin(named)
+	gfn, _, _ := types.LookupFieldOrMethod(orig, true, fn.Pkg(), fn.Name())
+	return gfn.(*types.Func)
+}
+
+// GenericAssignableTo is a generalization of types.AssignableTo that
+// implements the following rule for uninstantiated generic types:
+//
+// If V and T are generic named types, then V is considered assignable to T if,
+// for every possible instantation of V[A_1, ..., A_N], the instantiation
+// T[A_1, ..., A_N] is valid and V[A_1, ..., A_N] implements T[A_1, ..., A_N].
+//
+// If T has structural constraints, they must be satisfied by V.
+//
+// For example, consider the following type declarations:
+//
+//	type Interface[T any] interface {
+//		Accept(T)
+//	}
+//
+//	type Container[T any] struct {
+//		Element T
+//	}
+//
+//	func (c Container[T]) Accept(t T) { c.Element = t }
+//
+// In this case, GenericAssignableTo reports that instantiations of Container
+// are assignable to the corresponding instantiation of Interface.
+func GenericAssignableTo(ctxt *Context, V, T types.Type) bool {
+	// If V and T are not both named, or do not have matching non-empty type
+	// parameter lists, fall back on types.AssignableTo.
+
+	VN, Vnamed := V.(*types.Named)
+	TN, Tnamed := T.(*types.Named)
+	if !Vnamed || !Tnamed {
+		return types.AssignableTo(V, T)
+	}
+
+	vtparams := ForNamed(VN)
+	ttparams := ForNamed(TN)
+	if vtparams.Len() == 0 || vtparams.Len() != ttparams.Len() || NamedTypeArgs(VN).Len() != 0 || NamedTypeArgs(TN).Len() != 0 {
+		return types.AssignableTo(V, T)
+	}
+
+	// V and T have the same (non-zero) number of type params. Instantiate both
+	// with the type parameters of V. This must always succeed for V, and will
+	// succeed for T if and only if the type set of each type parameter of V is a
+	// subset of the type set of the corresponding type parameter of T, meaning
+	// that every instantiation of V corresponds to a valid instantiation of T.
+
+	// Minor optimization: ensure we share a context across the two
+	// instantiations below.
+	if ctxt == nil {
+		ctxt = NewContext()
+	}
+
+	var targs []types.Type
+	for i := 0; i < vtparams.Len(); i++ {
+		targs = append(targs, vtparams.At(i))
+	}
+
+	vinst, err := Instantiate(ctxt, V, targs, true)
+	if err != nil {
+		panic("type parameters should satisfy their own constraints")
+	}
+
+	tinst, err := Instantiate(ctxt, T, targs, true)
+	if err != nil {
+		return false
+	}
+
+	return types.AssignableTo(vinst, tinst)
+}

vendor/golang.org/x/exp/typeparams/normalize.go

@@ -0,0 +1,200 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package typeparams
+
+import (
+	"errors"
+	"fmt"
+	"go/types"
+	"os"
+	"strings"
+)
+
+const debug = false
+
+// ErrEmptyTypeSet is returned if a type set computation results in a type set
+// with no types.
+var ErrEmptyTypeSet = errors.New("empty type set")
+
+// NormalTerms returns a slice of terms representing the normalized structural
+// type restrictions of a type, if any.
+//
+// For all types whose underlying type is not *types.TypeParam,
+// *types.Interface, or *types.Union, this is just a single term with Tilde()
+// == false and Type() == typ. For types whose underlying type is
+// *types.TypeParam, *types.Interface, and *types.Union, see below.
+//
+// Structural type restrictions of a type parameter are created via
+// non-interface types embedded in its constraint interface (directly, or via a
+// chain of interface embeddings). For example, in the declaration type T[P
+// interface{~int; m()}] int is the structural restriction of the type
+// parameter P is ~int.
+//
+// With interface embedding and unions, the specification of structural type
+// restrictions may be arbitrarily complex. For example, consider the
+// following:
+//
+//	type A interface{ ~string|~[]byte }
+//
+//	type B interface{ int|string }
+//
+//	type C interface { ~string|~int }
+//
+//	type T[P interface{ A|B; C }] int
+//
+// In this example, the structural type restriction of P is ~string|int: A|B
+// expands to ~string|~[]byte|int|string, which reduces to ~string|~[]byte|int,
+// which when intersected with C (~string|~int) yields ~string|int.
+//
+// NormalTerms computes these expansions and reductions, producing a
+// "normalized" form of the embeddings. A structural restriction is normalized
+// if it is a single union containing no interface terms, and is minimal in the
+// sense that removing any term changes the set of types satisfying the
+// constraint. It is left as a proof for the reader that, modulo sorting, there
+// is exactly one such normalized form.
+//
+// Because the minimal representation always takes this form, NormalTerms
+// returns a slice of tilde terms corresponding to the terms of the union in
+// the normalized structural restriction. An error is returned if the type is
+// invalid, exceeds complexity bounds, or has an empty type set. In the latter
+// case, NormalTerms returns ErrEmptyTypeSet.
+//
+// NormalTerms makes no guarantees about the order of terms, except that it
+// is deterministic.
+func NormalTerms(typ types.Type) ([]*Term, error) {
+	if tparam, ok := typ.(*TypeParam); ok {
+		constraint := tparam.Constraint()
+		if constraint == nil {
+			return nil, fmt.Errorf("%s has nil constraint", tparam)
+		}
+		iface, _ := constraint.Underlying().(*types.Interface)
+		if iface == nil {
+			return nil, fmt.Errorf("constraint is %T, not *types.Interface", constraint.Underlying())
+		}
+		typ = iface
+	}
+	tset, err := computeTermSetInternal(typ, make(map[types.Type]*termSet), 0)
+	if err != nil {
+		return nil, err
+	}
+	if tset.terms.isEmpty() {
+		return nil, ErrEmptyTypeSet
+	}
+	if tset.terms.isAll() {
+		return nil, nil
+	}
+	var terms []*Term
+	for _, term := range tset.terms {
+		terms = append(terms, NewTerm(term.tilde, term.typ))
+	}
+	return terms, nil
+}
+
+// A termSet holds the normalized set of terms for a given type.
+//
+// The name termSet is intentionally distinct from 'type set': a type set is
+// all types that implement a type (and includes method restrictions), whereas
+// a term set just represents the structural restrictions on a type.
+type termSet struct {
+	complete bool
+	terms    termlist
+}
+
+func indentf(depth int, format string, args ...interface{}) {
+	fmt.Fprintf(os.Stderr, strings.Repeat(".", depth)+format+"\n", args...)
+}
+
+func computeTermSetInternal(t types.Type, seen map[types.Type]*termSet, depth int) (res *termSet, err error) {
+	if t == nil {
+		panic("nil type")
+	}
+
+	if debug {
+		indentf(depth, "%s", t.String())
+		defer func() {
+			if err != nil {
+				indentf(depth, "=> %s", err)
+			} else {
+				indentf(depth, "=> %s", res.terms.String())
+			}
+		}()
+	}
+
+	const maxTermCount = 100
+	if tset, ok := seen[t]; ok {
+		if !tset.complete {
+			return nil, fmt.Errorf("cycle detected in the declaration of %s", t)
+		}
+		return tset, nil
+	}
+
+	// Mark the current type as seen to avoid infinite recursion.
+	tset := new(termSet)
+	defer func() {
+		tset.complete = true
+	}()
+	seen[t] = tset
+
+	switch u := t.Underlying().(type) {
+	case *types.Interface:
+		// The term set of an interface is the intersection of the term sets of its
+		// embedded types.
+		tset.terms = allTermlist
+		for i := 0; i < u.NumEmbeddeds(); i++ {
+			embedded := u.EmbeddedType(i)
+			if _, ok := embedded.Underlying().(*TypeParam); ok {
+				return nil, fmt.Errorf("invalid embedded type %T", embedded)
+			}
+			tset2, err := computeTermSetInternal(embedded, seen, depth+1)
+			if err != nil {
+				return nil, err
+			}
+			tset.terms = tset.terms.intersect(tset2.terms)
+		}
+	case *Union:
+		// The term set of a union is the union of term sets of its terms.
+		tset.terms = nil
+		for i := 0; i < u.Len(); i++ {
+			t := u.Term(i)
+			var terms termlist
+			switch t.Type().Underlying().(type) {
+			case *types.Interface:
+				tset2, err := computeTermSetInternal(t.Type(), seen, depth+1)
+				if err != nil {
+					return nil, err
+				}
+				terms = tset2.terms
+			case *TypeParam, *Union:
+				// A stand-alone type parameter or union is not permitted as union
+				// term.
+				return nil, fmt.Errorf("invalid union term %T", t)
+			default:
+				if t.Type() == types.Typ[types.Invalid] {
+					continue
+				}
+				terms = termlist{{t.Tilde(), t.Type()}}
+			}
+			tset.terms = tset.terms.union(terms)
+			if len(tset.terms) > maxTermCount {
+				return nil, fmt.Errorf("exceeded max term count %d", maxTermCount)
+			}
+		}
+	case *TypeParam:
+		panic("unreachable")
+	default:
+		// For all other types, the term set is just a single non-tilde term
+		// holding the type itself.
+		if u != types.Typ[types.Invalid] {
+			tset.terms = termlist{{false, t}}
+		}
+	}
+	return tset, nil
+}
+
+// under is a facade for the go/types internal function of the same name. It is
+// used by typeterm.go.
+func under(t types.Type) types.Type {
+	return t.Underlying()
+}

vendor/golang.org/x/exp/typeparams/termlist.go

@@ -0,0 +1,172 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Code generated by copytermlist.go DO NOT EDIT.
+
+package typeparams
+
+import (
+	"bytes"
+	"go/types"
+)
+
+// A termlist represents the type set represented by the union
+// t1 ∪ y2 ∪ ... tn of the type sets of the terms t1 to tn.
+// A termlist is in normal form if all terms are disjoint.
+// termlist operations don't require the operands to be in
+// normal form.
+type termlist []*term
+
+// allTermlist represents the set of all types.
+// It is in normal form.
+var allTermlist = termlist{new(term)}
+
+// String prints the termlist exactly (without normalization).
+func (xl termlist) String() string {
+	if len(xl) == 0 {
+		return "∅"
+	}
+	var buf bytes.Buffer
+	for i, x := range xl {
+		if i > 0 {
+			buf.WriteString(" ∪ ")
+		}
+		buf.WriteString(x.String())
+	}
+	return buf.String()
+}
+
+// isEmpty reports whether the termlist xl represents the empty set of types.
+func (xl termlist) isEmpty() bool {
+	// If there's a non-nil term, the entire list is not empty.
+	// If the termlist is in normal form, this requires at most
+	// one iteration.
+	for _, x := range xl {
+		if x != nil {
+			return false
+		}
+	}
+	return true
+}
+
+// isAll reports whether the termlist xl represents the set of all types.
+func (xl termlist) isAll() bool {
+	// If there's a 𝓤 term, the entire list is 𝓤.
+	// If the termlist is in normal form, this requires at most
+	// one iteration.
+	for _, x := range xl {
+		if x != nil && x.typ == nil {
+			return true
+		}
+	}
+	return false
+}
+
+// norm returns the normal form of xl.
+func (xl termlist) norm() termlist {
+	// Quadratic algorithm, but good enough for now.
+	// TODO(gri) fix asymptotic performance
+	used := make([]bool, len(xl))
+	var rl termlist
+	for i, xi := range xl {
+		if xi == nil || used[i] {
+			continue
+		}
+		for j := i + 1; j < len(xl); j++ {
+			xj := xl[j]
+			if xj == nil || used[j] {
+				continue
+			}
+			if u1, u2 := xi.union(xj); u2 == nil {
+				// If we encounter a 𝓤 term, the entire list is 𝓤.
+				// Exit early.
+				// (Note that this is not just an optimization;
+				// if we continue, we may end up with a 𝓤 term
+				// and other terms and the result would not be
+				// in normal form.)
+				if u1.typ == nil {
+					return allTermlist
+				}
+				xi = u1
+				used[j] = true // xj is now unioned into xi - ignore it in future iterations
+			}
+		}
+		rl = append(rl, xi)
+	}
+	return rl
+}
+
+// If the type set represented by xl is specified by a single (non-𝓤) term,
+// singleType returns that type. Otherwise it returns nil.
+func (xl termlist) singleType() types.Type {
+	if nl := xl.norm(); len(nl) == 1 {
+		return nl[0].typ // if nl.isAll() then typ is nil, which is ok
+	}
+	return nil
+}
+
+// union returns the union xl ∪ yl.
+func (xl termlist) union(yl termlist) termlist {
+	return append(xl, yl...).norm()
+}
+
+// intersect returns the intersection xl ∩ yl.
+func (xl termlist) intersect(yl termlist) termlist {
+	if xl.isEmpty() || yl.isEmpty() {
+		return nil
+	}
+
+	// Quadratic algorithm, but good enough for now.
+	// TODO(gri) fix asymptotic performance
+	var rl termlist
+	for _, x := range xl {
+		for _, y := range yl {
+			if r := x.intersect(y); r != nil {
+				rl = append(rl, r)
+			}
+		}
+	}
+	return rl.norm()
+}
+
+// equal reports whether xl and yl represent the same type set.
+func (xl termlist) equal(yl termlist) bool {
+	// TODO(gri) this should be more efficient
+	return xl.subsetOf(yl) && yl.subsetOf(xl)
+}
+
+// includes reports whether t ∈ xl.
+func (xl termlist) includes(t types.Type) bool {
+	for _, x := range xl {
+		if x.includes(t) {
+			return true
+		}
+	}
+	return false
+}
+
+// supersetOf reports whether y ⊆ xl.
+func (xl termlist) supersetOf(y *term) bool {
+	for _, x := range xl {
+		if y.subsetOf(x) {
+			return true
+		}
+	}
+	return false
+}
+
+// subsetOf reports whether xl ⊆ yl.
+func (xl termlist) subsetOf(yl termlist) bool {
+	if yl.isEmpty() {
+		return xl.isEmpty()
+	}
+
+	// each term x of xl must be a subset of yl
+	for _, x := range xl {
+		if !yl.supersetOf(x) {
+			return false // x is not a subset yl
+		}
+	}
+	return true
+}

vendor/golang.org/x/exp/typeparams/typeparams_go117.go

@@ -0,0 +1,201 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build !go1.18
+
+package typeparams
+
+import (
+	"go/ast"
+	"go/token"
+	"go/types"
+)
+
+const enabled = false
+
+func unsupported() {
+	panic("type parameters are unsupported at this go version")
+}
+
+// IndexListExpr is a placeholder type, as type parameters are not supported at
+// this Go version. Its methods panic on use.
+type IndexListExpr struct {
+	ast.Expr
+	X       ast.Expr   // expression
+	Lbrack  token.Pos  // position of "["
+	Indices []ast.Expr // index expressions
+	Rbrack  token.Pos  // position of "]"
+}
+
+func (*IndexListExpr) Pos() token.Pos { unsupported(); return token.NoPos }
+func (*IndexListExpr) End() token.Pos { unsupported(); return token.NoPos }
+
+// ForTypeSpec returns an empty field list, as type parameters on not supported
+// at this Go version.
+func ForTypeSpec(*ast.TypeSpec) *ast.FieldList {
+	return nil
+}
+
+// ForFuncType returns an empty field list, as type parameters are not
+// supported at this Go version.
+func ForFuncType(*ast.FuncType) *ast.FieldList {
+	return nil
+}
+
+// TypeParam is a placeholder type, as type parameters are not supported at
+// this Go version. Its methods panic on use.
+type TypeParam struct{ types.Type }
+
+func (*TypeParam) String() string           { unsupported(); return "" }
+func (*TypeParam) Underlying() types.Type   { unsupported(); return nil }
+func (*TypeParam) Index() int               { unsupported(); return 0 }
+func (*TypeParam) Constraint() types.Type   { unsupported(); return nil }
+func (*TypeParam) SetConstraint(types.Type) { unsupported() }
+func (*TypeParam) Obj() *types.TypeName     { unsupported(); return nil }
+
+// TypeParamList is a placeholder for an empty type parameter list.
+type TypeParamList struct{}
+
+func (*TypeParamList) Len() int          { return 0 }
+func (*TypeParamList) At(int) *TypeParam { unsupported(); return nil }
+
+// TypeList is a placeholder for an empty type list.
+type TypeList struct{}
+
+func (*TypeList) Len() int          { return 0 }
+func (*TypeList) At(int) types.Type { unsupported(); return nil }
+
+// NewTypeParam is unsupported at this Go version, and panics.
+func NewTypeParam(name *types.TypeName, constraint types.Type) *TypeParam {
+	unsupported()
+	return nil
+}
+
+// NewSignatureType calls types.NewSignature, panicking if recvTypeParams or
+// typeParams is non-empty.
+func NewSignatureType(recv *types.Var, recvTypeParams, typeParams []*TypeParam, params, results *types.Tuple, variadic bool) *types.Signature {
+	if len(recvTypeParams) != 0 || len(typeParams) != 0 {
+		unsupported()
+	}
+	return types.NewSignature(recv, params, results, variadic)
+}
+
+// ForSignature returns an empty slice.
+func ForSignature(*types.Signature) *TypeParamList {
+	return nil
+}
+
+// RecvTypeParams returns a nil slice.
+func RecvTypeParams(sig *types.Signature) *TypeParamList {
+	return nil
+}
+
+// IsComparable returns false, as no interfaces are type-restricted at this Go
+// version.
+func IsComparable(*types.Interface) bool {
+	return false
+}
+
+// IsMethodSet returns true, as no interfaces are type-restricted at this Go
+// version.
+func IsMethodSet(*types.Interface) bool {
+	return true
+}
+
+// IsImplicit returns false, as no interfaces are implicit at this Go version.
+func IsImplicit(*types.Interface) bool {
+	return false
+}
+
+// MarkImplicit does nothing, because this Go version does not have implicit
+// interfaces.
+func MarkImplicit(*types.Interface) {}
+
+// ForNamed returns an empty type parameter list, as type parameters are not
+// supported at this Go version.
+func ForNamed(*types.Named) *TypeParamList {
+	return nil
+}
+
+// SetForNamed panics if tparams is non-empty.
+func SetForNamed(_ *types.Named, tparams []*TypeParam) {
+	if len(tparams) > 0 {
+		unsupported()
+	}
+}
+
+// NamedTypeArgs returns nil.
+func NamedTypeArgs(*types.Named) *TypeList {
+	return nil
+}
+
+// NamedTypeOrigin is the identity method at this Go version.
+func NamedTypeOrigin(named *types.Named) types.Type {
+	return named
+}
+
+// Term holds information about a structural type restriction.
+type Term struct {
+	tilde bool
+	typ   types.Type
+}
+
+func (m *Term) Tilde() bool      { return m.tilde }
+func (m *Term) Type() types.Type { return m.typ }
+func (m *Term) String() string {
+	pre := ""
+	if m.tilde {
+		pre = "~"
+	}
+	return pre + m.typ.String()
+}
+
+// NewTerm creates a new placeholder term type.
+func NewTerm(tilde bool, typ types.Type) *Term {
+	return &Term{tilde, typ}
+}
+
+// Union is a placeholder type, as type parameters are not supported at this Go
+// version. Its methods panic on use.
+type Union struct{ types.Type }
+
+func (*Union) String() string         { unsupported(); return "" }
+func (*Union) Underlying() types.Type { unsupported(); return nil }
+func (*Union) Len() int               { return 0 }
+func (*Union) Term(i int) *Term       { unsupported(); return nil }
+
+// NewUnion is unsupported at this Go version, and panics.
+func NewUnion(terms []*Term) *Union {
+	unsupported()
+	return nil
+}
+
+// InitInstances is a noop at this Go version.
+func InitInstances(*types.Info) {}
+
+// Instance is a placeholder type, as type parameters are not supported at this
+// Go version.
+type Instance struct {
+	TypeArgs *TypeList
+	Type     types.Type
+}
+
+// GetInstances returns a nil map, as type parameters are not supported at this
+// Go version.
+func GetInstances(info *types.Info) map[*ast.Ident]Instance { return nil }
+
+// Context is a placeholder type, as type parameters are not supported at
+// this Go version.
+type Context struct{}
+
+// NewContext returns a placeholder Context instance.
+func NewContext() *Context {
+	return &Context{}
+}
+
+// Instantiate is unsupported on this Go version, and panics.
+func Instantiate(ctxt *Context, typ types.Type, targs []types.Type, validate bool) (types.Type, error) {
+	unsupported()
+	return nil, nil
+}

vendor/golang.org/x/exp/typeparams/typeparams_go118.go

@@ -0,0 +1,147 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build go1.18
+
+package typeparams
+
+import (
+	"go/ast"
+	"go/types"
+)
+
+const enabled = true
+
+// IndexListExpr is an alias for ast.IndexListExpr.
+type IndexListExpr = ast.IndexListExpr
+
+// ForTypeSpec returns n.TypeParams.
+func ForTypeSpec(n *ast.TypeSpec) *ast.FieldList {
+	if n == nil {
+		return nil
+	}
+	return n.TypeParams
+}
+
+// ForFuncType returns n.TypeParams.
+func ForFuncType(n *ast.FuncType) *ast.FieldList {
+	if n == nil {
+		return nil
+	}
+	return n.TypeParams
+}
+
+// TypeParam is an alias for types.TypeParam
+type TypeParam = types.TypeParam
+
+// TypeParamList is an alias for types.TypeParamList
+type TypeParamList = types.TypeParamList
+
+// TypeList is an alias for types.TypeList
+type TypeList = types.TypeList
+
+// NewTypeParam calls types.NewTypeParam.
+func NewTypeParam(name *types.TypeName, constraint types.Type) *TypeParam {
+	return types.NewTypeParam(name, constraint)
+}
+
+// NewSignatureType calls types.NewSignatureType.
+func NewSignatureType(recv *types.Var, recvTypeParams, typeParams []*TypeParam, params, results *types.Tuple, variadic bool) *types.Signature {
+	return types.NewSignatureType(recv, recvTypeParams, typeParams, params, results, variadic)
+}
+
+// ForSignature returns sig.TypeParams()
+func ForSignature(sig *types.Signature) *TypeParamList {
+	return sig.TypeParams()
+}
+
+// RecvTypeParams returns sig.RecvTypeParams().
+func RecvTypeParams(sig *types.Signature) *TypeParamList {
+	return sig.RecvTypeParams()
+}
+
+// IsComparable calls iface.IsComparable().
+func IsComparable(iface *types.Interface) bool {
+	return iface.IsComparable()
+}
+
+// IsMethodSet calls iface.IsMethodSet().
+func IsMethodSet(iface *types.Interface) bool {
+	return iface.IsMethodSet()
+}
+
+// IsImplicit calls iface.IsImplicit().
+func IsImplicit(iface *types.Interface) bool {
+	return iface.IsImplicit()
+}
+
+// MarkImplicit calls iface.MarkImplicit().
+func MarkImplicit(iface *types.Interface) {
+	iface.MarkImplicit()
+}
+
+// ForNamed extracts the (possibly empty) type parameter object list from
+// named.
+func ForNamed(named *types.Named) *TypeParamList {
+	return named.TypeParams()
+}
+
+// SetForNamed sets the type params tparams on n. Each tparam must be of
+// dynamic type *types.TypeParam.
+func SetForNamed(n *types.Named, tparams []*TypeParam) {
+	n.SetTypeParams(tparams)
+}
+
+// NamedTypeArgs returns named.TypeArgs().
+func NamedTypeArgs(named *types.Named) *TypeList {
+	return named.TypeArgs()
+}
+
+// NamedTypeOrigin returns named.Orig().
+func NamedTypeOrigin(named *types.Named) types.Type {
+	return named.Origin()
+}
+
+// Term is an alias for types.Term.
+type Term = types.Term
+
+// NewTerm calls types.NewTerm.
+func NewTerm(tilde bool, typ types.Type) *Term {
+	return types.NewTerm(tilde, typ)
+}
+
+// Union is an alias for types.Union
+type Union = types.Union
+
+// NewUnion calls types.NewUnion.
+func NewUnion(terms []*Term) *Union {
+	return types.NewUnion(terms)
+}
+
+// InitInstances initializes info to record information about type and function
+// instances.
+func InitInstances(info *types.Info) {
+	info.Instances = make(map[*ast.Ident]types.Instance)
+}
+
+// Instance is an alias for types.Instance.
+type Instance = types.Instance
+
+// GetInstances returns info.Instances.
+func GetInstances(info *types.Info) map[*ast.Ident]Instance {
+	return info.Instances
+}
+
+// Context is an alias for types.Context.
+type Context = types.Context
+
+// NewContext calls types.NewContext.
+func NewContext() *Context {
+	return types.NewContext()
+}
+
+// Instantiate calls types.Instantiate.
+func Instantiate(ctxt *Context, typ types.Type, targs []types.Type, validate bool) (types.Type, error) {
+	return types.Instantiate(ctxt, typ, targs, validate)
+}

vendor/golang.org/x/exp/typeparams/typeterm.go

@@ -0,0 +1,169 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Code generated by copytermlist.go DO NOT EDIT.
+
+package typeparams
+
+import "go/types"
+
+// A term describes elementary type sets:
+//
+//	 ∅:  (*term)(nil)     == ∅                      // set of no types (empty set)
+//	 𝓤:  &term{}          == 𝓤                      // set of all types (𝓤niverse)
+//	 T:  &term{false, T}  == {T}                    // set of type T
+//	~t:  &term{true, t}   == {t' | under(t') == t}  // set of types with underlying type t
+type term struct {
+	tilde bool // valid if typ != nil
+	typ   types.Type
+}
+
+func (x *term) String() string {
+	switch {
+	case x == nil:
+		return "∅"
+	case x.typ == nil:
+		return "𝓤"
+	case x.tilde:
+		return "~" + x.typ.String()
+	default:
+		return x.typ.String()
+	}
+}
+
+// equal reports whether x and y represent the same type set.
+func (x *term) equal(y *term) bool {
+	// easy cases
+	switch {
+	case x == nil || y == nil:
+		return x == y
+	case x.typ == nil || y.typ == nil:
+		return x.typ == y.typ
+	}
+	// ∅ ⊂ x, y ⊂ 𝓤
+
+	return x.tilde == y.tilde && types.Identical(x.typ, y.typ)
+}
+
+// union returns the union x ∪ y: zero, one, or two non-nil terms.
+func (x *term) union(y *term) (_, _ *term) {
+	// easy cases
+	switch {
+	case x == nil && y == nil:
+		return nil, nil // ∅ ∪ ∅ == ∅
+	case x == nil:
+		return y, nil // ∅ ∪ y == y
+	case y == nil:
+		return x, nil // x ∪ ∅ == x
+	case x.typ == nil:
+		return x, nil // 𝓤 ∪ y == 𝓤
+	case y.typ == nil:
+		return y, nil // x ∪ 𝓤 == 𝓤
+	}
+	// ∅ ⊂ x, y ⊂ 𝓤
+
+	if x.disjoint(y) {
+		return x, y // x ∪ y == (x, y) if x ∩ y == ∅
+	}
+	// x.typ == y.typ
+
+	// ~t ∪ ~t == ~t
+	// ~t ∪  T == ~t
+	//  T ∪ ~t == ~t
+	//  T ∪  T ==  T
+	if x.tilde || !y.tilde {
+		return x, nil
+	}
+	return y, nil
+}
+
+// intersect returns the intersection x ∩ y.
+func (x *term) intersect(y *term) *term {
+	// easy cases
+	switch {
+	case x == nil || y == nil:
+		return nil // ∅ ∩ y == ∅ and ∩ ∅ == ∅
+	case x.typ == nil:
+		return y // 𝓤 ∩ y == y
+	case y.typ == nil:
+		return x // x ∩ 𝓤 == x
+	}
+	// ∅ ⊂ x, y ⊂ 𝓤
+
+	if x.disjoint(y) {
+		return nil // x ∩ y == ∅ if x ∩ y == ∅
+	}
+	// x.typ == y.typ
+
+	// ~t ∩ ~t == ~t
+	// ~t ∩  T ==  T
+	//  T ∩ ~t ==  T
+	//  T ∩  T ==  T
+	if !x.tilde || y.tilde {
+		return x
+	}
+	return y
+}
+
+// includes reports whether t ∈ x.
+func (x *term) includes(t types.Type) bool {
+	// easy cases
+	switch {
+	case x == nil:
+		return false // t ∈ ∅ == false
+	case x.typ == nil:
+		return true // t ∈ 𝓤 == true
+	}
+	// ∅ ⊂ x ⊂ 𝓤
+
+	u := t
+	if x.tilde {
+		u = under(u)
+	}
+	return types.Identical(x.typ, u)
+}
+
+// subsetOf reports whether x ⊆ y.
+func (x *term) subsetOf(y *term) bool {
+	// easy cases
+	switch {
+	case x == nil:
+		return true // ∅ ⊆ y == true
+	case y == nil:
+		return false // x ⊆ ∅ == false since x != ∅
+	case y.typ == nil:
+		return true // x ⊆ 𝓤 == true
+	case x.typ == nil:
+		return false // 𝓤 ⊆ y == false since y != 𝓤
+	}
+	// ∅ ⊂ x, y ⊂ 𝓤
+
+	if x.disjoint(y) {
+		return false // x ⊆ y == false if x ∩ y == ∅
+	}
+	// x.typ == y.typ
+
+	// ~t ⊆ ~t == true
+	// ~t ⊆ T == false
+	//  T ⊆ ~t == true
+	//  T ⊆  T == true
+	return !x.tilde || y.tilde
+}
+
+// disjoint reports whether x ∩ y == ∅.
+// x.typ and y.typ must not be nil.
+func (x *term) disjoint(y *term) bool {
+	if debug && (x.typ == nil || y.typ == nil) {
+		panic("invalid argument(s)")
+	}
+	ux := x.typ
+	if y.tilde {
+		ux = under(ux)
+	}
+	uy := y.typ
+	if x.tilde {
+		uy = under(uy)
+	}
+	return !types.Identical(ux, uy)
+}

vendor/golang.org/x/tools/go/analysis/analysis.go

@@ -0,0 +1,269 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package analysis
+
+import (
+	"flag"
+	"fmt"
+	"go/ast"
+	"go/token"
+	"go/types"
+	"reflect"
+	"time"
+)
+
+// An Analyzer describes an analysis function and its options.
+type Analyzer struct {
+	// The Name of the analyzer must be a valid Go identifier
+	// as it may appear in command-line flags, URLs, and so on.
+	Name string
+
+	// Doc is the documentation for the analyzer.
+	// The part before the first "\n\n" is the title
+	// (no capital or period, max ~60 letters).
+	Doc string
+
+	// URL holds an optional link to a web page with additional
+	// documentation for this analyzer.
+	URL string
+
+	// Flags defines any flags accepted by the analyzer.
+	// The manner in which these flags are exposed to the user
+	// depends on the driver which runs the analyzer.
+	Flags flag.FlagSet
+
+	// Run applies the analyzer to a package.
+	// It returns an error if the analyzer failed.
+	//
+	// On success, the Run function may return a result
+	// computed by the Analyzer; its type must match ResultType.
+	// The driver makes this result available as an input to
+	// another Analyzer that depends directly on this one (see
+	// Requires) when it analyzes the same package.
+	//
+	// To pass analysis results between packages (and thus
+	// potentially between address spaces), use Facts, which are
+	// serializable.
+	Run func(*Pass) (any, error)
+
+	// RunDespiteErrors allows the driver to invoke
+	// the Run method of this analyzer even on a
+	// package that contains parse or type errors.
+	// The [Pass.TypeErrors] field may consequently be non-empty.
+	RunDespiteErrors bool
+
+	// Requires is a set of analyzers that must run successfully
+	// before this one on a given package. This analyzer may inspect
+	// the outputs produced by each analyzer in Requires.
+	// The graph over analyzers implied by Requires edges must be acyclic.
+	//
+	// Requires establishes a "horizontal" dependency between
+	// analysis passes (different analyzers, same package).
+	Requires []*Analyzer
+
+	// ResultType is the type of the optional result of the Run function.
+	ResultType reflect.Type
+
+	// FactTypes indicates that this analyzer imports and exports
+	// Facts of the specified concrete types.
+	// An analyzer that uses facts may assume that its import
+	// dependencies have been similarly analyzed before it runs.
+	// Facts must be pointers.
+	//
+	// FactTypes establishes a "vertical" dependency between
+	// analysis passes (same analyzer, different packages).
+	FactTypes []Fact
+}
+
+func (a *Analyzer) String() string { return a.Name }
+
+// A Pass provides information to the Run function that
+// applies a specific analyzer to a single Go package.
+//
+// It forms the interface between the analysis logic and the driver
+// program, and has both input and an output components.
+//
+// As in a compiler, one pass may depend on the result computed by another.
+//
+// The Run function should not call any of the Pass functions concurrently.
+type Pass struct {
+	Analyzer *Analyzer // the identity of the current analyzer
+
+	// syntax and type information
+	Fset         *token.FileSet // file position information; Run may add new files
+	Files        []*ast.File    // the abstract syntax tree of each file
+	OtherFiles   []string       // names of non-Go files of this package
+	IgnoredFiles []string       // names of ignored source files in this package
+	Pkg          *types.Package // type information about the package
+	TypesInfo    *types.Info    // type information about the syntax trees
+	TypesSizes   types.Sizes    // function for computing sizes of types
+	TypeErrors   []types.Error  // type errors (only if Analyzer.RunDespiteErrors)
+
+	Module *Module // the package's enclosing module (possibly nil in some drivers)
+
+	// Report reports a Diagnostic, a finding about a specific location
+	// in the analyzed source code such as a potential mistake.
+	// It may be called by the Run function.
+	Report func(Diagnostic)
+
+	// ResultOf provides the inputs to this analysis pass, which are
+	// the corresponding results of its prerequisite analyzers.
+	// The map keys are the elements of Analysis.Required,
+	// and the type of each corresponding value is the required
+	// analysis's ResultType.
+	ResultOf map[*Analyzer]any
+
+	// ReadFile returns the contents of the named file.
+	//
+	// The only valid file names are the elements of OtherFiles
+	// and IgnoredFiles, and names returned by
+	// Fset.File(f.FileStart).Name() for each f in Files.
+	//
+	// Analyzers must use this function (if provided) instead of
+	// accessing the file system directly. This allows a driver to
+	// provide a virtualized file tree (including, for example,
+	// unsaved editor buffers) and to track dependencies precisely
+	// to avoid unnecessary recomputation.
+	ReadFile func(filename string) ([]byte, error)
+
+	// -- facts --
+
+	// ImportObjectFact retrieves a fact associated with obj.
+	// Given a value ptr of type *T, where *T satisfies Fact,
+	// ImportObjectFact copies the value to *ptr.
+	//
+	// ImportObjectFact panics if called after the pass is complete.
+	// ImportObjectFact is not concurrency-safe.
+	ImportObjectFact func(obj types.Object, fact Fact) bool
+
+	// ImportPackageFact retrieves a fact associated with package pkg,
+	// which must be this package or one of its dependencies.
+	// See comments for ImportObjectFact.
+	ImportPackageFact func(pkg *types.Package, fact Fact) bool
+
+	// ExportObjectFact associates a fact of type *T with the obj,
+	// replacing any previous fact of that type.
+	//
+	// ExportObjectFact panics if it is called after the pass is
+	// complete, or if obj does not belong to the package being analyzed.
+	// ExportObjectFact is not concurrency-safe.
+	ExportObjectFact func(obj types.Object, fact Fact)
+
+	// ExportPackageFact associates a fact with the current package.
+	// See comments for ExportObjectFact.
+	ExportPackageFact func(fact Fact)
+
+	// AllPackageFacts returns a new slice containing all package
+	// facts of the analysis's FactTypes in unspecified order.
+	// See comments for AllObjectFacts.
+	AllPackageFacts func() []PackageFact
+
+	// AllObjectFacts returns a new slice containing all object
+	// facts of the analysis's FactTypes in unspecified order.
+	//
+	// The result includes all facts exported by packages
+	// whose symbols are referenced by the current package
+	// (by qualified identifiers or field/method selections).
+	// And it includes all facts exported from the current
+	// package by the current analysis pass.
+	AllObjectFacts func() []ObjectFact
+
+	/* Further fields may be added in future. */
+}
+
+// PackageFact is a package together with an associated fact.
+type PackageFact struct {
+	Package *types.Package
+	Fact    Fact
+}
+
+// ObjectFact is an object together with an associated fact.
+type ObjectFact struct {
+	Object types.Object
+	Fact   Fact
+}
+
+// Reportf is a helper function that reports a Diagnostic using the
+// specified position and formatted error message.
+func (pass *Pass) Reportf(pos token.Pos, format string, args ...any) {
+	msg := fmt.Sprintf(format, args...)
+	pass.Report(Diagnostic{Pos: pos, Message: msg})
+}
+
+// The Range interface provides a range. It's equivalent to and satisfied by
+// ast.Node.
+type Range interface {
+	Pos() token.Pos // position of first character belonging to the node
+	End() token.Pos // position of first character immediately after the node
+}
+
+// ReportRangef is a helper function that reports a Diagnostic using the
+// range provided. ast.Node values can be passed in as the range because
+// they satisfy the Range interface.
+func (pass *Pass) ReportRangef(rng Range, format string, args ...any) {
+	msg := fmt.Sprintf(format, args...)
+	pass.Report(Diagnostic{Pos: rng.Pos(), End: rng.End(), Message: msg})
+}
+
+func (pass *Pass) String() string {
+	return fmt.Sprintf("%s@%s", pass.Analyzer.Name, pass.Pkg.Path())
+}
+
+// A Fact is an intermediate fact produced during analysis.
+//
+// Each fact is associated with a named declaration (a types.Object) or
+// with a package as a whole. A single object or package may have
+// multiple associated facts, but only one of any particular fact type.
+//
+// A Fact represents a predicate such as "never returns", but does not
+// represent the subject of the predicate such as "function F" or "package P".
+//
+// Facts may be produced in one analysis pass and consumed by another
+// analysis pass even if these are in different address spaces.
+// If package P imports Q, all facts about Q produced during
+// analysis of that package will be available during later analysis of P.
+// Facts are analogous to type export data in a build system:
+// just as export data enables separate compilation of several passes,
+// facts enable "separate analysis".
+//
+// Each pass (a, p) starts with the set of facts produced by the
+// same analyzer a applied to the packages directly imported by p.
+// The analysis may add facts to the set, and they may be exported in turn.
+// An analysis's Run function may retrieve facts by calling
+// Pass.Import{Object,Package}Fact and update them using
+// Pass.Export{Object,Package}Fact.
+//
+// A fact is logically private to its Analysis. To pass values
+// between different analyzers, use the results mechanism;
+// see Analyzer.Requires, Analyzer.ResultType, and Pass.ResultOf.
+//
+// A Fact type must be a pointer.
+// Facts are encoded and decoded using encoding/gob.
+// A Fact may implement the GobEncoder/GobDecoder interfaces
+// to customize its encoding. Fact encoding should not fail.
+//
+// A Fact should not be modified once exported.
+type Fact interface {
+	AFact() // dummy method to avoid type errors
+}
+
+// A Module describes the module to which a package belongs.
+type Module struct {
+	Path      string       // module path
+	Version   string       // module version ("" if unknown, such as for workspace modules)
+	Replace   *Module      // replaced by this module
+	Time      *time.Time   // time version was created
+	Main      bool         // is this the main module?
+	Indirect  bool         // is this module only an indirect dependency of main module?
+	Dir       string       // directory holding files for this module, if any
+	GoMod     string       // path to go.mod file used when loading this module, if any
+	GoVersion string       // go version used in module (e.g. "go1.22.0")
+	Error     *ModuleError // error loading module
+}
+
+// ModuleError holds errors loading a module.
+type ModuleError struct {
+	Err string // the error itself
+}

vendor/golang.org/x/tools/go/analysis/diagnostic.go

@@ -0,0 +1,88 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package analysis
+
+import "go/token"
+
+// A Diagnostic is a message associated with a source location or range.
+//
+// An Analyzer may return a variety of diagnostics; the optional Category,
+// which should be a constant, may be used to classify them.
+// It is primarily intended to make it easy to look up documentation.
+//
+// All Pos values are interpreted relative to Pass.Fset. If End is
+// provided, the diagnostic is specified to apply to the range between
+// Pos and End.
+type Diagnostic struct {
+	Pos      token.Pos
+	End      token.Pos // optional
+	Category string    // optional
+	Message  string
+
+	// URL is the optional location of a web page that provides
+	// additional documentation for this diagnostic.
+	//
+	// If URL is empty but a Category is specified, then the
+	// Analysis driver should treat the URL as "#"+Category.
+	//
+	// The URL may be relative. If so, the base URL is that of the
+	// Analyzer that produced the diagnostic;
+	// see https://pkg.go.dev/net/url#URL.ResolveReference.
+	URL string
+
+	// SuggestedFixes is an optional list of fixes to address the
+	// problem described by the diagnostic. Each one represents an
+	// alternative strategy, and should have a distinct and
+	// descriptive message; at most one may be applied.
+	//
+	// Fixes for different diagnostics should be treated as
+	// independent changes to the same baseline file state,
+	// analogous to a set of git commits all with the same parent.
+	// Combining fixes requires resolving any conflicts that
+	// arise, analogous to a git merge.
+	// Any conflicts that remain may be dealt with, depending on
+	// the tool, by discarding fixes, consulting the user, or
+	// aborting the operation.
+	SuggestedFixes []SuggestedFix
+
+	// Related contains optional secondary positions and messages
+	// related to the primary diagnostic.
+	Related []RelatedInformation
+}
+
+// RelatedInformation contains information related to a diagnostic.
+// For example, a diagnostic that flags duplicated declarations of a
+// variable may include one RelatedInformation per existing
+// declaration.
+type RelatedInformation struct {
+	Pos     token.Pos
+	End     token.Pos // optional
+	Message string
+}
+
+// A SuggestedFix is a code change associated with a Diagnostic that a
+// user can choose to apply to their code. Usually the SuggestedFix is
+// meant to fix the issue flagged by the diagnostic.
+//
+// The TextEdits must not overlap, nor contain edits for other
+// packages. Edits need not be totally ordered, but the order
+// determines how insertions at the same point will be applied.
+type SuggestedFix struct {
+	// A verb phrase describing the fix, to be shown to
+	// a user trying to decide whether to accept it.
+	//
+	// Example: "Remove the surplus argument"
+	Message   string
+	TextEdits []TextEdit
+}
+
+// A TextEdit represents the replacement of the code between Pos and End with the new text.
+// Each TextEdit should apply to a single file. End should not be earlier in the file than Pos.
+type TextEdit struct {
+	// For a pure insertion, End can either be set to Pos or token.NoPos.
+	Pos     token.Pos
+	End     token.Pos
+	NewText []byte
+}

vendor/golang.org/x/tools/go/analysis/doc.go

@@ -0,0 +1,317 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+/*
+Package analysis defines the interface between a modular static
+analysis and an analysis driver program.
+
+# Background
+
+A static analysis is a function that inspects a package of Go code and
+reports a set of diagnostics (typically mistakes in the code), and
+perhaps produces other results as well, such as suggested refactorings
+or other facts. An analysis that reports mistakes is informally called a
+"checker". For example, the printf checker reports mistakes in
+fmt.Printf format strings.
+
+A "modular" analysis is one that inspects one package at a time but can
+save information from a lower-level package and use it when inspecting a
+higher-level package, analogous to separate compilation in a toolchain.
+The printf checker is modular: when it discovers that a function such as
+log.Fatalf delegates to fmt.Printf, it records this fact, and checks
+calls to that function too, including calls made from another package.
+
+By implementing a common interface, checkers from a variety of sources
+can be easily selected, incorporated, and reused in a wide range of
+driver programs including command-line tools (such as vet), text editors and
+IDEs, build and test systems (such as go build, Bazel, or Buck), test
+frameworks, code review tools, code-base indexers (such as SourceGraph),
+documentation viewers (such as godoc), batch pipelines for large code
+bases, and so on.
+
+# Analyzer
+
+The primary type in the API is [Analyzer]. An Analyzer statically
+describes an analysis function: its name, documentation, flags,
+relationship to other analyzers, and of course, its logic.
+
+To define an analysis, a user declares a (logically constant) variable
+of type Analyzer. Here is a typical example from one of the analyzers in
+the go/analysis/passes/ subdirectory:
+
+	package unusedresult
+
+	var Analyzer = &analysis.Analyzer{
+		Name: "unusedresult",
+		Doc:  "check for unused results of calls to some functions",
+		Run:  run,
+		...
+	}
+
+	func run(pass *analysis.Pass) (interface{}, error) {
+		...
+	}
+
+An analysis driver is a program such as vet that runs a set of
+analyses and prints the diagnostics that they report.
+The driver program must import the list of Analyzers it needs.
+Typically each Analyzer resides in a separate package.
+To add a new Analyzer to an existing driver, add another item to the list:
+
+	import ( "unusedresult"; "nilness"; "printf" )
+
+	var analyses = []*analysis.Analyzer{
+		unusedresult.Analyzer,
+		nilness.Analyzer,
+		printf.Analyzer,
+	}
+
+A driver may use the name, flags, and documentation to provide on-line
+help that describes the analyses it performs.
+The doc comment contains a brief one-line summary,
+optionally followed by paragraphs of explanation.
+
+The [Analyzer] type has more fields besides those shown above:
+
+	type Analyzer struct {
+		Name             string
+		Doc              string
+		Flags            flag.FlagSet
+		Run              func(*Pass) (interface{}, error)
+		RunDespiteErrors bool
+		ResultType       reflect.Type
+		Requires         []*Analyzer
+		FactTypes        []Fact
+	}
+
+The Flags field declares a set of named (global) flag variables that
+control analysis behavior. Unlike vet, analysis flags are not declared
+directly in the command line FlagSet; it is up to the driver to set the
+flag variables. A driver for a single analysis, a, might expose its flag
+f directly on the command line as -f, whereas a driver for multiple
+analyses might prefix the flag name by the analysis name (-a.f) to avoid
+ambiguity. An IDE might expose the flags through a graphical interface,
+and a batch pipeline might configure them from a config file.
+See the "findcall" analyzer for an example of flags in action.
+
+The RunDespiteErrors flag indicates whether the analysis is equipped to
+handle ill-typed code. If not, the driver will skip the analysis if
+there were parse or type errors.
+The optional ResultType field specifies the type of the result value
+computed by this analysis and made available to other analyses.
+The Requires field specifies a list of analyses upon which
+this one depends and whose results it may access, and it constrains the
+order in which a driver may run analyses.
+The FactTypes field is discussed in the section on Modularity.
+The analysis package provides a Validate function to perform basic
+sanity checks on an Analyzer, such as that its Requires graph is
+acyclic, its fact and result types are unique, and so on.
+
+Finally, the Run field contains a function to be called by the driver to
+execute the analysis on a single package. The driver passes it an
+instance of the Pass type.
+
+# Pass
+
+A [Pass] describes a single unit of work: the application of a particular
+Analyzer to a particular package of Go code.
+The Pass provides information to the Analyzer's Run function about the
+package being analyzed, and provides operations to the Run function for
+reporting diagnostics and other information back to the driver.
+
+	type Pass struct {
+		Fset         *token.FileSet
+		Files        []*ast.File
+		OtherFiles   []string
+		IgnoredFiles []string
+		Pkg          *types.Package
+		TypesInfo    *types.Info
+		ResultOf     map[*Analyzer]interface{}
+		Report       func(Diagnostic)
+		...
+	}
+
+The Fset, Files, Pkg, and TypesInfo fields provide the syntax trees,
+type information, and source positions for a single package of Go code.
+
+The OtherFiles field provides the names of non-Go
+files such as assembly that are part of this package.
+Similarly, the IgnoredFiles field provides the names of Go and non-Go
+source files that are not part of this package with the current build
+configuration but may be part of other build configurations.
+The contents of these files may be read using Pass.ReadFile;
+see the "asmdecl" or "buildtags" analyzers for examples of loading
+non-Go files and reporting diagnostics against them.
+
+The ResultOf field provides the results computed by the analyzers
+required by this one, as expressed in its Analyzer.Requires field. The
+driver runs the required analyzers first and makes their results
+available in this map. Each Analyzer must return a value of the type
+described in its Analyzer.ResultType field.
+For example, the "ctrlflow" analyzer returns a *ctrlflow.CFGs, which
+provides a control-flow graph for each function in the package (see
+golang.org/x/tools/go/cfg); the "inspect" analyzer returns a value that
+enables other Analyzers to traverse the syntax trees of the package more
+efficiently; and the "buildssa" analyzer constructs an SSA-form
+intermediate representation.
+Each of these Analyzers extends the capabilities of later Analyzers
+without adding a dependency to the core API, so an analysis tool pays
+only for the extensions it needs.
+
+The Report function emits a diagnostic, a message associated with a
+source position. For most analyses, diagnostics are their primary
+result.
+For convenience, Pass provides a helper method, Reportf, to report a new
+diagnostic by formatting a string.
+Diagnostic is defined as:
+
+	type Diagnostic struct {
+		Pos      token.Pos
+		Category string // optional
+		Message  string
+	}
+
+The optional Category field is a short identifier that classifies the
+kind of message when an analysis produces several kinds of diagnostic.
+
+The [Diagnostic] struct does not have a field to indicate its severity
+because opinions about the relative importance of Analyzers and their
+diagnostics vary widely among users. The design of this framework does
+not hold each Analyzer responsible for identifying the severity of its
+diagnostics. Instead, we expect that drivers will allow the user to
+customize the filtering and prioritization of diagnostics based on the
+producing Analyzer and optional Category, according to the user's
+preferences.
+
+Most Analyzers inspect typed Go syntax trees, but a few, such as asmdecl
+and buildtag, inspect the raw text of Go source files or even non-Go
+files such as assembly. To report a diagnostic against a line of a
+raw text file, use the following sequence:
+
+	content, err := pass.ReadFile(filename)
+	if err != nil { ... }
+	tf := fset.AddFile(filename, -1, len(content))
+	tf.SetLinesForContent(content)
+	...
+	pass.Reportf(tf.LineStart(line), "oops")
+
+# Modular analysis with Facts
+
+To improve efficiency and scalability, large programs are routinely
+built using separate compilation: units of the program are compiled
+separately, and recompiled only when one of their dependencies changes;
+independent modules may be compiled in parallel. The same technique may
+be applied to static analyses, for the same benefits. Such analyses are
+described as "modular".
+
+A compiler’s type checker is an example of a modular static analysis.
+Many other checkers we would like to apply to Go programs can be
+understood as alternative or non-standard type systems. For example,
+vet's printf checker infers whether a function has the "printf wrapper"
+type, and it applies stricter checks to calls of such functions. In
+addition, it records which functions are printf wrappers for use by
+later analysis passes to identify other printf wrappers by induction.
+A result such as “f is a printf wrapper” that is not interesting by
+itself but serves as a stepping stone to an interesting result (such as
+a diagnostic) is called a [Fact].
+
+The analysis API allows an analysis to define new types of facts, to
+associate facts of these types with objects (named entities) declared
+within the current package, or with the package as a whole, and to query
+for an existing fact of a given type associated with an object or
+package.
+
+An Analyzer that uses facts must declare their types:
+
+	var Analyzer = &analysis.Analyzer{
+		Name:      "printf",
+		FactTypes: []analysis.Fact{new(isWrapper)},
+		...
+	}
+
+	type isWrapper struct{} // => *types.Func f “is a printf wrapper”
+
+The driver program ensures that facts for a pass’s dependencies are
+generated before analyzing the package and is responsible for propagating
+facts from one package to another, possibly across address spaces.
+Consequently, Facts must be serializable. The API requires that drivers
+use the gob encoding, an efficient, robust, self-describing binary
+protocol. A fact type may implement the GobEncoder/GobDecoder interfaces
+if the default encoding is unsuitable. Facts should be stateless.
+Because serialized facts may appear within build outputs, the gob encoding
+of a fact must be deterministic, to avoid spurious cache misses in
+build systems that use content-addressable caches.
+The driver makes a single call to the gob encoder for all facts
+exported by a given analysis pass, so that the topology of
+shared data structures referenced by multiple facts is preserved.
+
+The Pass type has functions to import and export facts,
+associated either with an object or with a package:
+
+	type Pass struct {
+		...
+		ExportObjectFact func(types.Object, Fact)
+		ImportObjectFact func(types.Object, Fact) bool
+
+		ExportPackageFact func(fact Fact)
+		ImportPackageFact func(*types.Package, Fact) bool
+	}
+
+An Analyzer may only export facts associated with the current package or
+its objects, though it may import facts from any package or object that
+is an import dependency of the current package.
+
+Conceptually, ExportObjectFact(obj, fact) inserts fact into a hidden map keyed by
+the pair (obj, TypeOf(fact)), and the ImportObjectFact function
+retrieves the entry from this map and copies its value into the variable
+pointed to by fact. This scheme assumes that the concrete type of fact
+is a pointer; this assumption is checked by the Validate function.
+See the "printf" analyzer for an example of object facts in action.
+
+Some driver implementations (such as those based on Bazel and Blaze) do
+not currently apply analyzers to packages of the standard library.
+Therefore, for best results, analyzer authors should not rely on
+analysis facts being available for standard packages.
+For example, although the printf checker is capable of deducing during
+analysis of the log package that log.Printf is a printf wrapper,
+this fact is built in to the analyzer so that it correctly checks
+calls to log.Printf even when run in a driver that does not apply
+it to standard packages. We would like to remove this limitation in future.
+
+# Testing an Analyzer
+
+The analysistest subpackage provides utilities for testing an Analyzer.
+In a few lines of code, it is possible to run an analyzer on a package
+of testdata files and check that it reported all the expected
+diagnostics and facts (and no more). Expectations are expressed using
+"// want ..." comments in the input code.
+
+# Standalone commands
+
+Analyzers are provided in the form of packages that a driver program is
+expected to import. The vet command imports a set of several analyzers,
+but users may wish to define their own analysis commands that perform
+additional checks. To simplify the task of creating an analysis command,
+either for a single analyzer or for a whole suite, we provide the
+singlechecker and multichecker subpackages.
+
+The singlechecker package provides the main function for a command that
+runs one analyzer. By convention, each analyzer such as
+go/analysis/passes/findcall should be accompanied by a singlechecker-based
+command such as go/analysis/passes/findcall/cmd/findcall, defined in its
+entirety as:
+
+	package main
+
+	import (
+		"golang.org/x/tools/go/analysis/passes/findcall"
+		"golang.org/x/tools/go/analysis/singlechecker"
+	)
+
+	func main() { singlechecker.Main(findcall.Analyzer) }
+
+A tool that provides multiple analyzers can use multichecker in a
+similar way, giving it the list of Analyzers.
+*/
+package analysis

vendor/golang.org/x/tools/go/analysis/passes/ctrlflow/ctrlflow.go

@@ -0,0 +1,278 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package ctrlflow is an analysis that provides a syntactic
+// control-flow graph (CFG) for the body of a function.
+// It records whether a function cannot return.
+// By itself, it does not report any diagnostics.
+package ctrlflow
+
+import (
+	"go/ast"
+	"go/types"
+	"log"
+	"reflect"
+
+	"golang.org/x/tools/go/analysis"
+	"golang.org/x/tools/go/analysis/passes/inspect"
+	"golang.org/x/tools/go/ast/inspector"
+	"golang.org/x/tools/go/cfg"
+	"golang.org/x/tools/go/types/typeutil"
+	"golang.org/x/tools/internal/typesinternal"
+)
+
+var Analyzer = &analysis.Analyzer{
+	Name:       "ctrlflow",
+	Doc:        "build a control-flow graph",
+	URL:        "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/ctrlflow",
+	Run:        run,
+	ResultType: reflect.TypeFor[*CFGs](),
+	FactTypes:  []analysis.Fact{new(noReturn)},
+	Requires:   []*analysis.Analyzer{inspect.Analyzer},
+}
+
+// noReturn is a fact indicating that a function does not return.
+type noReturn struct{}
+
+func (*noReturn) AFact() {}
+
+func (*noReturn) String() string { return "noReturn" }
+
+// A CFGs holds the control-flow graphs
+// for all the functions of the current package.
+type CFGs struct {
+	defs      map[*ast.Ident]types.Object // from Pass.TypesInfo.Defs
+	funcDecls map[*types.Func]*declInfo
+	funcLits  map[*ast.FuncLit]*litInfo
+	noReturn  map[*types.Func]bool // functions lacking a reachable return statement
+	pass      *analysis.Pass       // transient; nil after construction
+}
+
+// NoReturn reports whether the specified control-flow graph cannot return normally.
+//
+// It is defined for at least all function symbols that appear as the static callee of a
+// CallExpr in the current package, even if the callee was imported from a dependency.
+//
+// The result may incorporate interprocedural information based on induction of
+// the "no return" property over the static call graph within the package.
+// For example, if f simply calls g and g always calls os.Exit, then both f and g may
+// be deemed never to return.
+func (c *CFGs) NoReturn(fn *types.Func) bool {
+	return c.noReturn[fn]
+}
+
+// CFGs has two maps: funcDecls for named functions and funcLits for
+// unnamed ones. Unlike funcLits, the funcDecls map is not keyed by its
+// syntax node, *ast.FuncDecl, because callMayReturn needs to do a
+// look-up by *types.Func, and you can get from an *ast.FuncDecl to a
+// *types.Func but not the other way.
+
+type declInfo struct {
+	decl    *ast.FuncDecl
+	cfg     *cfg.CFG // iff decl.Body != nil
+	started bool     // to break cycles
+}
+
+type litInfo struct {
+	cfg      *cfg.CFG
+	noReturn bool // (currently unused)
+}
+
+// FuncDecl returns the control-flow graph for a named function.
+// It returns nil if decl.Body==nil.
+func (c *CFGs) FuncDecl(decl *ast.FuncDecl) *cfg.CFG {
+	if decl.Body == nil {
+		return nil
+	}
+	fn := c.defs[decl.Name].(*types.Func)
+	return c.funcDecls[fn].cfg
+}
+
+// FuncLit returns the control-flow graph for a literal function.
+func (c *CFGs) FuncLit(lit *ast.FuncLit) *cfg.CFG {
+	return c.funcLits[lit].cfg
+}
+
+func run(pass *analysis.Pass) (any, error) {
+	inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+
+	// Because CFG construction consumes and produces noReturn
+	// facts, CFGs for exported FuncDecls must be built before 'run'
+	// returns; we cannot construct them lazily.
+	// (We could build CFGs for FuncLits lazily,
+	// but the benefit is marginal.)
+
+	// Pass 1. Map types.Funcs to ast.FuncDecls in this package.
+	funcDecls := make(map[*types.Func]*declInfo) // functions and methods
+	funcLits := make(map[*ast.FuncLit]*litInfo)
+
+	var decls []*types.Func // keys(funcDecls), in order
+	var lits []*ast.FuncLit // keys(funcLits), in order
+
+	nodeFilter := []ast.Node{
+		(*ast.FuncDecl)(nil),
+		(*ast.FuncLit)(nil),
+	}
+	inspect.Preorder(nodeFilter, func(n ast.Node) {
+		switch n := n.(type) {
+		case *ast.FuncDecl:
+			// Type information may be incomplete.
+			if fn, ok := pass.TypesInfo.Defs[n.Name].(*types.Func); ok {
+				funcDecls[fn] = &declInfo{decl: n}
+				decls = append(decls, fn)
+			}
+		case *ast.FuncLit:
+			funcLits[n] = new(litInfo)
+			lits = append(lits, n)
+		}
+	})
+
+	c := &CFGs{
+		defs:      pass.TypesInfo.Defs,
+		funcDecls: funcDecls,
+		funcLits:  funcLits,
+		noReturn:  make(map[*types.Func]bool),
+		pass:      pass,
+	}
+
+	// Pass 2. Build CFGs.
+
+	// Build CFGs for named functions.
+	// Cycles in the static call graph are broken
+	// arbitrarily but deterministically.
+	// We create noReturn facts as discovered.
+	for _, fn := range decls {
+		c.buildDecl(fn, funcDecls[fn])
+	}
+
+	// Build CFGs for literal functions.
+	// These aren't relevant to facts (since they aren't named)
+	// but are required for the CFGs.FuncLit API.
+	for _, lit := range lits {
+		li := funcLits[lit]
+		if li.cfg == nil {
+			li.cfg = cfg.New(lit.Body, c.callMayReturn)
+			if li.cfg.NoReturn() {
+				li.noReturn = true
+			}
+		}
+	}
+
+	// All CFGs are now built.
+	c.pass = nil
+
+	return c, nil
+}
+
+// di.cfg may be nil on return.
+func (c *CFGs) buildDecl(fn *types.Func, di *declInfo) {
+	// buildDecl may call itself recursively for the same function,
+	// because cfg.New is passed the callMayReturn method, which
+	// builds the CFG of the callee, leading to recursion.
+	// The buildDecl call tree thus resembles the static call graph.
+	// We mark each node when we start working on it to break cycles.
+
+	if di.started {
+		return // break cycle
+	}
+	di.started = true
+
+	noreturn, known := knownIntrinsic(fn)
+	if !known {
+		if di.decl.Body != nil {
+			di.cfg = cfg.New(di.decl.Body, c.callMayReturn)
+			if di.cfg.NoReturn() {
+				noreturn = true
+			}
+		}
+	}
+	if noreturn {
+		c.pass.ExportObjectFact(fn, new(noReturn))
+		c.noReturn[fn] = true
+	}
+
+	// debugging
+	if false {
+		log.Printf("CFG for %s:\n%s (noreturn=%t)\n", fn, di.cfg.Format(c.pass.Fset), noreturn)
+	}
+}
+
+// callMayReturn reports whether the called function may return.
+// It is passed to the CFG builder.
+func (c *CFGs) callMayReturn(call *ast.CallExpr) (r bool) {
+	if id, ok := call.Fun.(*ast.Ident); ok && c.pass.TypesInfo.Uses[id] == panicBuiltin {
+		return false // panic never returns
+	}
+
+	// Is this a static call? Also includes static functions
+	// parameterized by a type. Such functions may or may not
+	// return depending on the parameter type, but in some
+	// cases the answer is definite. We let ctrlflow figure
+	// that out.
+	fn := typeutil.StaticCallee(c.pass.TypesInfo, call)
+	if fn == nil {
+		return true // callee not statically known; be conservative
+	}
+
+	// Function or method declared in this package?
+	if di, ok := c.funcDecls[fn]; ok {
+		c.buildDecl(fn, di)
+		return !c.noReturn[fn]
+	}
+
+	// Not declared in this package.
+	// Is there a fact from another package?
+	if c.pass.ImportObjectFact(fn, new(noReturn)) {
+		c.noReturn[fn] = true
+		return false
+	}
+
+	return true
+}
+
+var panicBuiltin = types.Universe.Lookup("panic").(*types.Builtin)
+
+// knownIntrinsic reports whether a function intrinsically never
+// returns because it stops execution of the calling thread, or does
+// in fact return, contrary to its apparent body, because it is
+// handled specially by the compiler.
+//
+// It is the base case in the recursion.
+func knownIntrinsic(fn *types.Func) (noreturn, known bool) {
+	// Add functions here as the need arises, but don't allocate memory.
+
+	// Functions known intrinsically never to return.
+	if typesinternal.IsFunctionNamed(fn, "syscall", "Exit", "ExitProcess", "ExitThread") ||
+		typesinternal.IsFunctionNamed(fn, "runtime", "Goexit", "fatalthrow", "fatalpanic", "exit") ||
+		// Following staticcheck (see go/ir/exits.go) we include functions
+		// in several popular logging packages whose no-return status is
+		// beyond the analysis to infer.
+		// TODO(adonovan): make this list extensible.
+		typesinternal.IsMethodNamed(fn, "go.uber.org/zap", "Logger", "Fatal", "Panic") ||
+		typesinternal.IsMethodNamed(fn, "go.uber.org/zap", "SugaredLogger", "Fatal", "Fatalw", "Fatalf", "Panic", "Panicw", "Panicf") ||
+		typesinternal.IsMethodNamed(fn, "github.com/sirupsen/logrus", "Logger", "Exit", "Panic", "Panicf", "Panicln") ||
+		typesinternal.IsMethodNamed(fn, "github.com/sirupsen/logrus", "Entry", "Panicf", "Panicln") ||
+		typesinternal.IsFunctionNamed(fn, "k8s.io/klog", "Exit", "ExitDepth", "Exitf", "Exitln", "Fatal", "FatalDepth", "Fatalf", "Fatalln") ||
+		typesinternal.IsFunctionNamed(fn, "k8s.io/klog/v2", "Exit", "ExitDepth", "Exitf", "Exitln", "Fatal", "FatalDepth", "Fatalf", "Fatalln") {
+		return true, true
+	}
+
+	// Compiler intrinsics known to return, contrary to
+	// what analysis of the function body would conclude.
+	//
+	// Not all such intrinsics must be listed here: ctrlflow
+	// considers any function called for its value--such as
+	// crypto/internal/constanttime.bool2Uint8--to potentially
+	// return; only functions called as a statement, for effects,
+	// are no-return candidates.
+	//
+	// Unfortunately this does sometimes mean peering into internals.
+	// Where possible, use the nearest enclosing public API function.
+	if typesinternal.IsFunctionNamed(fn, "internal/abi", "EscapeNonString") ||
+		typesinternal.IsFunctionNamed(fn, "hash/maphash", "Comparable") {
+		return false, true
+	}
+
+	return // unknown
+}

vendor/golang.org/x/tools/go/analysis/passes/inspect/inspect.go

@@ -0,0 +1,49 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package inspect defines an Analyzer that provides an AST inspector
+// (golang.org/x/tools/go/ast/inspector.Inspector) for the syntax trees
+// of a package. It is only a building block for other analyzers.
+//
+// Example of use in another analysis:
+//
+//	import (
+//		"golang.org/x/tools/go/analysis"
+//		"golang.org/x/tools/go/analysis/passes/inspect"
+//		"golang.org/x/tools/go/ast/inspector"
+//	)
+//
+//	var Analyzer = &analysis.Analyzer{
+//		...
+//		Requires:       []*analysis.Analyzer{inspect.Analyzer},
+//	}
+//
+//	func run(pass *analysis.Pass) (interface{}, error) {
+//		inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+//		inspect.Preorder(nil, func(n ast.Node) {
+//			...
+//		})
+//		return nil, nil
+//	}
+package inspect
+
+import (
+	"reflect"
+
+	"golang.org/x/tools/go/analysis"
+	"golang.org/x/tools/go/ast/inspector"
+)
+
+var Analyzer = &analysis.Analyzer{
+	Name:             "inspect",
+	Doc:              "optimize AST traversal for later passes",
+	URL:              "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/inspect",
+	Run:              run,
+	RunDespiteErrors: true,
+	ResultType:       reflect.TypeFor[*inspector.Inspector](),
+}
+
+func run(pass *analysis.Pass) (any, error) {
+	return inspector.New(pass.Files), nil
+}

vendor/golang.org/x/tools/go/analysis/validate.go

@@ -0,0 +1,137 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package analysis
+
+import (
+	"fmt"
+	"reflect"
+	"strings"
+	"unicode"
+)
+
+// Validate reports an error if any of the analyzers are misconfigured.
+// Checks include:
+// that the name is a valid identifier;
+// that the Doc is not empty;
+// that the Run is non-nil;
+// that the Requires graph is acyclic;
+// that analyzer fact types are unique;
+// that each fact type is a pointer.
+//
+// Analyzer names need not be unique, though this may be confusing.
+func Validate(analyzers []*Analyzer) error {
+	// Map each fact type to its sole generating analyzer.
+	factTypes := make(map[reflect.Type]*Analyzer)
+
+	// Traverse the Requires graph, depth first.
+	const (
+		white = iota
+		grey
+		black
+		finished
+	)
+	color := make(map[*Analyzer]uint8)
+	var visit func(a *Analyzer) error
+	visit = func(a *Analyzer) error {
+		if a == nil {
+			return fmt.Errorf("nil *Analyzer")
+		}
+		if color[a] == white {
+			color[a] = grey
+
+			// names
+			if !validIdent(a.Name) {
+				return fmt.Errorf("invalid analyzer name %q", a)
+			}
+
+			if a.Doc == "" {
+				return fmt.Errorf("analyzer %q is undocumented", a)
+			}
+
+			if a.Run == nil {
+				return fmt.Errorf("analyzer %q has nil Run", a)
+			}
+			// fact types
+			for _, f := range a.FactTypes {
+				if f == nil {
+					return fmt.Errorf("analyzer %s has nil FactType", a)
+				}
+				t := reflect.TypeOf(f)
+				if prev := factTypes[t]; prev != nil {
+					return fmt.Errorf("fact type %s registered by two analyzers: %v, %v",
+						t, a, prev)
+				}
+				if t.Kind() != reflect.Pointer {
+					return fmt.Errorf("%s: fact type %s is not a pointer", a, t)
+				}
+				factTypes[t] = a
+			}
+
+			// recursion
+			for _, req := range a.Requires {
+				if err := visit(req); err != nil {
+					return err
+				}
+			}
+			color[a] = black
+		}
+
+		if color[a] == grey {
+			stack := []*Analyzer{a}
+			inCycle := map[string]bool{}
+			for len(stack) > 0 {
+				current := stack[len(stack)-1]
+				stack = stack[:len(stack)-1]
+				if color[current] == grey && !inCycle[current.Name] {
+					inCycle[current.Name] = true
+					stack = append(stack, current.Requires...)
+				}
+			}
+			return &CycleInRequiresGraphError{AnalyzerNames: inCycle}
+		}
+
+		return nil
+	}
+	for _, a := range analyzers {
+		if err := visit(a); err != nil {
+			return err
+		}
+	}
+
+	// Reject duplicates among analyzers.
+	// Precondition:  color[a] == black.
+	// Postcondition: color[a] == finished.
+	for _, a := range analyzers {
+		if color[a] == finished {
+			return fmt.Errorf("duplicate analyzer: %s", a.Name)
+		}
+		color[a] = finished
+	}
+
+	return nil
+}
+
+func validIdent(name string) bool {
+	for i, r := range name {
+		if !(r == '_' || unicode.IsLetter(r) || i > 0 && unicode.IsDigit(r)) {
+			return false
+		}
+	}
+	return name != ""
+}
+
+type CycleInRequiresGraphError struct {
+	AnalyzerNames map[string]bool
+}
+
+func (e *CycleInRequiresGraphError) Error() string {
+	var b strings.Builder
+	b.WriteString("cycle detected involving the following analyzers:")
+	for n := range e.AnalyzerNames {
+		b.WriteByte(' ')
+		b.WriteString(n)
+	}
+	return b.String()
+}

vendor/golang.org/x/tools/go/cfg/builder.go

@@ -0,0 +1,519 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package cfg
+
+// This file implements the CFG construction pass.
+
+import (
+	"fmt"
+	"go/ast"
+	"go/token"
+)
+
+type builder struct {
+	blocks    []*Block
+	mayReturn func(*ast.CallExpr) bool
+	current   *Block
+	lblocks   map[string]*lblock // labeled blocks
+	targets   *targets           // linked stack of branch targets
+}
+
+func (b *builder) stmt(_s ast.Stmt) {
+	// The label of the current statement.  If non-nil, its _goto
+	// target is always set; its _break and _continue are set only
+	// within the body of switch/typeswitch/select/for/range.
+	// It is effectively an additional default-nil parameter of stmt().
+	var label *lblock
+start:
+	switch s := _s.(type) {
+	case *ast.BadStmt,
+		*ast.SendStmt,
+		*ast.IncDecStmt,
+		*ast.GoStmt,
+		*ast.EmptyStmt,
+		*ast.AssignStmt:
+		// No effect on control flow.
+		b.add(s)
+
+	case *ast.DeferStmt:
+		b.add(s)
+		// Assume conservatively that this behaves like:
+		//    defer func() { recover() }
+		// so any subsequent panic may act like a return.
+		b.current.returns = true
+
+	case *ast.ExprStmt:
+		b.add(s)
+		if call, ok := s.X.(*ast.CallExpr); ok && !b.mayReturn(call) {
+			// Calls to panic, os.Exit, etc, never return.
+			b.current = b.newBlock(KindUnreachable, s)
+		}
+
+	case *ast.DeclStmt:
+		// Treat each var ValueSpec as a separate statement.
+		d := s.Decl.(*ast.GenDecl)
+		if d.Tok == token.VAR {
+			for _, spec := range d.Specs {
+				if spec, ok := spec.(*ast.ValueSpec); ok {
+					b.add(spec)
+				}
+			}
+		}
+
+	case *ast.LabeledStmt:
+		label = b.labeledBlock(s.Label, s)
+		b.jump(label._goto)
+		b.current = label._goto
+		_s = s.Stmt
+		goto start // effectively: tailcall stmt(g, s.Stmt, label)
+
+	case *ast.ReturnStmt:
+		b.current.returns = true
+		b.add(s)
+		b.current = b.newBlock(KindUnreachable, s)
+
+	case *ast.BranchStmt:
+		b.branchStmt(s)
+
+	case *ast.BlockStmt:
+		b.stmtList(s.List)
+
+	case *ast.IfStmt:
+		if s.Init != nil {
+			b.stmt(s.Init)
+		}
+		then := b.newBlock(KindIfThen, s)
+		done := b.newBlock(KindIfDone, s)
+		_else := done
+		if s.Else != nil {
+			_else = b.newBlock(KindIfElse, s)
+		}
+		b.add(s.Cond)
+		b.ifelse(then, _else)
+		b.current = then
+		b.stmt(s.Body)
+		b.jump(done)
+
+		if s.Else != nil {
+			b.current = _else
+			b.stmt(s.Else)
+			b.jump(done)
+		}
+
+		b.current = done
+
+	case *ast.SwitchStmt:
+		b.switchStmt(s, label)
+
+	case *ast.TypeSwitchStmt:
+		b.typeSwitchStmt(s, label)
+
+	case *ast.SelectStmt:
+		b.selectStmt(s, label)
+
+	case *ast.ForStmt:
+		b.forStmt(s, label)
+
+	case *ast.RangeStmt:
+		b.rangeStmt(s, label)
+
+	default:
+		panic(fmt.Sprintf("unexpected statement kind: %T", s))
+	}
+}
+
+func (b *builder) stmtList(list []ast.Stmt) {
+	for _, s := range list {
+		b.stmt(s)
+	}
+}
+
+func (b *builder) branchStmt(s *ast.BranchStmt) {
+	var block *Block
+	switch s.Tok {
+	case token.BREAK:
+		if s.Label != nil {
+			if lb := b.labeledBlock(s.Label, nil); lb != nil {
+				block = lb._break
+			}
+		} else {
+			for t := b.targets; t != nil && block == nil; t = t.tail {
+				block = t._break
+			}
+		}
+
+	case token.CONTINUE:
+		if s.Label != nil {
+			if lb := b.labeledBlock(s.Label, nil); lb != nil {
+				block = lb._continue
+			}
+		} else {
+			for t := b.targets; t != nil && block == nil; t = t.tail {
+				block = t._continue
+			}
+		}
+
+	case token.FALLTHROUGH:
+		for t := b.targets; t != nil && block == nil; t = t.tail {
+			block = t._fallthrough
+		}
+
+	case token.GOTO:
+		if s.Label != nil {
+			block = b.labeledBlock(s.Label, nil)._goto
+		}
+	}
+	if block == nil { // ill-typed (e.g. undefined label)
+		block = b.newBlock(KindUnreachable, s)
+	}
+	b.jump(block)
+	b.current = b.newBlock(KindUnreachable, s)
+}
+
+func (b *builder) switchStmt(s *ast.SwitchStmt, label *lblock) {
+	if s.Init != nil {
+		b.stmt(s.Init)
+	}
+	if s.Tag != nil {
+		b.add(s.Tag)
+	}
+	done := b.newBlock(KindSwitchDone, s)
+	if label != nil {
+		label._break = done
+	}
+	// We pull the default case (if present) down to the end.
+	// But each fallthrough label must point to the next
+	// body block in source order, so we preallocate a
+	// body block (fallthru) for the next case.
+	// Unfortunately this makes for a confusing block order.
+	var defaultBody *[]ast.Stmt
+	var defaultFallthrough *Block
+	var fallthru, defaultBlock *Block
+	ncases := len(s.Body.List)
+	for i, clause := range s.Body.List {
+		body := fallthru
+		if body == nil {
+			body = b.newBlock(KindSwitchCaseBody, clause) // first case only
+		}
+
+		// Preallocate body block for the next case.
+		fallthru = done
+		if i+1 < ncases {
+			fallthru = b.newBlock(KindSwitchCaseBody, s.Body.List[i+1])
+		}
+
+		cc := clause.(*ast.CaseClause)
+		if cc.List == nil {
+			// Default case.
+			defaultBody = &cc.Body
+			defaultFallthrough = fallthru
+			defaultBlock = body
+			continue
+		}
+
+		var nextCond *Block
+		for _, cond := range cc.List {
+			nextCond = b.newBlock(KindSwitchNextCase, cc)
+			b.add(cond) // one half of the tag==cond condition
+			b.ifelse(body, nextCond)
+			b.current = nextCond
+		}
+		b.current = body
+		b.targets = &targets{
+			tail:         b.targets,
+			_break:       done,
+			_fallthrough: fallthru,
+		}
+		b.stmtList(cc.Body)
+		b.targets = b.targets.tail
+		b.jump(done)
+		b.current = nextCond
+	}
+	if defaultBlock != nil {
+		b.jump(defaultBlock)
+		b.current = defaultBlock
+		b.targets = &targets{
+			tail:         b.targets,
+			_break:       done,
+			_fallthrough: defaultFallthrough,
+		}
+		b.stmtList(*defaultBody)
+		b.targets = b.targets.tail
+	}
+	b.jump(done)
+	b.current = done
+}
+
+func (b *builder) typeSwitchStmt(s *ast.TypeSwitchStmt, label *lblock) {
+	if s.Init != nil {
+		b.stmt(s.Init)
+	}
+	if s.Assign != nil {
+		b.add(s.Assign)
+	}
+
+	done := b.newBlock(KindSwitchDone, s)
+	if label != nil {
+		label._break = done
+	}
+	var default_ *ast.CaseClause
+	for _, clause := range s.Body.List {
+		cc := clause.(*ast.CaseClause)
+		if cc.List == nil {
+			default_ = cc
+			continue
+		}
+		body := b.newBlock(KindSwitchCaseBody, cc)
+		var next *Block
+		for _, casetype := range cc.List {
+			next = b.newBlock(KindSwitchNextCase, cc)
+			// casetype is a type, so don't call b.add(casetype).
+			// This block logically contains a type assertion,
+			// x.(casetype), but it's unclear how to represent x.
+			_ = casetype
+			b.ifelse(body, next)
+			b.current = next
+		}
+		b.current = body
+		b.typeCaseBody(cc, done)
+		b.current = next
+	}
+	if default_ != nil {
+		b.typeCaseBody(default_, done)
+	} else {
+		b.jump(done)
+	}
+	b.current = done
+}
+
+func (b *builder) typeCaseBody(cc *ast.CaseClause, done *Block) {
+	b.targets = &targets{
+		tail:   b.targets,
+		_break: done,
+	}
+	b.stmtList(cc.Body)
+	b.targets = b.targets.tail
+	b.jump(done)
+}
+
+func (b *builder) selectStmt(s *ast.SelectStmt, label *lblock) {
+	// First evaluate channel expressions.
+	// TODO(adonovan): fix: evaluate only channel exprs here.
+	for _, clause := range s.Body.List {
+		if comm := clause.(*ast.CommClause).Comm; comm != nil {
+			b.stmt(comm)
+		}
+	}
+
+	done := b.newBlock(KindSelectDone, s)
+	if label != nil {
+		label._break = done
+	}
+
+	var defaultBody *[]ast.Stmt
+	for _, cc := range s.Body.List {
+		clause := cc.(*ast.CommClause)
+		if clause.Comm == nil {
+			defaultBody = &clause.Body
+			continue
+		}
+		body := b.newBlock(KindSelectCaseBody, clause)
+		next := b.newBlock(KindSelectAfterCase, clause)
+		b.ifelse(body, next)
+		b.current = body
+		b.targets = &targets{
+			tail:   b.targets,
+			_break: done,
+		}
+		switch comm := clause.Comm.(type) {
+		case *ast.ExprStmt: // <-ch
+			// nop
+		case *ast.AssignStmt: // x := <-states[state].Chan
+			b.add(comm.Lhs[0])
+		}
+		b.stmtList(clause.Body)
+		b.targets = b.targets.tail
+		b.jump(done)
+		b.current = next
+	}
+	if defaultBody != nil {
+		b.targets = &targets{
+			tail:   b.targets,
+			_break: done,
+		}
+		b.stmtList(*defaultBody)
+		b.targets = b.targets.tail
+		b.jump(done)
+	}
+	b.current = done
+}
+
+func (b *builder) forStmt(s *ast.ForStmt, label *lblock) {
+	//	...init...
+	//      jump loop
+	// loop:
+	//      if cond goto body else done
+	// body:
+	//      ...body...
+	//      jump post
+	// post:				 (target of continue)
+	//      ...post...
+	//      jump loop
+	// done:                                 (target of break)
+	if s.Init != nil {
+		b.stmt(s.Init)
+	}
+	body := b.newBlock(KindForBody, s)
+	done := b.newBlock(KindForDone, s) // target of 'break'
+	loop := body                       // target of back-edge
+	if s.Cond != nil {
+		loop = b.newBlock(KindForLoop, s)
+	}
+	cont := loop // target of 'continue'
+	if s.Post != nil {
+		cont = b.newBlock(KindForPost, s)
+	}
+	if label != nil {
+		label._break = done
+		label._continue = cont
+	}
+	b.jump(loop)
+	b.current = loop
+	if loop != body {
+		b.add(s.Cond)
+		b.ifelse(body, done)
+		b.current = body
+	}
+	b.targets = &targets{
+		tail:      b.targets,
+		_break:    done,
+		_continue: cont,
+	}
+	b.stmt(s.Body)
+	b.targets = b.targets.tail
+	b.jump(cont)
+
+	if s.Post != nil {
+		b.current = cont
+		b.stmt(s.Post)
+		b.jump(loop) // back-edge
+	}
+	b.current = done
+}
+
+func (b *builder) rangeStmt(s *ast.RangeStmt, label *lblock) {
+	b.add(s.X)
+
+	if s.Key != nil {
+		b.add(s.Key)
+	}
+	if s.Value != nil {
+		b.add(s.Value)
+	}
+
+	//      ...
+	// loop:                                   (target of continue)
+	// 	if ... goto body else done
+	// body:
+	//      ...
+	// 	jump loop
+	// done:                                   (target of break)
+
+	loop := b.newBlock(KindRangeLoop, s)
+	b.jump(loop)
+	b.current = loop
+
+	body := b.newBlock(KindRangeBody, s)
+	done := b.newBlock(KindRangeDone, s)
+	b.ifelse(body, done)
+	b.current = body
+
+	if label != nil {
+		label._break = done
+		label._continue = loop
+	}
+	b.targets = &targets{
+		tail:      b.targets,
+		_break:    done,
+		_continue: loop,
+	}
+	b.stmt(s.Body)
+	b.targets = b.targets.tail
+	b.jump(loop) // back-edge
+	b.current = done
+}
+
+// -------- helpers --------
+
+// Destinations associated with unlabeled for/switch/select stmts.
+// We push/pop one of these as we enter/leave each construct and for
+// each BranchStmt we scan for the innermost target of the right type.
+type targets struct {
+	tail         *targets // rest of stack
+	_break       *Block
+	_continue    *Block
+	_fallthrough *Block
+}
+
+// Destinations associated with a labeled block.
+// We populate these as labels are encountered in forward gotos or
+// labeled statements.
+type lblock struct {
+	_goto     *Block
+	_break    *Block
+	_continue *Block
+}
+
+// labeledBlock returns the branch target associated with the
+// specified label, creating it if needed.
+func (b *builder) labeledBlock(label *ast.Ident, stmt *ast.LabeledStmt) *lblock {
+	lb := b.lblocks[label.Name]
+	if lb == nil {
+		lb = &lblock{_goto: b.newBlock(KindLabel, nil)}
+		if b.lblocks == nil {
+			b.lblocks = make(map[string]*lblock)
+		}
+		b.lblocks[label.Name] = lb
+	}
+	// Fill in the label later (in case of forward goto).
+	// Stmt may be set already if labels are duplicated (ill-typed).
+	if stmt != nil && lb._goto.Stmt == nil {
+		lb._goto.Stmt = stmt
+	}
+	return lb
+}
+
+// newBlock appends a new unconnected basic block to b.cfg's block
+// slice and returns it.
+// It does not automatically become the current block.
+// comment is an optional string for more readable debugging output.
+func (b *builder) newBlock(kind BlockKind, stmt ast.Stmt) *Block {
+	block := &Block{
+		Index: int32(len(b.blocks)),
+		Kind:  kind,
+		Stmt:  stmt,
+	}
+	block.Succs = block.succs2[:0]
+	b.blocks = append(b.blocks, block)
+	return block
+}
+
+func (b *builder) add(n ast.Node) {
+	b.current.Nodes = append(b.current.Nodes, n)
+}
+
+// jump adds an edge from the current block to the target block,
+// and sets b.current to nil.
+func (b *builder) jump(target *Block) {
+	b.current.Succs = append(b.current.Succs, target)
+	b.current = nil
+}
+
+// ifelse emits edges from the current block to the t and f blocks,
+// and sets b.current to nil.
+func (b *builder) ifelse(t, f *Block) {
+	b.current.Succs = append(b.current.Succs, t, f)
+	b.current = nil
+}

vendor/golang.org/x/tools/go/cfg/cfg.go

@@ -0,0 +1,273 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package cfg constructs a simple control-flow graph (CFG) of the
+// statements and expressions within a single function.
+//
+// Use cfg.New to construct the CFG for a function body.
+//
+// The blocks of the CFG contain all the function's non-control
+// statements.  The CFG does not contain control statements such as If,
+// Switch, Select, and Branch, but does contain their subexpressions;
+// also, each block records the control statement (Block.Stmt) that
+// gave rise to it and its relationship (Block.Kind) to that statement.
+//
+// For example, this source code:
+//
+//	if x := f(); x != nil {
+//		T()
+//	} else {
+//		F()
+//	}
+//
+// produces this CFG:
+//
+//	1:  x := f()		Body
+//	    x != nil
+//	    succs: 2, 3
+//	2:  T()			IfThen
+//	    succs: 4
+//	3:  F()			IfElse
+//	    succs: 4
+//	4:			IfDone
+//
+// The CFG does contain Return statements; even implicit returns are
+// materialized (at the position of the function's closing brace).
+//
+// The CFG does not record conditions associated with conditional branch
+// edges, nor the short-circuit semantics of the && and || operators,
+// nor abnormal control flow caused by panic.  If you need this
+// information, use golang.org/x/tools/go/ssa instead.
+package cfg
+
+import (
+	"bytes"
+	"fmt"
+	"go/ast"
+	"go/format"
+	"go/token"
+)
+
+// A CFG represents the control-flow graph of a single function.
+//
+// The entry point is Blocks[0]; there may be multiple return blocks.
+type CFG struct {
+	Blocks   []*Block // block[0] is entry; order otherwise undefined
+	noreturn bool     // function body lacks a reachable return statement
+}
+
+// NoReturn reports whether the function has no reachable return.
+func (cfg *CFG) NoReturn() bool { return cfg.noreturn }
+
+// A Block represents a basic block: a list of statements and
+// expressions that are always evaluated sequentially.
+//
+// A block may have 0-2 successors: zero for a return block or a block
+// that calls a function such as panic that never returns; one for a
+// normal (jump) block; and two for a conditional (if) block.
+//
+// In a conditional block, the last entry in Nodes is the condition and always
+// an [ast.Expr], Succs[0] is the successor if the condition is true, and
+// Succs[1] is the successor if the condition is false.
+type Block struct {
+	Nodes   []ast.Node // statements, expressions, and ValueSpecs
+	Succs   []*Block   // successor nodes in the graph
+	Index   int32      // index within CFG.Blocks
+	Live    bool       // block is reachable from entry
+	returns bool       // block contains return or defer (which may recover and return)
+	Kind    BlockKind  // block kind
+	Stmt    ast.Stmt   // statement that gave rise to this block (see BlockKind for details)
+
+	succs2 [2]*Block // underlying array for Succs
+}
+
+// A BlockKind identifies the purpose of a block.
+// It also determines the possible types of its Stmt field.
+type BlockKind uint8
+
+const (
+	KindInvalid BlockKind = iota // Stmt=nil
+
+	KindUnreachable     // unreachable block after {Branch,Return}Stmt / no-return call ExprStmt
+	KindBody            // function body BlockStmt
+	KindForBody         // body of ForStmt
+	KindForDone         // block after ForStmt
+	KindForLoop         // head of ForStmt
+	KindForPost         // post condition of ForStmt
+	KindIfDone          // block after IfStmt
+	KindIfElse          // else block of IfStmt
+	KindIfThen          // then block of IfStmt
+	KindLabel           // labeled block of BranchStmt (Stmt may be nil for dangling label)
+	KindRangeBody       // body of RangeStmt
+	KindRangeDone       // block after RangeStmt
+	KindRangeLoop       // head of RangeStmt
+	KindSelectCaseBody  // body of SelectStmt
+	KindSelectDone      // block after SelectStmt
+	KindSelectAfterCase // block after a CommClause
+	KindSwitchCaseBody  // body of CaseClause
+	KindSwitchDone      // block after {Type.}SwitchStmt
+	KindSwitchNextCase  // secondary expression of a multi-expression CaseClause
+)
+
+func (kind BlockKind) String() string {
+	return [...]string{
+		KindInvalid:         "Invalid",
+		KindUnreachable:     "Unreachable",
+		KindBody:            "Body",
+		KindForBody:         "ForBody",
+		KindForDone:         "ForDone",
+		KindForLoop:         "ForLoop",
+		KindForPost:         "ForPost",
+		KindIfDone:          "IfDone",
+		KindIfElse:          "IfElse",
+		KindIfThen:          "IfThen",
+		KindLabel:           "Label",
+		KindRangeBody:       "RangeBody",
+		KindRangeDone:       "RangeDone",
+		KindRangeLoop:       "RangeLoop",
+		KindSelectCaseBody:  "SelectCaseBody",
+		KindSelectDone:      "SelectDone",
+		KindSelectAfterCase: "SelectAfterCase",
+		KindSwitchCaseBody:  "SwitchCaseBody",
+		KindSwitchDone:      "SwitchDone",
+		KindSwitchNextCase:  "SwitchNextCase",
+	}[kind]
+}
+
+// New returns a new control-flow graph for the specified function body,
+// which must be non-nil.
+//
+// The CFG builder calls mayReturn to determine whether a given function
+// call may return.  For example, calls to panic, os.Exit, and log.Fatal
+// do not return, so the builder can remove infeasible graph edges
+// following such calls.  The builder calls mayReturn only for a
+// CallExpr beneath an ExprStmt.
+func New(body *ast.BlockStmt, mayReturn func(*ast.CallExpr) bool) *CFG {
+	b := builder{
+		mayReturn: mayReturn,
+	}
+	b.current = b.newBlock(KindBody, body)
+	b.stmt(body)
+
+	// Compute liveness (reachability from entry point),
+	// breadth-first, marking Block.Live flags.
+	q := make([]*Block, 0, len(b.blocks))
+	q = append(q, b.blocks[0]) // entry point
+	for len(q) > 0 {
+		b := q[len(q)-1]
+		q = q[:len(q)-1]
+
+		if !b.Live {
+			b.Live = true
+			q = append(q, b.Succs...)
+		}
+	}
+
+	// Does control fall off the end of the function's body?
+	// Make implicit return explicit.
+	if b.current != nil && b.current.Live {
+		b.current.returns = true
+		b.add(&ast.ReturnStmt{
+			Return: body.End() - 1,
+		})
+	}
+
+	// Is any return (or defer+recover) block reachable?
+	noreturn := true
+	for _, bl := range b.blocks {
+		if bl.Live && bl.returns {
+			noreturn = false
+			break
+		}
+	}
+
+	return &CFG{Blocks: b.blocks, noreturn: noreturn}
+}
+
+func (b *Block) String() string {
+	return fmt.Sprintf("block %d (%s)", b.Index, b.comment(nil))
+}
+
+func (b *Block) comment(fset *token.FileSet) string {
+	s := b.Kind.String()
+	if fset != nil && b.Stmt != nil {
+		s = fmt.Sprintf("%s@L%d", s, fset.Position(b.Stmt.Pos()).Line)
+	}
+	return s
+}
+
+// Return returns the return statement at the end of this block if present, nil
+// otherwise.
+//
+// When control falls off the end of the function, the ReturnStmt is synthetic
+// and its [ast.Node.End] position may be beyond the end of the file.
+//
+// A function that contains no return statement (explicit or implied)
+// may yet return normally, and may even return a nonzero value. For example:
+//
+//	func() (res any) {
+//		defer func() { res = recover() }()
+//		panic(123)
+//	}
+func (b *Block) Return() (ret *ast.ReturnStmt) {
+	if len(b.Nodes) > 0 {
+		ret, _ = b.Nodes[len(b.Nodes)-1].(*ast.ReturnStmt)
+	}
+	return
+}
+
+// Format formats the control-flow graph for ease of debugging.
+func (g *CFG) Format(fset *token.FileSet) string {
+	var buf bytes.Buffer
+	for _, b := range g.Blocks {
+		fmt.Fprintf(&buf, ".%d: # %s\n", b.Index, b.comment(fset))
+		for _, n := range b.Nodes {
+			fmt.Fprintf(&buf, "\t%s\n", formatNode(fset, n))
+		}
+		if len(b.Succs) > 0 {
+			fmt.Fprintf(&buf, "\tsuccs:")
+			for _, succ := range b.Succs {
+				fmt.Fprintf(&buf, " %d", succ.Index)
+			}
+			buf.WriteByte('\n')
+		}
+		buf.WriteByte('\n')
+	}
+	return buf.String()
+}
+
+// Dot returns the control-flow graph in the [Dot graph description language].
+// Use a command such as 'dot -Tsvg' to render it in a form viewable in a browser.
+// This method is provided as a debugging aid; the details of the
+// output are unspecified and may change.
+//
+// [Dot graph description language]: ​​https://en.wikipedia.org/wiki/DOT_(graph_description_language)
+func (g *CFG) Dot(fset *token.FileSet) string {
+	var buf bytes.Buffer
+	buf.WriteString("digraph CFG {\n")
+	buf.WriteString("  node [shape=box];\n")
+	for _, b := range g.Blocks {
+		// node label
+		var text bytes.Buffer
+		text.WriteString(b.comment(fset))
+		for _, n := range b.Nodes {
+			fmt.Fprintf(&text, "\n%s", formatNode(fset, n))
+		}
+
+		// node and edges
+		fmt.Fprintf(&buf, "  n%d [label=%q];\n", b.Index, &text)
+		for _, succ := range b.Succs {
+			fmt.Fprintf(&buf, "  n%d -> n%d;\n", b.Index, succ.Index)
+		}
+	}
+	buf.WriteString("}\n")
+	return buf.String()
+}
+
+func formatNode(fset *token.FileSet, n ast.Node) string {
+	var buf bytes.Buffer
+	format.Node(&buf, fset, n)
+	// Indent secondary lines by a tab.
+	return string(bytes.Replace(buf.Bytes(), []byte("\n"), []byte("\n\t"), -1))
+}

vendor/honnef.co/go/tools/LICENSE

@@ -0,0 +1,20 @@
+Copyright (c) 2016 Dominik Honnef
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

vendor/honnef.co/go/tools/LICENSE-THIRD-PARTY

@@ -0,0 +1,121 @@
+Staticcheck and its related tools make use of third party projects,
+either by reusing their code, or by statically linking them into
+resulting binaries. These projects are:
+
+* The Go Programming Language - https://golang.org/
+  golang.org/x/mod - https://github.com/golang/mod
+  golang.org/x/tools - https://github.com/golang/tools
+  golang.org/x/sys - https://github.com/golang/sys
+  golang.org/x/xerrors - https://github.com/golang/xerrors
+
+    Copyright (c) 2009 The Go Authors. All rights reserved.
+
+    Redistribution and use in source and binary forms, with or without
+    modification, are permitted provided that the following conditions are
+    met:
+
+       * Redistributions of source code must retain the above copyright
+    notice, this list of conditions and the following disclaimer.
+       * Redistributions in binary form must reproduce the above
+    copyright notice, this list of conditions and the following disclaimer
+    in the documentation and/or other materials provided with the
+    distribution.
+       * Neither the name of Google Inc. nor the names of its
+    contributors may be used to endorse or promote products derived from
+    this software without specific prior written permission.
+
+    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+    A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+    OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+    SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+    LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+    OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
+* github.com/BurntSushi/toml - https://github.com/BurntSushi/toml
+
+    The MIT License (MIT)
+
+    Copyright (c) 2013 TOML authors
+
+    Permission is hereby granted, free of charge, to any person obtaining a copy
+    of this software and associated documentation files (the "Software"), to deal
+    in the Software without restriction, including without limitation the rights
+    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+    copies of the Software, and to permit persons to whom the Software is
+    furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included in
+    all copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+    THE SOFTWARE.
+
+* gogrep - https://github.com/mvdan/gogrep
+
+    Copyright (c) 2017, Daniel Martí. All rights reserved.
+
+    Redistribution and use in source and binary forms, with or without
+    modification, are permitted provided that the following conditions are
+    met:
+
+       * Redistributions of source code must retain the above copyright
+    notice, this list of conditions and the following disclaimer.
+       * Redistributions in binary form must reproduce the above
+    copyright notice, this list of conditions and the following disclaimer
+    in the documentation and/or other materials provided with the
+    distribution.
+       * Neither the name of the copyright holder nor the names of its
+    contributors may be used to endorse or promote products derived from
+    this software without specific prior written permission.
+
+    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+    A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+    OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+    SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+    LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+    OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+* gosmith - https://github.com/dvyukov/gosmith
+
+    Copyright (c) 2014 Dmitry Vyukov. All rights reserved.
+
+    Redistribution and use in source and binary forms, with or without
+    modification, are permitted provided that the following conditions are
+    met:
+
+       * Redistributions of source code must retain the above copyright
+    notice, this list of conditions and the following disclaimer.
+       * Redistributions in binary form must reproduce the above
+    copyright notice, this list of conditions and the following disclaimer
+    in the documentation and/or other materials provided with the
+    distribution.
+       * The name of Dmitry Vyukov may be used to endorse or promote
+    products derived from this software without specific prior written permission.
+
+    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+    A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+    OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+    SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+    LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+    OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

vendor/honnef.co/go/tools/analysis/callcheck/callcheck.go

@@ -0,0 +1,161 @@
+// Package callcheck provides a framework for validating arguments in function calls.
+package callcheck
+
+import (
+	"fmt"
+	"go/ast"
+	"go/constant"
+	"go/types"
+
+	"golang.org/x/tools/go/analysis"
+	"honnef.co/go/tools/analysis/report"
+	"honnef.co/go/tools/go/ir"
+	"honnef.co/go/tools/go/ir/irutil"
+	"honnef.co/go/tools/go/types/typeutil"
+	"honnef.co/go/tools/internal/passes/buildir"
+)
+
+type Call struct {
+	Pass  *analysis.Pass
+	Instr ir.CallInstruction
+	Args  []*Argument
+
+	Parent *ir.Function
+
+	invalids []string
+}
+
+func (c *Call) Invalid(msg string) {
+	c.invalids = append(c.invalids, msg)
+}
+
+type Argument struct {
+	Value    Value
+	invalids []string
+}
+
+type Value struct {
+	Value ir.Value
+}
+
+func (arg *Argument) Invalid(msg string) {
+	arg.invalids = append(arg.invalids, msg)
+}
+
+type Check func(call *Call)
+
+func Analyzer(rules map[string]Check) func(pass *analysis.Pass) (any, error) {
+	return func(pass *analysis.Pass) (any, error) {
+		return checkCalls(pass, rules)
+	}
+}
+
+func checkCalls(pass *analysis.Pass, rules map[string]Check) (any, error) {
+	cb := func(caller *ir.Function, site ir.CallInstruction, callee *ir.Function) {
+		obj, ok := callee.Object().(*types.Func)
+		if !ok {
+			return
+		}
+
+		r, ok := rules[typeutil.FuncName(obj)]
+		if !ok {
+			return
+		}
+		var args []*Argument
+		irargs := site.Common().Args
+		if callee.Signature.Recv() != nil {
+			irargs = irargs[1:]
+		}
+		for _, arg := range irargs {
+			if iarg, ok := arg.(*ir.MakeInterface); ok {
+				arg = iarg.X
+			}
+			args = append(args, &Argument{Value: Value{arg}})
+		}
+		call := &Call{
+			Pass:   pass,
+			Instr:  site,
+			Args:   args,
+			Parent: site.Parent(),
+		}
+		r(call)
+
+		var astcall *ast.CallExpr
+		switch source := site.Source().(type) {
+		case *ast.CallExpr:
+			astcall = source
+		case *ast.DeferStmt:
+			astcall = source.Call
+		case *ast.GoStmt:
+			astcall = source.Call
+		case nil:
+			// TODO(dh): I am not sure this can actually happen. If it
+			// can't, we should remove this case, and also stop
+			// checking for astcall == nil in the code that follows.
+		default:
+			panic(fmt.Sprintf("unhandled case %T", source))
+		}
+
+		for idx, arg := range call.Args {
+			for _, e := range arg.invalids {
+				if astcall != nil {
+					if idx < len(astcall.Args) {
+						report.Report(pass, astcall.Args[idx], e)
+					} else {
+						// this is an instance of fn1(fn2()) where fn2
+						// returns multiple values. Report the error
+						// at the next-best position that we have, the
+						// first argument. An example of a check that
+						// triggers this is checkEncodingBinaryRules.
+						report.Report(pass, astcall.Args[0], e)
+					}
+				} else {
+					report.Report(pass, site, e)
+				}
+			}
+		}
+		for _, e := range call.invalids {
+			report.Report(pass, call.Instr, e)
+		}
+	}
+	for _, fn := range pass.ResultOf[buildir.Analyzer].(*buildir.IR).SrcFuncs {
+		eachCall(fn, cb)
+	}
+	return nil, nil
+}
+
+func eachCall(fn *ir.Function, cb func(caller *ir.Function, site ir.CallInstruction, callee *ir.Function)) {
+	for _, b := range fn.Blocks {
+		for _, instr := range b.Instrs {
+			if site, ok := instr.(ir.CallInstruction); ok {
+				if g := site.Common().StaticCallee(); g != nil {
+					cb(fn, site, g)
+				}
+			}
+		}
+	}
+}
+
+func ExtractConstExpectKind(v Value, kind constant.Kind) *ir.Const {
+	k := extractConst(v.Value)
+	if k == nil || k.Value == nil || k.Value.Kind() != kind {
+		return nil
+	}
+	return k
+}
+
+func ExtractConst(v Value) *ir.Const {
+	return extractConst(v.Value)
+}
+
+func extractConst(v ir.Value) *ir.Const {
+	v = irutil.Flatten(v)
+	switch v := v.(type) {
+	case *ir.Const:
+		return v
+	case *ir.MakeInterface:
+		return extractConst(v.X)
+	default:
+		return nil
+	}
+}

vendor/honnef.co/go/tools/analysis/code/code.go

@@ -0,0 +1,589 @@
+// Package code answers structural and type questions about Go code.
+package code
+
+import (
+	"fmt"
+	"go/ast"
+	"go/build/constraint"
+	"go/constant"
+	"go/token"
+	"go/types"
+	"go/version"
+	"path/filepath"
+	"slices"
+	"strings"
+
+	"honnef.co/go/tools/analysis/facts/generated"
+	"honnef.co/go/tools/analysis/facts/purity"
+	"honnef.co/go/tools/analysis/facts/tokenfile"
+	"honnef.co/go/tools/go/ast/astutil"
+	"honnef.co/go/tools/go/types/typeutil"
+	"honnef.co/go/tools/knowledge"
+	"honnef.co/go/tools/pattern"
+
+	"golang.org/x/tools/go/analysis"
+)
+
+type Positioner interface {
+	Pos() token.Pos
+}
+
+func IsOfStringConvertibleByteSlice(pass *analysis.Pass, expr ast.Expr) bool {
+	typ, ok := pass.TypesInfo.TypeOf(expr).Underlying().(*types.Slice)
+	if !ok {
+		return false
+	}
+	elem := types.Unalias(typ.Elem())
+	if version.Compare(LanguageVersion(pass, expr), "go1.18") >= 0 {
+		// Before Go 1.18, one could not directly convert from []T (where 'type T byte')
+		// to string. See also https://github.com/golang/go/issues/23536.
+		elem = elem.Underlying()
+	}
+	return types.Identical(elem, types.Typ[types.Byte])
+}
+
+func IsOfPointerToTypeWithName(pass *analysis.Pass, expr ast.Expr, name string) bool {
+	ptr, ok := types.Unalias(pass.TypesInfo.TypeOf(expr)).(*types.Pointer)
+	if !ok {
+		return false
+	}
+	return typeutil.IsTypeWithName(ptr.Elem(), name)
+}
+
+func IsOfTypeWithName(pass *analysis.Pass, expr ast.Expr, name string) bool {
+	return typeutil.IsTypeWithName(pass.TypesInfo.TypeOf(expr), name)
+}
+
+func IsInTest(pass *analysis.Pass, node Positioner) bool {
+	// FIXME(dh): this doesn't work for global variables with
+	// initializers
+	f := pass.Fset.File(node.Pos())
+	return f != nil && strings.HasSuffix(f.Name(), "_test.go")
+}
+
+// IsMain reports whether the package being processed is a package
+// main.
+func IsMain(pass *analysis.Pass) bool {
+	return pass.Pkg.Name() == "main"
+}
+
+// IsMainLike reports whether the package being processed is a
+// main-like package. A main-like package is a package that is
+// package main, or that is intended to be used by a tool framework
+// such as cobra to implement a command.
+//
+// Note that this function errs on the side of false positives; it may
+// return true for packages that aren't main-like. IsMainLike is
+// intended for analyses that wish to suppress diagnostics for
+// main-like packages to avoid false positives.
+func IsMainLike(pass *analysis.Pass) bool {
+	if pass.Pkg.Name() == "main" {
+		return true
+	}
+	for _, imp := range pass.Pkg.Imports() {
+		if imp.Path() == "github.com/spf13/cobra" {
+			return true
+		}
+	}
+	return false
+}
+
+func SelectorName(pass *analysis.Pass, expr *ast.SelectorExpr) string {
+	info := pass.TypesInfo
+	sel := info.Selections[expr]
+	if sel == nil {
+		if x, ok := expr.X.(*ast.Ident); ok {
+			pkg, ok := info.ObjectOf(x).(*types.PkgName)
+			if !ok {
+				// This shouldn't happen
+				return fmt.Sprintf("%s.%s", x.Name, expr.Sel.Name)
+			}
+			return fmt.Sprintf("%s.%s", pkg.Imported().Path(), expr.Sel.Name)
+		}
+		panic(fmt.Sprintf("unsupported selector: %v", expr))
+	}
+	if v, ok := sel.Obj().(*types.Var); ok && v.IsField() {
+		return fmt.Sprintf("(%s).%s", typeutil.DereferenceR(sel.Recv()), sel.Obj().Name())
+	} else {
+		return fmt.Sprintf("(%s).%s", sel.Recv(), sel.Obj().Name())
+	}
+}
+
+func IsNil(pass *analysis.Pass, expr ast.Expr) bool {
+	return pass.TypesInfo.Types[expr].IsNil()
+}
+
+func BoolConst(pass *analysis.Pass, expr ast.Expr) bool {
+	val := pass.TypesInfo.ObjectOf(expr.(*ast.Ident)).(*types.Const).Val()
+	return constant.BoolVal(val)
+}
+
+func IsBoolConst(pass *analysis.Pass, expr ast.Expr) bool {
+	// We explicitly don't support typed bools because more often than
+	// not, custom bool types are used as binary enums and the explicit
+	// comparison is desired. We err on the side of false negatives and
+	// treat aliases like other custom types.
+
+	ident, ok := expr.(*ast.Ident)
+	if !ok {
+		return false
+	}
+	obj := pass.TypesInfo.ObjectOf(ident)
+	c, ok := obj.(*types.Const)
+	if !ok {
+		return false
+	}
+	basic, ok := c.Type().(*types.Basic)
+	if !ok {
+		return false
+	}
+	if basic.Kind() != types.UntypedBool && basic.Kind() != types.Bool {
+		return false
+	}
+	return true
+}
+
+func ExprToInt(pass *analysis.Pass, expr ast.Expr) (int64, bool) {
+	tv := pass.TypesInfo.Types[expr]
+	if tv.Value == nil {
+		return 0, false
+	}
+	if tv.Value.Kind() != constant.Int {
+		return 0, false
+	}
+	return constant.Int64Val(tv.Value)
+}
+
+func ExprToString(pass *analysis.Pass, expr ast.Expr) (string, bool) {
+	val := pass.TypesInfo.Types[expr].Value
+	if val == nil {
+		return "", false
+	}
+	if val.Kind() != constant.String {
+		return "", false
+	}
+	return constant.StringVal(val), true
+}
+
+func CallName(pass *analysis.Pass, call *ast.CallExpr) string {
+	// See the comment in typeutil.FuncName for why this doesn't require special handling
+	// of aliases.
+
+	fun := astutil.Unparen(call.Fun)
+
+	// Instantiating a function cannot return another generic function, so doing this once is enough
+	switch idx := fun.(type) {
+	case *ast.IndexExpr:
+		fun = idx.X
+	case *ast.IndexListExpr:
+		fun = idx.X
+	}
+
+	// (foo)[T] is not a valid instantiation, so no need to unparen again.
+
+	switch fun := fun.(type) {
+	case *ast.SelectorExpr:
+		fn, ok := pass.TypesInfo.ObjectOf(fun.Sel).(*types.Func)
+		if !ok {
+			return ""
+		}
+		return typeutil.FuncName(fn)
+	case *ast.Ident:
+		obj := pass.TypesInfo.ObjectOf(fun)
+		switch obj := obj.(type) {
+		case *types.Func:
+			return typeutil.FuncName(obj)
+		case *types.Builtin:
+			return obj.Name()
+		default:
+			return ""
+		}
+	default:
+		return ""
+	}
+}
+
+func IsCallTo(pass *analysis.Pass, node ast.Node, name string) bool {
+	// See the comment in typeutil.FuncName for why this doesn't require special handling
+	// of aliases.
+
+	call, ok := node.(*ast.CallExpr)
+	if !ok {
+		return false
+	}
+	return CallName(pass, call) == name
+}
+
+func IsCallToAny(pass *analysis.Pass, node ast.Node, names ...string) bool {
+	// See the comment in typeutil.FuncName for why this doesn't require special handling
+	// of aliases.
+
+	call, ok := node.(*ast.CallExpr)
+	if !ok {
+		return false
+	}
+	q := CallName(pass, call)
+	return slices.Contains(names, q)
+}
+
+func File(pass *analysis.Pass, node Positioner) *ast.File {
+	m := pass.ResultOf[tokenfile.Analyzer].(map[*token.File]*ast.File)
+	return m[pass.Fset.File(node.Pos())]
+}
+
+// BuildConstraints returns the build constraints for file f. It considers both //go:build lines as well as
+// GOOS and GOARCH in file names.
+func BuildConstraints(pass *analysis.Pass, f *ast.File) (constraint.Expr, bool) {
+	var expr constraint.Expr
+	for _, cmt := range f.Comments {
+		if len(cmt.List) == 0 {
+			continue
+		}
+		for _, el := range cmt.List {
+			if el.Pos() > f.Package {
+				break
+			}
+			if line := el.Text; strings.HasPrefix(line, "//go:build") {
+				var err error
+				expr, err = constraint.Parse(line)
+				if err != nil {
+					expr = nil
+				}
+				break
+			}
+		}
+	}
+
+	name := pass.Fset.PositionFor(f.Pos(), false).Filename
+	oexpr := constraintsFromName(name)
+	if oexpr != nil {
+		if expr == nil {
+			expr = oexpr
+		} else {
+			expr = &constraint.AndExpr{X: expr, Y: oexpr}
+		}
+	}
+
+	return expr, expr != nil
+}
+
+func constraintsFromName(name string) constraint.Expr {
+	name = filepath.Base(name)
+	name = strings.TrimSuffix(name, ".go")
+	name = strings.TrimSuffix(name, "_test")
+	var goos, goarch string
+	switch strings.Count(name, "_") {
+	case 0:
+		// No GOOS or GOARCH in the file name.
+	case 1:
+		_, c, _ := strings.Cut(name, "_")
+		if _, ok := knowledge.KnownGOOS[c]; ok {
+			goos = c
+		} else if _, ok := knowledge.KnownGOARCH[c]; ok {
+			goarch = c
+		}
+	default:
+		n := strings.LastIndex(name, "_")
+		if _, ok := knowledge.KnownGOOS[name[n+1:]]; ok {
+			// The file name is *_stuff_GOOS.go
+			goos = name[n+1:]
+		} else if _, ok := knowledge.KnownGOARCH[name[n+1:]]; ok {
+			// The file name is *_GOOS_GOARCH.go or *_stuff_GOARCH.go
+			goarch = name[n+1:]
+			_, c, _ := strings.Cut(name[:n], "_")
+			if _, ok := knowledge.KnownGOOS[c]; ok {
+				// The file name is *_GOOS_GOARCH.go
+				goos = c
+			}
+		} else {
+			// The file name could also be something like foo_windows_nonsense.go — and because nonsense
+			// isn't a known GOARCH, "windows" won't be interpreted as a GOOS, either.
+		}
+	}
+
+	var expr constraint.Expr
+	if goos != "" {
+		expr = &constraint.TagExpr{Tag: goos}
+	}
+	if goarch != "" {
+		if expr == nil {
+			expr = &constraint.TagExpr{Tag: goarch}
+		} else {
+			expr = &constraint.AndExpr{X: expr, Y: &constraint.TagExpr{Tag: goarch}}
+		}
+	}
+	return expr
+}
+
+// IsGenerated reports whether pos is in a generated file. It ignores
+// //line directives.
+func IsGenerated(pass *analysis.Pass, pos token.Pos) bool {
+	_, ok := Generator(pass, pos)
+	return ok
+}
+
+// Generator returns the generator that generated the file containing
+// pos. It ignores //line directives.
+func Generator(pass *analysis.Pass, pos token.Pos) (generated.Generator, bool) {
+	file := pass.Fset.PositionFor(pos, false).Filename
+	m := pass.ResultOf[generated.Analyzer].(map[string]generated.Generator)
+	g, ok := m[file]
+	return g, ok
+}
+
+// MayHaveSideEffects reports whether expr may have side effects. If
+// the purity argument is nil, this function implements a purely
+// syntactic check, meaning that any function call may have side
+// effects, regardless of the called function's body. Otherwise,
+// purity will be consulted to determine the purity of function calls.
+func MayHaveSideEffects(pass *analysis.Pass, expr ast.Expr, purity purity.Result) bool {
+	switch expr := expr.(type) {
+	case *ast.BadExpr:
+		return true
+	case *ast.Ellipsis:
+		return MayHaveSideEffects(pass, expr.Elt, purity)
+	case *ast.FuncLit:
+		// the literal itself cannot have side effects, only calling it
+		// might, which is handled by CallExpr.
+		return false
+	case *ast.ArrayType, *ast.StructType, *ast.FuncType, *ast.InterfaceType, *ast.MapType, *ast.ChanType:
+		// types cannot have side effects
+		return false
+	case *ast.BasicLit:
+		return false
+	case *ast.BinaryExpr:
+		return MayHaveSideEffects(pass, expr.X, purity) || MayHaveSideEffects(pass, expr.Y, purity)
+	case *ast.CallExpr:
+		if purity == nil {
+			return true
+		}
+		switch obj := typeutil.Callee(pass.TypesInfo, expr).(type) {
+		case *types.Func:
+			if _, ok := purity[obj]; !ok {
+				return true
+			}
+		case *types.Builtin:
+			switch obj.Name() {
+			case "len", "cap":
+			default:
+				return true
+			}
+		default:
+			return true
+		}
+		for _, arg := range expr.Args {
+			if MayHaveSideEffects(pass, arg, purity) {
+				return true
+			}
+		}
+		return false
+	case *ast.CompositeLit:
+		if MayHaveSideEffects(pass, expr.Type, purity) {
+			return true
+		}
+		for _, elt := range expr.Elts {
+			if MayHaveSideEffects(pass, elt, purity) {
+				return true
+			}
+		}
+		return false
+	case *ast.Ident:
+		return false
+	case *ast.IndexExpr:
+		return MayHaveSideEffects(pass, expr.X, purity) || MayHaveSideEffects(pass, expr.Index, purity)
+	case *ast.IndexListExpr:
+		// In theory, none of the checks are necessary, as IndexListExpr only involves types. But there is no harm in
+		// being safe.
+		if MayHaveSideEffects(pass, expr.X, purity) {
+			return true
+		}
+		for _, idx := range expr.Indices {
+			if MayHaveSideEffects(pass, idx, purity) {
+				return true
+			}
+		}
+		return false
+	case *ast.KeyValueExpr:
+		return MayHaveSideEffects(pass, expr.Key, purity) || MayHaveSideEffects(pass, expr.Value, purity)
+	case *ast.SelectorExpr:
+		return MayHaveSideEffects(pass, expr.X, purity)
+	case *ast.SliceExpr:
+		return MayHaveSideEffects(pass, expr.X, purity) ||
+			MayHaveSideEffects(pass, expr.Low, purity) ||
+			MayHaveSideEffects(pass, expr.High, purity) ||
+			MayHaveSideEffects(pass, expr.Max, purity)
+	case *ast.StarExpr:
+		return MayHaveSideEffects(pass, expr.X, purity)
+	case *ast.TypeAssertExpr:
+		return MayHaveSideEffects(pass, expr.X, purity)
+	case *ast.UnaryExpr:
+		if MayHaveSideEffects(pass, expr.X, purity) {
+			return true
+		}
+		return expr.Op == token.ARROW || expr.Op == token.AND
+	case *ast.ParenExpr:
+		return MayHaveSideEffects(pass, expr.X, purity)
+	case nil:
+		return false
+	default:
+		panic(fmt.Sprintf("internal error: unhandled type %T", expr))
+	}
+}
+
+// LanguageVersion returns the version of the Go language that node has access to. This
+// might differ from the version of the Go standard library.
+func LanguageVersion(pass *analysis.Pass, node Positioner) string {
+	// As of Go 1.21, two places can specify the minimum Go version:
+	// - 'go' directives in go.mod and go.work files
+	// - individual files by using '//go:build'
+	//
+	// Individual files can upgrade to a higher version than the module version. Individual files
+	// can also downgrade to a lower version, but only if the module version is at least Go 1.21.
+	//
+	// The restriction on downgrading doesn't matter to us. All language changes before Go 1.22 will
+	// not type-check on versions that are too old, and thus never reach our analyzes. In practice,
+	// such ineffective downgrading will always be useless, as the compiler will not restrict the
+	// language features used, and doesn't ever rely on minimum versions to restrict the use of the
+	// standard library. However, for us, both choices (respecting or ignoring ineffective
+	// downgrading) have equal complexity, but only respecting it has a non-zero chance of reducing
+	// noisy positives.
+	//
+	// The minimum Go versions are exposed via go/ast.File.GoVersion and go/types.Package.GoVersion.
+	// ast.File's version is populated by the parser, whereas types.Package's version is populated
+	// from the Go version specified in the types.Config, which is set by our package loader, based
+	// on the module information provided by go/packages, via 'go list -json'.
+	//
+	// As of Go 1.21, standard library packages do not present themselves as modules, and thus do
+	// not have a version set on their types.Package. In this case, we fall back to the version
+	// provided by our '-go' flag. In most cases, '-go' defaults to 'module', which falls back to
+	// the Go version that Staticcheck was built with when no module information exists. In the
+	// future, the standard library will hopefully be a proper module (see
+	// https://github.com/golang/go/issues/61174#issuecomment-1622471317). In that case, the version
+	// of standard library packages will match that of the used Go version. At that point,
+	// Staticcheck will refuse to work with Go versions that are too new, to avoid misinterpreting
+	// code due to language changes.
+	//
+	// We also lack module information when building in GOPATH mode. In this case, the implied
+	// language version is at most Go 1.21, as per https://github.com/golang/go/issues/60915. We
+	// don't handle this yet, and it will not matter until Go 1.22.
+	//
+	// It is not clear how per-file downgrading behaves in GOPATH mode. On the one hand, no module
+	// version at all is provided, which should preclude per-file downgrading. On the other hand,
+	// https://github.com/golang/go/issues/60915 suggests that the language version is at most 1.21
+	// in GOPATH mode, which would allow per-file downgrading. Again it doesn't affect us, as all
+	// relevant language changes before Go 1.22 will lead to type-checking failures and never reach
+	// us.
+	//
+	// Per-file upgrading is permitted in GOPATH mode.
+
+	// If the file has its own Go version, we will return that. Otherwise, we default to
+	// the type checker's GoVersion, which is populated from either the Go module, or from
+	// our '-go' flag.
+	return pass.TypesInfo.FileVersions[File(pass, node)]
+}
+
+// StdlibVersion returns the version of the Go standard library that node can expect to
+// have access to. This might differ from the language version for versions of Go older
+// than 1.21.
+func StdlibVersion(pass *analysis.Pass, node Positioner) string {
+	// The Go version as specified in go.mod or via the '-go' flag
+	n := pass.Pkg.GoVersion()
+
+	f := File(pass, node)
+	if f == nil {
+		panic(fmt.Sprintf("no file found for node with position %s", pass.Fset.PositionFor(node.Pos(), false)))
+	}
+
+	if nf := f.GoVersion; nf != "" {
+		if version.Compare(n, "go1.21") == -1 {
+			// Before Go 1.21, the Go version set in go.mod specified the maximum language
+			// version available to the module. It wasn't uncommon to set the version to
+			// Go 1.20 but restrict usage of 1.20 functionality (both language and stdlib)
+			// to files tagged for 1.20, and supporting a lower version overall. As such,
+			// a file tagged lower than the module version couldn't expect to have access
+			// to the standard library of the version set in go.mod.
+			//
+			// At the same time, a file tagged higher than the module version, while not
+			// able to use newer language features, would still have been able to use a
+			// newer standard library.
+			//
+			// While Go 1.21's behavior has been backported to 1.19.11 and 1.20.6, users'
+			// expectations have not.
+			return nf
+		} else {
+			// Go 1.21 and newer refuse to build modules that depend on versions newer
+			// than the used version of the Go toolchain. This means that in a 1.22 module
+			// with a file tagged as 1.17, the file can expect to have access to 1.22's
+			// standard library (but not to 1.22 language features). A file tagged with a
+			// version higher than the minimum version has access to the newer standard
+			// library (and language features.)
+			//
+			// Do note that strictly speaking we're conflating the Go version and the
+			// module version in our check. Nothing is stopping a user from using Go 1.17
+			// (which didn't implement the new rules for versions in go.mod) to build a Go
+			// 1.22 module, in which case a file tagged with go1.17 will not have access to the 1.22
+			// standard library. However, we believe that if a module requires 1.21 or
+			// newer, then the author clearly expects the new behavior, and doesn't care
+			// for the old one. Otherwise they would've specified an older version.
+			//
+			// In other words, the module version also specifies what it itself actually means, with
+			// >=1.21 being a minimum version for the toolchain, and <1.21 being a maximum version for
+			// the language.
+
+			if version.Compare(nf, n) == 1 {
+				return nf
+			}
+		}
+	}
+
+	return n
+}
+
+var integerLiteralQ = pattern.MustParse(`(IntegerLiteral tv)`)
+
+func IntegerLiteral(pass *analysis.Pass, node ast.Node) (types.TypeAndValue, bool) {
+	m, ok := Match(pass, integerLiteralQ, node)
+	if !ok {
+		return types.TypeAndValue{}, false
+	}
+	return m.State["tv"].(types.TypeAndValue), true
+}
+
+func IsIntegerLiteral(pass *analysis.Pass, node ast.Node, value constant.Value) bool {
+	tv, ok := IntegerLiteral(pass, node)
+	if !ok {
+		return false
+	}
+	return constant.Compare(tv.Value, token.EQL, value)
+}
+
+// IsMethod reports whether expr is a method call of a named method with signature meth.
+// If name is empty, it is not checked.
+// For now, method expressions (Type.Method(recv, ..)) are not considered method calls.
+func IsMethod(pass *analysis.Pass, expr *ast.SelectorExpr, name string, meth *types.Signature) bool {
+	if name != "" && expr.Sel.Name != name {
+		return false
+	}
+	sel, ok := pass.TypesInfo.Selections[expr]
+	if !ok || sel.Kind() != types.MethodVal {
+		return false
+	}
+	return types.Identical(sel.Type(), meth)
+}
+
+func RefersTo(pass *analysis.Pass, expr ast.Expr, ident types.Object) bool {
+	found := false
+	fn := func(node ast.Node) bool {
+		ident2, ok := node.(*ast.Ident)
+		if !ok {
+			return true
+		}
+		if ident == pass.TypesInfo.ObjectOf(ident2) {
+			found = true
+			return false
+		}
+		return true
+	}
+	ast.Inspect(expr, fn)
+	return found
+}

vendor/honnef.co/go/tools/analysis/code/visit.go

@@ -0,0 +1,153 @@
+package code
+
+import (
+	"bytes"
+	"fmt"
+	"go/ast"
+	"go/format"
+	"go/types"
+	"iter"
+	"slices"
+
+	typeindexanalyzer "honnef.co/go/tools/internal/analysisinternal/typeindex"
+	"honnef.co/go/tools/internal/typesinternal/typeindex"
+	"honnef.co/go/tools/pattern"
+
+	"golang.org/x/tools/go/analysis"
+	"golang.org/x/tools/go/analysis/passes/inspect"
+	"golang.org/x/tools/go/ast/inspector"
+)
+
+var RequiredAnalyzers = []*analysis.Analyzer{inspect.Analyzer, typeindexanalyzer.Analyzer}
+
+func Cursor(pass *analysis.Pass) inspector.Cursor {
+	return pass.ResultOf[inspect.Analyzer].(*inspector.Inspector).Root()
+}
+
+func Preorder(pass *analysis.Pass, fn func(ast.Node), types ...ast.Node) {
+	pass.ResultOf[inspect.Analyzer].(*inspector.Inspector).Preorder(types, fn)
+}
+
+func PreorderStack(pass *analysis.Pass, fn func(ast.Node, []ast.Node), types ...ast.Node) {
+	pass.ResultOf[inspect.Analyzer].(*inspector.Inspector).WithStack(types, func(n ast.Node, push bool, stack []ast.Node) (proceed bool) {
+		if push {
+			fn(n, stack)
+		}
+		return true
+	})
+}
+
+func Matches(pass *analysis.Pass, qs ...pattern.Pattern) iter.Seq2[ast.Node, *pattern.Matcher] {
+	return func(yield func(ast.Node, *pattern.Matcher) bool) {
+		for _, q := range qs {
+			if !CouldMatchAny(pass, q) {
+				continue
+			}
+
+			if len(q.RootCallSymbols) != 0 {
+				index := pass.ResultOf[typeindexanalyzer.Analyzer].(*typeindex.Index)
+				for _, isym := range q.RootCallSymbols {
+					var obj types.Object
+					if isym.Type == "" {
+						obj = index.Object(isym.Path, isym.Ident)
+					} else {
+						obj = index.Selection(isym.Path, isym.Type, isym.Ident)
+					}
+					for c := range index.Calls(obj) {
+						node := c.Node()
+						if m, ok := Match(pass, q, node); ok {
+							if !yield(node, m) {
+								return
+							}
+						}
+					}
+				}
+			} else {
+				ins := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+				fn := func(node ast.Node, push bool) bool {
+					if !push {
+						return true
+					}
+
+					if m, ok := Match(pass, q, node); ok {
+						return yield(node, m)
+					}
+					return true
+				}
+				ins.Nodes(q.EntryNodes, fn)
+			}
+		}
+	}
+}
+
+func Match(pass *analysis.Pass, q pattern.Pattern, node ast.Node) (*pattern.Matcher, bool) {
+	// Note that we ignore q.Relevant – callers of Match usually use
+	// AST inspectors that already filter on nodes we're interested
+	// in.
+	m := &pattern.Matcher{TypesInfo: pass.TypesInfo}
+	ok := m.Match(q, node)
+	return m, ok
+}
+
+func CouldMatchAny(pass *analysis.Pass, qs ...pattern.Pattern) bool {
+	index := pass.ResultOf[typeindexanalyzer.Analyzer].(*typeindex.Index)
+	var do func(node pattern.Node) bool
+	do = func(node pattern.Node) bool {
+		switch node := node.(type) {
+		case pattern.Any:
+			return true
+		case pattern.Or:
+			return slices.ContainsFunc(node.Nodes, do)
+		case pattern.And:
+			for _, child := range node.Nodes {
+				if !do(child) {
+					return false
+				}
+			}
+			return true
+		case pattern.IndexSymbol:
+			if node.Type == "" {
+				return index.Object(node.Path, node.Ident) != nil
+			} else {
+				return index.Selection(node.Path, node.Type, node.Ident) != nil
+			}
+		default:
+			panic(fmt.Sprintf("internal error: unexpected type %T", node))
+		}
+	}
+
+	for _, q := range qs {
+		if do(q.SymbolsPattern) {
+			return true
+		}
+	}
+	return false
+}
+
+func MatchAndEdit(pass *analysis.Pass, before, after pattern.Pattern, node ast.Node) (*pattern.Matcher, []analysis.TextEdit, bool) {
+	m, ok := Match(pass, before, node)
+	if !ok {
+		return m, nil, false
+	}
+	r := pattern.NodeToAST(after.Root, m.State)
+	buf := &bytes.Buffer{}
+	format.Node(buf, pass.Fset, r)
+	edit := []analysis.TextEdit{{
+		Pos:     node.Pos(),
+		End:     node.End(),
+		NewText: buf.Bytes(),
+	}}
+	return m, edit, true
+}
+
+func EditMatch(pass *analysis.Pass, node ast.Node, m *pattern.Matcher, after pattern.Pattern) []analysis.TextEdit {
+	r := pattern.NodeToAST(after.Root, m.State)
+	buf := &bytes.Buffer{}
+	format.Node(buf, pass.Fset, r)
+	edit := []analysis.TextEdit{{
+		Pos:     node.Pos(),
+		End:     node.End(),
+		NewText: buf.Bytes(),
+	}}
+	return edit
+}

vendor/honnef.co/go/tools/analysis/edit/edit.go

@@ -0,0 +1,83 @@
+// Package edit contains helpers for creating suggested fixes.
+package edit
+
+import (
+	"bytes"
+	"go/ast"
+	"go/format"
+	"go/token"
+
+	"golang.org/x/tools/go/analysis"
+	"honnef.co/go/tools/pattern"
+)
+
+// Ranger describes values that have a start and end position.
+// In most cases these are either ast.Node or manually constructed ranges.
+type Ranger interface {
+	Pos() token.Pos
+	End() token.Pos
+}
+
+// Range implements the Ranger interface.
+type Range [2]token.Pos
+
+func (r Range) Pos() token.Pos { return r[0] }
+func (r Range) End() token.Pos { return r[1] }
+
+// ReplaceWithString replaces a range with a string.
+func ReplaceWithString(old Ranger, new string) analysis.TextEdit {
+	return analysis.TextEdit{
+		Pos:     old.Pos(),
+		End:     old.End(),
+		NewText: []byte(new),
+	}
+}
+
+// ReplaceWithNode replaces a range with an AST node.
+func ReplaceWithNode(fset *token.FileSet, old Ranger, new ast.Node) analysis.TextEdit {
+	buf := &bytes.Buffer{}
+	if err := format.Node(buf, fset, new); err != nil {
+		panic("internal error: " + err.Error())
+	}
+	return analysis.TextEdit{
+		Pos:     old.Pos(),
+		End:     old.End(),
+		NewText: buf.Bytes(),
+	}
+}
+
+// ReplaceWithPattern replaces a range with the result of executing a pattern.
+func ReplaceWithPattern(fset *token.FileSet, old Ranger, new pattern.Pattern, state pattern.State) analysis.TextEdit {
+	r := pattern.NodeToAST(new.Root, state)
+	buf := &bytes.Buffer{}
+	format.Node(buf, fset, r)
+	return analysis.TextEdit{
+		Pos:     old.Pos(),
+		End:     old.End(),
+		NewText: buf.Bytes(),
+	}
+}
+
+// Delete deletes a range of code.
+func Delete(old Ranger) analysis.TextEdit {
+	return analysis.TextEdit{
+		Pos:     old.Pos(),
+		End:     old.End(),
+		NewText: nil,
+	}
+}
+
+func Fix(msg string, edits ...analysis.TextEdit) analysis.SuggestedFix {
+	return analysis.SuggestedFix{
+		Message:   msg,
+		TextEdits: edits,
+	}
+}
+
+// Selector creates a new selector expression.
+func Selector(x, sel string) *ast.SelectorExpr {
+	return &ast.SelectorExpr{
+		X:   &ast.Ident{Name: x},
+		Sel: &ast.Ident{Name: sel},
+	}
+}

vendor/honnef.co/go/tools/analysis/facts/deprecated/deprecated.go

@@ -0,0 +1,154 @@
+package deprecated
+
+import (
+	"go/ast"
+	"go/token"
+	"go/types"
+	"reflect"
+	"strings"
+
+	"golang.org/x/tools/go/analysis"
+)
+
+type IsDeprecated struct{ Msg string }
+
+func (*IsDeprecated) AFact()           {}
+func (d *IsDeprecated) String() string { return "Deprecated: " + d.Msg }
+
+type Result struct {
+	Objects  map[types.Object]*IsDeprecated
+	Packages map[*types.Package]*IsDeprecated
+}
+
+var Analyzer = &analysis.Analyzer{
+	Name:       "fact_deprecated",
+	Doc:        "Mark deprecated objects",
+	Run:        deprecated,
+	FactTypes:  []analysis.Fact{(*IsDeprecated)(nil)},
+	ResultType: reflect.TypeFor[Result](),
+}
+
+func deprecated(pass *analysis.Pass) (any, error) {
+	var names []*ast.Ident
+
+	extractDeprecatedMessage := func(docs []*ast.CommentGroup) string {
+		for _, doc := range docs {
+			if doc == nil {
+				continue
+			}
+			parts := strings.SplitSeq(doc.Text(), "\n\n")
+			for part := range parts {
+				if !strings.HasPrefix(part, "Deprecated: ") {
+					continue
+				}
+				alt := part[len("Deprecated: "):]
+				alt = strings.Replace(alt, "\n", " ", -1)
+				return alt
+			}
+		}
+		return ""
+	}
+
+	doDocs := func(names []*ast.Ident, docs []*ast.CommentGroup) {
+		alt := extractDeprecatedMessage(docs)
+		if alt == "" {
+			return
+		}
+
+		for _, name := range names {
+			obj := pass.TypesInfo.ObjectOf(name)
+			pass.ExportObjectFact(obj, &IsDeprecated{alt})
+		}
+	}
+
+	var docs []*ast.CommentGroup
+	for _, f := range pass.Files {
+		docs = append(docs, f.Doc)
+	}
+	if alt := extractDeprecatedMessage(docs); alt != "" {
+		// Don't mark package syscall as deprecated, even though
+		// it is. A lot of people still use it for simple
+		// constants like SIGKILL, and I am not comfortable
+		// telling them to use x/sys for that.
+		if pass.Pkg.Path() != "syscall" {
+			pass.ExportPackageFact(&IsDeprecated{alt})
+		}
+	}
+
+	docs = docs[:0]
+	for _, f := range pass.Files {
+		fn := func(node ast.Node) bool {
+			if node == nil {
+				return true
+			}
+			var ret bool
+			switch node := node.(type) {
+			case *ast.GenDecl:
+				switch node.Tok {
+				case token.TYPE, token.CONST, token.VAR:
+					docs = append(docs, node.Doc)
+					for i := range node.Specs {
+						switch n := node.Specs[i].(type) {
+						case *ast.ValueSpec:
+							names = append(names, n.Names...)
+						case *ast.TypeSpec:
+							names = append(names, n.Name)
+						}
+					}
+					ret = true
+				default:
+					return false
+				}
+			case *ast.FuncDecl:
+				docs = append(docs, node.Doc)
+				names = []*ast.Ident{node.Name}
+				ret = false
+			case *ast.TypeSpec:
+				docs = append(docs, node.Doc)
+				names = []*ast.Ident{node.Name}
+				ret = true
+			case *ast.ValueSpec:
+				docs = append(docs, node.Doc)
+				names = node.Names
+				ret = false
+			case *ast.File:
+				return true
+			case *ast.StructType:
+				for _, field := range node.Fields.List {
+					doDocs(field.Names, []*ast.CommentGroup{field.Doc})
+				}
+				return false
+			case *ast.InterfaceType:
+				for _, field := range node.Methods.List {
+					doDocs(field.Names, []*ast.CommentGroup{field.Doc})
+				}
+				return false
+			default:
+				return false
+			}
+			if len(names) == 0 || len(docs) == 0 {
+				return ret
+			}
+			doDocs(names, docs)
+
+			docs = docs[:0]
+			names = nil
+			return ret
+		}
+		ast.Inspect(f, fn)
+	}
+
+	out := Result{
+		Objects:  map[types.Object]*IsDeprecated{},
+		Packages: map[*types.Package]*IsDeprecated{},
+	}
+
+	for _, fact := range pass.AllObjectFacts() {
+		out.Objects[fact.Object] = fact.Fact.(*IsDeprecated)
+	}
+	for _, fact := range pass.AllPackageFacts() {
+		out.Packages[fact.Package] = fact.Fact.(*IsDeprecated)
+	}
+
+	return out, nil
+}

vendor/honnef.co/go/tools/analysis/facts/directives/directives.go

@@ -0,0 +1,20 @@
+package directives
+
+import (
+	"reflect"
+
+	"golang.org/x/tools/go/analysis"
+	"honnef.co/go/tools/analysis/lint"
+)
+
+func directives(pass *analysis.Pass) (any, error) {
+	return lint.ParseDirectives(pass.Files, pass.Fset), nil
+}
+
+var Analyzer = &analysis.Analyzer{
+	Name:             "directives",
+	Doc:              "extracts linter directives",
+	Run:              directives,
+	RunDespiteErrors: true,
+	ResultType:       reflect.TypeFor[[]lint.Directive](),
+}

vendor/honnef.co/go/tools/analysis/facts/generated/generated.go

@@ -0,0 +1,97 @@
+package generated
+
+import (
+	"bufio"
+	"bytes"
+	"io"
+	"os"
+	"reflect"
+	"strings"
+
+	"golang.org/x/tools/go/analysis"
+)
+
+type Generator int
+
+// A list of known generators we can detect
+const (
+	Unknown Generator = iota
+	Goyacc
+	Cgo
+	Stringer
+	ProtocGenGo
+)
+
+var (
+	// used by cgo before Go 1.11
+	oldCgo = []byte("// Created by cgo - DO NOT EDIT")
+	prefix = []byte("// Code generated ")
+	suffix = []byte(" DO NOT EDIT.")
+	nl     = []byte("\n")
+	crnl   = []byte("\r\n")
+)
+
+func isGenerated(path string) (Generator, bool) {
+	f, err := os.Open(path)
+	if err != nil {
+		return 0, false
+	}
+	defer f.Close()
+	br := bufio.NewReader(f)
+	for {
+		s, err := br.ReadBytes('\n')
+		if err != nil && err != io.EOF {
+			return 0, false
+		}
+		s = bytes.TrimSuffix(s, crnl)
+		s = bytes.TrimSuffix(s, nl)
+		if bytes.HasPrefix(s, prefix) && bytes.HasSuffix(s, suffix) {
+			if len(s)-len(suffix) < len(prefix) {
+				return Unknown, true
+			}
+
+			text := string(s[len(prefix) : len(s)-len(suffix)])
+			switch text {
+			case "by goyacc.":
+				return Goyacc, true
+			case "by cmd/cgo;":
+				return Cgo, true
+			case "by protoc-gen-go.":
+				return ProtocGenGo, true
+			}
+			if strings.HasPrefix(text, `by "stringer `) {
+				return Stringer, true
+			}
+			if strings.HasPrefix(text, `by goyacc `) {
+				return Goyacc, true
+			}
+
+			return Unknown, true
+		}
+		if bytes.Equal(s, oldCgo) {
+			return Cgo, true
+		}
+		if err == io.EOF {
+			break
+		}
+	}
+	return 0, false
+}
+
+var Analyzer = &analysis.Analyzer{
+	Name: "isgenerated",
+	Doc:  "annotate file names that have been code generated",
+	Run: func(pass *analysis.Pass) (any, error) {
+		m := map[string]Generator{}
+		for _, f := range pass.Files {
+			path := pass.Fset.PositionFor(f.Pos(), false).Filename
+			g, ok := isGenerated(path)
+			if ok {
+				m[path] = g
+			}
+		}
+		return m, nil
+	},
+	RunDespiteErrors: true,
+	ResultType:       reflect.TypeFor[map[string]Generator](),
+}

vendor/honnef.co/go/tools/analysis/facts/nilness/nilness.go

@@ -0,0 +1,255 @@
+package nilness
+
+import (
+	"fmt"
+	"go/token"
+	"go/types"
+	"reflect"
+
+	"honnef.co/go/tools/go/ir"
+	"honnef.co/go/tools/go/types/typeutil"
+	"honnef.co/go/tools/internal/passes/buildir"
+
+	"golang.org/x/tools/go/analysis"
+)
+
+// neverReturnsNilFact denotes that a function's return value will never
+// be nil (typed or untyped). The analysis errs on the side of false
+// negatives.
+type neverReturnsNilFact struct {
+	Rets []neverNilness
+}
+
+func (*neverReturnsNilFact) AFact() {}
+func (fact *neverReturnsNilFact) String() string {
+	return fmt.Sprintf("never returns nil: %v", fact.Rets)
+}
+
+type Result struct {
+	m map[*types.Func][]neverNilness
+}
+
+var Analysis = &analysis.Analyzer{
+	Name:       "nilness",
+	Doc:        "Annotates return values that will never be nil (typed or untyped)",
+	Run:        run,
+	Requires:   []*analysis.Analyzer{buildir.Analyzer},
+	FactTypes:  []analysis.Fact{(*neverReturnsNilFact)(nil)},
+	ResultType: reflect.TypeFor[*Result](),
+}
+
+// MayReturnNil reports whether the ret's return value of fn might be
+// a typed or untyped nil value. The value of ret is zero-based. When
+// globalOnly is true, the only possible nil values are global
+// variables.
+//
+// The analysis has false positives: MayReturnNil can incorrectly
+// report true, but never incorrectly reports false.
+func (r *Result) MayReturnNil(fn *types.Func, ret int) (yes bool, globalOnly bool) {
+	if !typeutil.IsPointerLike(fn.Type().(*types.Signature).Results().At(ret).Type()) {
+		return false, false
+	}
+	if len(r.m[fn]) == 0 {
+		return true, false
+	}
+
+	v := r.m[fn][ret]
+	return v != neverNil, v == onlyGlobal
+}
+
+func run(pass *analysis.Pass) (any, error) {
+	seen := map[*ir.Function]struct{}{}
+	out := &Result{
+		m: map[*types.Func][]neverNilness{},
+	}
+	for _, fn := range pass.ResultOf[buildir.Analyzer].(*buildir.IR).SrcFuncs {
+		impl(pass, fn, seen)
+	}
+
+	for _, fact := range pass.AllObjectFacts() {
+		out.m[fact.Object.(*types.Func)] = fact.Fact.(*neverReturnsNilFact).Rets
+	}
+
+	return out, nil
+}
+
+type neverNilness uint8
+
+const (
+	neverNil   neverNilness = 1
+	onlyGlobal neverNilness = 2
+	nilly      neverNilness = 3
+)
+
+func (n neverNilness) String() string {
+	switch n {
+	case neverNil:
+		return "never"
+	case onlyGlobal:
+		return "global"
+	case nilly:
+		return "nil"
+	default:
+		return "BUG"
+	}
+}
+
+func impl(pass *analysis.Pass, fn *ir.Function, seenFns map[*ir.Function]struct{}) []neverNilness {
+	if fn.Object() == nil {
+		// TODO(dh): support closures
+		return nil
+	}
+	if fact := new(neverReturnsNilFact); pass.ImportObjectFact(fn.Object(), fact) {
+		return fact.Rets
+	}
+	if fn.Pkg != pass.ResultOf[buildir.Analyzer].(*buildir.IR).Pkg {
+		return nil
+	}
+	if fn.Blocks == nil {
+		return nil
+	}
+	if _, ok := seenFns[fn]; ok {
+		// break recursion
+		return nil
+	}
+
+	seenFns[fn] = struct{}{}
+
+	seen := map[ir.Value]struct{}{}
+
+	var mightReturnNil func(v ir.Value) neverNilness
+	mightReturnNil = func(v ir.Value) neverNilness {
+		if _, ok := seen[v]; ok {
+			// break cycle
+			return nilly
+		}
+		if !typeutil.IsPointerLike(v.Type()) {
+			return neverNil
+		}
+		seen[v] = struct{}{}
+		switch v := v.(type) {
+		case *ir.MakeInterface:
+			return mightReturnNil(v.X)
+		case *ir.Convert:
+			return mightReturnNil(v.X)
+		case *ir.SliceToArrayPointer:
+			if typeutil.CoreType(v.Type()).(*types.Pointer).Elem().Underlying().(*types.Array).Len() == 0 {
+				return mightReturnNil(v.X)
+			} else {
+				// converting a slice to an array pointer of length > 0 panics if the slice is nil
+				return neverNil
+			}
+		case *ir.Slice:
+			return mightReturnNil(v.X)
+		case *ir.Phi:
+			ret := neverNil
+			for _, e := range v.Edges {
+				if n := mightReturnNil(e); n > ret {
+					ret = n
+				}
+			}
+			return ret
+		case *ir.Extract:
+			switch d := v.Tuple.(type) {
+			case *ir.Call:
+				if callee := d.Call.StaticCallee(); callee != nil {
+					ret := impl(pass, callee, seenFns)
+					if len(ret) == 0 {
+						return nilly
+					}
+					return ret[v.Index]
+				} else {
+					return nilly
+				}
+			case *ir.TypeAssert, *ir.Next, *ir.Select, *ir.MapLookup, *ir.TypeSwitch, *ir.Recv, *ir.Sigma:
+				// we don't need to look at the Extract's index
+				// because we've already checked its type.
+				return nilly
+			default:
+				panic(fmt.Sprintf("internal error: unhandled type %T", d))
+			}
+		case *ir.Call:
+			if callee := v.Call.StaticCallee(); callee != nil {
+				ret := impl(pass, callee, seenFns)
+				if len(ret) == 0 {
+					return nilly
+				}
+				return ret[0]
+			} else {
+				return nilly
+			}
+		case *ir.BinOp, *ir.UnOp, *ir.Alloc, *ir.FieldAddr, *ir.IndexAddr, *ir.Global, *ir.MakeSlice, *ir.MakeClosure, *ir.Function, *ir.MakeMap, *ir.MakeChan:
+			return neverNil
+		case *ir.Sigma:
+			iff, ok := v.From.Control().(*ir.If)
+			if !ok {
+				return nilly
+			}
+			binop, ok := iff.Cond.(*ir.BinOp)
+			if !ok {
+				return nilly
+			}
+			isNil := func(v ir.Value) bool {
+				k, ok := v.(*ir.Const)
+				if !ok {
+					return false
+				}
+				return k.Value == nil
+			}
+			if binop.X == v.X && isNil(binop.Y) || binop.Y == v.X && isNil(binop.X) {
+				op := binop.Op
+				if v.From.Succs[0] != v.Block() {
+					// we're in the false branch, negate op
+					switch op {
+					case token.EQL:
+						op = token.NEQ
+					case token.NEQ:
+						op = token.EQL
+					default:
+						panic(fmt.Sprintf("internal error: unhandled token %v", op))
+					}
+				}
+				switch op {
+				case token.EQL:
+					return nilly
+				case token.NEQ:
+					return neverNil
+				default:
+					panic(fmt.Sprintf("internal error: unhandled token %v", op))
+				}
+			}
+			return nilly
+		case *ir.ChangeType:
+			return mightReturnNil(v.X)
+		case *ir.MultiConvert:
+			return mightReturnNil(v.X)
+		case *ir.Load:
+			if _, ok := v.X.(*ir.Global); ok {
+				return onlyGlobal
+			}
+			return nilly
+		case *ir.AggregateConst:
+			return neverNil
+		case *ir.TypeAssert, *ir.ChangeInterface, *ir.Field, *ir.Const, *ir.GenericConst, *ir.Index, *ir.MapLookup, *ir.Parameter, *ir.Recv, *ir.TypeSwitch:
+			return nilly
+		default:
+			panic(fmt.Sprintf("internal error: unhandled type %T", v))
+		}
+	}
+	ret := fn.Exit.Control().(*ir.Return)
+	out := make([]neverNilness, len(ret.Results))
+	export := false
+	for i, v := range ret.Results {
+		// OPT(dh): couldn't we check the result type's pointer-likeness early, and skip
+		// processing the return value altogether?
+		v := mightReturnNil(v)
+		out[i] = v
+		if v != nilly && typeutil.IsPointerLike(fn.Signature.Results().At(i).Type()) {
+			export = true
+		}
+	}
+	if export {
+		pass.ExportObjectFact(fn.Object(), &neverReturnsNilFact{out})
+	}
+	return out
+}

vendor/honnef.co/go/tools/analysis/facts/purity/purity.go

@@ -0,0 +1,264 @@
+package purity
+
+// TODO(dh): we should split this into two facts, one tracking actual purity, and one tracking side-effects. A function
+// that returns a heap allocation isn't pure, but it may be free of side effects.
+
+import (
+	"go/types"
+	"reflect"
+
+	"honnef.co/go/tools/go/ir"
+	"honnef.co/go/tools/go/ir/irutil"
+	"honnef.co/go/tools/internal/passes/buildir"
+
+	"golang.org/x/tools/go/analysis"
+)
+
+type IsPure struct{}
+
+func (*IsPure) AFact()           {}
+func (d *IsPure) String() string { return "is pure" }
+
+type Result map[*types.Func]*IsPure
+
+var Analyzer = &analysis.Analyzer{
+	Name:       "fact_purity",
+	Doc:        "Mark pure functions",
+	Run:        purity,
+	Requires:   []*analysis.Analyzer{buildir.Analyzer},
+	FactTypes:  []analysis.Fact{(*IsPure)(nil)},
+	ResultType: reflect.TypeFor[Result](),
+}
+
+var pureStdlib = map[string]struct{}{
+	"errors.New":                      {},
+	"fmt.Errorf":                      {},
+	"fmt.Sprintf":                     {},
+	"fmt.Sprint":                      {},
+	"sort.Reverse":                    {},
+	"strings.Map":                     {},
+	"strings.Repeat":                  {},
+	"strings.Replace":                 {},
+	"strings.Title":                   {},
+	"strings.ToLower":                 {},
+	"strings.ToLowerSpecial":          {},
+	"strings.ToTitle":                 {},
+	"strings.ToTitleSpecial":          {},
+	"strings.ToUpper":                 {},
+	"strings.ToUpperSpecial":          {},
+	"strings.Trim":                    {},
+	"strings.TrimFunc":                {},
+	"strings.TrimLeft":                {},
+	"strings.TrimLeftFunc":            {},
+	"strings.TrimPrefix":              {},
+	"strings.TrimRight":               {},
+	"strings.TrimRightFunc":           {},
+	"strings.TrimSpace":               {},
+	"strings.TrimSuffix":              {},
+	"(*net/http.Request).WithContext": {},
+	"time.Now":                        {},
+	"time.Parse":                      {},
+	"time.ParseInLocation":            {},
+	"time.Unix":                       {},
+	"time.UnixMicro":                  {},
+	"time.UnixMilli":                  {},
+	"(time.Time).Add":                 {},
+	"(time.Time).AddDate":             {},
+	"(time.Time).After":               {},
+	"(time.Time).Before":              {},
+	"(time.Time).Clock":               {},
+	"(time.Time).Compare":             {},
+	"(time.Time).Date":                {},
+	"(time.Time).Day":                 {},
+	"(time.Time).Equal":               {},
+	"(time.Time).Format":              {},
+	"(time.Time).GoString":            {},
+	"(time.Time).GobEncode":           {},
+	"(time.Time).Hour":                {},
+	"(time.Time).ISOWeek":             {},
+	"(time.Time).In":                  {},
+	"(time.Time).IsDST":               {},
+	"(time.Time).IsZero":              {},
+	"(time.Time).Local":               {},
+	"(time.Time).Location":            {},
+	"(time.Time).MarshalBinary":       {},
+	"(time.Time).MarshalJSON":         {},
+	"(time.Time).MarshalText":         {},
+	"(time.Time).Minute":              {},
+	"(time.Time).Month":               {},
+	"(time.Time).Nanosecond":          {},
+	"(time.Time).Round":               {},
+	"(time.Time).Second":              {},
+	"(time.Time).String":              {},
+	"(time.Time).Sub":                 {},
+	"(time.Time).Truncate":            {},
+	"(time.Time).UTC":                 {},
+	"(time.Time).Unix":                {},
+	"(time.Time).UnixMicro":           {},
+	"(time.Time).UnixMilli":           {},
+	"(time.Time).UnixNano":            {},
+	"(time.Time).Weekday":             {},
+	"(time.Time).Year":                {},
+	"(time.Time).YearDay":             {},
+	"(time.Time).Zone":                {},
+	"(time.Time).ZoneBounds":          {},
+}
+
+func purity(pass *analysis.Pass) (any, error) {
+	seen := map[*ir.Function]struct{}{}
+	irpkg := pass.ResultOf[buildir.Analyzer].(*buildir.IR).Pkg
+	var check func(fn *ir.Function) (ret bool)
+	check = func(fn *ir.Function) (ret bool) {
+		if fn.Object() == nil {
+			// TODO(dh): support closures
+			return false
+		}
+		if pass.ImportObjectFact(fn.Object(), new(IsPure)) {
+			return true
+		}
+		if fn.Pkg != irpkg {
+			// Function is in another package but wasn't marked as
+			// pure, ergo it isn't pure
+			return false
+		}
+		// Break recursion
+		if _, ok := seen[fn]; ok {
+			return false
+		}
+
+		seen[fn] = struct{}{}
+		defer func() {
+			if ret {
+				pass.ExportObjectFact(fn.Object(), &IsPure{})
+			}
+		}()
+
+		if irutil.IsStub(fn) {
+			return false
+		}
+
+		if _, ok := pureStdlib[fn.Object().(*types.Func).FullName()]; ok {
+			return true
+		}
+
+		if fn.Signature.Results().Len() == 0 {
+			// A function with no return values is empty or is doing some
+			// work we cannot see (for example because of build tags);
+			// don't consider it pure.
+			return false
+		}
+
+		var isBasic func(typ types.Type) bool
+		isBasic = func(typ types.Type) bool {
+			switch u := typ.Underlying().(type) {
+			case *types.Basic:
+				return true
+			case *types.Struct:
+				for field := range u.Fields() {
+					if !isBasic(field.Type()) {
+						return false
+					}
+				}
+				return true
+			default:
+				return false
+			}
+		}
+
+		for _, param := range fn.Params {
+			// TODO(dh): this may not be strictly correct. pure code can, to an extent, operate on non-basic types.
+			if !isBasic(param.Type()) {
+				return false
+			}
+		}
+
+		// Don't consider external functions pure.
+		if fn.Blocks == nil {
+			return false
+		}
+		checkCall := func(common *ir.CallCommon) bool {
+			if common.IsInvoke() {
+				return false
+			}
+			builtin, ok := common.Value.(*ir.Builtin)
+			if !ok {
+				if common.StaticCallee() != fn {
+					if common.StaticCallee() == nil {
+						return false
+					}
+					if !check(common.StaticCallee()) {
+						return false
+					}
+				}
+			} else {
+				switch builtin.Name() {
+				case "len", "cap":
+				default:
+					return false
+				}
+			}
+			return true
+		}
+
+		var isStackAddr func(ir.Value) bool
+		isStackAddr = func(v ir.Value) bool {
+			switch v := v.(type) {
+			case *ir.Alloc:
+				return !v.Heap
+			case *ir.FieldAddr:
+				return isStackAddr(v.X)
+			default:
+				return false
+			}
+		}
+		for _, b := range fn.Blocks {
+			for _, ins := range b.Instrs {
+				switch ins := ins.(type) {
+				case *ir.Call:
+					if !checkCall(ins.Common()) {
+						return false
+					}
+				case *ir.Defer:
+					if !checkCall(&ins.Call) {
+						return false
+					}
+				case *ir.Select:
+					return false
+				case *ir.Send:
+					return false
+				case *ir.Go:
+					return false
+				case *ir.Panic:
+					return false
+				case *ir.Store:
+					if !isStackAddr(ins.Addr) {
+						return false
+					}
+				case *ir.FieldAddr:
+					if !isStackAddr(ins.X) {
+						return false
+					}
+				case *ir.Alloc:
+					// TODO(dh): make use of proper escape analysis
+					if ins.Heap {
+						return false
+					}
+				case *ir.Load:
+					if !isStackAddr(ins.X) {
+						return false
+					}
+				}
+			}
+		}
+		return true
+	}
+	for _, fn := range pass.ResultOf[buildir.Analyzer].(*buildir.IR).SrcFuncs {
+		check(fn)
+	}
+
+	out := Result{}
+	for _, fact := range pass.AllObjectFacts() {
+		out[fact.Object.(*types.Func)] = fact.Fact.(*IsPure)
+	}
+	return out, nil
+}

vendor/honnef.co/go/tools/analysis/facts/tokenfile/token.go

@@ -0,0 +1,24 @@
+package tokenfile
+
+import (
+	"go/ast"
+	"go/token"
+	"reflect"
+
+	"golang.org/x/tools/go/analysis"
+)
+
+var Analyzer = &analysis.Analyzer{
+	Name: "tokenfileanalyzer",
+	Doc:  "creates a mapping of *token.File to *ast.File",
+	Run: func(pass *analysis.Pass) (any, error) {
+		m := map[*token.File]*ast.File{}
+		for _, af := range pass.Files {
+			tf := pass.Fset.File(af.Pos())
+			m[tf] = af
+		}
+		return m, nil
+	},
+	RunDespiteErrors: true,
+	ResultType:       reflect.TypeFor[map[*token.File]*ast.File](),
+}

vendor/honnef.co/go/tools/analysis/facts/typedness/typedness.go

@@ -0,0 +1,253 @@
+package typedness
+
+import (
+	"fmt"
+	"go/token"
+	"go/types"
+	"reflect"
+
+	"honnef.co/go/tools/go/ir"
+	"honnef.co/go/tools/go/ir/irutil"
+	"honnef.co/go/tools/internal/passes/buildir"
+
+	"golang.org/x/exp/typeparams"
+	"golang.org/x/tools/go/analysis"
+)
+
+// alwaysTypedFact denotes that a function's return value will never
+// be untyped nil. The analysis errs on the side of false negatives.
+type alwaysTypedFact struct {
+	Rets uint8
+}
+
+func (*alwaysTypedFact) AFact() {}
+func (fact *alwaysTypedFact) String() string {
+	return fmt.Sprintf("always typed: %08b", fact.Rets)
+}
+
+type Result struct {
+	m map[*types.Func]uint8
+}
+
+var Analysis = &analysis.Analyzer{
+	Name:       "typedness",
+	Doc:        "Annotates return values that are always typed values",
+	Run:        run,
+	Requires:   []*analysis.Analyzer{buildir.Analyzer},
+	FactTypes:  []analysis.Fact{(*alwaysTypedFact)(nil)},
+	ResultType: reflect.TypeFor[*Result](),
+}
+
+// MustReturnTyped reports whether the ret's return value of fn must
+// be a typed value, i.e. an interface value containing a concrete
+// type or trivially a concrete type. The value of ret is zero-based.
+//
+// The analysis has false negatives: MustReturnTyped may incorrectly
+// report false, but never incorrectly reports true.
+func (r *Result) MustReturnTyped(fn *types.Func, ret int) bool {
+	if _, ok := fn.Type().(*types.Signature).Results().At(ret).Type().Underlying().(*types.Interface); !ok {
+		return true
+	}
+	return (r.m[fn] & (1 << ret)) != 0
+}
+
+func run(pass *analysis.Pass) (any, error) {
+	seen := map[*ir.Function]struct{}{}
+	out := &Result{
+		m: map[*types.Func]uint8{},
+	}
+	for _, fn := range pass.ResultOf[buildir.Analyzer].(*buildir.IR).SrcFuncs {
+		impl(pass, fn, seen)
+	}
+
+	for _, fact := range pass.AllObjectFacts() {
+		out.m[fact.Object.(*types.Func)] = fact.Fact.(*alwaysTypedFact).Rets
+	}
+
+	return out, nil
+}
+
+func impl(pass *analysis.Pass, fn *ir.Function, seenFns map[*ir.Function]struct{}) (out uint8) {
+	if fn.Signature.Results().Len() > 8 {
+		return 0
+	}
+	if fn.Object() == nil {
+		// TODO(dh): support closures
+		return 0
+	}
+	if fact := new(alwaysTypedFact); pass.ImportObjectFact(fn.Object(), fact) {
+		return fact.Rets
+	}
+	if fn.Pkg != pass.ResultOf[buildir.Analyzer].(*buildir.IR).Pkg {
+		return 0
+	}
+	if fn.Blocks == nil {
+		return 0
+	}
+	if irutil.IsStub(fn) {
+		return 0
+	}
+	if _, ok := seenFns[fn]; ok {
+		// break recursion
+		return 0
+	}
+
+	seenFns[fn] = struct{}{}
+	defer func() {
+		for i := 0; i < fn.Signature.Results().Len(); i++ {
+			if _, ok := fn.Signature.Results().At(i).Type().Underlying().(*types.Interface); !ok {
+				// we don't need facts to know that non-interface
+				// types can't be untyped nil. zeroing out those bits
+				// may result in all bits being zero, in which case we
+				// don't have to save any fact.
+				out &= ^(1 << i)
+			}
+		}
+		if out > 0 {
+			pass.ExportObjectFact(fn.Object(), &alwaysTypedFact{out})
+		}
+	}()
+
+	isUntypedNil := func(v ir.Value) bool {
+		k, ok := v.(*ir.Const)
+		if !ok {
+			return false
+		}
+		if _, ok := k.Type().Underlying().(*types.Interface); !ok {
+			return false
+		}
+		return k.Value == nil
+	}
+
+	var do func(v ir.Value, seen map[ir.Value]struct{}) bool
+	do = func(v ir.Value, seen map[ir.Value]struct{}) bool {
+		if _, ok := seen[v]; ok {
+			// break cycle
+			return false
+		}
+		seen[v] = struct{}{}
+		switch v := v.(type) {
+		case *ir.Const:
+			// can't be a typed nil, because then we'd be returning the
+			// result of MakeInterface.
+			return false
+		case *ir.ChangeInterface:
+			return do(v.X, seen)
+		case *ir.Extract:
+			call, ok := v.Tuple.(*ir.Call)
+			if !ok {
+				// We only care about extracts of function results. For
+				// everything else (e.g. channel receives and map
+				// lookups), we can either not deduce any information, or
+				// will see a MakeInterface.
+				return false
+			}
+			if callee := call.Call.StaticCallee(); callee != nil {
+				return impl(pass, callee, seenFns)&(1<<v.Index) != 0
+			} else {
+				// we don't know what function we're calling. no need
+				// to look at the signature, though. if it weren't an
+				// interface, we'd be seeing a MakeInterface
+				// instruction.
+				return false
+			}
+		case *ir.Call:
+			if callee := v.Call.StaticCallee(); callee != nil {
+				return impl(pass, callee, seenFns)&1 != 0
+			} else {
+				// we don't know what function we're calling. no need
+				// to look at the signature, though. if it weren't an
+				// interface, we'd be seeing a MakeInterface
+				// instruction.
+				return false
+			}
+		case *ir.Sigma:
+			iff, ok := v.From.Control().(*ir.If)
+			if !ok {
+				// give up
+				return false
+			}
+
+			binop, ok := iff.Cond.(*ir.BinOp)
+			if !ok {
+				// give up
+				return false
+			}
+
+			if (binop.X == v.X && isUntypedNil(binop.Y)) || (isUntypedNil(binop.X) && binop.Y == v.X) {
+				op := binop.Op
+				if v.From.Succs[0] != v.Block() {
+					// we're in the false branch, negate op
+					switch op {
+					case token.EQL:
+						op = token.NEQ
+					case token.NEQ:
+						op = token.EQL
+					default:
+						panic(fmt.Sprintf("internal error: unhandled token %v", op))
+					}
+				}
+
+				switch op {
+				case token.EQL:
+					// returned value equals untyped nil
+					return false
+				case token.NEQ:
+					// returned value does not equal untyped nil
+					return true
+				default:
+					panic(fmt.Sprintf("internal error: unhandled token %v", op))
+				}
+			}
+
+			// TODO(dh): handle comparison with typed nil
+
+			// give up
+			return false
+		case *ir.Phi:
+			for _, pv := range v.Edges {
+				if !do(pv, seen) {
+					return false
+				}
+			}
+			return true
+		case *ir.MakeInterface:
+			terms, err := typeparams.NormalTerms(v.X.Type())
+			if len(terms) == 0 || err != nil {
+				// Type is a type parameter with no type terms (or we couldn't determine the terms). Such a type
+				// _can_ be nil when put in an interface value.
+				//
+				// There is no instruction that can create a guaranteed non-nil instance of a type parameter without
+				// type constraints, so we return false right away, without checking v.X's typedness.
+				return false
+			}
+			return true
+		case *ir.TypeAssert:
+			// type assertions fail for untyped nils. Either we have a
+			// single lhs and the type assertion succeeds or panics,
+			// or we have two lhs and we'll return Extract instead.
+			return true
+		case *ir.ChangeType:
+			// we'll only see interface->interface conversions, which
+			// don't tell us anything about the nilness.
+			return false
+		case *ir.MapLookup, *ir.Index, *ir.Recv, *ir.Parameter, *ir.Load, *ir.Field:
+			// All other instructions that tell us nothing about the
+			// typedness of interface values.
+			return false
+		default:
+			panic(fmt.Sprintf("internal error: unhandled type %T", v))
+		}
+	}
+
+	ret := fn.Exit.Control().(*ir.Return)
+	for i, v := range ret.Results {
+		typ := fn.Signature.Results().At(i).Type()
+		if _, ok := typ.Underlying().(*types.Interface); ok && !typeparams.IsTypeParam(typ) {
+			if do(v, map[ir.Value]struct{}{}) {
+				out |= 1 << i
+			}
+		}
+	}
+	return out
+}

vendor/honnef.co/go/tools/analysis/lint/lint.go

@@ -0,0 +1,221 @@
+// Package lint provides abstractions on top of go/analysis.
+// These abstractions add extra information to analyzes, such as structured documentation and severities.
+package lint
+
+import (
+	"fmt"
+	"go/ast"
+	"go/token"
+	"strings"
+
+	"golang.org/x/tools/go/analysis"
+	"honnef.co/go/tools/analysis/facts/tokenfile"
+)
+
+// Analyzer wraps a go/analysis.Analyzer and provides structured documentation.
+type Analyzer struct {
+	// The analyzer's documentation. Unlike go/analysis.Analyzer.Doc,
+	// this field is structured, providing access to severity, options
+	// etc.
+	Doc      *RawDocumentation
+	Analyzer *analysis.Analyzer
+}
+
+func InitializeAnalyzer(a *Analyzer) *Analyzer {
+	a.Analyzer.Doc = a.Doc.Compile().String()
+	a.Analyzer.URL = "https://staticcheck.dev/docs/checks/#" + a.Analyzer.Name
+	a.Analyzer.Requires = append(a.Analyzer.Requires, tokenfile.Analyzer)
+	return a
+}
+
+// Severity describes the severity of diagnostics reported by an analyzer.
+type Severity int
+
+const (
+	SeverityNone Severity = iota
+	SeverityError
+	SeverityDeprecated
+	SeverityWarning
+	SeverityInfo
+	SeverityHint
+)
+
+// MergeStrategy sets how merge mode should behave for diagnostics of an analyzer.
+type MergeStrategy int
+
+const (
+	MergeIfAny MergeStrategy = iota
+	MergeIfAll
+)
+
+type RawDocumentation struct {
+	Title      string
+	Text       string
+	Before     string
+	After      string
+	Since      string
+	NonDefault bool
+	Options    []string
+	Severity   Severity
+	MergeIf    MergeStrategy
+}
+
+type Documentation struct {
+	Title string
+	Text  string
+
+	TitleMarkdown string
+	TextMarkdown  string
+
+	Before     string
+	After      string
+	Since      string
+	NonDefault bool
+	Options    []string
+	Severity   Severity
+	MergeIf    MergeStrategy
+}
+
+func (doc RawDocumentation) Compile() *Documentation {
+	return &Documentation{
+		Title: strings.TrimSpace(stripMarkdown(doc.Title)),
+		Text:  strings.TrimSpace(stripMarkdown(doc.Text)),
+
+		TitleMarkdown: strings.TrimSpace(toMarkdown(doc.Title)),
+		TextMarkdown:  strings.TrimSpace(toMarkdown(doc.Text)),
+
+		Before:     strings.TrimSpace(doc.Before),
+		After:      strings.TrimSpace(doc.After),
+		Since:      doc.Since,
+		NonDefault: doc.NonDefault,
+		Options:    doc.Options,
+		Severity:   doc.Severity,
+		MergeIf:    doc.MergeIf,
+	}
+}
+
+func toMarkdown(s string) string {
+	return strings.NewReplacer(`\'`, "`", `\"`, "`").Replace(s)
+}
+
+func stripMarkdown(s string) string {
+	return strings.NewReplacer(`\'`, "", `\"`, "'").Replace(s)
+}
+
+func (doc *Documentation) Format(metadata bool) string {
+	return doc.format(false, metadata)
+}
+
+func (doc *Documentation) FormatMarkdown(metadata bool) string {
+	return doc.format(true, metadata)
+}
+
+func (doc *Documentation) format(markdown bool, metadata bool) string {
+	b := &strings.Builder{}
+	if markdown {
+		fmt.Fprintf(b, "%s\n\n", doc.TitleMarkdown)
+		if doc.Text != "" {
+			fmt.Fprintf(b, "%s\n\n", doc.TextMarkdown)
+		}
+	} else {
+		fmt.Fprintf(b, "%s\n\n", doc.Title)
+		if doc.Text != "" {
+			fmt.Fprintf(b, "%s\n\n", doc.Text)
+		}
+	}
+
+	if doc.Before != "" {
+		fmt.Fprintln(b, "Before:")
+		fmt.Fprintln(b, "")
+		for line := range strings.SplitSeq(doc.Before, "\n") {
+			fmt.Fprint(b, "    ", line, "\n")
+		}
+		fmt.Fprintln(b, "")
+		fmt.Fprintln(b, "After:")
+		fmt.Fprintln(b, "")
+		for line := range strings.SplitSeq(doc.After, "\n") {
+			fmt.Fprint(b, "    ", line, "\n")
+		}
+		fmt.Fprintln(b, "")
+	}
+
+	if metadata {
+		fmt.Fprint(b, "Available since\n    ")
+		if doc.Since == "" {
+			fmt.Fprint(b, "unreleased")
+		} else {
+			fmt.Fprintf(b, "%s", doc.Since)
+		}
+		if doc.NonDefault {
+			fmt.Fprint(b, ", non-default")
+		}
+		fmt.Fprint(b, "\n")
+		if len(doc.Options) > 0 {
+			fmt.Fprintf(b, "\nOptions\n")
+			for _, opt := range doc.Options {
+				fmt.Fprintf(b, "    %s", opt)
+			}
+			fmt.Fprint(b, "\n")
+		}
+	}
+
+	return b.String()
+}
+
+func (doc *Documentation) String() string {
+	return doc.Format(true)
+}
+
+// ExhaustiveTypeSwitch panics when called. It can be used to ensure
+// that type switches are exhaustive.
+func ExhaustiveTypeSwitch(v any) {
+	panic(fmt.Sprintf("internal error: unhandled case %T", v))
+}
+
+// A directive is a comment of the form '//lint:<command>
+// [arguments...]'. It represents instructions to the static analysis
+// tool.
+type Directive struct {
+	Command   string
+	Arguments []string
+	Directive *ast.Comment
+	Node      ast.Node
+}
+
+func parseDirective(s string) (cmd string, args []string) {
+	if !strings.HasPrefix(s, "//lint:") {
+		return "", nil
+	}
+	s = strings.TrimPrefix(s, "//lint:")
+	fields := strings.Split(s, " ")
+	return fields[0], fields[1:]
+}
+
+// ParseDirectives extracts all directives from a list of Go files.
+func ParseDirectives(files []*ast.File, fset *token.FileSet) []Directive {
+	var dirs []Directive
+	for _, f := range files {
+		// OPT(dh): in our old code, we skip all the comment map work if we
+		// couldn't find any directives, benchmark if that's actually
+		// worth doing
+		cm := ast.NewCommentMap(fset, f, f.Comments)
+		for node, cgs := range cm {
+			for _, cg := range cgs {
+				for _, c := range cg.List {
+					if !strings.HasPrefix(c.Text, "//lint:") {
+						continue
+					}
+					cmd, args := parseDirective(c.Text)
+					d := Directive{
+						Command:   cmd,
+						Arguments: args,
+						Directive: c,
+						Node:      node,
+					}
+					dirs = append(dirs, d)
+				}
+			}
+		}
+	}
+	return dirs
+}

vendor/honnef.co/go/tools/analysis/report/report.go

@@ -0,0 +1,281 @@
+package report
+
+import (
+	"bytes"
+	"fmt"
+	"go/ast"
+	"go/format"
+	"go/token"
+	"go/version"
+	"path/filepath"
+	"strconv"
+	"strings"
+
+	"honnef.co/go/tools/analysis/code"
+	"honnef.co/go/tools/analysis/facts/generated"
+	"honnef.co/go/tools/go/ast/astutil"
+
+	"golang.org/x/tools/go/analysis"
+)
+
+type Options struct {
+	ShortRange             bool
+	FilterGenerated        bool
+	Fixes                  []analysis.SuggestedFix
+	Related                []analysis.RelatedInformation
+	MinimumLanguageVersion string
+	MaximumLanguageVersion string
+	MinimumStdlibVersion   string
+	MaximumStdlibVersion   string
+}
+
+type Option func(*Options)
+
+func ShortRange() Option {
+	return func(opts *Options) {
+		opts.ShortRange = true
+	}
+}
+
+func FilterGenerated() Option {
+	return func(opts *Options) {
+		opts.FilterGenerated = true
+	}
+}
+
+func Fixes(fixes ...analysis.SuggestedFix) Option {
+	return func(opts *Options) {
+		opts.Fixes = append(opts.Fixes, fixes...)
+	}
+}
+
+func Related(node Positioner, message string) Option {
+	return func(opts *Options) {
+		pos, end, ok := getRange(node, opts.ShortRange)
+		if !ok {
+			return
+		}
+		r := analysis.RelatedInformation{
+			Pos:     pos,
+			End:     end,
+			Message: message,
+		}
+		opts.Related = append(opts.Related, r)
+	}
+}
+
+func MinimumLanguageVersion(vers string) Option {
+	return func(opts *Options) { opts.MinimumLanguageVersion = vers }
+}
+func MaximumLanguageVersion(vers string) Option {
+	return func(opts *Options) { opts.MinimumLanguageVersion = vers }
+}
+func MinimumStdlibVersion(vers string) Option {
+	return func(opts *Options) { opts.MinimumStdlibVersion = vers }
+}
+func MaximumStdlibVersion(vers string) Option {
+	return func(opts *Options) { opts.MaximumStdlibVersion = vers }
+}
+
+type Positioner interface {
+	Pos() token.Pos
+}
+
+type fullPositioner interface {
+	Pos() token.Pos
+	End() token.Pos
+}
+
+type sourcer interface {
+	Source() ast.Node
+}
+
+// shortRange returns the position and end of the main component of an
+// AST node. For nodes that have no body, the short range is identical
+// to the node's Pos and End. For nodes that do have a body, the short
+// range excludes the body.
+func shortRange(node ast.Node) (pos, end token.Pos) {
+	switch node := node.(type) {
+	case *ast.File:
+		return node.Pos(), node.Name.End()
+	case *ast.CaseClause:
+		return node.Pos(), node.Colon + 1
+	case *ast.CommClause:
+		return node.Pos(), node.Colon + 1
+	case *ast.DeferStmt:
+		return node.Pos(), node.Defer + token.Pos(len("defer"))
+	case *ast.ExprStmt:
+		return shortRange(node.X)
+	case *ast.ForStmt:
+		if node.Post != nil {
+			return node.For, node.Post.End()
+		} else if node.Cond != nil {
+			return node.For, node.Cond.End()
+		} else if node.Init != nil {
+			// +1 to catch the semicolon, for gofmt'ed code
+			return node.Pos(), node.Init.End() + 1
+		} else {
+			return node.Pos(), node.For + token.Pos(len("for"))
+		}
+	case *ast.FuncDecl:
+		return node.Pos(), node.Type.End()
+	case *ast.FuncLit:
+		return node.Pos(), node.Type.End()
+	case *ast.GoStmt:
+		if _, ok := astutil.Unparen(node.Call.Fun).(*ast.FuncLit); ok {
+			return node.Pos(), node.Go + token.Pos(len("go"))
+		} else {
+			return node.Pos(), node.End()
+		}
+	case *ast.IfStmt:
+		return node.Pos(), node.Cond.End()
+	case *ast.RangeStmt:
+		return node.Pos(), node.X.End()
+	case *ast.SelectStmt:
+		return node.Pos(), node.Pos() + token.Pos(len("select"))
+	case *ast.SwitchStmt:
+		if node.Tag != nil {
+			return node.Pos(), node.Tag.End()
+		} else if node.Init != nil {
+			// +1 to catch the semicolon, for gofmt'ed code
+			return node.Pos(), node.Init.End() + 1
+		} else {
+			return node.Pos(), node.Pos() + token.Pos(len("switch"))
+		}
+	case *ast.TypeSwitchStmt:
+		return node.Pos(), node.Assign.End()
+	default:
+		return node.Pos(), node.End()
+	}
+}
+
+func HasRange(node Positioner) bool {
+	// we don't know if getRange will be called with shortRange set to
+	// true, so make sure that both work.
+	_, _, ok := getRange(node, false)
+	if !ok {
+		return false
+	}
+	_, _, ok = getRange(node, true)
+	return ok
+}
+
+func getRange(node Positioner, short bool) (pos, end token.Pos, ok bool) {
+	switch n := node.(type) {
+	case sourcer:
+		s := n.Source()
+		if s == nil {
+			return 0, 0, false
+		}
+		if short {
+			p, e := shortRange(s)
+			return p, e, true
+		}
+		return s.Pos(), s.End(), true
+	case fullPositioner:
+		if short {
+			p, e := shortRange(n)
+			return p, e, true
+		}
+		return n.Pos(), n.End(), true
+	default:
+		return n.Pos(), token.NoPos, true
+	}
+}
+
+func Report(pass *analysis.Pass, node Positioner, message string, opts ...Option) {
+	cfg := &Options{}
+	for _, opt := range opts {
+		opt(cfg)
+	}
+
+	langVersion := code.LanguageVersion(pass, node)
+	stdlibVersion := code.StdlibVersion(pass, node)
+	if n := cfg.MaximumLanguageVersion; n != "" && version.Compare(n, langVersion) == -1 {
+		return
+	}
+	if n := cfg.MaximumStdlibVersion; n != "" && version.Compare(n, stdlibVersion) == -1 {
+		return
+	}
+	if n := cfg.MinimumLanguageVersion; n != "" && version.Compare(n, langVersion) == 1 {
+		return
+	}
+	if n := cfg.MinimumStdlibVersion; n != "" && version.Compare(n, stdlibVersion) == 1 {
+		return
+	}
+
+	file := DisplayPosition(pass.Fset, node.Pos()).Filename
+	if cfg.FilterGenerated {
+		m := pass.ResultOf[generated.Analyzer].(map[string]generated.Generator)
+		if _, ok := m[file]; ok {
+			return
+		}
+	}
+
+	pos, end, ok := getRange(node, cfg.ShortRange)
+	if !ok {
+		panic(fmt.Sprintf("no valid position for reporting node %v", node))
+	}
+	d := analysis.Diagnostic{
+		Pos:            pos,
+		End:            end,
+		Message:        message,
+		SuggestedFixes: cfg.Fixes,
+		Related:        cfg.Related,
+	}
+	pass.Report(d)
+}
+
+func Render(pass *analysis.Pass, x any) string {
+	var buf bytes.Buffer
+	if err := format.Node(&buf, pass.Fset, x); err != nil {
+		panic(err)
+	}
+	return buf.String()
+}
+
+func RenderArgs(pass *analysis.Pass, args []ast.Expr) string {
+	var ss []string
+	for _, arg := range args {
+		ss = append(ss, Render(pass, arg))
+	}
+	return strings.Join(ss, ", ")
+}
+
+func DisplayPosition(fset *token.FileSet, p token.Pos) token.Position {
+	if p == token.NoPos {
+		return token.Position{}
+	}
+
+	// Only use the adjusted position if it points to another Go file.
+	// This means we'll point to the original file for cgo files, but
+	// we won't point to a YACC grammar file.
+	pos := fset.PositionFor(p, false)
+	adjPos := fset.PositionFor(p, true)
+
+	if filepath.Ext(adjPos.Filename) == ".go" {
+		return adjPos
+	}
+
+	return pos
+}
+
+func Ordinal(n int) string {
+	suffix := "th"
+	if n < 10 || n > 20 {
+		switch n % 10 {
+		case 0:
+			suffix = "th"
+		case 1:
+			suffix = "st"
+		case 2:
+			suffix = "nd"
+		case 3:
+			suffix = "rd"
+		default:
+			suffix = "th"
+		}
+	}
+
+	return strconv.Itoa(n) + suffix
+}

vendor/honnef.co/go/tools/cmd/staticcheck/README.md

@@ -0,0 +1,15 @@
+# staticcheck
+
+_staticcheck_ offers extensive analysis of Go code, covering a myriad
+of categories. It will detect bugs, suggest code simplifications,
+point out dead code, and more.
+
+## Installation
+
+See [the main README](https://github.com/dominikh/go-tools#installation) for installation instructions.
+
+## Documentation
+
+Detailed documentation can be found on
+[staticcheck.dev](https://staticcheck.dev/docs/).
+

vendor/honnef.co/go/tools/cmd/staticcheck/staticcheck.go

@@ -0,0 +1,45 @@
+// staticcheck analyses Go code and makes it better.
+package main
+
+import (
+	"log"
+	"os"
+
+	"honnef.co/go/tools/lintcmd"
+	"honnef.co/go/tools/lintcmd/version"
+	"honnef.co/go/tools/quickfix"
+	"honnef.co/go/tools/simple"
+	"honnef.co/go/tools/staticcheck"
+	"honnef.co/go/tools/stylecheck"
+	"honnef.co/go/tools/unused"
+)
+
+func main() {
+	cmd := lintcmd.NewCommand("staticcheck")
+	cmd.SetVersion(version.Version, version.MachineVersion)
+
+	fs := cmd.FlagSet()
+	debug := fs.String("debug.unused-graph", "", "Write unused's object graph to `file`")
+	qf := fs.Bool("debug.run-quickfix-analyzers", false, "Run quickfix analyzers")
+
+	cmd.ParseFlags(os.Args[1:])
+
+	cmd.AddAnalyzers(simple.Analyzers...)
+	cmd.AddAnalyzers(staticcheck.Analyzers...)
+	cmd.AddAnalyzers(stylecheck.Analyzers...)
+	cmd.AddAnalyzers(unused.Analyzer)
+
+	if *qf {
+		cmd.AddAnalyzers(quickfix.Analyzers...)
+	}
+
+	if *debug != "" {
+		f, err := os.OpenFile(*debug, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0666)
+		if err != nil {
+			log.Fatal(err)
+		}
+		unused.Debug = f
+	}
+
+	cmd.Run()
+}

vendor/honnef.co/go/tools/config/config.go

@@ -0,0 +1,278 @@
+package config
+
+import (
+	"bytes"
+	"fmt"
+	"go/ast"
+	"go/token"
+	"os"
+	"path/filepath"
+	"reflect"
+	"strings"
+
+	"github.com/BurntSushi/toml"
+	"golang.org/x/tools/go/analysis"
+)
+
+// Dir looks at a list of absolute file names, which should make up a
+// single package, and returns the path of the directory that may
+// contain a staticcheck.conf file. It returns the empty string if no
+// such directory could be determined, for example because all files
+// were located in Go's build cache.
+func Dir(files []string) string {
+	if len(files) == 0 {
+		return ""
+	}
+	cache, err := os.UserCacheDir()
+	if err != nil {
+		cache = ""
+	}
+	var path string
+	for _, p := range files {
+		// FIXME(dh): using strings.HasPrefix isn't technically
+		// correct, but it should be good enough for now.
+		if cache != "" && strings.HasPrefix(p, cache) {
+			// File in the build cache of the standard Go build system
+			continue
+		}
+		path = p
+		break
+	}
+
+	if path == "" {
+		// The package only consists of generated files.
+		return ""
+	}
+
+	dir := filepath.Dir(path)
+	return dir
+}
+
+func dirAST(files []*ast.File, fset *token.FileSet) string {
+	names := make([]string, len(files))
+	for i, f := range files {
+		names[i] = fset.PositionFor(f.Pos(), true).Filename
+	}
+	return Dir(names)
+}
+
+var Analyzer = &analysis.Analyzer{
+	Name: "config",
+	Doc:  "loads configuration for the current package tree",
+	Run: func(pass *analysis.Pass) (any, error) {
+		dir := dirAST(pass.Files, pass.Fset)
+		if dir == "" {
+			cfg := DefaultConfig
+			return &cfg, nil
+		}
+		cfg, err := Load(dir)
+		if err != nil {
+			return nil, fmt.Errorf("error loading staticcheck.conf: %s", err)
+		}
+		return &cfg, nil
+	},
+	RunDespiteErrors: true,
+	ResultType:       reflect.TypeFor[*Config](),
+}
+
+func For(pass *analysis.Pass) *Config {
+	return pass.ResultOf[Analyzer].(*Config)
+}
+
+func mergeLists(a, b []string) []string {
+	out := make([]string, 0, len(a)+len(b))
+	for _, el := range b {
+		if el == "inherit" {
+			out = append(out, a...)
+		} else {
+			out = append(out, el)
+		}
+	}
+
+	return out
+}
+
+func normalizeList(list []string) []string {
+	if len(list) > 1 {
+		nlist := make([]string, 0, len(list))
+		nlist = append(nlist, list[0])
+		for i, el := range list[1:] {
+			if el != list[i] {
+				nlist = append(nlist, el)
+			}
+		}
+		list = nlist
+	}
+
+	for _, el := range list {
+		if el == "inherit" {
+			// This should never happen, because the default config
+			// should not use "inherit"
+			panic(`unresolved "inherit"`)
+		}
+	}
+
+	return list
+}
+
+func (cfg Config) Merge(ocfg Config) Config {
+	if ocfg.Checks != nil {
+		cfg.Checks = mergeLists(cfg.Checks, ocfg.Checks)
+	}
+	if ocfg.Initialisms != nil {
+		cfg.Initialisms = mergeLists(cfg.Initialisms, ocfg.Initialisms)
+	}
+	if ocfg.DotImportWhitelist != nil {
+		cfg.DotImportWhitelist = mergeLists(cfg.DotImportWhitelist, ocfg.DotImportWhitelist)
+	}
+	if ocfg.HTTPStatusCodeWhitelist != nil {
+		cfg.HTTPStatusCodeWhitelist = mergeLists(cfg.HTTPStatusCodeWhitelist, ocfg.HTTPStatusCodeWhitelist)
+	}
+	return cfg
+}
+
+type Config struct {
+	// TODO(dh): this implementation makes it impossible for external
+	// clients to add their own checkers with configuration. At the
+	// moment, we don't really care about that; we don't encourage
+	// that people use this package. In the future, we may. The
+	// obvious solution would be using map[string]interface{}, but
+	// that's obviously subpar.
+
+	Checks                  []string `toml:"checks"`
+	Initialisms             []string `toml:"initialisms"`
+	DotImportWhitelist      []string `toml:"dot_import_whitelist"`
+	HTTPStatusCodeWhitelist []string `toml:"http_status_code_whitelist"`
+}
+
+func (c Config) String() string {
+	buf := &bytes.Buffer{}
+
+	fmt.Fprintf(buf, "Checks: %#v\n", c.Checks)
+	fmt.Fprintf(buf, "Initialisms: %#v\n", c.Initialisms)
+	fmt.Fprintf(buf, "DotImportWhitelist: %#v\n", c.DotImportWhitelist)
+	fmt.Fprintf(buf, "HTTPStatusCodeWhitelist: %#v", c.HTTPStatusCodeWhitelist)
+
+	return buf.String()
+}
+
+// DefaultConfig is the default configuration.
+// Its initial value describes the majority of the default configuration,
+// but the Checks field can be updated at runtime based on the analyzers being used, to disable non-default checks.
+// For cmd/staticcheck, this is handled by (*lintcmd.Command).Run.
+//
+// Note that DefaultConfig shouldn't be modified while analyzers are executing.
+var DefaultConfig = Config{
+	Checks: []string{"all"},
+	Initialisms: []string{
+		"ACL", "API", "ASCII", "CPU", "CSS", "DNS",
+		"EOF", "GUID", "HTML", "HTTP", "HTTPS", "ID",
+		"IP", "JSON", "QPS", "RAM", "RPC", "SLA",
+		"SMTP", "SQL", "SSH", "TCP", "TLS", "TTL",
+		"UDP", "UI", "GID", "UID", "UUID", "URI",
+		"URL", "UTF8", "VM", "XML", "XMPP", "XSRF",
+		"XSS", "SIP", "RTP", "AMQP", "DB", "TS",
+	},
+	DotImportWhitelist: []string{
+		"simd/archsimd",
+		"github.com/mmcloughlin/avo/build",
+		"github.com/mmcloughlin/avo/operand",
+		"github.com/mmcloughlin/avo/reg",
+	},
+	HTTPStatusCodeWhitelist: []string{"200", "400", "404", "500"},
+}
+
+const ConfigName = "staticcheck.conf"
+
+type ParseError struct {
+	Filename string
+	toml.ParseError
+}
+
+func parseConfigs(dir string) ([]Config, error) {
+	var out []Config
+
+	// TODO(dh): consider stopping at the GOPATH/module boundary
+	for dir != "" {
+		path := filepath.Join(dir, ConfigName)
+		fi, err := os.Stat(path)
+		if os.IsNotExist(err) || (err == nil && !fi.Mode().IsRegular()) {
+			// walk up
+			ndir := filepath.Dir(dir)
+			if ndir == dir {
+				break
+			}
+			dir = ndir
+			continue
+		}
+		if err != nil {
+			return nil, err
+		}
+
+		// There is a small TOCTOU window here, but we're fine with reporting an
+		// error if the source tree is modified concurrently in weird ways while
+		// running Staticcheck.
+		f, err := os.Open(path)
+		if err != nil {
+			return nil, err
+		}
+
+		var cfg Config
+		_, err = toml.NewDecoder(f).Decode(&cfg)
+		f.Close()
+		if err != nil {
+			if err, ok := err.(toml.ParseError); ok {
+				return nil, ParseError{
+					Filename:   filepath.Join(dir, ConfigName),
+					ParseError: err,
+				}
+			}
+			return nil, err
+		}
+		out = append(out, cfg)
+		ndir := filepath.Dir(dir)
+		if ndir == dir {
+			break
+		}
+		dir = ndir
+	}
+	out = append(out, DefaultConfig)
+	if len(out) < 2 {
+		return out, nil
+	}
+	for i := 0; i < len(out)/2; i++ {
+		out[i], out[len(out)-1-i] = out[len(out)-1-i], out[i]
+	}
+	return out, nil
+}
+
+func mergeConfigs(confs []Config) Config {
+	if len(confs) == 0 {
+		// This shouldn't happen because we always have at least a
+		// default config.
+		panic("trying to merge zero configs")
+	}
+	if len(confs) == 1 {
+		return confs[0]
+	}
+	conf := confs[0]
+	for _, oconf := range confs[1:] {
+		conf = conf.Merge(oconf)
+	}
+	return conf
+}
+
+func Load(dir string) (Config, error) {
+	confs, err := parseConfigs(dir)
+	if err != nil {
+		return Config{}, err
+	}
+	conf := mergeConfigs(confs)
+
+	conf.Checks = normalizeList(conf.Checks)
+	conf.Initialisms = normalizeList(conf.Initialisms)
+	conf.DotImportWhitelist = normalizeList(conf.DotImportWhitelist)
+	conf.HTTPStatusCodeWhitelist = normalizeList(conf.HTTPStatusCodeWhitelist)
+
+	return conf, nil
+}

vendor/honnef.co/go/tools/config/example.conf

@@ -0,0 +1,15 @@
+checks = ["all", "-SA9003", "-ST1000", "-ST1003", "-ST1016", "-ST1020", "-ST1021", "-ST1022", "-ST1023"]
+initialisms = ["ACL", "API", "ASCII", "CPU", "CSS", "DNS",
+	"EOF", "GUID", "HTML", "HTTP", "HTTPS", "ID",
+	"IP", "JSON", "QPS", "RAM", "RPC", "SLA",
+	"SMTP", "SQL", "SSH", "TCP", "TLS", "TTL",
+	"UDP", "UI", "GID", "UID", "UUID", "URI",
+	"URL", "UTF8", "VM", "XML", "XMPP", "XSRF",
+	"XSS", "SIP", "RTP", "AMQP", "DB", "TS"]
+dot_import_whitelist = [
+    "simd/archsimd",
+    "github.com/mmcloughlin/avo/build",
+    "github.com/mmcloughlin/avo/operand",
+    "github.com/mmcloughlin/avo/reg",
+]
+http_status_code_whitelist = ["200", "400", "404", "500"]

vendor/honnef.co/go/tools/go/ast/astutil/upstream.go

@@ -0,0 +1,20 @@
+package astutil
+
+import (
+	"go/ast"
+	"go/token"
+	_ "unsafe"
+
+	"golang.org/x/tools/go/ast/astutil"
+)
+
+type Cursor = astutil.Cursor
+type ApplyFunc = astutil.ApplyFunc
+
+func Apply(root ast.Node, pre, post ApplyFunc) (result ast.Node) {
+	return astutil.Apply(root, pre, post)
+}
+
+func PathEnclosingInterval(root *ast.File, start, end token.Pos) (path []ast.Node, exact bool) {
+	return astutil.PathEnclosingInterval(root, start, end)
+}

vendor/honnef.co/go/tools/go/ast/astutil/util.go

@@ -0,0 +1,473 @@
+package astutil
+
+import (
+	"fmt"
+	"go/ast"
+	"go/token"
+	"reflect"
+	"strings"
+
+	"golang.org/x/tools/go/ast/astutil"
+)
+
+func IsIdent(expr ast.Expr, ident string) bool {
+	id, ok := expr.(*ast.Ident)
+	return ok && id.Name == ident
+}
+
+// isBlank returns whether id is the blank identifier "_".
+// If id == nil, the answer is false.
+func IsBlank(id ast.Expr) bool {
+	ident, _ := id.(*ast.Ident)
+	return ident != nil && ident.Name == "_"
+}
+
+// Deprecated: use code.IsIntegerLiteral instead.
+func IsIntLiteral(expr ast.Expr, literal string) bool {
+	lit, ok := expr.(*ast.BasicLit)
+	return ok && lit.Kind == token.INT && lit.Value == literal
+}
+
+// Deprecated: use IsIntLiteral instead
+func IsZero(expr ast.Expr) bool {
+	return IsIntLiteral(expr, "0")
+}
+
+func Preamble(f *ast.File) string {
+	cutoff := f.Package
+	if f.Doc != nil {
+		cutoff = f.Doc.Pos()
+	}
+	var out []string
+	for _, cmt := range f.Comments {
+		if cmt.Pos() >= cutoff {
+			break
+		}
+		out = append(out, cmt.Text())
+	}
+	return strings.Join(out, "\n")
+}
+
+func GroupSpecs(fset *token.FileSet, specs []ast.Spec) [][]ast.Spec {
+	if len(specs) == 0 {
+		return nil
+	}
+	groups := make([][]ast.Spec, 1)
+	groups[0] = append(groups[0], specs[0])
+
+	for _, spec := range specs[1:] {
+		g := groups[len(groups)-1]
+		if fset.PositionFor(spec.Pos(), false).Line-1 !=
+			fset.PositionFor(g[len(g)-1].End(), false).Line {
+
+			groups = append(groups, nil)
+		}
+
+		groups[len(groups)-1] = append(groups[len(groups)-1], spec)
+	}
+
+	return groups
+}
+
+// Unparen returns e with any enclosing parentheses stripped.
+func Unparen(e ast.Expr) ast.Expr {
+	for {
+		p, ok := e.(*ast.ParenExpr)
+		if !ok {
+			return e
+		}
+		e = p.X
+	}
+}
+
+// CopyExpr creates a deep copy of an expression.
+// It doesn't support copying FuncLits and returns ok == false when encountering one.
+func CopyExpr(node ast.Expr) (ast.Expr, bool) {
+	switch node := node.(type) {
+	case *ast.BasicLit:
+		cp := *node
+		return &cp, true
+	case *ast.BinaryExpr:
+		cp := *node
+		var ok1, ok2 bool
+		cp.X, ok1 = CopyExpr(cp.X)
+		cp.Y, ok2 = CopyExpr(cp.Y)
+		return &cp, ok1 && ok2
+	case *ast.CallExpr:
+		var ok bool
+		cp := *node
+		cp.Fun, ok = CopyExpr(cp.Fun)
+		if !ok {
+			return nil, false
+		}
+		cp.Args = make([]ast.Expr, len(node.Args))
+		for i, v := range node.Args {
+			cp.Args[i], ok = CopyExpr(v)
+			if !ok {
+				return nil, false
+			}
+		}
+		return &cp, true
+	case *ast.CompositeLit:
+		var ok bool
+		cp := *node
+		cp.Type, ok = CopyExpr(cp.Type)
+		if !ok {
+			return nil, false
+		}
+		cp.Elts = make([]ast.Expr, len(node.Elts))
+		for i, v := range node.Elts {
+			cp.Elts[i], ok = CopyExpr(v)
+			if !ok {
+				return nil, false
+			}
+		}
+		return &cp, true
+	case *ast.Ident:
+		cp := *node
+		return &cp, true
+	case *ast.IndexExpr:
+		var ok1, ok2 bool
+		cp := *node
+		cp.X, ok1 = CopyExpr(cp.X)
+		cp.Index, ok2 = CopyExpr(cp.Index)
+		return &cp, ok1 && ok2
+	case *ast.IndexListExpr:
+		var ok bool
+		cp := *node
+		cp.X, ok = CopyExpr(cp.X)
+		if !ok {
+			return nil, false
+		}
+		for i, v := range node.Indices {
+			cp.Indices[i], ok = CopyExpr(v)
+			if !ok {
+				return nil, false
+			}
+		}
+		return &cp, true
+	case *ast.KeyValueExpr:
+		var ok1, ok2 bool
+		cp := *node
+		cp.Key, ok1 = CopyExpr(cp.Key)
+		cp.Value, ok2 = CopyExpr(cp.Value)
+		return &cp, ok1 && ok2
+	case *ast.ParenExpr:
+		var ok bool
+		cp := *node
+		cp.X, ok = CopyExpr(cp.X)
+		return &cp, ok
+	case *ast.SelectorExpr:
+		var ok bool
+		cp := *node
+		cp.X, ok = CopyExpr(cp.X)
+		if !ok {
+			return nil, false
+		}
+		sel, ok := CopyExpr(cp.Sel)
+		if !ok {
+			// this is impossible
+			return nil, false
+		}
+		cp.Sel = sel.(*ast.Ident)
+		return &cp, true
+	case *ast.SliceExpr:
+		var ok1, ok2, ok3, ok4 bool
+		cp := *node
+		cp.X, ok1 = CopyExpr(cp.X)
+		cp.Low, ok2 = CopyExpr(cp.Low)
+		cp.High, ok3 = CopyExpr(cp.High)
+		cp.Max, ok4 = CopyExpr(cp.Max)
+		return &cp, ok1 && ok2 && ok3 && ok4
+	case *ast.StarExpr:
+		var ok bool
+		cp := *node
+		cp.X, ok = CopyExpr(cp.X)
+		return &cp, ok
+	case *ast.TypeAssertExpr:
+		var ok1, ok2 bool
+		cp := *node
+		cp.X, ok1 = CopyExpr(cp.X)
+		cp.Type, ok2 = CopyExpr(cp.Type)
+		return &cp, ok1 && ok2
+	case *ast.UnaryExpr:
+		var ok bool
+		cp := *node
+		cp.X, ok = CopyExpr(cp.X)
+		return &cp, ok
+	case *ast.MapType:
+		var ok1, ok2 bool
+		cp := *node
+		cp.Key, ok1 = CopyExpr(cp.Key)
+		cp.Value, ok2 = CopyExpr(cp.Value)
+		return &cp, ok1 && ok2
+	case *ast.ArrayType:
+		var ok1, ok2 bool
+		cp := *node
+		cp.Len, ok1 = CopyExpr(cp.Len)
+		cp.Elt, ok2 = CopyExpr(cp.Elt)
+		return &cp, ok1 && ok2
+	case *ast.Ellipsis:
+		var ok bool
+		cp := *node
+		cp.Elt, ok = CopyExpr(cp.Elt)
+		return &cp, ok
+	case *ast.InterfaceType:
+		cp := *node
+		return &cp, true
+	case *ast.StructType:
+		cp := *node
+		return &cp, true
+	case *ast.FuncLit, *ast.FuncType:
+		// TODO(dh): implement copying of function literals and types.
+		return nil, false
+	case *ast.ChanType:
+		var ok bool
+		cp := *node
+		cp.Value, ok = CopyExpr(cp.Value)
+		return &cp, ok
+	case nil:
+		return nil, true
+	default:
+		panic(fmt.Sprintf("unreachable: %T", node))
+	}
+}
+
+func Equal(a, b ast.Node) bool {
+	if a == b {
+		return true
+	}
+	if a == nil || b == nil {
+		return false
+	}
+	if reflect.TypeOf(a) != reflect.TypeOf(b) {
+		return false
+	}
+
+	switch a := a.(type) {
+	case *ast.BasicLit:
+		b := b.(*ast.BasicLit)
+		return a.Kind == b.Kind && a.Value == b.Value
+	case *ast.BinaryExpr:
+		b := b.(*ast.BinaryExpr)
+		return Equal(a.X, b.X) && a.Op == b.Op && Equal(a.Y, b.Y)
+	case *ast.CallExpr:
+		b := b.(*ast.CallExpr)
+		if len(a.Args) != len(b.Args) {
+			return false
+		}
+		for i, arg := range a.Args {
+			if !Equal(arg, b.Args[i]) {
+				return false
+			}
+		}
+		return Equal(a.Fun, b.Fun) &&
+			(a.Ellipsis == token.NoPos && b.Ellipsis == token.NoPos || a.Ellipsis != token.NoPos && b.Ellipsis != token.NoPos)
+	case *ast.CompositeLit:
+		b := b.(*ast.CompositeLit)
+		if len(a.Elts) != len(b.Elts) {
+			return false
+		}
+		for i, elt := range b.Elts {
+			if !Equal(elt, b.Elts[i]) {
+				return false
+			}
+		}
+		return Equal(a.Type, b.Type) && a.Incomplete == b.Incomplete
+	case *ast.Ident:
+		b := b.(*ast.Ident)
+		return a.Name == b.Name
+	case *ast.IndexExpr:
+		b := b.(*ast.IndexExpr)
+		return Equal(a.X, b.X) && Equal(a.Index, b.Index)
+	case *ast.IndexListExpr:
+		b := b.(*ast.IndexListExpr)
+		if len(a.Indices) != len(b.Indices) {
+			return false
+		}
+		for i, v := range a.Indices {
+			if !Equal(v, b.Indices[i]) {
+				return false
+			}
+		}
+		return Equal(a.X, b.X)
+	case *ast.KeyValueExpr:
+		b := b.(*ast.KeyValueExpr)
+		return Equal(a.Key, b.Key) && Equal(a.Value, b.Value)
+	case *ast.ParenExpr:
+		b := b.(*ast.ParenExpr)
+		return Equal(a.X, b.X)
+	case *ast.SelectorExpr:
+		b := b.(*ast.SelectorExpr)
+		return Equal(a.X, b.X) && Equal(a.Sel, b.Sel)
+	case *ast.SliceExpr:
+		b := b.(*ast.SliceExpr)
+		return Equal(a.X, b.X) && Equal(a.Low, b.Low) && Equal(a.High, b.High) && Equal(a.Max, b.Max) && a.Slice3 == b.Slice3
+	case *ast.StarExpr:
+		b := b.(*ast.StarExpr)
+		return Equal(a.X, b.X)
+	case *ast.TypeAssertExpr:
+		b := b.(*ast.TypeAssertExpr)
+		return Equal(a.X, b.X) && Equal(a.Type, b.Type)
+	case *ast.UnaryExpr:
+		b := b.(*ast.UnaryExpr)
+		return a.Op == b.Op && Equal(a.X, b.X)
+	case *ast.MapType:
+		b := b.(*ast.MapType)
+		return Equal(a.Key, b.Key) && Equal(a.Value, b.Value)
+	case *ast.ArrayType:
+		b := b.(*ast.ArrayType)
+		return Equal(a.Len, b.Len) && Equal(a.Elt, b.Elt)
+	case *ast.Ellipsis:
+		b := b.(*ast.Ellipsis)
+		return Equal(a.Elt, b.Elt)
+	case *ast.InterfaceType:
+		b := b.(*ast.InterfaceType)
+		return a.Incomplete == b.Incomplete && Equal(a.Methods, b.Methods)
+	case *ast.StructType:
+		b := b.(*ast.StructType)
+		return a.Incomplete == b.Incomplete && Equal(a.Fields, b.Fields)
+	case *ast.FuncLit:
+		// TODO(dh): support function literals
+		return false
+	case *ast.ChanType:
+		b := b.(*ast.ChanType)
+		return a.Dir == b.Dir && (a.Arrow == token.NoPos && b.Arrow == token.NoPos || a.Arrow != token.NoPos && b.Arrow != token.NoPos)
+	case *ast.FieldList:
+		b := b.(*ast.FieldList)
+		if len(a.List) != len(b.List) {
+			return false
+		}
+		for i, fieldA := range a.List {
+			if !Equal(fieldA, b.List[i]) {
+				return false
+			}
+		}
+		return true
+	case *ast.Field:
+		b := b.(*ast.Field)
+		if len(a.Names) != len(b.Names) {
+			return false
+		}
+		for j, name := range a.Names {
+			if !Equal(name, b.Names[j]) {
+				return false
+			}
+		}
+		if !Equal(a.Type, b.Type) || !Equal(a.Tag, b.Tag) {
+			return false
+		}
+		return true
+	default:
+		panic(fmt.Sprintf("unreachable: %T", a))
+	}
+}
+
+func NegateDeMorgan(expr ast.Expr, recursive bool) ast.Expr {
+	switch expr := expr.(type) {
+	case *ast.BinaryExpr:
+		var out ast.BinaryExpr
+		switch expr.Op {
+		case token.EQL:
+			out.X = expr.X
+			out.Op = token.NEQ
+			out.Y = expr.Y
+		case token.LSS:
+			out.X = expr.X
+			out.Op = token.GEQ
+			out.Y = expr.Y
+		case token.GTR:
+			out.X = expr.X
+			out.Op = token.LEQ
+			out.Y = expr.Y
+		case token.NEQ:
+			out.X = expr.X
+			out.Op = token.EQL
+			out.Y = expr.Y
+		case token.LEQ:
+			out.X = expr.X
+			out.Op = token.GTR
+			out.Y = expr.Y
+		case token.GEQ:
+			out.X = expr.X
+			out.Op = token.LSS
+			out.Y = expr.Y
+
+		case token.LAND:
+			out.X = NegateDeMorgan(expr.X, recursive)
+			out.Op = token.LOR
+			out.Y = NegateDeMorgan(expr.Y, recursive)
+		case token.LOR:
+			out.X = NegateDeMorgan(expr.X, recursive)
+			out.Op = token.LAND
+			out.Y = NegateDeMorgan(expr.Y, recursive)
+		}
+		return &out
+
+	case *ast.ParenExpr:
+		if recursive {
+			return &ast.ParenExpr{
+				X: NegateDeMorgan(expr.X, recursive),
+			}
+		} else {
+			return &ast.UnaryExpr{
+				Op: token.NOT,
+				X:  expr,
+			}
+		}
+
+	case *ast.UnaryExpr:
+		if expr.Op == token.NOT {
+			return expr.X
+		} else {
+			return &ast.UnaryExpr{
+				Op: token.NOT,
+				X:  expr,
+			}
+		}
+
+	default:
+		return &ast.UnaryExpr{
+			Op: token.NOT,
+			X:  expr,
+		}
+	}
+}
+
+func SimplifyParentheses(node ast.Expr) ast.Expr {
+	var changed bool
+	// XXX accept list of ops to operate on
+	// XXX copy AST node, don't modify in place
+	post := func(c *astutil.Cursor) bool {
+		out := c.Node()
+		if paren, ok := c.Node().(*ast.ParenExpr); ok {
+			out = paren.X
+		}
+
+		if binop, ok := out.(*ast.BinaryExpr); ok {
+			if right, ok := binop.Y.(*ast.BinaryExpr); ok && binop.Op == right.Op {
+				// XXX also check that Op is associative
+
+				root := binop
+				pivot := root.Y.(*ast.BinaryExpr)
+				root.Y = pivot.X
+				pivot.X = root
+				root = pivot
+				out = root
+			}
+		}
+
+		if out != c.Node() {
+			changed = true
+			c.Replace(out)
+		}
+		return true
+	}
+
+	for changed = true; changed; {
+		changed = false
+		node = astutil.Apply(node, nil, post).(ast.Expr)
+	}
+
+	return node
+}

vendor/honnef.co/go/tools/go/buildid/UPSTREAM

@@ -0,0 +1,5 @@
+This package extracts buildid.go and note.go from cmd/internal/buildid/.
+
+We have modified it to remove support for AIX big archive files, to cut down on our dependencies.
+
+The last upstream commit we've looked at was: d3ddc4854429185e6e06ca1f7628bb790404abb5

vendor/honnef.co/go/tools/go/buildid/buildid.go

@@ -0,0 +1,238 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package buildid
+
+import (
+	"bytes"
+	"debug/elf"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"strconv"
+	"strings"
+)
+
+var errBuildIDMalformed = fmt.Errorf("malformed object file")
+
+var (
+	bangArch = []byte("!<arch>")
+	pkgdef   = []byte("__.PKGDEF")
+	goobject = []byte("go object ")
+	buildid  = []byte("build id ")
+)
+
+// ReadFile reads the build ID from an archive or executable file.
+func ReadFile(name string) (id string, err error) {
+	f, err := os.Open(name)
+	if err != nil {
+		return "", err
+	}
+	defer f.Close()
+
+	buf := make([]byte, 8)
+	if _, err := f.ReadAt(buf, 0); err != nil {
+		return "", err
+	}
+	if string(buf) != "!<arch>\n" {
+		if string(buf) == "<bigaf>\n" {
+			return "", errors.New("unsupported")
+		}
+		return readBinary(name, f)
+	}
+
+	// Read just enough of the target to fetch the build ID.
+	// The archive is expected to look like:
+	//
+	//	!<arch>
+	//	__.PKGDEF       0           0     0     644     7955      `
+	//	go object darwin amd64 devel X:none
+	//	build id "b41e5c45250e25c9fd5e9f9a1de7857ea0d41224"
+	//
+	// The variable-sized strings are GOOS, GOARCH, and the experiment list (X:none).
+	// Reading the first 1024 bytes should be plenty.
+	data := make([]byte, 1024)
+	n, err := io.ReadFull(f, data)
+	if err != nil && n == 0 {
+		return "", err
+	}
+
+	tryGccgo := func() (string, error) {
+		return readGccgoArchive(name, f)
+	}
+
+	// Archive header.
+	for i := 0; ; i++ { // returns during i==3
+		j := bytes.IndexByte(data, '\n')
+		if j < 0 {
+			return tryGccgo()
+		}
+		line := data[:j]
+		data = data[j+1:]
+		switch i {
+		case 0:
+			if !bytes.Equal(line, bangArch) {
+				return tryGccgo()
+			}
+		case 1:
+			if !bytes.HasPrefix(line, pkgdef) {
+				return tryGccgo()
+			}
+		case 2:
+			if !bytes.HasPrefix(line, goobject) {
+				return tryGccgo()
+			}
+		case 3:
+			if !bytes.HasPrefix(line, buildid) {
+				// Found the object header, just doesn't have a build id line.
+				// Treat as successful, with empty build id.
+				return "", nil
+			}
+			id, err := strconv.Unquote(string(line[len(buildid):]))
+			if err != nil {
+				return tryGccgo()
+			}
+			return id, nil
+		}
+	}
+}
+
+// readGccgoArchive tries to parse the archive as a standard Unix
+// archive file, and fetch the build ID from the _buildid.o entry.
+// The _buildid.o entry is written by (*Builder).gccgoBuildIDELFFile
+// in cmd/go/internal/work/exec.go.
+func readGccgoArchive(name string, f *os.File) (string, error) {
+	bad := func() (string, error) {
+		return "", &os.PathError{Op: "parse", Path: name, Err: errBuildIDMalformed}
+	}
+
+	off := int64(8)
+	for {
+		if _, err := f.Seek(off, io.SeekStart); err != nil {
+			return "", err
+		}
+
+		// TODO(iant): Make a debug/ar package, and use it
+		// here and in cmd/link.
+		var hdr [60]byte
+		if _, err := io.ReadFull(f, hdr[:]); err != nil {
+			if err == io.EOF {
+				// No more entries, no build ID.
+				return "", nil
+			}
+			return "", err
+		}
+		off += 60
+
+		sizeStr := strings.TrimSpace(string(hdr[48:58]))
+		size, err := strconv.ParseInt(sizeStr, 0, 64)
+		if err != nil {
+			return bad()
+		}
+
+		name := strings.TrimSpace(string(hdr[:16]))
+		if name == "_buildid.o/" {
+			sr := io.NewSectionReader(f, off, size)
+			e, err := elf.NewFile(sr)
+			if err != nil {
+				return bad()
+			}
+			s := e.Section(".go.buildid")
+			if s == nil {
+				return bad()
+			}
+			data, err := s.Data()
+			if err != nil {
+				return bad()
+			}
+			return string(data), nil
+		}
+
+		off += size
+		if off&1 != 0 {
+			off++
+		}
+	}
+}
+
+var (
+	goBuildPrefix = []byte("\xff Go build ID: \"")
+	goBuildEnd    = []byte("\"\n \xff")
+
+	elfPrefix = []byte("\x7fELF")
+
+	machoPrefixes = [][]byte{
+		{0xfe, 0xed, 0xfa, 0xce},
+		{0xfe, 0xed, 0xfa, 0xcf},
+		{0xce, 0xfa, 0xed, 0xfe},
+		{0xcf, 0xfa, 0xed, 0xfe},
+	}
+)
+
+var readSize = 32 * 1024 // changed for testing
+
+// readBinary reads the build ID from a binary.
+//
+// ELF binaries store the build ID in a proper PT_NOTE section.
+//
+// Other binary formats are not so flexible. For those, the linker
+// stores the build ID as non-instruction bytes at the very beginning
+// of the text segment, which should appear near the beginning
+// of the file. This is clumsy but fairly portable. Custom locations
+// can be added for other binary types as needed, like we did for ELF.
+func readBinary(name string, f *os.File) (id string, err error) {
+	// Read the first 32 kB of the binary file.
+	// That should be enough to find the build ID.
+	// In ELF files, the build ID is in the leading headers,
+	// which are typically less than 4 kB, not to mention 32 kB.
+	// In Mach-O files, there's no limit, so we have to parse the file.
+	// On other systems, we're trying to read enough that
+	// we get the beginning of the text segment in the read.
+	// The offset where the text segment begins in a hello
+	// world compiled for each different object format today:
+	//
+	//	Plan 9: 0x20
+	//	Windows: 0x600
+	//
+	data := make([]byte, readSize)
+	_, err = io.ReadFull(f, data)
+	if err == io.ErrUnexpectedEOF {
+		err = nil
+	}
+	if err != nil {
+		return "", err
+	}
+
+	if bytes.HasPrefix(data, elfPrefix) {
+		return readELF(name, f, data)
+	}
+	for _, m := range machoPrefixes {
+		if bytes.HasPrefix(data, m) {
+			return readMacho(name, f, data)
+		}
+	}
+	return readRaw(name, data)
+}
+
+// readRaw finds the raw build ID stored in text segment data.
+func readRaw(name string, data []byte) (id string, err error) {
+	i := bytes.Index(data, goBuildPrefix)
+	if i < 0 {
+		// Missing. Treat as successful but build ID empty.
+		return "", nil
+	}
+
+	j := bytes.Index(data[i+len(goBuildPrefix):], goBuildEnd)
+	if j < 0 {
+		return "", &os.PathError{Op: "parse", Path: name, Err: errBuildIDMalformed}
+	}
+
+	quoted := data[i+len(goBuildPrefix)-1 : i+len(goBuildPrefix)+j+1]
+	id, err = strconv.Unquote(string(quoted))
+	if err != nil {
+		return "", &os.PathError{Op: "parse", Path: name, Err: errBuildIDMalformed}
+	}
+	return id, nil
+}

vendor/honnef.co/go/tools/go/buildid/note.go

@@ -0,0 +1,204 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package buildid
+
+import (
+	"bytes"
+	"debug/elf"
+	"debug/macho"
+	"encoding/binary"
+	"fmt"
+	"io"
+	"os"
+)
+
+func readAligned4(r io.Reader, sz int32) ([]byte, error) {
+	full := (sz + 3) &^ 3
+	data := make([]byte, full)
+	_, err := io.ReadFull(r, data)
+	if err != nil {
+		return nil, err
+	}
+	data = data[:sz]
+	return data, nil
+}
+
+func ReadELFNote(filename, name string, typ int32) ([]byte, error) {
+	f, err := elf.Open(filename)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+	for _, sect := range f.Sections {
+		if sect.Type != elf.SHT_NOTE {
+			continue
+		}
+		r := sect.Open()
+		for {
+			var namesize, descsize, noteType int32
+			err = binary.Read(r, f.ByteOrder, &namesize)
+			if err != nil {
+				if err == io.EOF {
+					break
+				}
+				return nil, fmt.Errorf("read namesize failed: %v", err)
+			}
+			err = binary.Read(r, f.ByteOrder, &descsize)
+			if err != nil {
+				return nil, fmt.Errorf("read descsize failed: %v", err)
+			}
+			err = binary.Read(r, f.ByteOrder, &noteType)
+			if err != nil {
+				return nil, fmt.Errorf("read type failed: %v", err)
+			}
+			noteName, err := readAligned4(r, namesize)
+			if err != nil {
+				return nil, fmt.Errorf("read name failed: %v", err)
+			}
+			desc, err := readAligned4(r, descsize)
+			if err != nil {
+				return nil, fmt.Errorf("read desc failed: %v", err)
+			}
+			if name == string(noteName) && typ == noteType {
+				return desc, nil
+			}
+		}
+	}
+	return nil, nil
+}
+
+var elfGoNote = []byte("Go\x00\x00")
+var elfGNUNote = []byte("GNU\x00")
+
+// The Go build ID is stored in a note described by an ELF PT_NOTE prog
+// header. The caller has already opened filename, to get f, and read
+// at least 4 kB out, in data.
+func readELF(name string, f *os.File, data []byte) (buildid string, err error) {
+	// Assume the note content is in the data, already read.
+	// Rewrite the ELF header to set shnum to 0, so that we can pass
+	// the data to elf.NewFile and it will decode the Prog list but not
+	// try to read the section headers and the string table from disk.
+	// That's a waste of I/O when all we care about is the Prog list
+	// and the one ELF note.
+	switch elf.Class(data[elf.EI_CLASS]) {
+	case elf.ELFCLASS32:
+		data[48] = 0
+		data[49] = 0
+	case elf.ELFCLASS64:
+		data[60] = 0
+		data[61] = 0
+	}
+
+	const elfGoBuildIDTag = 4
+	const gnuBuildIDTag = 3
+
+	ef, err := elf.NewFile(bytes.NewReader(data))
+	if err != nil {
+		return "", &os.PathError{Path: name, Op: "parse", Err: err}
+	}
+	var gnu string
+	for _, p := range ef.Progs {
+		if p.Type != elf.PT_NOTE || p.Filesz < 16 {
+			continue
+		}
+
+		var note []byte
+		if p.Off+p.Filesz < uint64(len(data)) {
+			note = data[p.Off : p.Off+p.Filesz]
+		} else {
+			// For some linkers, such as the Solaris linker,
+			// the buildid may not be found in data (which
+			// likely contains the first 16kB of the file)
+			// or even the first few megabytes of the file
+			// due to differences in note segment placement;
+			// in that case, extract the note data manually.
+			_, err = f.Seek(int64(p.Off), io.SeekStart)
+			if err != nil {
+				return "", err
+			}
+
+			note = make([]byte, p.Filesz)
+			_, err = io.ReadFull(f, note)
+			if err != nil {
+				return "", err
+			}
+		}
+
+		filesz := p.Filesz
+		off := p.Off
+		for filesz >= 16 {
+			nameSize := ef.ByteOrder.Uint32(note)
+			valSize := ef.ByteOrder.Uint32(note[4:])
+			tag := ef.ByteOrder.Uint32(note[8:])
+			nname := note[12:16]
+			if nameSize == 4 && 16+valSize <= uint32(len(note)) && tag == elfGoBuildIDTag && bytes.Equal(nname, elfGoNote) {
+				return string(note[16 : 16+valSize]), nil
+			}
+
+			if nameSize == 4 && 16+valSize <= uint32(len(note)) && tag == gnuBuildIDTag && bytes.Equal(nname, elfGNUNote) {
+				gnu = string(note[16 : 16+valSize])
+			}
+
+			nameSize = (nameSize + 3) &^ 3
+			valSize = (valSize + 3) &^ 3
+			notesz := uint64(12 + nameSize + valSize)
+			if filesz <= notesz {
+				break
+			}
+			off += notesz
+			align := p.Align
+			alignedOff := (off + align - 1) &^ (align - 1)
+			notesz += alignedOff - off
+			off = alignedOff
+			filesz -= notesz
+			note = note[notesz:]
+		}
+	}
+
+	// If we didn't find a Go note, use a GNU note if available.
+	// This is what gccgo uses.
+	if gnu != "" {
+		return gnu, nil
+	}
+
+	// No note. Treat as successful but build ID empty.
+	return "", nil
+}
+
+// The Go build ID is stored at the beginning of the Mach-O __text segment.
+// The caller has already opened filename, to get f, and read a few kB out, in data.
+// Sadly, that's not guaranteed to hold the note, because there is an arbitrary amount
+// of other junk placed in the file ahead of the main text.
+func readMacho(name string, f *os.File, data []byte) (buildid string, err error) {
+	// If the data we want has already been read, don't worry about Mach-O parsing.
+	// This is both an optimization and a hedge against the Mach-O parsing failing
+	// in the future due to, for example, the name of the __text section changing.
+	if b, err := readRaw(name, data); b != "" && err == nil {
+		return b, err
+	}
+
+	mf, err := macho.NewFile(f)
+	if err != nil {
+		return "", &os.PathError{Path: name, Op: "parse", Err: err}
+	}
+
+	sect := mf.Section("__text")
+	if sect == nil {
+		// Every binary has a __text section. Something is wrong.
+		return "", &os.PathError{Path: name, Op: "parse", Err: fmt.Errorf("cannot find __text section")}
+	}
+
+	// It should be in the first few bytes, but read a lot just in case,
+	// especially given our past problems on OS X with the build ID moving.
+	// There shouldn't be much difference between reading 4kB and 32kB:
+	// the hard part is getting to the data, not transferring it.
+	n := min(sect.Size, uint64(readSize))
+	buf := make([]byte, n)
+	if _, err := f.ReadAt(buf, int64(sect.Offset)); err != nil {
+		return "", err
+	}
+
+	return readRaw(name, buf)
+}

vendor/honnef.co/go/tools/go/ir/LICENSE

@@ -0,0 +1,28 @@
+Copyright (c) 2009 The Go Authors. All rights reserved.
+Copyright (c) 2016 Dominik Honnef. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+   * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+   * Neither the name of Google Inc. nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

vendor/honnef.co/go/tools/go/ir/UPSTREAM

@@ -0,0 +1,9 @@
+This package started as a copy of golang.org/x/tools/go/ssa, imported from an unknown commit in 2016.
+It has since been heavily modified to match our own needs in an IR.
+The changes are too many to list here, and it is best to consider this package independent of go/ssa.
+
+Upstream changes still get applied when they address bugs in portions of code we have inherited.
+
+The last upstream commit we've looked at was:
+05409620da166985e94b711ad4103bee40406eee
+

vendor/honnef.co/go/tools/go/ir/blockopt.go

@@ -0,0 +1,205 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package ir
+
+// Simple block optimizations to simplify the control flow graph.
+
+// TODO(adonovan): opt: instead of creating several "unreachable" blocks
+// per function in the Builder, reuse a single one (e.g. at Blocks[1])
+// to reduce garbage.
+
+import (
+	"fmt"
+	"os"
+)
+
+// If true, perform sanity checking and show progress at each
+// successive iteration of optimizeBlocks.  Very verbose.
+const debugBlockOpt = false
+
+// markReachable sets Index=-1 for all blocks reachable from b.
+func markReachable(b *BasicBlock) {
+	b.gaps = -1
+	for _, succ := range b.Succs {
+		if succ.gaps == 0 {
+			markReachable(succ)
+		}
+	}
+}
+
+// deleteUnreachableBlocks marks all reachable blocks of f and
+// eliminates (nils) all others, including possibly cyclic subgraphs.
+func deleteUnreachableBlocks(f *Function) {
+	const white, black = 0, -1
+	// We borrow b.gaps temporarily as the mark bit.
+	for _, b := range f.Blocks {
+		b.gaps = white
+	}
+	markReachable(f.Blocks[0])
+	// In SSI form, we need the exit to be reachable for correct
+	// post-dominance information. In original form, however, we
+	// cannot unconditionally mark it reachable because we won't
+	// be adding fake edges, and this breaks the calculation of
+	// dominance information.
+	markReachable(f.Exit)
+	for i, b := range f.Blocks {
+		if b.gaps == white {
+			for _, c := range b.Succs {
+				if c.gaps == black {
+					c.removePred(b) // delete white->black edge
+				}
+			}
+			if debugBlockOpt {
+				fmt.Fprintln(os.Stderr, "unreachable", b)
+			}
+			f.Blocks[i] = nil // delete b
+		}
+	}
+	f.removeNilBlocks()
+}
+
+// jumpThreading attempts to apply simple jump-threading to block b,
+// in which a->b->c become a->c if b is just a Jump.
+// The result is true if the optimization was applied.
+func jumpThreading(f *Function, b *BasicBlock) bool {
+	if b.Index == 0 {
+		return false // don't apply to entry block
+	}
+	if b.Instrs == nil {
+		return false
+	}
+	for _, pred := range b.Preds {
+		switch pred.Control().(type) {
+		case *ConstantSwitch:
+			// don't optimize away the head blocks of switch statements
+			return false
+		}
+	}
+	if _, ok := b.Instrs[0].(*Jump); !ok {
+		return false // not just a jump
+	}
+	c := b.Succs[0]
+	if c == b {
+		return false // don't apply to degenerate jump-to-self.
+	}
+	if c.hasPhi() {
+		return false // not sound without more effort
+	}
+	for j, a := range b.Preds {
+		a.replaceSucc(b, c)
+
+		// If a now has two edges to c, replace its degenerate If by Jump.
+		if len(a.Succs) == 2 && a.Succs[0] == c && a.Succs[1] == c {
+			jump := new(Jump)
+			jump.setBlock(a)
+			a.Instrs[len(a.Instrs)-1] = jump
+			a.Succs = a.Succs[:1]
+			c.removePred(b)
+		} else {
+			if j == 0 {
+				c.replacePred(b, a)
+			} else {
+				c.Preds = append(c.Preds, a)
+			}
+		}
+
+		if debugBlockOpt {
+			fmt.Fprintln(os.Stderr, "jumpThreading", a, b, c)
+		}
+	}
+	f.Blocks[b.Index] = nil // delete b
+	return true
+}
+
+// fuseBlocks attempts to apply the block fusion optimization to block
+// a, in which a->b becomes ab if len(a.Succs)==len(b.Preds)==1.
+// The result is true if the optimization was applied.
+func fuseBlocks(f *Function, a *BasicBlock) bool {
+	if len(a.Succs) != 1 {
+		return false
+	}
+	if a.Succs[0] == f.Exit {
+		return false
+	}
+	b := a.Succs[0]
+	if len(b.Preds) != 1 {
+		return false
+	}
+	if _, ok := a.Instrs[len(a.Instrs)-1].(*Panic); ok {
+		// panics aren't simple jumps, they have side effects.
+		return false
+	}
+
+	// Degenerate &&/|| ops may result in a straight-line CFG
+	// containing φ-nodes. (Ideally we'd replace such them with
+	// their sole operand but that requires Referrers, built later.)
+	if b.hasPhi() {
+		return false // not sound without further effort
+	}
+
+	// Eliminate jump at end of A, then copy all of B across.
+	a.Instrs = append(a.Instrs[:len(a.Instrs)-1], b.Instrs...)
+	for _, instr := range b.Instrs {
+		instr.setBlock(a)
+	}
+
+	// A inherits B's successors
+	a.Succs = append(a.succs2[:0], b.Succs...)
+
+	// Fix up Preds links of all successors of B.
+	for _, c := range b.Succs {
+		c.replacePred(b, a)
+	}
+
+	if debugBlockOpt {
+		fmt.Fprintln(os.Stderr, "fuseBlocks", a, b)
+	}
+
+	f.Blocks[b.Index] = nil // delete b
+	return true
+}
+
+// optimizeBlocks() performs some simple block optimizations on a
+// completed function: dead block elimination, block fusion, jump
+// threading.
+func optimizeBlocks(f *Function) {
+	if debugBlockOpt {
+		f.WriteTo(os.Stderr)
+		mustSanityCheck(f, nil)
+	}
+
+	deleteUnreachableBlocks(f)
+
+	// Loop until no further progress.
+	changed := true
+	for changed {
+		changed = false
+
+		if debugBlockOpt {
+			f.WriteTo(os.Stderr)
+			mustSanityCheck(f, nil)
+		}
+
+		for _, b := range f.Blocks {
+			// f.Blocks will temporarily contain nils to indicate
+			// deleted blocks; we remove them at the end.
+			if b == nil {
+				continue
+			}
+
+			// Fuse blocks.  b->c becomes bc.
+			if fuseBlocks(f, b) {
+				changed = true
+			}
+
+			// a->b->c becomes a->c if b contains only a Jump.
+			if jumpThreading(f, b) {
+				changed = true
+				continue // (b was disconnected)
+			}
+		}
+	}
+	f.removeNilBlocks()
+}

vendor/honnef.co/go/tools/go/ir/const.go

@@ -0,0 +1,297 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package ir
+
+// This file defines the Const SSA value type.
+
+import (
+	"fmt"
+	"go/ast"
+	"go/constant"
+	"go/types"
+	"strconv"
+	"strings"
+
+	"golang.org/x/exp/typeparams"
+	"honnef.co/go/tools/go/types/typeutil"
+)
+
+// NewConst returns a new constant of the specified value and type.
+// val must be valid according to the specification of Const.Value.
+func NewConst(val constant.Value, typ types.Type, source ast.Node) *Const {
+	c := &Const{
+		register: register{
+			typ: typ,
+		},
+		Value: val,
+	}
+	c.setSource(source)
+	return c
+}
+
+// intConst returns an 'int' constant that evaluates to i.
+// (i is an int64 in case the host is narrower than the target.)
+func intConst(i int64, source ast.Node) *Const {
+	return NewConst(constant.MakeInt64(i), tInt, source)
+}
+
+// nilConst returns a nil constant of the specified type, which may
+// be any reference type, including interfaces.
+func nilConst(typ types.Type, source ast.Node) *Const {
+	return NewConst(nil, typ, source)
+}
+
+// stringConst returns a 'string' constant that evaluates to s.
+func stringConst(s string, source ast.Node) *Const {
+	return NewConst(constant.MakeString(s), tString, source)
+}
+
+// zeroConst returns a new "zero" constant of the specified type.
+func zeroConst(t types.Type, source ast.Node) Constant {
+	if _, ok := t.Underlying().(*types.Interface); ok && !typeparams.IsTypeParam(t) {
+		// Handle non-generic interface early to simplify following code.
+		return nilConst(t, source)
+	}
+
+	tset := typeutil.NewTypeSet(t)
+
+	switch typ := tset.CoreType().(type) {
+	case *types.Struct:
+		values := make([]Value, typ.NumFields())
+		for i := 0; i < typ.NumFields(); i++ {
+			values[i] = zeroConst(typ.Field(i).Type(), source)
+		}
+		ac := &AggregateConst{
+			register: register{typ: t},
+			Values:   values,
+		}
+		ac.setSource(source)
+		return ac
+	case *types.Tuple:
+		values := make([]Value, typ.Len())
+		for i := 0; i < typ.Len(); i++ {
+			values[i] = zeroConst(typ.At(i).Type(), source)
+		}
+		ac := &AggregateConst{
+			register: register{typ: t},
+			Values:   values,
+		}
+		ac.setSource(source)
+		return ac
+	}
+
+	isNillable := func(term *types.Term) bool {
+		switch typ := term.Type().Underlying().(type) {
+		case *types.Pointer, *types.Slice, *types.Interface, *types.Chan, *types.Map, *types.Signature, *typeutil.Iterator:
+			return true
+		case *types.Basic:
+			switch typ.Kind() {
+			case types.UnsafePointer, types.UntypedNil:
+				return true
+			default:
+				return false
+			}
+		default:
+			return false
+		}
+	}
+
+	isInfo := func(info types.BasicInfo) func(*types.Term) bool {
+		return func(term *types.Term) bool {
+			basic, ok := term.Type().Underlying().(*types.Basic)
+			if !ok {
+				return false
+			}
+			return (basic.Info() & info) != 0
+		}
+	}
+
+	isArray := func(term *types.Term) bool {
+		_, ok := term.Type().Underlying().(*types.Array)
+		return ok
+	}
+
+	switch {
+	case tset.All(isInfo(types.IsNumeric)):
+		return NewConst(constant.MakeInt64(0), t, source)
+	case tset.All(isInfo(types.IsString)):
+		return NewConst(constant.MakeString(""), t, source)
+	case tset.All(isInfo(types.IsBoolean)):
+		return NewConst(constant.MakeBool(false), t, source)
+	case tset.All(isNillable):
+		return nilConst(t, source)
+	case tset.All(isArray):
+		var k ArrayConst
+		k.setType(t)
+		k.setSource(source)
+		return &k
+	default:
+		var k GenericConst
+		k.setType(t)
+		k.setSource(source)
+		return &k
+	}
+}
+
+func (c *Const) RelString(from *types.Package) string {
+	var p string
+	if c.Value == nil {
+		p = "nil"
+	} else if c.Value.Kind() == constant.String {
+		v := constant.StringVal(c.Value)
+		const max = 20
+		// TODO(adonovan): don't cut a rune in half.
+		if len(v) > max {
+			v = v[:max-3] + "..." // abbreviate
+		}
+		p = strconv.Quote(v)
+	} else {
+		p = c.Value.String()
+	}
+	return fmt.Sprintf("Const <%s> {%s}", relType(c.Type(), from), p)
+}
+
+func (c *Const) String() string {
+	if c.block == nil {
+		// Constants don't have a block till late in the compilation process. But we want to print consts during
+		// debugging.
+		return c.RelString(nil)
+	}
+	return c.RelString(c.Parent().pkg())
+}
+
+func (v *ArrayConst) RelString(pkg *types.Package) string {
+	return fmt.Sprintf("ArrayConst <%s>", relType(v.Type(), pkg))
+}
+
+func (v *ArrayConst) String() string {
+	return v.RelString(v.Parent().pkg())
+}
+
+func (v *AggregateConst) RelString(pkg *types.Package) string {
+	values := make([]string, len(v.Values))
+	for i, v := range v.Values {
+		if v != nil {
+			values[i] = v.Name()
+		} else {
+			values[i] = "nil"
+		}
+	}
+	return fmt.Sprintf("AggregateConst <%s> (%s)", relType(v.Type(), pkg), strings.Join(values, ", "))
+}
+
+func (v *AggregateConst) String() string {
+	if v.block == nil {
+		return v.RelString(nil)
+	}
+	return v.RelString(v.Parent().pkg())
+}
+
+func (v *GenericConst) RelString(pkg *types.Package) string {
+	return fmt.Sprintf("GenericConst <%s>", relType(v.Type(), pkg))
+}
+
+func (v *GenericConst) String() string {
+	return v.RelString(v.Parent().pkg())
+}
+
+// IsNil returns true if this constant represents a typed or untyped nil value.
+func (c *Const) IsNil() bool {
+	return c.Value == nil
+}
+
+// Int64 returns the numeric value of this constant truncated to fit
+// a signed 64-bit integer.
+func (c *Const) Int64() int64 {
+	switch x := constant.ToInt(c.Value); x.Kind() {
+	case constant.Int:
+		if i, ok := constant.Int64Val(x); ok {
+			return i
+		}
+		return 0
+	case constant.Float:
+		f, _ := constant.Float64Val(x)
+		return int64(f)
+	}
+	panic(fmt.Sprintf("unexpected constant value: %T", c.Value))
+}
+
+// Uint64 returns the numeric value of this constant truncated to fit
+// an unsigned 64-bit integer.
+func (c *Const) Uint64() uint64 {
+	switch x := constant.ToInt(c.Value); x.Kind() {
+	case constant.Int:
+		if u, ok := constant.Uint64Val(x); ok {
+			return u
+		}
+		return 0
+	case constant.Float:
+		f, _ := constant.Float64Val(x)
+		return uint64(f)
+	}
+	panic(fmt.Sprintf("unexpected constant value: %T", c.Value))
+}
+
+// Float64 returns the numeric value of this constant truncated to fit
+// a float64.
+func (c *Const) Float64() float64 {
+	f, _ := constant.Float64Val(c.Value)
+	return f
+}
+
+// Complex128 returns the complex value of this constant truncated to
+// fit a complex128.
+func (c *Const) Complex128() complex128 {
+	re, _ := constant.Float64Val(constant.Real(c.Value))
+	im, _ := constant.Float64Val(constant.Imag(c.Value))
+	return complex(re, im)
+}
+
+func (c *Const) equal(o Constant) bool {
+	// TODO(dh): don't use == for types, this will miss identical pointer types, among others
+	oc, ok := o.(*Const)
+	if !ok {
+		return false
+	}
+	return c.typ == oc.typ && c.Value == oc.Value && c.source == oc.source
+}
+
+func (c *AggregateConst) equal(o Constant) bool {
+	oc, ok := o.(*AggregateConst)
+	if !ok {
+		return false
+	}
+	// TODO(dh): don't use == for types, this will miss identical pointer types, among others
+	if c.typ != oc.typ {
+		return false
+	}
+	if c.source != oc.source {
+		return false
+	}
+	for i, v := range c.Values {
+		if !v.(Constant).equal(oc.Values[i].(Constant)) {
+			return false
+		}
+	}
+	return true
+}
+
+func (c *ArrayConst) equal(o Constant) bool {
+	oc, ok := o.(*ArrayConst)
+	if !ok {
+		return false
+	}
+	// TODO(dh): don't use == for types, this will miss identical pointer types, among others
+	return c.typ == oc.typ && c.source == oc.source
+}
+
+func (c *GenericConst) equal(o Constant) bool {
+	oc, ok := o.(*GenericConst)
+	if !ok {
+		return false
+	}
+	// TODO(dh): don't use == for types, this will miss identical pointer types, among others
+	return c.typ == oc.typ && c.source == oc.source
+}

vendor/honnef.co/go/tools/go/ir/create.go

@@ -0,0 +1,300 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package ir
+
+// This file implements the CREATE phase of IR construction.
+// See builder.go for explanation.
+
+import (
+	"fmt"
+	"go/ast"
+	"go/token"
+	"go/types"
+	"go/version"
+	"os"
+	"sync"
+
+	"honnef.co/go/tools/go/types/typeutil"
+)
+
+// measured on the standard library and rounded up to powers of two,
+// on average there are 8 blocks and 16 instructions per block in a
+// function.
+const avgBlocks = 8
+const avgInstructionsPerBlock = 16
+
+// NewProgram returns a new IR Program.
+//
+// mode controls diagnostics and checking during IR construction.
+func NewProgram(fset *token.FileSet, mode BuilderMode) *Program {
+	prog := &Program{
+		Fset:     fset,
+		imported: make(map[string]*Package),
+		packages: make(map[*types.Package]*Package),
+		mode:     mode,
+	}
+
+	h := typeutil.MakeHasher() // protected by methodsMu, in effect
+	prog.methodSets.SetHasher(h)
+	prog.canon.SetHasher(h)
+
+	return prog
+}
+
+// memberFromObject populates package pkg with a member for the
+// typechecker object obj.
+//
+// For objects from Go source code, syntax is the associated syntax tree
+// (for funcs and vars only) and goversion defines the appropriate
+// interpretation; they will be used during the build phase.
+func memberFromObject(pkg *Package, obj types.Object, syntax ast.Node, goversion string) {
+	name := obj.Name()
+	switch obj := obj.(type) {
+	case *types.Builtin:
+		if pkg.Pkg != types.Unsafe {
+			panic("unexpected builtin object: " + obj.String())
+		}
+
+	case *types.TypeName:
+		if name != "_" {
+			pkg.Members[name] = &Type{
+				object: obj,
+				pkg:    pkg,
+			}
+		}
+
+	case *types.Const:
+		c := &NamedConst{
+			object: obj,
+			Value:  NewConst(obj.Val(), obj.Type(), syntax),
+			pkg:    pkg,
+		}
+		pkg.values[obj] = c.Value
+		if name != "_" {
+			pkg.Members[name] = c
+		}
+
+	case *types.Var:
+		g := &Global{
+			Pkg:    pkg,
+			name:   name,
+			object: obj,
+			typ:    types.NewPointer(obj.Type()), // address
+		}
+		pkg.values[obj] = g
+		if name != "_" {
+			pkg.Members[name] = g
+		}
+
+	case *types.Func:
+		sig := obj.Type().(*types.Signature)
+		if sig.Recv() == nil && name == "init" {
+			pkg.ninit++
+			name = fmt.Sprintf("init#%d", pkg.ninit)
+		}
+		fn := &Function{
+			name:      name,
+			object:    obj,
+			Signature: sig,
+			Pkg:       pkg,
+			Prog:      pkg.Prog,
+			goversion: goversion,
+		}
+
+		fn.source = syntax
+		fn.initHTML(pkg.printFunc)
+		if syntax == nil {
+			fn.Synthetic = SyntheticLoadedFromExportData
+		} else {
+			// Note: we initialize fn.Blocks in
+			// (*builder).buildFunction and not here because Blocks
+			// being nil is used to indicate that building of the
+			// function hasn't started yet.
+
+			fn.functionBody = &functionBody{
+				scratchInstructions: make([]Instruction, avgBlocks*avgInstructionsPerBlock),
+			}
+		}
+
+		pkg.values[obj] = fn
+		pkg.Functions = append(pkg.Functions, fn)
+		if name != "_" && sig.Recv() == nil {
+			pkg.Members[name] = fn // package-level function
+		}
+
+	default: // (incl. *types.Package)
+		panic("unexpected Object type: " + obj.String())
+	}
+}
+
+// membersFromDecl populates package pkg with members for each
+// typechecker object (var, func, const or type) associated with the
+// specified decl.
+func membersFromDecl(pkg *Package, decl ast.Decl, goversion string) {
+	switch decl := decl.(type) {
+	case *ast.GenDecl: // import, const, type or var
+		switch decl.Tok {
+		case token.CONST:
+			for _, spec := range decl.Specs {
+				for _, id := range spec.(*ast.ValueSpec).Names {
+					memberFromObject(pkg, pkg.info.Defs[id], nil, "")
+				}
+			}
+
+		case token.VAR:
+			for _, spec := range decl.Specs {
+				for _, rhs := range spec.(*ast.ValueSpec).Values {
+					pkg.initVersion[rhs] = goversion
+				}
+				for _, id := range spec.(*ast.ValueSpec).Names {
+					memberFromObject(pkg, pkg.info.Defs[id], spec, goversion)
+				}
+			}
+
+		case token.TYPE:
+			for _, spec := range decl.Specs {
+				id := spec.(*ast.TypeSpec).Name
+				memberFromObject(pkg, pkg.info.Defs[id], nil, "")
+			}
+		}
+
+	case *ast.FuncDecl:
+		id := decl.Name
+		obj, ok := pkg.info.Defs[id]
+		if !ok {
+			panic(fmt.Sprintf("couldn't find object for id %q at %s",
+				id.Name, pkg.Prog.Fset.PositionFor(id.Pos(), false)))
+		}
+		if obj == nil {
+			panic(fmt.Sprintf("found nil object for id %q at %s",
+				id.Name, pkg.Prog.Fset.PositionFor(id.Pos(), false)))
+		}
+		memberFromObject(pkg, obj, decl, goversion)
+	}
+}
+
+// CreatePackage constructs and returns an IR Package from the
+// specified type-checked, error-free file ASTs, and populates its
+// Members mapping.
+//
+// importable determines whether this package should be returned by a
+// subsequent call to ImportedPackage(pkg.Path()).
+//
+// The real work of building IR form for each function is not done
+// until a subsequent call to Package.Build().
+func (prog *Program) CreatePackage(pkg *types.Package, files []*ast.File, info *types.Info, importable bool) *Package {
+	p := &Package{
+		Prog:    prog,
+		Members: make(map[string]Member),
+		values:  make(map[types.Object]Value),
+		Pkg:     pkg,
+		// transient values (CREATE and BUILD phases)
+		info:        info,
+		files:       files,
+		printFunc:   prog.PrintFunc,
+		initVersion: make(map[ast.Expr]string),
+	}
+
+	// Add init() function.
+	p.init = &Function{
+		name:         "init",
+		Signature:    new(types.Signature),
+		Synthetic:    SyntheticPackageInitializer,
+		Pkg:          p,
+		Prog:         prog,
+		functionBody: new(functionBody),
+		goversion:    "", // See Package.build for details.
+	}
+	p.init.initHTML(prog.PrintFunc)
+	p.Members[p.init.name] = p.init
+	p.Functions = append(p.Functions, p.init)
+
+	// CREATE phase.
+	// Allocate all package members: vars, funcs, consts and types.
+	if len(files) > 0 {
+		// Go source package.
+		for _, file := range files {
+			goversion := version.Lang(p.info.FileVersions[file])
+			for _, decl := range file.Decls {
+				membersFromDecl(p, decl, goversion)
+			}
+		}
+	} else {
+		// GC-compiled binary package (or "unsafe")
+		// No code.
+		// No position information.
+		scope := p.Pkg.Scope()
+		for _, name := range scope.Names() {
+			obj := scope.Lookup(name)
+			memberFromObject(p, obj, nil, "")
+			if obj, ok := obj.(*types.TypeName); ok {
+				if named, ok := obj.Type().(*types.Named); ok {
+					for i, n := 0, named.NumMethods(); i < n; i++ {
+						memberFromObject(p, named.Method(i), nil, "")
+					}
+				}
+			}
+		}
+	}
+
+	// Add initializer guard variable.
+	initguard := &Global{
+		Pkg:  p,
+		name: "init$guard",
+		typ:  types.NewPointer(tBool),
+	}
+	p.Members[initguard.Name()] = initguard
+
+	if prog.mode&GlobalDebug != 0 {
+		p.SetDebugMode(true)
+	}
+
+	if prog.mode&PrintPackages != 0 {
+		printMu.Lock()
+		p.WriteTo(os.Stdout)
+		printMu.Unlock()
+	}
+
+	if importable {
+		prog.imported[p.Pkg.Path()] = p
+	}
+	prog.packages[p.Pkg] = p
+
+	return p
+}
+
+// printMu serializes printing of Packages/Functions to stdout.
+var printMu sync.Mutex
+
+// AllPackages returns a new slice containing all packages in the
+// program prog in unspecified order.
+func (prog *Program) AllPackages() []*Package {
+	pkgs := make([]*Package, 0, len(prog.packages))
+	for _, pkg := range prog.packages {
+		pkgs = append(pkgs, pkg)
+	}
+	return pkgs
+}
+
+// ImportedPackage returns the importable Package whose PkgPath
+// is path, or nil if no such Package has been created.
+//
+// A parameter to CreatePackage determines whether a package should be
+// considered importable. For example, no import declaration can resolve
+// to the ad-hoc main package created by 'go build foo.go'.
+//
+// TODO(adonovan): rethink this function and the "importable" concept;
+// most packages are importable. This function assumes that all
+// types.Package.Path values are unique within the ir.Program, which is
+// false---yet this function remains very convenient.
+// Clients should use (*Program).Package instead where possible.
+// IR doesn't really need a string-keyed map of packages.
+func (prog *Program) ImportedPackage(path string) *Package {
+	return prog.imported[path]
+}
+
+func (prog *Program) SetNoReturn(fn func(*types.Func) bool) {
+	prog.noReturn = fn
+}

vendor/honnef.co/go/tools/go/ir/doc.go

@@ -0,0 +1,131 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package ir defines a representation of the elements of Go programs
+// (packages, types, functions, variables and constants) using a
+// static single-information (SSI) form intermediate representation
+// (IR) for the bodies of functions.
+//
+// THIS INTERFACE IS EXPERIMENTAL AND IS LIKELY TO CHANGE.
+//
+// For an introduction to SSA form, upon which SSI builds, see
+// https://en.wikipedia.org/wiki/Static_single_assignment_form.
+// This page provides a broader reading list:
+// https://www.dcs.gla.ac.uk/~jsinger/ssa.html.
+//
+// For an introduction to SSI form, see The static single information
+// form by C. Scott Ananian.
+//
+// The level of abstraction of the IR form is intentionally close to
+// the source language to facilitate construction of source analysis
+// tools.  It is not intended for machine code generation.
+//
+// The simplest way to create the IR of a package is
+// to load typed syntax trees using golang.org/x/tools/go/packages, then
+// invoke the irutil.Packages helper function. See ExampleLoadPackages
+// and ExampleWholeProgram for examples.
+// The resulting ir.Program contains all the packages and their
+// members, but IR code is not created for function bodies until a
+// subsequent call to (*Package).Build or (*Program).Build.
+//
+// The builder initially builds a naive IR form in which all local
+// variables are addresses of stack locations with explicit loads and
+// stores.  Registerization of eligible locals and φ-node insertion
+// using dominance and dataflow are then performed as a second pass
+// called "lifting" to improve the accuracy and performance of
+// subsequent analyses; this pass can be skipped by setting the
+// NaiveForm builder flag.
+//
+// The primary interfaces of this package are:
+//
+//   - Member: a named member of a Go package.
+//   - Value: an expression that yields a value.
+//   - Instruction: a statement that consumes values and performs computation.
+//   - Node: a Value or Instruction (emphasizing its membership in the IR value graph)
+//
+// A computation that yields a result implements both the Value and
+// Instruction interfaces.  The following table shows for each
+// concrete type which of these interfaces it implements.
+//
+//	                   Value?          Instruction?    Member?
+//	*Alloc                ✔               ✔
+//	*BinOp                ✔               ✔
+//	*BlankStore                           ✔
+//	*Builtin              ✔
+//	*Call                 ✔               ✔
+//	*ChangeInterface      ✔               ✔
+//	*ChangeType           ✔               ✔
+//	*Const                ✔               ✔
+//	*Convert              ✔               ✔
+//	*DebugRef                             ✔
+//	*Defer                ✔               ✔
+//	*Extract              ✔               ✔
+//	*Field                ✔               ✔
+//	*FieldAddr            ✔               ✔
+//	*FreeVar              ✔
+//	*Function             ✔                               ✔ (func)
+//	*Global               ✔                               ✔ (var)
+//	*Go                   ✔               ✔
+//	*If                                   ✔
+//	*Index                ✔               ✔
+//	*IndexAddr            ✔               ✔
+//	*Jump                                 ✔
+//	*Load                 ✔               ✔
+//	*MakeChan             ✔               ✔
+//	*MakeClosure          ✔               ✔
+//	*MakeInterface        ✔               ✔
+//	*MakeMap              ✔               ✔
+//	*MakeSlice            ✔               ✔
+//	*MapLookup            ✔               ✔
+//	*MapUpdate            ✔               ✔
+//	*MultiConvert         ✔               ✔
+//	*NamedConst                                           ✔ (const)
+//	*Next                 ✔               ✔
+//	*Panic                                ✔
+//	*Parameter            ✔               ✔
+//	*Phi                  ✔               ✔
+//	*Range                ✔               ✔
+//	*Recv                 ✔               ✔
+//	*Return                               ✔
+//	*RunDefers                            ✔
+//	*Select               ✔               ✔
+//	*Send                 ✔               ✔
+//	*Sigma                ✔               ✔
+//	*Slice                ✔               ✔
+//	*SliceToArrayPointer  ✔               ✔
+//	*SliceToArray         ✔               ✔
+//	*Store                ✔               ✔
+//	*StringLookup         ✔               ✔
+//	*Type                                                 ✔ (type)
+//	*TypeAssert           ✔               ✔
+//	*UnOp                 ✔               ✔
+//	*Unreachable                          ✔
+//
+// Other key types in this package include: Program, Package, Function
+// and BasicBlock.
+//
+// The program representation constructed by this package is fully
+// resolved internally, i.e. it does not rely on the names of Values,
+// Packages, Functions, Types or BasicBlocks for the correct
+// interpretation of the program.  Only the identities of objects and
+// the topology of the IR and type graphs are semantically
+// significant.  (There is one exception: Ids, used to identify field
+// and method names, contain strings.)  Avoidance of name-based
+// operations simplifies the implementation of subsequent passes and
+// can make them very efficient.  Many objects are nonetheless named
+// to aid in debugging, but it is not essential that the names be
+// either accurate or unambiguous.  The public API exposes a number of
+// name-based maps for client convenience.
+//
+// The ir/irutil package provides various utilities that depend only
+// on the public API of this package.
+//
+// TODO(adonovan): Consider the exceptional control-flow implications
+// of defer and recover().
+//
+// TODO(adonovan): write a how-to document for all the various cases
+// of trying to determine corresponding elements across the four
+// domains of source locations, ast.Nodes, types.Objects,
+// ir.Values/Instructions.
+package ir

vendor/honnef.co/go/tools/go/ir/dom.go

@@ -0,0 +1,466 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package ir
+
+// This file defines algorithms related to dominance.
+
+// Dominator tree construction ----------------------------------------
+//
+// We use the algorithm described in Lengauer & Tarjan. 1979.  A fast
+// algorithm for finding dominators in a flowgraph.
+// https://doi.acm.org/10.1145/357062.357071
+//
+// We also apply the optimizations to SLT described in Georgiadis et
+// al, Finding Dominators in Practice, JGAA 2006,
+// https://jgaa.info/accepted/2006/GeorgiadisTarjanWerneck2006.10.1.pdf
+// to avoid the need for buckets of size > 1.
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"math/big"
+	"os"
+	"sort"
+)
+
+// Idom returns the block that immediately dominates b:
+// its parent in the dominator tree, if any.
+// The entry node (b.Index==0) does not have a parent.
+func (b *BasicBlock) Idom() *BasicBlock { return b.dom.idom }
+
+// Dominees returns the list of blocks that b immediately dominates:
+// its children in the dominator tree.
+func (b *BasicBlock) Dominees() []*BasicBlock { return b.dom.children }
+
+// Dominates reports whether b dominates c.
+func (b *BasicBlock) Dominates(c *BasicBlock) bool {
+	return b.dom.pre <= c.dom.pre && c.dom.post <= b.dom.post
+}
+
+type byDomPreorder []*BasicBlock
+
+func (a byDomPreorder) Len() int           { return len(a) }
+func (a byDomPreorder) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }
+func (a byDomPreorder) Less(i, j int) bool { return a[i].dom.pre < a[j].dom.pre }
+
+// DomPreorder returns a new slice containing the blocks of f in
+// dominator tree preorder.
+func (f *Function) DomPreorder() []*BasicBlock {
+	n := len(f.Blocks)
+	order := make(byDomPreorder, n)
+	copy(order, f.Blocks)
+	sort.Sort(order)
+	return order
+}
+
+// domInfo contains a BasicBlock's dominance information.
+type domInfo struct {
+	idom      *BasicBlock   // immediate dominator (parent in domtree)
+	children  []*BasicBlock // nodes immediately dominated by this one
+	pre, post int32         // pre- and post-order numbering within domtree
+}
+
+// buildDomTree computes the dominator tree of f using the LT algorithm.
+// Precondition: all blocks are reachable (e.g. optimizeBlocks has been run).
+func buildDomTree(fn *Function) {
+	// The step numbers refer to the original LT paper; the
+	// reordering is due to Georgiadis.
+
+	// Clear any previous domInfo.
+	for _, b := range fn.Blocks {
+		b.dom = domInfo{}
+	}
+
+	idoms := make([]*BasicBlock, len(fn.Blocks))
+
+	order := make([]*BasicBlock, 0, len(fn.Blocks))
+	seen := fn.blockset(0)
+	var dfs func(b *BasicBlock)
+	dfs = func(b *BasicBlock) {
+		if !seen.Add(b) {
+			return
+		}
+		for _, succ := range b.Succs {
+			dfs(succ)
+		}
+		if fn.fakeExits.Has(b) {
+			dfs(fn.Exit)
+		}
+		order = append(order, b)
+		b.post = len(order) - 1
+	}
+	dfs(fn.Blocks[0])
+
+	for i := 0; i < len(order)/2; i++ {
+		o := len(order) - i - 1
+		order[i], order[o] = order[o], order[i]
+	}
+
+	idoms[fn.Blocks[0].Index] = fn.Blocks[0]
+	changed := true
+	for changed {
+		changed = false
+		// iterate over all nodes in reverse postorder, except for the
+		// entry node
+		for _, b := range order[1:] {
+			var newIdom *BasicBlock
+			do := func(p *BasicBlock) {
+				if idoms[p.Index] == nil {
+					return
+				}
+				if newIdom == nil {
+					newIdom = p
+				} else {
+					finger1 := p
+					finger2 := newIdom
+					for finger1 != finger2 {
+						for finger1.post < finger2.post {
+							finger1 = idoms[finger1.Index]
+						}
+						for finger2.post < finger1.post {
+							finger2 = idoms[finger2.Index]
+						}
+					}
+					newIdom = finger1
+				}
+			}
+			for _, p := range b.Preds {
+				do(p)
+			}
+			if b == fn.Exit {
+				for _, p := range fn.Blocks {
+					if fn.fakeExits.Has(p) {
+						do(p)
+					}
+				}
+			}
+
+			if idoms[b.Index] != newIdom {
+				idoms[b.Index] = newIdom
+				changed = true
+			}
+		}
+	}
+
+	for i, b := range idoms {
+		fn.Blocks[i].dom.idom = b
+		if b == nil {
+			// malformed CFG
+			continue
+		}
+		if i == b.Index {
+			continue
+		}
+		b.dom.children = append(b.dom.children, fn.Blocks[i])
+	}
+
+	numberDomTree(fn.Blocks[0], 0, 0)
+
+	// printDomTreeDot(os.Stderr, fn) // debugging
+	// printDomTreeText(os.Stderr, root, 0) // debugging
+
+	if fn.Prog.mode&SanityCheckFunctions != 0 {
+		sanityCheckDomTree(fn)
+	}
+}
+
+// buildPostDomTree is like buildDomTree, but builds the post-dominator tree instead.
+func buildPostDomTree(fn *Function) {
+	// The step numbers refer to the original LT paper; the
+	// reordering is due to Georgiadis.
+
+	// Clear any previous domInfo.
+	for _, b := range fn.Blocks {
+		b.pdom = domInfo{}
+	}
+
+	idoms := make([]*BasicBlock, len(fn.Blocks))
+
+	order := make([]*BasicBlock, 0, len(fn.Blocks))
+	seen := fn.blockset(0)
+	var dfs func(b *BasicBlock)
+	dfs = func(b *BasicBlock) {
+		if !seen.Add(b) {
+			return
+		}
+		for _, pred := range b.Preds {
+			dfs(pred)
+		}
+		if b == fn.Exit {
+			for _, p := range fn.Blocks {
+				if fn.fakeExits.Has(p) {
+					dfs(p)
+				}
+			}
+		}
+		order = append(order, b)
+		b.post = len(order) - 1
+	}
+	dfs(fn.Exit)
+
+	for i := 0; i < len(order)/2; i++ {
+		o := len(order) - i - 1
+		order[i], order[o] = order[o], order[i]
+	}
+
+	idoms[fn.Exit.Index] = fn.Exit
+	changed := true
+	for changed {
+		changed = false
+		// iterate over all nodes in reverse postorder, except for the
+		// exit node
+		for _, b := range order[1:] {
+			var newIdom *BasicBlock
+			do := func(p *BasicBlock) {
+				if idoms[p.Index] == nil {
+					return
+				}
+				if newIdom == nil {
+					newIdom = p
+				} else {
+					finger1 := p
+					finger2 := newIdom
+					for finger1 != finger2 {
+						for finger1.post < finger2.post {
+							finger1 = idoms[finger1.Index]
+						}
+						for finger2.post < finger1.post {
+							finger2 = idoms[finger2.Index]
+						}
+					}
+					newIdom = finger1
+				}
+			}
+			for _, p := range b.Succs {
+				do(p)
+			}
+			if fn.fakeExits.Has(b) {
+				do(fn.Exit)
+			}
+
+			if idoms[b.Index] != newIdom {
+				idoms[b.Index] = newIdom
+				changed = true
+			}
+		}
+	}
+
+	for i, b := range idoms {
+		fn.Blocks[i].pdom.idom = b
+		if b == nil {
+			// malformed CFG
+			continue
+		}
+		if i == b.Index {
+			continue
+		}
+		b.pdom.children = append(b.pdom.children, fn.Blocks[i])
+	}
+
+	numberPostDomTree(fn.Exit, 0, 0)
+
+	// printPostDomTreeDot(os.Stderr, fn) // debugging
+	// printPostDomTreeText(os.Stderr, fn.Exit, 0) // debugging
+
+	if fn.Prog.mode&SanityCheckFunctions != 0 { // XXX
+		sanityCheckDomTree(fn) // XXX
+	}
+}
+
+// numberDomTree sets the pre- and post-order numbers of a depth-first
+// traversal of the dominator tree rooted at v.  These are used to
+// answer dominance queries in constant time.
+func numberDomTree(v *BasicBlock, pre, post int32) (int32, int32) {
+	v.dom.pre = pre
+	pre++
+	for _, child := range v.dom.children {
+		pre, post = numberDomTree(child, pre, post)
+	}
+	v.dom.post = post
+	post++
+	return pre, post
+}
+
+// numberPostDomTree sets the pre- and post-order numbers of a depth-first
+// traversal of the post-dominator tree rooted at v.  These are used to
+// answer post-dominance queries in constant time.
+func numberPostDomTree(v *BasicBlock, pre, post int32) (int32, int32) {
+	v.pdom.pre = pre
+	pre++
+	for _, child := range v.pdom.children {
+		pre, post = numberPostDomTree(child, pre, post)
+	}
+	v.pdom.post = post
+	post++
+	return pre, post
+}
+
+// Testing utilities ----------------------------------------
+
+// sanityCheckDomTree checks the correctness of the dominator tree
+// computed by the LT algorithm by comparing against the dominance
+// relation computed by a naive Kildall-style forward dataflow
+// analysis (Algorithm 10.16 from the "Dragon" book).
+func sanityCheckDomTree(f *Function) {
+	n := len(f.Blocks)
+
+	// D[i] is the set of blocks that dominate f.Blocks[i],
+	// represented as a bit-set of block indices.
+	D := make([]big.Int, n)
+
+	one := big.NewInt(1)
+
+	// all is the set of all blocks; constant.
+	var all big.Int
+	all.Set(one).Lsh(&all, uint(n)).Sub(&all, one)
+
+	// Initialization.
+	for i := range f.Blocks {
+		if i == 0 {
+			// A root is dominated only by itself.
+			D[i].SetBit(&D[0], 0, 1)
+		} else {
+			// All other blocks are (initially) dominated
+			// by every block.
+			D[i].Set(&all)
+		}
+	}
+
+	// Iteration until fixed point.
+	for changed := true; changed; {
+		changed = false
+		for i, b := range f.Blocks {
+			if i == 0 {
+				continue
+			}
+			// Compute intersection across predecessors.
+			var x big.Int
+			x.Set(&all)
+			for _, pred := range b.Preds {
+				x.And(&x, &D[pred.Index])
+			}
+			if b == f.Exit {
+				for _, p := range f.Blocks {
+					if f.fakeExits.Has(p) {
+						x.And(&x, &D[p.Index])
+					}
+				}
+			}
+			x.SetBit(&x, i, 1) // a block always dominates itself.
+			if D[i].Cmp(&x) != 0 {
+				D[i].Set(&x)
+				changed = true
+			}
+		}
+	}
+
+	// Check the entire relation.  O(n^2).
+	ok := true
+	for i := range n {
+		for j := range n {
+			b, c := f.Blocks[i], f.Blocks[j]
+			actual := b.Dominates(c)
+			expected := D[j].Bit(i) == 1
+			if actual != expected {
+				fmt.Fprintf(os.Stderr, "dominates(%s, %s)==%t, want %t\n", b, c, actual, expected)
+				ok = false
+			}
+		}
+	}
+
+	preorder := f.DomPreorder()
+	for _, b := range f.Blocks {
+		if got := preorder[b.dom.pre]; got != b {
+			fmt.Fprintf(os.Stderr, "preorder[%d]==%s, want %s\n", b.dom.pre, got, b)
+			ok = false
+		}
+	}
+
+	if !ok {
+		panic("sanityCheckDomTree failed for " + f.String())
+	}
+
+}
+
+// Printing functions ----------------------------------------
+
+// printDomTree prints the dominator tree as text, using indentation.
+//
+//lint:ignore U1000 used during debugging
+func printDomTreeText(buf *bytes.Buffer, v *BasicBlock, indent int) {
+	fmt.Fprintf(buf, "%*s%s\n", 4*indent, "", v)
+	for _, child := range v.dom.children {
+		printDomTreeText(buf, child, indent+1)
+	}
+}
+
+// printDomTreeDot prints the dominator tree of f in AT&T GraphViz
+// (.dot) format.
+//
+//lint:ignore U1000 used during debugging
+func printDomTreeDot(buf io.Writer, f *Function) {
+	fmt.Fprintln(buf, "//", f)
+	fmt.Fprintln(buf, "digraph domtree {")
+	for i, b := range f.Blocks {
+		v := b.dom
+		fmt.Fprintf(buf, "\tn%d [label=\"%s (%d, %d)\",shape=\"rectangle\"];\n", v.pre, b, v.pre, v.post)
+		// TODO(adonovan): improve appearance of edges
+		// belonging to both dominator tree and CFG.
+
+		// Dominator tree edge.
+		if i != 0 {
+			fmt.Fprintf(buf, "\tn%d -> n%d [style=\"solid\",weight=100];\n", v.idom.dom.pre, v.pre)
+		}
+		// CFG edges.
+		for _, pred := range b.Preds {
+			fmt.Fprintf(buf, "\tn%d -> n%d [style=\"dotted\",weight=0];\n", pred.dom.pre, v.pre)
+		}
+
+		if f.fakeExits.Has(b) {
+			fmt.Fprintf(buf, "\tn%d -> n%d [style=\"dotted\",weight=0,color=red];\n", b.dom.pre, f.Exit.dom.pre)
+		}
+	}
+	fmt.Fprintln(buf, "}")
+}
+
+// printDomTree prints the dominator tree as text, using indentation.
+//
+//lint:ignore U1000 used during debugging
+func printPostDomTreeText(buf io.Writer, v *BasicBlock, indent int) {
+	fmt.Fprintf(buf, "%*s%s\n", 4*indent, "", v)
+	for _, child := range v.pdom.children {
+		printPostDomTreeText(buf, child, indent+1)
+	}
+}
+
+// printDomTreeDot prints the dominator tree of f in AT&T GraphViz
+// (.dot) format.
+//
+//lint:ignore U1000 used during debugging
+func printPostDomTreeDot(buf io.Writer, f *Function) {
+	fmt.Fprintln(buf, "//", f)
+	fmt.Fprintln(buf, "digraph pdomtree {")
+	for _, b := range f.Blocks {
+		v := b.pdom
+		fmt.Fprintf(buf, "\tn%d [label=\"%s (%d, %d)\",shape=\"rectangle\"];\n", v.pre, b, v.pre, v.post)
+		// TODO(adonovan): improve appearance of edges
+		// belonging to both dominator tree and CFG.
+
+		// Dominator tree edge.
+		if b != f.Exit {
+			fmt.Fprintf(buf, "\tn%d -> n%d [style=\"solid\",weight=100];\n", v.idom.pdom.pre, v.pre)
+		}
+		// CFG edges.
+		for _, pred := range b.Preds {
+			fmt.Fprintf(buf, "\tn%d -> n%d [style=\"dotted\",weight=0];\n", pred.pdom.pre, v.pre)
+		}
+
+		if f.fakeExits.Has(b) {
+			fmt.Fprintf(buf, "\tn%d -> n%d [style=\"dotted\",weight=0,color=red];\n", b.dom.pre, f.Exit.dom.pre)
+		}
+	}
+	fmt.Fprintln(buf, "}")
+}

vendor/honnef.co/go/tools/go/ir/emit.go

@@ -0,0 +1,658 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package ir
+
+// Helpers for emitting IR instructions.
+
+import (
+	"fmt"
+	"go/ast"
+	"go/constant"
+	"go/token"
+	"go/types"
+
+	"honnef.co/go/tools/go/types/typeutil"
+
+	"golang.org/x/exp/typeparams"
+)
+
+// emitAlloc emits to f a new Alloc instruction allocating a variable
+// of type typ.
+//
+// The caller must set Alloc.Heap=true (for a heap-allocated variable)
+// or add the Alloc to f.Locals (for a frame-allocated variable).
+//
+// During building, a variable in f.Locals may have its Heap flag
+// set when it is discovered that its address is taken.
+// These Allocs are removed from f.Locals at the end.
+//
+// The builder should generally call one of the emit{New,Local,LocalVar} wrappers instead.
+func emitAlloc(f *Function, typ types.Type, source ast.Node, comment string) *Alloc {
+	v := &Alloc{}
+	v.comment = comment
+	v.setType(types.NewPointer(typ))
+	f.emit(v, source)
+	return v
+}
+
+// emitNew emits to f a new Alloc instruction heap-allocating a
+// variable of type typ.
+func emitNew(f *Function, typ types.Type, source ast.Node, comment string) *Alloc {
+	alloc := emitAlloc(f, typ, source, comment)
+	alloc.Heap = true
+	return alloc
+}
+
+// emitLocal creates a local var for (t, source, comment) and
+// emits an Alloc instruction for it.
+//
+// (Use this function or emitNew for synthetic variables;
+// for source-level variables, use emitLocalVar.)
+func emitLocal(f *Function, t types.Type, source ast.Node, comment string) *Alloc {
+	local := emitAlloc(f, t, source, comment)
+	f.Locals = append(f.Locals, local)
+	return local
+}
+
+// emitLocalVar creates a local var for v and emits an Alloc instruction for it.
+// Subsequent calls to f.lookup(v) return it.
+func emitLocalVar(f *Function, v *types.Var, source ast.Node) *Alloc {
+	alloc := emitLocal(f, v.Type(), source, v.Name())
+	f.vars[v] = alloc
+	return alloc
+}
+
+// emitLoad emits to f an instruction to load the address addr into a
+// new temporary, and returns the value so defined.
+func emitLoad(f *Function, addr Value, source ast.Node) *Load {
+	v := &Load{X: addr}
+	v.setType(deref(addr.Type()))
+	f.emit(v, source)
+	return v
+}
+
+func emitRecv(f *Function, ch Value, commaOk bool, typ types.Type, source ast.Node) Value {
+	recv := &Recv{
+		Chan:    ch,
+		CommaOk: commaOk,
+	}
+	recv.setType(typ)
+	return f.emit(recv, source)
+}
+
+// emitDebugRef emits to f a DebugRef pseudo-instruction associating
+// expression e with value v.
+func emitDebugRef(f *Function, e ast.Expr, v Value, isAddr bool) {
+	ref := makeDebugRef(f, e, v, isAddr)
+	if ref == nil {
+		return
+	}
+	f.emit(ref, nil)
+}
+
+func makeDebugRef(f *Function, e ast.Expr, v Value, isAddr bool) *DebugRef {
+	if !f.debugInfo() {
+		return nil // debugging not enabled
+	}
+	if v == nil || e == nil {
+		panic("nil")
+	}
+	var obj types.Object
+	e = unparen(e)
+	if id, ok := e.(*ast.Ident); ok {
+		if isBlankIdent(id) {
+			return nil
+		}
+		obj = f.Pkg.objectOf(id)
+		switch obj.(type) {
+		case *types.Nil, *types.Const, *types.Builtin:
+			return nil
+		}
+	}
+	return &DebugRef{
+		X:      v,
+		Expr:   e,
+		IsAddr: isAddr,
+		object: obj,
+	}
+}
+
+// emitArith emits to f code to compute the binary operation op(x, y)
+// where op is an eager shift, logical or arithmetic operation.
+// (Use emitCompare() for comparisons and Builder.logicalBinop() for
+// non-eager operations.)
+func emitArith(f *Function, op token.Token, x, y Value, t types.Type, source ast.Node) Value {
+	switch op {
+	case token.SHL, token.SHR:
+		x = emitConv(f, x, t, source)
+		// y may be signed or an 'untyped' constant.
+		// There is a runtime panic if y is signed and <0. Instead of inserting a check for y<0
+		// and converting to an unsigned value (like the compiler) leave y as is.
+		if b, ok := y.Type().Underlying().(*types.Basic); ok && b.Info()&types.IsUntyped != 0 {
+			// Untyped conversion:
+			// Spec https://go.dev/ref/spec#Operators:
+			// The right operand in a shift expression must have integer type or be an untyped constant
+			// representable by a value of type uint.
+			y = emitConv(f, y, types.Typ[types.Uint], source)
+		}
+
+	case token.ADD, token.SUB, token.MUL, token.QUO, token.REM, token.AND, token.OR, token.XOR, token.AND_NOT:
+		x = emitConv(f, x, t, source)
+		y = emitConv(f, y, t, source)
+
+	default:
+		panic("illegal op in emitArith: " + op.String())
+
+	}
+	v := &BinOp{
+		Op: op,
+		X:  x,
+		Y:  y,
+	}
+	v.setType(t)
+	return f.emit(v, source)
+}
+
+// emitCompare emits to f code compute the boolean result of
+// comparison 'x op y'.
+func emitCompare(f *Function, op token.Token, x, y Value, source ast.Node) Value {
+	xt := x.Type().Underlying()
+	yt := y.Type().Underlying()
+
+	// Special case to optimise a tagless SwitchStmt so that
+	// these are equivalent
+	//   switch { case e: ...}
+	//   switch true { case e: ... }
+	//   if e==true { ... }
+	// even in the case when e's type is an interface.
+	// TODO(adonovan): opt: generalise to x==true, false!=y, etc.
+	if x, ok := x.(*Const); ok && op == token.EQL && x.Value != nil && x.Value.Kind() == constant.Bool && constant.BoolVal(x.Value) {
+		if yt, ok := yt.(*types.Basic); ok && yt.Info()&types.IsBoolean != 0 {
+			return y
+		}
+	}
+
+	if types.Identical(xt, yt) {
+		// no conversion necessary
+	} else if _, ok := xt.(*types.Interface); ok && !typeparams.IsTypeParam(x.Type()) {
+		y = emitConv(f, y, x.Type(), source)
+	} else if _, ok := yt.(*types.Interface); ok && !typeparams.IsTypeParam(y.Type()) {
+		x = emitConv(f, x, y.Type(), source)
+	} else if _, ok := x.(*Const); ok {
+		x = emitConv(f, x, y.Type(), source)
+	} else if _, ok := y.(*Const); ok {
+		y = emitConv(f, y, x.Type(), source)
+		//lint:ignore SA9003 no-op
+	} else {
+		// other cases, e.g. channels.  No-op.
+	}
+
+	v := &BinOp{
+		Op: op,
+		X:  x,
+		Y:  y,
+	}
+	v.setType(tBool)
+	return f.emit(v, source)
+}
+
+// isValuePreserving returns true if a conversion from ut_src to
+// ut_dst is value-preserving, i.e. just a change of type.
+// Precondition: neither argument is a named type.
+func isValuePreserving(ut_src, ut_dst types.Type) bool {
+	// Identical underlying types?
+	if types.IdenticalIgnoreTags(ut_dst, ut_src) {
+		return true
+	}
+
+	switch ut_dst.(type) {
+	case *types.Chan:
+		// Conversion between channel types?
+		_, ok := ut_src.(*types.Chan)
+		return ok
+
+	case *types.Pointer:
+		// Conversion between pointers with identical base types?
+		_, ok := ut_src.(*types.Pointer)
+		return ok
+	}
+	return false
+}
+
+// emitConv emits to f code to convert Value val to exactly type typ,
+// and returns the converted value.  Implicit conversions are required
+// by language assignability rules in assignments, parameter passing,
+// etc.
+func emitConv(f *Function, val Value, t_dst types.Type, source ast.Node) Value {
+	t_src := val.Type()
+
+	// Identical types?  Conversion is a no-op.
+	if types.Identical(t_src, t_dst) {
+		return val
+	}
+
+	ut_dst := t_dst.Underlying()
+	ut_src := t_src.Underlying()
+
+	// Conversion to, or construction of a value of, an interface type?
+	if isNonTypeParamInterface(t_dst) {
+		// Interface name change?
+		if isValuePreserving(ut_src, ut_dst) {
+			c := &ChangeType{X: val}
+			c.setType(t_dst)
+			return f.emit(c, source)
+		}
+
+		// Assignment from one interface type to another?
+		if isNonTypeParamInterface(t_src) {
+			c := &ChangeInterface{X: val}
+			c.setType(t_dst)
+			return f.emit(c, source)
+		}
+
+		// Untyped nil constant?  Return interface-typed nil constant.
+		if ut_src == tUntypedNil {
+			return emitConst(f, zeroConst(t_dst, source))
+		}
+
+		// Convert (non-nil) "untyped" literals to their default type.
+		if t, ok := ut_src.(*types.Basic); ok && t.Info()&types.IsUntyped != 0 {
+			val = emitConv(f, val, types.Default(ut_src), source)
+		}
+
+		f.Pkg.Prog.needMethodsOf(val.Type())
+		mi := &MakeInterface{X: val}
+		mi.setType(t_dst)
+		return f.emit(mi, source)
+	}
+
+	// In the common case, the typesets of src and dst are singletons
+	// and we emit an appropriate conversion. But if either contains
+	// a type parameter, the conversion may represent a cross product,
+	// in which case which we emit a MultiConvert.
+	tset_dst := typeutil.NewTypeSet(ut_dst)
+	tset_src := typeutil.NewTypeSet(ut_src)
+
+	// conversionCase describes an instruction pattern that may be emitted to
+	// model d <- s for d in dst_terms and s in src_terms.
+	// Multiple conversions can match the same pattern.
+	type conversionCase uint8
+	const (
+		changeType conversionCase = 1 << iota
+		sliceToArray
+		sliceToArrayPtr
+		sliceTo0Array
+		sliceTo0ArrayPtr
+		convert
+	)
+
+	classify := func(s, d types.Type) conversionCase {
+		// Just a change of type, but not value or representation?
+		if isValuePreserving(s, d) {
+			return changeType
+		}
+
+		// Conversion from slice to array or slice to array pointer?
+		if slice, ok := s.(*types.Slice); ok {
+			var arr *types.Array
+			var ptr bool
+			// Conversion from slice to array pointer?
+			switch d := d.(type) {
+			case *types.Array:
+				arr = d
+			case *types.Pointer:
+				arr, _ = d.Elem().Underlying().(*types.Array)
+				ptr = true
+			}
+			if arr != nil && types.Identical(slice.Elem(), arr.Elem()) {
+				if arr.Len() == 0 {
+					if ptr {
+						return sliceTo0ArrayPtr
+					} else {
+						return sliceTo0Array
+					}
+				}
+				if ptr {
+					return sliceToArrayPtr
+				} else {
+					return sliceToArray
+				}
+			}
+		}
+
+		// The only remaining case in well-typed code is a representation-
+		// changing conversion of basic types (possibly with []byte/[]rune).
+		if !isBasic(s) && !isBasic(d) {
+			panic(fmt.Sprintf("in %s: cannot convert term %s (%s [within %s]) to type %s [within %s]", f, val, val.Type(), s, t_dst, d))
+		}
+		return convert
+	}
+
+	var classifications conversionCase
+	for _, s := range tset_src.Terms {
+		us := s.Type().Underlying()
+		for _, d := range tset_dst.Terms {
+			ud := d.Type().Underlying()
+			classifications |= classify(us, ud)
+		}
+	}
+	if classifications == 0 {
+		panic(fmt.Sprintf("in %s: cannot convert %s (%s) to %s", f, val, val.Type(), t_dst))
+	}
+
+	// Conversion of a compile-time constant value?
+	if c, ok := val.(*Const); ok {
+		// Conversion to a basic type?
+		if isBasic(ut_dst) {
+			// Conversion of a compile-time constant to
+			// another constant type results in a new
+			// constant of the destination type and
+			// (initially) the same abstract value.
+			// We don't truncate the value yet.
+			return emitConst(f, NewConst(c.Value, t_dst, source))
+		}
+		// Can we always convert from zero value without panicking?
+		const mayPanic = sliceToArray | sliceToArrayPtr
+		if c.Value == nil && classifications&mayPanic == 0 {
+			return emitConst(f, NewConst(nil, t_dst, source))
+		}
+
+		// We're converting from constant to non-constant type,
+		// e.g. string -> []byte/[]rune.
+	}
+
+	switch classifications {
+	case changeType: // representation-preserving change
+		c := &ChangeType{X: val}
+		c.setType(t_dst)
+		return f.emit(c, source)
+
+	case sliceToArrayPtr, sliceTo0ArrayPtr: // slice to array pointer
+		c := &SliceToArrayPointer{X: val}
+		c.setType(t_dst)
+		return f.emit(c, source)
+
+	case sliceToArray: // slice to arrays (not zero-length)
+		p := &SliceToArray{X: val}
+		p.setType(t_dst)
+		return f.emit(p, source)
+
+	case sliceTo0Array: // slice to zero-length arrays (constant)
+		return emitConst(f, zeroConst(t_dst, source))
+
+	case convert: // representation-changing conversion
+		c := &Convert{X: val}
+		c.setType(t_dst)
+		return f.emit(c, source)
+
+	default: // multiple conversion
+		c := &MultiConvert{X: val, from: tset_src, to: tset_dst}
+		c.setType(t_dst)
+		return f.emit(c, source)
+	}
+}
+
+// emitStore emits to f an instruction to store value val at location
+// addr, applying implicit conversions as required by assignability rules.
+func emitStore(f *Function, addr, val Value, source ast.Node) *Store {
+	s := &Store{
+		Addr: addr,
+		Val:  emitConv(f, val, deref(addr.Type()), source),
+	}
+	f.emit(s, source)
+	return s
+}
+
+// emitJump emits to f a jump to target, and updates the control-flow graph.
+// Postcondition: f.currentBlock is nil.
+func emitJump(f *Function, target *BasicBlock, source ast.Node) *Jump {
+	b := f.currentBlock
+	j := new(Jump)
+	b.emit(j, source)
+	addEdge(b, target)
+	f.currentBlock = nil
+	return j
+}
+
+// emitIf emits to f a conditional jump to tblock or fblock based on
+// cond, and updates the control-flow graph.
+// Postcondition: f.currentBlock is nil.
+func emitIf(f *Function, cond Value, tblock, fblock *BasicBlock, source ast.Node) *If {
+	b := f.currentBlock
+	stmt := &If{Cond: cond}
+	b.emit(stmt, source)
+	addEdge(b, tblock)
+	addEdge(b, fblock)
+	f.currentBlock = nil
+	return stmt
+}
+
+// emitExtract emits to f an instruction to extract the index'th
+// component of tuple.  It returns the extracted value.
+func emitExtract(f *Function, tuple Value, index int, source ast.Node) Value {
+	e := &Extract{Tuple: tuple, Index: index}
+	e.setType(tuple.Type().(*types.Tuple).At(index).Type())
+	return f.emit(e, source)
+}
+
+// emitTypeAssert emits to f a type assertion value := x.(t) and
+// returns the value.  x.Type() must be an interface.
+func emitTypeAssert(f *Function, x Value, t types.Type, source ast.Node) Value {
+	a := &TypeAssert{X: x, AssertedType: t}
+	a.setType(t)
+	return f.emit(a, source)
+}
+
+// emitTypeTest emits to f a type test value,ok := x.(t) and returns
+// a (value, ok) tuple.  x.Type() must be an interface.
+func emitTypeTest(f *Function, x Value, t types.Type, source ast.Node) Value {
+	a := &TypeAssert{
+		X:            x,
+		AssertedType: t,
+		CommaOk:      true,
+	}
+	a.setType(types.NewTuple(
+		newVar("value", t),
+		varOk,
+	))
+	return f.emit(a, source)
+}
+
+// emitTailCall emits to f a function call in tail position.  The
+// caller is responsible for all fields of 'call' except its type.
+// Intended for wrapper methods.
+// Precondition: f does/will not use deferred procedure calls.
+// Postcondition: f.currentBlock is nil.
+func emitTailCall(f *Function, call *Call, source ast.Node) {
+	tresults := f.Signature.Results()
+	nr := tresults.Len()
+	if nr == 1 {
+		call.typ = tresults.At(0).Type()
+	} else {
+		call.typ = tresults
+	}
+	tuple := f.emit(call, source)
+	var ret Return
+	switch nr {
+	case 0:
+		// no-op
+	case 1:
+		ret.Results = []Value{tuple}
+	default:
+		for i := range nr {
+			v := emitExtract(f, tuple, i, source)
+			// TODO(adonovan): in principle, this is required:
+			//   v = emitConv(f, o.Type, f.Signature.Results[i].Type)
+			// but in practice emitTailCall is only used when
+			// the types exactly match.
+			ret.Results = append(ret.Results, v)
+		}
+	}
+
+	f.Exit = f.newBasicBlock("exit")
+	emitJump(f, f.Exit, source)
+	f.currentBlock = f.Exit
+	f.emit(&ret, source)
+	f.currentBlock = nil
+}
+
+func emitCall(fn *Function, call *Call, source ast.Node) Value {
+	res := fn.emit(call, source)
+
+	callee := call.Call.StaticCallee()
+	if callee != nil &&
+		callee.object != nil &&
+		fn.Prog.noReturn != nil &&
+		fn.Prog.noReturn(callee.object) {
+		// Call doesn't return normally. Either it doesn't return at all
+		// (infinitely blocked or exitting the process), or it unwinds the stack
+		// (panic, runtime.Goexit). In case it unwinds, jump to the exit block.
+		fn.emit(new(Jump), source)
+		addEdge(fn.currentBlock, fn.Exit)
+		fn.currentBlock = fn.newBasicBlock("unreachable")
+	}
+
+	return res
+}
+
+// emitImplicitSelections emits to f code to apply the sequence of
+// implicit field selections specified by indices to base value v, and
+// returns the selected value.
+//
+// If v is the address of a struct, the result will be the address of
+// a field; if it is the value of a struct, the result will be the
+// value of a field.
+func emitImplicitSelections(f *Function, v Value, indices []int, source ast.Node) Value {
+	for _, index := range indices {
+		// We may have a generic type containing a pointer, or a pointer to a generic type containing a struct. A
+		// pointer to a generic containing a pointer to a struct shouldn't be possible because the outer pointer gets
+		// dereferenced implicitly before we get here.
+		fld := typeutil.CoreType(deref(v.Type())).Underlying().(*types.Struct).Field(index)
+
+		if isPointer(v.Type()) {
+			instr := &FieldAddr{
+				X:     v,
+				Field: index,
+			}
+			instr.setType(types.NewPointer(fld.Type()))
+			v = f.emit(instr, source)
+			// Load the field's value iff indirectly embedded.
+			if isPointer(fld.Type()) {
+				v = emitLoad(f, v, source)
+			}
+		} else {
+			instr := &Field{
+				X:     v,
+				Field: index,
+			}
+			instr.setType(fld.Type())
+			v = f.emit(instr, source)
+		}
+	}
+	return v
+}
+
+// emitFieldSelection emits to f code to select the index'th field of v.
+//
+// If wantAddr, the input must be a pointer-to-struct and the result
+// will be the field's address; otherwise the result will be the
+// field's value.
+// Ident id is used for position and debug info.
+func emitFieldSelection(f *Function, v Value, index int, wantAddr bool, id *ast.Ident) Value {
+	// We may have a generic type containing a pointer, or a pointer to a generic type containing a struct. A
+	// pointer to a generic containing a pointer to a struct shouldn't be possible because the outer pointer gets
+	// dereferenced implicitly before we get here.
+	vut := typeutil.CoreType(deref(v.Type())).Underlying().(*types.Struct)
+	fld := vut.Field(index)
+	if isPointer(v.Type()) {
+		instr := &FieldAddr{
+			X:     v,
+			Field: index,
+		}
+		instr.setSource(id)
+		instr.setType(types.NewPointer(fld.Type()))
+		v = f.emit(instr, id)
+		// Load the field's value iff we don't want its address.
+		if !wantAddr {
+			v = emitLoad(f, v, id)
+		}
+	} else {
+		instr := &Field{
+			X:     v,
+			Field: index,
+		}
+		instr.setSource(id)
+		instr.setType(fld.Type())
+		v = f.emit(instr, id)
+	}
+	emitDebugRef(f, id, v, wantAddr)
+	return v
+}
+
+// zeroValue emits to f code to produce a zero value of type t,
+// and returns it.
+func zeroValue(f *Function, t types.Type, source ast.Node) Value {
+	return emitConst(f, zeroConst(t, source))
+}
+
+type constKey struct {
+	typ    types.Type
+	value  constant.Value
+	source ast.Node
+}
+
+func emitConst(f *Function, c Constant) Constant {
+	if f.consts == nil {
+		f.consts = map[constKey]constValue{}
+	}
+
+	typ := c.Type()
+	var val constant.Value
+	switch c := c.(type) {
+	case *Const:
+		val = c.Value
+	case *ArrayConst, *GenericConst:
+		// These can only represent zero values, so all we need is the type
+	case *AggregateConst:
+		candidates, _ := f.aggregateConsts.At(c.typ)
+		for _, candidate := range candidates {
+			if c.equal(candidate) {
+				return candidate
+			}
+		}
+
+		for i := range c.Values {
+			c.Values[i] = emitConst(f, c.Values[i].(Constant))
+		}
+
+		c.setBlock(f.Blocks[0])
+		rands := c.Operands(nil)
+		updateOperandsReferrers(c, rands)
+		candidates = append(candidates, c)
+		f.aggregateConsts.Set(c.typ, candidates)
+		return c
+
+	default:
+		panic(fmt.Sprintf("unexpected type %T", c))
+	}
+	k := constKey{
+		typ:    typ,
+		value:  val,
+		source: c.Source(),
+	}
+	dup, ok := f.consts[k]
+	if ok {
+		return dup.c
+	} else {
+		c.setBlock(f.Blocks[0])
+		f.consts[k] = constValue{
+			c:   c,
+			idx: len(f.consts),
+		}
+		rands := c.Operands(nil)
+		updateOperandsReferrers(c, rands)
+		return c
+	}
+}

vendor/honnef.co/go/tools/go/ir/irutil/load.go

@@ -0,0 +1,183 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package irutil
+
+// This file defines utility functions for constructing programs in IR form.
+
+import (
+	"go/ast"
+	"go/token"
+	"go/types"
+
+	"honnef.co/go/tools/go/ir"
+
+	//lint:ignore SA1019 go/loader is deprecated, but works fine for our tests
+	"golang.org/x/tools/go/loader"
+	"golang.org/x/tools/go/packages"
+)
+
+type Options struct {
+	// Which function, if any, to print in HTML form
+	PrintFunc string
+}
+
+// Packages creates an IR program for a set of packages.
+//
+// The packages must have been loaded from source syntax using the
+// golang.org/x/tools/go/packages.Load function in LoadSyntax or
+// LoadAllSyntax mode.
+//
+// Packages creates an IR package for each well-typed package in the
+// initial list, plus all their dependencies. The resulting list of
+// packages corresponds to the list of initial packages, and may contain
+// a nil if IR code could not be constructed for the corresponding initial
+// package due to type errors.
+//
+// Code for bodies of functions is not built until Build is called on
+// the resulting Program. IR code is constructed only for the initial
+// packages with well-typed syntax trees.
+//
+// The mode parameter controls diagnostics and checking during IR construction.
+func Packages(initial []*packages.Package, mode ir.BuilderMode, opts *Options) (*ir.Program, []*ir.Package) {
+	return doPackages(initial, mode, false, opts)
+}
+
+// AllPackages creates an IR program for a set of packages plus all
+// their dependencies.
+//
+// The packages must have been loaded from source syntax using the
+// golang.org/x/tools/go/packages.Load function in LoadAllSyntax mode.
+//
+// AllPackages creates an IR package for each well-typed package in the
+// initial list, plus all their dependencies. The resulting list of
+// packages corresponds to the list of initial packages, and may contain
+// a nil if IR code could not be constructed for the corresponding
+// initial package due to type errors.
+//
+// Code for bodies of functions is not built until Build is called on
+// the resulting Program. IR code is constructed for all packages with
+// well-typed syntax trees.
+//
+// The mode parameter controls diagnostics and checking during IR construction.
+func AllPackages(initial []*packages.Package, mode ir.BuilderMode, opts *Options) (*ir.Program, []*ir.Package) {
+	return doPackages(initial, mode, true, opts)
+}
+
+func doPackages(initial []*packages.Package, mode ir.BuilderMode, deps bool, opts *Options) (*ir.Program, []*ir.Package) {
+
+	var fset *token.FileSet
+	if len(initial) > 0 {
+		fset = initial[0].Fset
+	}
+
+	prog := ir.NewProgram(fset, mode)
+	if opts != nil {
+		prog.PrintFunc = opts.PrintFunc
+	}
+
+	isInitial := make(map[*packages.Package]bool, len(initial))
+	for _, p := range initial {
+		isInitial[p] = true
+	}
+
+	irmap := make(map[*packages.Package]*ir.Package)
+	packages.Visit(initial, nil, func(p *packages.Package) {
+		if p.Types != nil && !p.IllTyped {
+			var files []*ast.File
+			if deps || isInitial[p] {
+				files = p.Syntax
+			}
+			irmap[p] = prog.CreatePackage(p.Types, files, p.TypesInfo, true)
+		}
+	})
+
+	var irpkgs []*ir.Package
+	for _, p := range initial {
+		irpkgs = append(irpkgs, irmap[p]) // may be nil
+	}
+	return prog, irpkgs
+}
+
+// CreateProgram returns a new program in IR form, given a program
+// loaded from source.  An IR package is created for each transitively
+// error-free package of lprog.
+//
+// Code for bodies of functions is not built until Build is called
+// on the result.
+//
+// The mode parameter controls diagnostics and checking during IR construction.
+//
+// Deprecated: use golang.org/x/tools/go/packages and the Packages
+// function instead; see ir.ExampleLoadPackages.
+func CreateProgram(lprog *loader.Program, mode ir.BuilderMode) *ir.Program {
+	prog := ir.NewProgram(lprog.Fset, mode)
+
+	for _, info := range lprog.AllPackages {
+		if info.TransitivelyErrorFree {
+			prog.CreatePackage(info.Pkg, info.Files, &info.Info, info.Importable)
+		}
+	}
+
+	return prog
+}
+
+// BuildPackage builds an IR program with IR for a single package.
+//
+// It populates pkg by type-checking the specified file ASTs.  All
+// dependencies are loaded using the importer specified by tc, which
+// typically loads compiler export data; IR code cannot be built for
+// those packages.  BuildPackage then constructs an ir.Program with all
+// dependency packages created, and builds and returns the IR package
+// corresponding to pkg.
+//
+// The caller must have set pkg.Path() to the import path.
+//
+// The operation fails if there were any type-checking or import errors.
+//
+// See ../ir/example_test.go for an example.
+func BuildPackage(tc *types.Config, fset *token.FileSet, pkg *types.Package, files []*ast.File, mode ir.BuilderMode) (*ir.Package, *types.Info, error) {
+	if fset == nil {
+		panic("no token.FileSet")
+	}
+	if pkg.Path() == "" {
+		panic("package has no import path")
+	}
+
+	info := &types.Info{
+		Types:        make(map[ast.Expr]types.TypeAndValue),
+		Defs:         make(map[*ast.Ident]types.Object),
+		Uses:         make(map[*ast.Ident]types.Object),
+		Implicits:    make(map[ast.Node]types.Object),
+		Scopes:       make(map[ast.Node]*types.Scope),
+		Selections:   make(map[*ast.SelectorExpr]*types.Selection),
+		Instances:    make(map[*ast.Ident]types.Instance),
+		FileVersions: make(map[*ast.File]string),
+	}
+	if err := types.NewChecker(tc, fset, pkg, info).Files(files); err != nil {
+		return nil, nil, err
+	}
+
+	prog := ir.NewProgram(fset, mode)
+
+	// Create IR packages for all imports.
+	// Order is not significant.
+	created := make(map[*types.Package]bool)
+	var createAll func(pkgs []*types.Package)
+	createAll = func(pkgs []*types.Package) {
+		for _, p := range pkgs {
+			if !created[p] {
+				created[p] = true
+				prog.CreatePackage(p, nil, nil, true)
+				createAll(p.Imports())
+			}
+		}
+	}
+	createAll(pkg.Imports())
+
+	// Create and build the primary package.
+	irpkg := prog.CreatePackage(pkg, files, info, false)
+	irpkg.Build()
+	return irpkg, info, nil
+}

vendor/honnef.co/go/tools/go/ir/irutil/loops.go

@@ -0,0 +1,54 @@
+package irutil
+
+import "honnef.co/go/tools/go/ir"
+
+type Loop struct{ *ir.BlockSet }
+
+func FindLoops(fn *ir.Function) []Loop {
+	if fn.Blocks == nil {
+		return nil
+	}
+	tree := fn.DomPreorder()
+	var sets []Loop
+	for _, h := range tree {
+		for _, n := range h.Preds {
+			if !h.Dominates(n) {
+				continue
+			}
+			// n is a back-edge to h
+			// h is the loop header
+			if n == h {
+				set := Loop{ir.NewBlockSet(len(fn.Blocks))}
+				set.Add(n)
+				sets = append(sets, set)
+				continue
+			}
+			set := Loop{ir.NewBlockSet(len(fn.Blocks))}
+			set.Add(h)
+			set.Add(n)
+			for _, b := range allPredsBut(n, h, nil) {
+				set.Add(b)
+			}
+			sets = append(sets, set)
+		}
+	}
+	return sets
+}
+
+func allPredsBut(b, but *ir.BasicBlock, list []*ir.BasicBlock) []*ir.BasicBlock {
+outer:
+	for _, pred := range b.Preds {
+		if pred == but {
+			continue
+		}
+		for _, p := range list {
+			// TODO improve big-o complexity of this function
+			if pred == p {
+				continue outer
+			}
+		}
+		list = append(list, pred)
+		list = allPredsBut(pred, but, list)
+	}
+	return list
+}

vendor/honnef.co/go/tools/go/ir/irutil/stub.go

@@ -0,0 +1,32 @@
+package irutil
+
+import (
+	"honnef.co/go/tools/go/ir"
+)
+
+// IsStub reports whether a function is a stub. A function is
+// considered a stub if it has no instructions or if all it does is
+// return a constant value.
+func IsStub(fn *ir.Function) bool {
+	for _, b := range fn.Blocks {
+		for _, instr := range b.Instrs {
+			switch instr.(type) {
+			case *ir.Const:
+				// const naturally has no side-effects
+			case *ir.Panic:
+				// panic is a stub if it only uses constants
+			case *ir.Return:
+				// return is a stub if it only uses constants
+			case *ir.DebugRef:
+			case *ir.Jump:
+				// if there are no disallowed instructions, then we're
+				// only jumping to the exit block (or possibly
+				// somewhere else that's stubby?)
+			default:
+				// all other instructions are assumed to do actual work
+				return false
+			}
+		}
+	}
+	return true
+}

vendor/honnef.co/go/tools/go/ir/irutil/switch.go

@@ -0,0 +1,260 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package irutil
+
+// This file implements discovery of switch and type-switch constructs
+// from low-level control flow.
+//
+// Many techniques exist for compiling a high-level switch with
+// constant cases to efficient machine code.  The optimal choice will
+// depend on the data type, the specific case values, the code in the
+// body of each case, and the hardware.
+// Some examples:
+// - a lookup table (for a switch that maps constants to constants)
+// - a computed goto
+// - a binary tree
+// - a perfect hash
+// - a two-level switch (to partition constant strings by their first byte).
+
+import (
+	"bytes"
+	"fmt"
+	"go/token"
+	"go/types"
+
+	"honnef.co/go/tools/go/ir"
+)
+
+// A ConstCase represents a single constant comparison.
+// It is part of a Switch.
+type ConstCase struct {
+	Block *ir.BasicBlock // block performing the comparison
+	Body  *ir.BasicBlock // body of the case
+	Value *ir.Const      // case comparand
+}
+
+// A TypeCase represents a single type assertion.
+// It is part of a Switch.
+type TypeCase struct {
+	Block   *ir.BasicBlock // block performing the type assert
+	Body    *ir.BasicBlock // body of the case
+	Type    types.Type     // case type
+	Binding ir.Value       // value bound by this case
+}
+
+// A Switch is a logical high-level control flow operation
+// (a multiway branch) discovered by analysis of a CFG containing
+// only if/else chains.  It is not part of the ir.Instruction set.
+//
+// One of ConstCases and TypeCases has length >= 2;
+// the other is nil.
+//
+// In a value switch, the list of cases may contain duplicate constants.
+// A type switch may contain duplicate types, or types assignable
+// to an interface type also in the list.
+// TODO(adonovan): eliminate such duplicates.
+type Switch struct {
+	Start      *ir.BasicBlock // block containing start of if/else chain
+	X          ir.Value       // the switch operand
+	ConstCases []ConstCase    // ordered list of constant comparisons
+	TypeCases  []TypeCase     // ordered list of type assertions
+	Default    *ir.BasicBlock // successor if all comparisons fail
+}
+
+func (sw *Switch) String() string {
+	// We represent each block by the String() of its
+	// first Instruction, e.g. "print(42:int)".
+	var buf bytes.Buffer
+	if sw.ConstCases != nil {
+		fmt.Fprintf(&buf, "switch %s {\n", sw.X.Name())
+		for _, c := range sw.ConstCases {
+			fmt.Fprintf(&buf, "case %s: %s\n", c.Value.Name(), c.Body.Instrs[0])
+		}
+	} else {
+		fmt.Fprintf(&buf, "switch %s.(type) {\n", sw.X.Name())
+		for _, c := range sw.TypeCases {
+			fmt.Fprintf(&buf, "case %s %s: %s\n",
+				c.Binding.Name(), c.Type, c.Body.Instrs[0])
+		}
+	}
+	if sw.Default != nil {
+		fmt.Fprintf(&buf, "default: %s\n", sw.Default.Instrs[0])
+	}
+	fmt.Fprintf(&buf, "}")
+	return buf.String()
+}
+
+// Switches examines the control-flow graph of fn and returns the
+// set of inferred value and type switches.  A value switch tests an
+// ir.Value for equality against two or more compile-time constant
+// values.  Switches involving link-time constants (addresses) are
+// ignored.  A type switch type-asserts an ir.Value against two or
+// more types.
+//
+// The switches are returned in dominance order.
+//
+// The resulting switches do not necessarily correspond to uses of the
+// 'switch' keyword in the source: for example, a single source-level
+// switch statement with non-constant cases may result in zero, one or
+// many Switches, one per plural sequence of constant cases.
+// Switches may even be inferred from if/else- or goto-based control flow.
+// (In general, the control flow constructs of the source program
+// cannot be faithfully reproduced from the IR.)
+func Switches(fn *ir.Function) []Switch {
+	// Traverse the CFG in dominance order, so we don't
+	// enter an if/else-chain in the middle.
+	var switches []Switch
+	seen := make(map[*ir.BasicBlock]bool) // TODO(adonovan): opt: use ir.blockSet
+	for _, b := range fn.DomPreorder() {
+		if x, k := isComparisonBlock(b); x != nil {
+			// Block b starts a switch.
+			sw := Switch{Start: b, X: x}
+			valueSwitch(&sw, k, seen)
+			if len(sw.ConstCases) > 1 {
+				switches = append(switches, sw)
+			}
+		}
+
+		if y, x, T := isTypeAssertBlock(b); y != nil {
+			// Block b starts a type switch.
+			sw := Switch{Start: b, X: x}
+			typeSwitch(&sw, y, T, seen)
+			if len(sw.TypeCases) > 1 {
+				switches = append(switches, sw)
+			}
+		}
+	}
+	return switches
+}
+
+func isSameX(x1 ir.Value, x2 ir.Value) bool {
+	if x1 == x2 {
+		return true
+	}
+	if x2, ok := x2.(*ir.Sigma); ok {
+		return isSameX(x1, x2.X)
+	}
+	return false
+}
+
+func valueSwitch(sw *Switch, k *ir.Const, seen map[*ir.BasicBlock]bool) {
+	b := sw.Start
+	x := sw.X
+	for isSameX(sw.X, x) {
+		if seen[b] {
+			break
+		}
+		seen[b] = true
+
+		sw.ConstCases = append(sw.ConstCases, ConstCase{
+			Block: b,
+			Body:  b.Succs[0],
+			Value: k,
+		})
+		b = b.Succs[1]
+		n := 0
+		for _, instr := range b.Instrs {
+			switch instr.(type) {
+			case *ir.If, *ir.BinOp:
+				n++
+			case *ir.Sigma, *ir.Phi, *ir.DebugRef:
+			default:
+				n += 1000
+			}
+		}
+		if n != 2 {
+			// Block b contains not just 'if x == k' and σ/ϕ nodes,
+			// so it may have side effects that
+			// make it unsafe to elide.
+			break
+		}
+		if len(b.Preds) != 1 {
+			// Block b has multiple predecessors,
+			// so it cannot be treated as a case.
+			break
+		}
+		x, k = isComparisonBlock(b)
+	}
+	sw.Default = b
+}
+
+func typeSwitch(sw *Switch, y ir.Value, T types.Type, seen map[*ir.BasicBlock]bool) {
+	b := sw.Start
+	x := sw.X
+	for isSameX(sw.X, x) {
+		if seen[b] {
+			break
+		}
+		seen[b] = true
+
+		sw.TypeCases = append(sw.TypeCases, TypeCase{
+			Block:   b,
+			Body:    b.Succs[0],
+			Type:    T,
+			Binding: y,
+		})
+		b = b.Succs[1]
+		n := 0
+		for _, instr := range b.Instrs {
+			switch instr.(type) {
+			case *ir.TypeAssert, *ir.Extract, *ir.If:
+				n++
+			case *ir.Sigma, *ir.Phi:
+			default:
+				n += 1000
+			}
+		}
+		if n != 4 {
+			// Block b contains not just
+			//  {TypeAssert; Extract #0; Extract #1; If}
+			// so it may have side effects that
+			// make it unsafe to elide.
+			break
+		}
+		if len(b.Preds) != 1 {
+			// Block b has multiple predecessors,
+			// so it cannot be treated as a case.
+			break
+		}
+		y, x, T = isTypeAssertBlock(b)
+	}
+	sw.Default = b
+}
+
+// isComparisonBlock returns the operands (v, k) if a block ends with
+// a comparison v==k, where k is a compile-time constant.
+func isComparisonBlock(b *ir.BasicBlock) (v ir.Value, k *ir.Const) {
+	if n := len(b.Instrs); n >= 2 {
+		if i, ok := b.Instrs[n-1].(*ir.If); ok {
+			if binop, ok := i.Cond.(*ir.BinOp); ok && binop.Block() == b && binop.Op == token.EQL {
+				if k, ok := binop.Y.(*ir.Const); ok {
+					return binop.X, k
+				}
+				if k, ok := binop.X.(*ir.Const); ok {
+					return binop.Y, k
+				}
+			}
+		}
+	}
+	return
+}
+
+// isTypeAssertBlock returns the operands (y, x, T) if a block ends with
+// a type assertion "if y, ok := x.(T); ok {".
+func isTypeAssertBlock(b *ir.BasicBlock) (y, x ir.Value, T types.Type) {
+	if n := len(b.Instrs); n >= 4 {
+		if i, ok := b.Instrs[n-1].(*ir.If); ok {
+			if ext1, ok := i.Cond.(*ir.Extract); ok && ext1.Block() == b && ext1.Index == 1 {
+				if ta, ok := ext1.Tuple.(*ir.TypeAssert); ok && ta.Block() == b {
+					// hack: relies upon instruction ordering.
+					if ext0, ok := b.Instrs[n-3].(*ir.Extract); ok {
+						return ext0, ta.X, ta.AssertedType
+					}
+				}
+			}
+		}
+	}
+	return
+}

vendor/honnef.co/go/tools/go/ir/irutil/terminates.go

@@ -0,0 +1,70 @@
+package irutil
+
+import (
+	"go/types"
+
+	"honnef.co/go/tools/go/ir"
+)
+
+// Terminates reports whether fn is supposed to return, that is if it
+// has at least one theoretic path that returns from the function.
+// Explicit panics do not count as terminating.
+func Terminates(fn *ir.Function) bool {
+	if fn.Blocks == nil {
+		// assuming that a function terminates is the conservative
+		// choice
+		return true
+	}
+
+	for _, block := range fn.Blocks {
+		if _, ok := block.Control().(*ir.Return); ok {
+			if len(block.Preds) == 0 {
+				return true
+			}
+			for _, pred := range block.Preds {
+				switch ctrl := pred.Control().(type) {
+				case *ir.Panic:
+					// explicit panics do not count as terminating
+				case *ir.If:
+					// Check if we got here by receiving from a closed
+					// time.Tick channel – this cannot happen at
+					// runtime and thus doesn't constitute termination
+					iff := ctrl
+					if !ok {
+						return true
+					}
+					ex, ok := iff.Cond.(*ir.Extract)
+					if !ok {
+						return true
+					}
+					if ex.Index != 1 {
+						return true
+					}
+					recv, ok := ex.Tuple.(*ir.Recv)
+					if !ok {
+						return true
+					}
+					call, ok := recv.Chan.(*ir.Call)
+					if !ok {
+						return true
+					}
+					fn, ok := call.Common().Value.(*ir.Function)
+					if !ok {
+						return true
+					}
+					fn2, ok := fn.Object().(*types.Func)
+					if !ok {
+						return true
+					}
+					if fn2.FullName() != "time.Tick" {
+						return true
+					}
+				default:
+					// we've reached the exit block
+					return true
+				}
+			}
+		}
+	}
+	return false
+}

vendor/honnef.co/go/tools/go/ir/irutil/util.go

@@ -0,0 +1,174 @@
+package irutil
+
+import (
+	"go/types"
+	"slices"
+	"strings"
+
+	"honnef.co/go/tools/go/ir"
+	"honnef.co/go/tools/go/types/typeutil"
+)
+
+func Reachable(from, to *ir.BasicBlock) bool {
+	if from == to {
+		return true
+	}
+	if from.Dominates(to) {
+		return true
+	}
+
+	found := false
+	Walk(from, func(b *ir.BasicBlock) bool {
+		if b == to {
+			found = true
+			return false
+		}
+		return true
+	})
+	return found
+}
+
+func Walk(b *ir.BasicBlock, fn func(*ir.BasicBlock) bool) {
+	seen := map[*ir.BasicBlock]bool{}
+	wl := []*ir.BasicBlock{b}
+	for len(wl) > 0 {
+		b := wl[len(wl)-1]
+		wl = wl[:len(wl)-1]
+		if seen[b] {
+			continue
+		}
+		seen[b] = true
+		if !fn(b) {
+			continue
+		}
+		wl = append(wl, b.Succs...)
+	}
+}
+
+func Vararg(x *ir.Slice) ([]ir.Value, bool) {
+	var out []ir.Value
+	alloc, ok := ir.Unwrap(x.X).(*ir.Alloc)
+	if !ok {
+		return nil, false
+	}
+	var checkAlloc func(alloc ir.Value) bool
+	checkAlloc = func(alloc ir.Value) bool {
+		for _, ref := range *alloc.Referrers() {
+			if ref == x {
+				continue
+			}
+			if ref.Block() != x.Block() {
+				return false
+			}
+			switch ref := ref.(type) {
+			case *ir.IndexAddr:
+				idx := ref
+				if len(*idx.Referrers()) != 1 {
+					return false
+				}
+				store, ok := (*idx.Referrers())[0].(*ir.Store)
+				if !ok {
+					return false
+				}
+				out = append(out, store.Val)
+			case *ir.Copy:
+				if !checkAlloc(ref) {
+					return false
+				}
+			default:
+				return false
+			}
+		}
+		return true
+	}
+	if !checkAlloc(alloc) {
+		return nil, false
+	}
+	return out, true
+}
+
+func CallName(call *ir.CallCommon) string {
+	if call.IsInvoke() {
+		return ""
+	}
+	switch v := call.Value.(type) {
+	case *ir.Function:
+		fn, ok := v.Object().(*types.Func)
+		if !ok {
+			return ""
+		}
+		return typeutil.FuncName(fn)
+	case *ir.Builtin:
+		return v.Name()
+	}
+	return ""
+}
+
+func IsCallTo(call *ir.CallCommon, name string) bool { return CallName(call) == name }
+
+func IsCallToAny(call *ir.CallCommon, names ...string) bool {
+	q := CallName(call)
+	return slices.Contains(names, q)
+}
+
+func FilterDebug(instr []ir.Instruction) []ir.Instruction {
+	var out []ir.Instruction
+	for _, ins := range instr {
+		if _, ok := ins.(*ir.DebugRef); !ok {
+			out = append(out, ins)
+		}
+	}
+	return out
+}
+
+func IsExample(fn *ir.Function) bool {
+	if !strings.HasPrefix(fn.Name(), "Example") {
+		return false
+	}
+	f := fn.Prog.Fset.File(fn.Pos())
+	if f == nil {
+		return false
+	}
+	return strings.HasSuffix(f.Name(), "_test.go")
+}
+
+// Flatten recursively returns the underlying value of an ir.Sigma or
+// ir.Phi node. If all edges in an ir.Phi node are the same (after
+// flattening), the flattened edge will get returned. If flattening is
+// not possible, nil is returned.
+func Flatten(v ir.Value) ir.Value {
+	failed := false
+	seen := map[ir.Value]struct{}{}
+	var out ir.Value
+	var dfs func(v ir.Value)
+	dfs = func(v ir.Value) {
+		if failed {
+			return
+		}
+		if _, ok := seen[v]; ok {
+			return
+		}
+		seen[v] = struct{}{}
+
+		switch v := v.(type) {
+		case *ir.Sigma:
+			dfs(v.X)
+		case *ir.Phi:
+			for _, e := range v.Edges {
+				dfs(e)
+			}
+		default:
+			if out == nil {
+				out = v
+			} else if out != v {
+				failed = true
+			}
+		}
+	}
+	dfs(v)
+
+	if failed {
+		return nil
+	}
+	return out
+}

vendor/honnef.co/go/tools/go/ir/irutil/visit.go

@@ -0,0 +1,78 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package irutil
+
+import "honnef.co/go/tools/go/ir"
+
+// This file defines utilities for visiting the IR of
+// a Program.
+//
+// TODO(adonovan): test coverage.
+
+// AllFunctions finds and returns the set of functions potentially
+// needed by program prog, as determined by a simple linker-style
+// reachability algorithm starting from the members and method-sets of
+// each package.  The result may include anonymous functions and
+// synthetic wrappers.
+//
+// Precondition: all packages are built.
+func AllFunctions(prog *ir.Program) map[*ir.Function]bool {
+	visit := visitor{
+		prog: prog,
+		seen: make(map[*ir.Function]bool),
+	}
+	visit.program()
+	return visit.seen
+}
+
+type visitor struct {
+	prog *ir.Program
+	seen map[*ir.Function]bool
+}
+
+func (visit *visitor) program() {
+	for _, pkg := range visit.prog.AllPackages() {
+		for _, mem := range pkg.Members {
+			if fn, ok := mem.(*ir.Function); ok {
+				visit.function(fn)
+			}
+		}
+	}
+	for _, T := range visit.prog.RuntimeTypes() {
+		mset := visit.prog.MethodSets.MethodSet(T)
+		for i, n := 0, mset.Len(); i < n; i++ {
+			visit.function(visit.prog.MethodValue(mset.At(i)))
+		}
+	}
+}
+
+func (visit *visitor) function(fn *ir.Function) {
+	if !visit.seen[fn] {
+		visit.seen[fn] = true
+		var buf [10]*ir.Value // avoid alloc in common case
+		for _, b := range fn.Blocks {
+			for _, instr := range b.Instrs {
+				for _, op := range instr.Operands(buf[:0]) {
+					if fn, ok := (*op).(*ir.Function); ok {
+						visit.function(fn)
+					}
+				}
+			}
+		}
+	}
+}
+
+// MainPackages returns the subset of the specified packages
+// named "main" that define a main function.
+// The result may include synthetic "testmain" packages.
+func MainPackages(pkgs []*ir.Package) []*ir.Package {
+	var mains []*ir.Package
+	for _, pkg := range pkgs {
+		if pkg.Pkg.Name() == "main" && pkg.Func("main") != nil {
+			mains = append(mains, pkg)
+		}
+	}
+	return mains
+}

vendor/honnef.co/go/tools/go/ir/lvalue.go

@@ -0,0 +1,175 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package ir
+
+// lvalues are the union of addressable expressions and map-index
+// expressions.
+
+import (
+	"go/ast"
+	"go/types"
+)
+
+// An lvalue represents an assignable location that may appear on the
+// left-hand side of an assignment.  This is a generalization of a
+// pointer to permit updates to elements of maps.
+type lvalue interface {
+	store(fn *Function, v Value, source ast.Node) // stores v into the location
+	load(fn *Function, source ast.Node) Value     // loads the contents of the location
+	address(fn *Function) Value                   // address of the location
+	typ() types.Type                              // returns the type of the location
+}
+
+// An address is an lvalue represented by a true pointer.
+type address struct {
+	addr Value
+	expr ast.Expr // source syntax of the value (not address) [debug mode]
+}
+
+func (a *address) load(fn *Function, source ast.Node) Value {
+	return emitLoad(fn, a.addr, source)
+}
+
+func (a *address) store(fn *Function, v Value, source ast.Node) {
+	store := emitStore(fn, a.addr, v, source)
+	if a.expr != nil {
+		// store.Val is v, converted for assignability.
+		emitDebugRef(fn, a.expr, store.Val, false)
+	}
+}
+
+func (a *address) address(fn *Function) Value {
+	if a.expr != nil {
+		emitDebugRef(fn, a.expr, a.addr, true)
+	}
+	return a.addr
+}
+
+func (a *address) typ() types.Type {
+	return deref(a.addr.Type())
+}
+
+type compositeElement struct {
+	cv   *CompositeValue
+	idx  int
+	t    types.Type
+	expr ast.Expr
+}
+
+func (ce *compositeElement) load(fn *Function, source ast.Node) Value {
+	panic("not implemented")
+}
+
+func (ce *compositeElement) store(fn *Function, v Value, source ast.Node) {
+	v = emitConv(fn, v, ce.t, source)
+	ce.cv.Values[ce.idx] = v
+	if ce.expr != nil {
+		// store.Val is v, converted for assignability.
+		emitDebugRef(fn, ce.expr, v, false)
+	}
+}
+
+func (ce *compositeElement) address(fn *Function) Value {
+	panic("not implemented")
+}
+
+func (ce *compositeElement) typ() types.Type {
+	return ce.t
+}
+
+// An element is an lvalue represented by m[k], the location of an
+// element of a map.  These locations are not addressable
+// since pointers cannot be formed from them, but they do support
+// load() and store().
+type element struct {
+	m, k Value      // map
+	t    types.Type // map element type
+}
+
+func (e *element) load(fn *Function, source ast.Node) Value {
+	l := &MapLookup{
+		X:     e.m,
+		Index: e.k,
+	}
+	l.setType(e.t)
+	return fn.emit(l, source)
+}
+
+func (e *element) store(fn *Function, v Value, source ast.Node) {
+	up := &MapUpdate{
+		Map:   e.m,
+		Key:   e.k,
+		Value: emitConv(fn, v, e.t, source),
+	}
+	fn.emit(up, source)
+}
+
+func (e *element) address(fn *Function) Value {
+	panic("map elements are not addressable")
+}
+
+func (e *element) typ() types.Type {
+	return e.t
+}
+
+// A lazyAddress is an lvalue whose address is the result of an instruction.
+// These work like an *address except a new address.address() Value
+// is created on each load, store and address call.
+// A lazyAddress can be used to control when a side effect (nil pointer
+// dereference, index out of bounds) of using a location happens.
+type lazyAddress struct {
+	addr func(fn *Function) Value // emit to fn the computation of the address
+	t    types.Type               // type of the location
+	expr ast.Expr                 // source syntax of the value (not address) [debug mode]
+}
+
+func (l *lazyAddress) load(fn *Function, source ast.Node) Value {
+	load := emitLoad(fn, l.addr(fn), source)
+	return load
+}
+
+func (l *lazyAddress) store(fn *Function, v Value, source ast.Node) {
+	store := emitStore(fn, l.addr(fn), v, source)
+	if l.expr != nil {
+		// store.Val is v, converted for assignability.
+		emitDebugRef(fn, l.expr, store.Val, false)
+	}
+}
+
+func (l *lazyAddress) address(fn *Function) Value {
+	addr := l.addr(fn)
+	if l.expr != nil {
+		emitDebugRef(fn, l.expr, addr, true)
+	}
+	return addr
+}
+
+func (l *lazyAddress) typ() types.Type { return l.t }
+
+// A blank is a dummy variable whose name is "_".
+// It is not reified: loads are illegal and stores are ignored.
+type blank struct{}
+
+func (bl blank) load(fn *Function, source ast.Node) Value {
+	panic("blank.load is illegal")
+}
+
+func (bl blank) store(fn *Function, v Value, source ast.Node) {
+	s := &BlankStore{
+		Val: v,
+	}
+	fn.emit(s, source)
+}
+
+func (bl blank) address(fn *Function) Value {
+	panic("blank var is not addressable")
+}
+
+func (bl blank) typ() types.Type {
+	// This should be the type of the blank Ident; the typechecker
+	// doesn't provide this yet, but fortunately, we don't need it
+	// yet either.
+	panic("blank.typ is unimplemented")
+}

vendor/honnef.co/go/tools/go/ir/methods.go

@@ -0,0 +1,244 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package ir
+
+// This file defines utilities for population of method sets.
+
+import (
+	"fmt"
+	"go/types"
+
+	"honnef.co/go/tools/analysis/lint"
+)
+
+// MethodValue returns the Function implementing method sel, building
+// wrapper methods on demand.  It returns nil if sel denotes an
+// abstract (interface) method.
+//
+// Precondition: sel.Kind() == MethodVal.
+//
+// Thread-safe.
+//
+// EXCLUSIVE_LOCKS_ACQUIRED(prog.methodsMu)
+func (prog *Program) MethodValue(sel *types.Selection) *Function {
+	if sel.Kind() != types.MethodVal {
+		panic(fmt.Sprintf("MethodValue(%s) kind != MethodVal", sel))
+	}
+	T := sel.Recv()
+	if types.IsInterface(T) {
+		return nil // abstract method
+	}
+	if prog.mode&LogSource != 0 {
+		defer logStack("MethodValue %s %v", T, sel)()
+	}
+
+	prog.methodsMu.Lock()
+	defer prog.methodsMu.Unlock()
+
+	return prog.addMethod(prog.createMethodSet(T), sel)
+}
+
+// LookupMethod returns the implementation of the method of type T
+// identified by (pkg, name).  It returns nil if the method exists but
+// is abstract, and panics if T has no such method.
+func (prog *Program) LookupMethod(T types.Type, pkg *types.Package, name string) *Function {
+	sel := prog.MethodSets.MethodSet(T).Lookup(pkg, name)
+	if sel == nil {
+		panic(fmt.Sprintf("%s has no method %s", T, types.Id(pkg, name)))
+	}
+	return prog.MethodValue(sel)
+}
+
+// methodSet contains the (concrete) methods of a non-interface type.
+type methodSet struct {
+	mapping  map[string]*Function // populated lazily
+	complete bool                 // mapping contains all methods
+}
+
+// Precondition: !isInterface(T).
+// EXCLUSIVE_LOCKS_REQUIRED(prog.methodsMu)
+func (prog *Program) createMethodSet(T types.Type) *methodSet {
+	mset, ok := prog.methodSets.At(T)
+	if !ok {
+		mset = &methodSet{mapping: make(map[string]*Function)}
+		prog.methodSets.Set(T, mset)
+	}
+	return mset
+}
+
+// EXCLUSIVE_LOCKS_REQUIRED(prog.methodsMu)
+func (prog *Program) addMethod(mset *methodSet, sel *types.Selection) *Function {
+	if sel.Kind() == types.MethodExpr {
+		panic(sel)
+	}
+	id := sel.Obj().Id()
+	fn := mset.mapping[id]
+	if fn == nil {
+		obj := sel.Obj().(*types.Func)
+
+		needsPromotion := len(sel.Index()) > 1
+		needsIndirection := !isPointer(recvType(obj)) && isPointer(sel.Recv())
+		if needsPromotion || needsIndirection {
+			fn = makeWrapper(prog, sel)
+		} else {
+			fn = prog.declaredFunc(obj)
+		}
+		if fn.Signature.Recv() == nil {
+			panic(fn) // missing receiver
+		}
+		mset.mapping[id] = fn
+	}
+	return fn
+}
+
+// RuntimeTypes returns a new unordered slice containing all
+// concrete types in the program for which a complete (non-empty)
+// method set is required at run-time.
+//
+// Thread-safe.
+//
+// EXCLUSIVE_LOCKS_ACQUIRED(prog.methodsMu)
+func (prog *Program) RuntimeTypes() []types.Type {
+	prog.methodsMu.Lock()
+	defer prog.methodsMu.Unlock()
+
+	var res []types.Type
+	prog.methodSets.Iterate(func(T types.Type, v *methodSet) {
+		if v.complete {
+			res = append(res, T)
+		}
+	})
+	return res
+}
+
+// declaredFunc returns the concrete function/method denoted by obj.
+// Panic ensues if there is none.
+func (prog *Program) declaredFunc(obj *types.Func) *Function {
+	if origin := obj.Origin(); origin != obj {
+		// Calling method on instantiated type, create a wrapper that calls the generic type's method
+		base := prog.packageLevelValue(origin)
+		return makeInstance(prog, base.(*Function), obj.Type().(*types.Signature), nil)
+	} else {
+		if v := prog.packageLevelValue(obj); v != nil {
+			return v.(*Function)
+		}
+	}
+	panic("no concrete method: " + obj.String())
+}
+
+// needMethodsOf ensures that runtime type information (including the
+// complete method set) is available for the specified type T and all
+// its subcomponents.
+//
+// needMethodsOf must be called for at least every type that is an
+// operand of some MakeInterface instruction, and for the type of
+// every exported package member.
+//
+// Precondition: T is not a method signature (*Signature with Recv()!=nil).
+//
+// Thread-safe.  (Called via emitConv from multiple builder goroutines.)
+//
+// TODO(adonovan): make this faster.  It accounts for 20% of SSA build time.
+//
+// EXCLUSIVE_LOCKS_ACQUIRED(prog.methodsMu)
+func (prog *Program) needMethodsOf(T types.Type) {
+	prog.methodsMu.Lock()
+	prog.needMethods(T, false)
+	prog.methodsMu.Unlock()
+}
+
+// Precondition: T is not a method signature (*Signature with Recv()!=nil).
+// Recursive case: skip => don't create methods for T.
+//
+// EXCLUSIVE_LOCKS_REQUIRED(prog.methodsMu)
+func (prog *Program) needMethods(T types.Type, skip bool) {
+	// Each package maintains its own set of types it has visited.
+	if prevSkip, ok := prog.runtimeTypes.At(T); ok {
+		// needMethods(T) was previously called
+		if !prevSkip || skip {
+			return // already seen, with same or false 'skip' value
+		}
+	}
+	prog.runtimeTypes.Set(T, skip)
+
+	tmset := prog.MethodSets.MethodSet(T)
+
+	if !skip && !types.IsInterface(T) && tmset.Len() > 0 {
+		// Create methods of T.
+		mset := prog.createMethodSet(T)
+		if !mset.complete {
+			mset.complete = true
+			n := tmset.Len()
+			for i := range n {
+				prog.addMethod(mset, tmset.At(i))
+			}
+		}
+	}
+
+	// Recursion over signatures of each method.
+	for method := range tmset.Methods() {
+		sig := method.Type().(*types.Signature)
+		prog.needMethods(sig.Params(), false)
+		prog.needMethods(sig.Results(), false)
+	}
+
+	switch t := T.(type) {
+	case *types.Basic:
+		// nop
+
+	case *types.Interface, *types.TypeParam:
+		// nop---handled by recursion over method set.
+
+	case *types.Pointer:
+		prog.needMethods(t.Elem(), false)
+
+	case *types.Slice:
+		prog.needMethods(t.Elem(), false)
+
+	case *types.Chan:
+		prog.needMethods(t.Elem(), false)
+
+	case *types.Map:
+		prog.needMethods(t.Key(), false)
+		prog.needMethods(t.Elem(), false)
+
+	case *types.Signature:
+		if t.Recv() != nil {
+			panic(fmt.Sprintf("Signature %s has Recv %s", t, t.Recv()))
+		}
+		prog.needMethods(t.Params(), false)
+		prog.needMethods(t.Results(), false)
+
+	case *types.Named:
+		// A pointer-to-named type can be derived from a named
+		// type via reflection.  It may have methods too.
+		prog.needMethods(types.NewPointer(t), false)
+
+		// Consider 'type T struct{S}' where S has methods.
+		// Reflection provides no way to get from T to struct{S},
+		// only to S, so the method set of struct{S} is unwanted,
+		// so set 'skip' flag during recursion.
+		prog.needMethods(t.Underlying(), true)
+
+	case *types.Array:
+		prog.needMethods(t.Elem(), false)
+
+	case *types.Struct:
+		for i, n := 0, t.NumFields(); i < n; i++ {
+			prog.needMethods(t.Field(i).Type(), false)
+		}
+
+	case *types.Tuple:
+		for i, n := 0, t.Len(); i < n; i++ {
+			prog.needMethods(t.At(i).Type(), false)
+		}
+
+	case *types.Alias:
+		prog.needMethods(types.Unalias(t), false)
+
+	default:
+		lint.ExhaustiveTypeSwitch(T)
+	}
+}

vendor/honnef.co/go/tools/go/ir/mode.go

@@ -0,0 +1,104 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package ir
+
+// This file defines the BuilderMode type and its command-line flag.
+
+import (
+	"bytes"
+	"fmt"
+)
+
+// BuilderMode is a bitmask of options for diagnostics and checking.
+//
+// *BuilderMode satisfies the flag.Value interface.  Example:
+//
+//	var mode = ir.BuilderMode(0)
+//	func init() { flag.Var(&mode, "build", ir.BuilderModeDoc) }
+type BuilderMode uint
+
+const (
+	PrintPackages            BuilderMode = 1 << iota // Print package inventory to stdout
+	PrintFunctions                                   // Print function IR code to stdout
+	PrintSource                                      // Print source code when printing function IR
+	LogSource                                        // Log source locations as IR builder progresses
+	SanityCheckFunctions                             // Perform sanity checking of function bodies
+	NaiveForm                                        // Build naïve IR form: don't replace local loads/stores with registers
+	GlobalDebug                                      // Enable debug info for all packages
+	SplitAfterNewInformation                         // Split live range after we learn something new about a value
+)
+
+const BuilderModeDoc = `Options controlling the IR builder.
+The value is a sequence of zero or more of these symbols:
+C	perform sanity [C]hecking of the IR form.
+D	include [D]ebug info for every function.
+P	print [P]ackage inventory.
+F	print [F]unction IR code.
+A	print [A]ST nodes responsible for IR instructions
+S	log [S]ource locations as IR builder progresses.
+N	build [N]aive IR form: don't replace local loads/stores with registers.
+I	Split live range after a value is used as slice or array index
+`
+
+func (m BuilderMode) String() string {
+	var buf bytes.Buffer
+	if m&GlobalDebug != 0 {
+		buf.WriteByte('D')
+	}
+	if m&PrintPackages != 0 {
+		buf.WriteByte('P')
+	}
+	if m&PrintFunctions != 0 {
+		buf.WriteByte('F')
+	}
+	if m&PrintSource != 0 {
+		buf.WriteByte('A')
+	}
+	if m&LogSource != 0 {
+		buf.WriteByte('S')
+	}
+	if m&SanityCheckFunctions != 0 {
+		buf.WriteByte('C')
+	}
+	if m&NaiveForm != 0 {
+		buf.WriteByte('N')
+	}
+	if m&SplitAfterNewInformation != 0 {
+		buf.WriteByte('I')
+	}
+	return buf.String()
+}
+
+// Set parses the flag characters in s and updates *m.
+func (m *BuilderMode) Set(s string) error {
+	var mode BuilderMode
+	for _, c := range s {
+		switch c {
+		case 'D':
+			mode |= GlobalDebug
+		case 'P':
+			mode |= PrintPackages
+		case 'F':
+			mode |= PrintFunctions
+		case 'A':
+			mode |= PrintSource
+		case 'S':
+			mode |= LogSource
+		case 'C':
+			mode |= SanityCheckFunctions
+		case 'N':
+			mode |= NaiveForm
+		case 'I':
+			mode |= SplitAfterNewInformation
+		default:
+			return fmt.Errorf("unknown BuilderMode option: %q", c)
+		}
+	}
+	*m = mode
+	return nil
+}
+
+// Get returns m.
+func (m BuilderMode) Get() any { return m }

vendor/honnef.co/go/tools/go/ir/print.go

@@ -0,0 +1,539 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package ir
+
+// This file implements the String() methods for all Value and
+// Instruction types.
+
+import (
+	"bytes"
+	"fmt"
+	"go/types"
+	"io"
+	"reflect"
+	"sort"
+	"strings"
+
+	"honnef.co/go/tools/go/types/typeutil"
+)
+
+// relName returns the name of v relative to i.
+// In most cases, this is identical to v.Name(), but references to
+// Functions (including methods) and Globals use RelString and
+// all types are displayed with relType, so that only cross-package
+// references are package-qualified.
+func relName(v Value, i Instruction) string {
+	if v == nil {
+		return "<nil>"
+	}
+	var from *types.Package
+	if i != nil {
+		from = i.Parent().pkg()
+	}
+	switch v := v.(type) {
+	case Member: // *Function or *Global
+		return v.RelString(from)
+	}
+	return v.Name()
+}
+
+func relType(t types.Type, from *types.Package) string {
+	return types.TypeString(t, types.RelativeTo(from))
+}
+
+func relTerm(term *types.Term, from *types.Package) string {
+	s := relType(term.Type(), from)
+	if term.Tilde() {
+		return "~" + s
+	}
+	return s
+}
+
+func relString(m Member, from *types.Package) string {
+	// NB: not all globals have an Object (e.g. init$guard),
+	// so use Package().Object not Object.Package().
+	if pkg := m.Package().Pkg; pkg != nil && pkg != from {
+		return fmt.Sprintf("%s.%s", pkg.Path(), m.Name())
+	}
+	return m.Name()
+}
+
+// Value.String()
+//
+// This method is provided only for debugging.
+// It never appears in disassembly, which uses Value.Name().
+
+func (v *Parameter) String() string {
+	from := v.Parent().pkg()
+	return fmt.Sprintf("Parameter <%s> {%s}", relType(v.Type(), from), v.name)
+}
+
+func (v *FreeVar) String() string {
+	from := v.Parent().pkg()
+	return fmt.Sprintf("FreeVar <%s> %s", relType(v.Type(), from), v.Name())
+}
+
+func (v *Builtin) String() string {
+	return fmt.Sprintf("Builtin %s", v.Name())
+}
+
+// Instruction.String()
+
+func (v *Alloc) String() string {
+	from := v.Parent().pkg()
+	storage := "Stack"
+	if v.Heap {
+		storage = "Heap"
+	}
+	return fmt.Sprintf("%sAlloc <%s>", storage, relType(v.Type(), from))
+}
+
+func (v *Sigma) String() string {
+	from := v.Parent().pkg()
+	s := fmt.Sprintf("Sigma <%s> [b%d] %s", relType(v.Type(), from), v.From.Index, v.X.Name())
+	return s
+}
+
+func (v *Phi) String() string {
+	var b bytes.Buffer
+	fmt.Fprintf(&b, "Phi <%s>", v.Type())
+	for i, edge := range v.Edges {
+		b.WriteString(" ")
+		// Be robust against malformed CFG.
+		if v.block == nil {
+			b.WriteString("??")
+			continue
+		}
+		block := -1
+		if i < len(v.block.Preds) {
+			block = v.block.Preds[i].Index
+		}
+		fmt.Fprintf(&b, "%d:", block)
+		edgeVal := "<nil>" // be robust
+		if edge != nil {
+			edgeVal = relName(edge, v)
+		}
+		b.WriteString(edgeVal)
+	}
+	return b.String()
+}
+
+func printCall(v *CallCommon, prefix string, instr Instruction) string {
+	var b bytes.Buffer
+	if !v.IsInvoke() {
+		if value, ok := instr.(Value); ok {
+			fmt.Fprintf(&b, "%s <%s> %s", prefix, relType(value.Type(), instr.Parent().pkg()), relName(v.Value, instr))
+		} else {
+			fmt.Fprintf(&b, "%s %s", prefix, relName(v.Value, instr))
+		}
+	} else {
+		if value, ok := instr.(Value); ok {
+			fmt.Fprintf(&b, "%sInvoke <%s> %s.%s", prefix, relType(value.Type(), instr.Parent().pkg()), relName(v.Value, instr), v.Method.Name())
+		} else {
+			fmt.Fprintf(&b, "%sInvoke %s.%s", prefix, relName(v.Value, instr), v.Method.Name())
+		}
+	}
+	for _, arg := range v.TypeArgs {
+		b.WriteString(" ")
+		b.WriteString(relType(arg, instr.Parent().pkg()))
+	}
+	for _, arg := range v.Args {
+		b.WriteString(" ")
+		b.WriteString(relName(arg, instr))
+	}
+	return b.String()
+}
+
+func (c *CallCommon) String() string {
+	return printCall(c, "", nil)
+}
+
+func (v *Call) String() string {
+	return printCall(&v.Call, "Call", v)
+}
+
+func (v *BinOp) String() string {
+	return fmt.Sprintf("BinOp <%s> {%s} %s %s", relType(v.Type(), v.Parent().pkg()), v.Op.String(), relName(v.X, v), relName(v.Y, v))
+}
+
+func (v *UnOp) String() string {
+	return fmt.Sprintf("UnOp <%s> {%s} %s", relType(v.Type(), v.Parent().pkg()), v.Op.String(), relName(v.X, v))
+}
+
+func (v *Load) String() string {
+	return fmt.Sprintf("Load <%s> %s", relType(v.Type(), v.Parent().pkg()), relName(v.X, v))
+}
+
+func (v *Copy) String() string {
+	return fmt.Sprintf("Copy <%s> %s", relType(v.Type(), v.Parent().pkg()), relName(v.X, v))
+}
+
+func printConv(prefix string, v, x Value) string {
+	from := v.Parent().pkg()
+	return fmt.Sprintf("%s <%s> %s",
+		prefix,
+		relType(v.Type(), from),
+		relName(x, v.(Instruction)))
+}
+
+func (v *ChangeType) String() string          { return printConv("ChangeType", v, v.X) }
+func (v *Convert) String() string             { return printConv("Convert", v, v.X) }
+func (v *ChangeInterface) String() string     { return printConv("ChangeInterface", v, v.X) }
+func (v *SliceToArrayPointer) String() string { return printConv("SliceToArrayPointer", v, v.X) }
+func (v *SliceToArray) String() string        { return printConv("SliceToArray", v, v.X) }
+func (v *MakeInterface) String() string       { return printConv("MakeInterface", v, v.X) }
+
+func (v *MakeClosure) String() string {
+	from := v.Parent().pkg()
+	var b bytes.Buffer
+	fmt.Fprintf(&b, "MakeClosure <%s> %s", relType(v.Type(), from), relName(v.Fn, v))
+	if v.Bindings != nil {
+		for _, c := range v.Bindings {
+			b.WriteString(" ")
+			b.WriteString(relName(c, v))
+		}
+	}
+	return b.String()
+}
+
+func (v *MakeSlice) String() string {
+	from := v.Parent().pkg()
+	return fmt.Sprintf("MakeSlice <%s> %s %s",
+		relType(v.Type(), from),
+		relName(v.Len, v),
+		relName(v.Cap, v))
+}
+
+func (v *Slice) String() string {
+	from := v.Parent().pkg()
+	return fmt.Sprintf("Slice <%s> %s %s %s %s",
+		relType(v.Type(), from), relName(v.X, v), relName(v.Low, v), relName(v.High, v), relName(v.Max, v))
+}
+
+func (v *MakeMap) String() string {
+	res := ""
+	if v.Reserve != nil {
+		res = relName(v.Reserve, v)
+	}
+	from := v.Parent().pkg()
+	return fmt.Sprintf("MakeMap <%s> %s", relType(v.Type(), from), res)
+}
+
+func (v *MakeChan) String() string {
+	from := v.Parent().pkg()
+	return fmt.Sprintf("MakeChan <%s> %s", relType(v.Type(), from), relName(v.Size, v))
+}
+
+func (v *FieldAddr) String() string {
+	from := v.Parent().pkg()
+	// v.X.Type() might be a pointer to a type parameter whose core type is a pointer to a struct
+	st := deref(typeutil.CoreType(deref(v.X.Type()))).Underlying().(*types.Struct)
+	// Be robust against a bad index.
+	name := "?"
+	if 0 <= v.Field && v.Field < st.NumFields() {
+		name = st.Field(v.Field).Name()
+	}
+	return fmt.Sprintf("FieldAddr <%s> [%d] (%s) %s", relType(v.Type(), from), v.Field, name, relName(v.X, v))
+}
+
+func (v *Field) String() string {
+	st := typeutil.CoreType(v.X.Type()).Underlying().(*types.Struct)
+	// Be robust against a bad index.
+	name := "?"
+	if 0 <= v.Field && v.Field < st.NumFields() {
+		name = st.Field(v.Field).Name()
+	}
+	from := v.Parent().pkg()
+	return fmt.Sprintf("Field <%s> [%d] (%s) %s", relType(v.Type(), from), v.Field, name, relName(v.X, v))
+}
+
+func (v *IndexAddr) String() string {
+	from := v.Parent().pkg()
+	return fmt.Sprintf("IndexAddr <%s> %s %s", relType(v.Type(), from), relName(v.X, v), relName(v.Index, v))
+}
+
+func (v *Index) String() string {
+	from := v.Parent().pkg()
+	return fmt.Sprintf("Index <%s> %s %s", relType(v.Type(), from), relName(v.X, v), relName(v.Index, v))
+}
+
+func (v *MapLookup) String() string {
+	from := v.Parent().pkg()
+	return fmt.Sprintf("MapLookup <%s> %s %s", relType(v.Type(), from), relName(v.X, v), relName(v.Index, v))
+}
+
+func (v *StringLookup) String() string {
+	from := v.Parent().pkg()
+	return fmt.Sprintf("StringLookup <%s> %s %s", relType(v.Type(), from), relName(v.X, v), relName(v.Index, v))
+}
+
+func (v *Range) String() string {
+	from := v.Parent().pkg()
+	return fmt.Sprintf("Range <%s> %s", relType(v.Type(), from), relName(v.X, v))
+}
+
+func (v *Next) String() string {
+	from := v.Parent().pkg()
+	return fmt.Sprintf("Next <%s> %s", relType(v.Type(), from), relName(v.Iter, v))
+}
+
+func (v *TypeAssert) String() string {
+	from := v.Parent().pkg()
+	return fmt.Sprintf("TypeAssert <%s> %s", relType(v.Type(), from), relName(v.X, v))
+}
+
+func (v *Extract) String() string {
+	from := v.Parent().pkg()
+	name := v.Tuple.Type().(*types.Tuple).At(v.Index).Name()
+	return fmt.Sprintf("Extract <%s> [%d] (%s) %s", relType(v.Type(), from), v.Index, name, relName(v.Tuple, v))
+}
+
+func (s *Jump) String() string {
+	// Be robust against malformed CFG.
+	block := -1
+	if s.block != nil && len(s.block.Succs) == 1 {
+		block = s.block.Succs[0].Index
+	}
+	str := fmt.Sprintf("Jump → b%d", block)
+	if s.Comment() != "" {
+		str = fmt.Sprintf("%s # %s", str, s.Comment())
+	}
+	return str
+}
+
+func (s *Unreachable) String() string {
+	// Be robust against malformed CFG.
+	block := -1
+	if s.block != nil && len(s.block.Succs) == 1 {
+		block = s.block.Succs[0].Index
+	}
+	return fmt.Sprintf("Unreachable → b%d", block)
+}
+
+func (s *If) String() string {
+	// Be robust against malformed CFG.
+	tblock, fblock := -1, -1
+	if s.block != nil && len(s.block.Succs) == 2 {
+		tblock = s.block.Succs[0].Index
+		fblock = s.block.Succs[1].Index
+	}
+	return fmt.Sprintf("If %s → b%d b%d", relName(s.Cond, s), tblock, fblock)
+}
+
+func (s *ConstantSwitch) String() string {
+	var b bytes.Buffer
+	fmt.Fprintf(&b, "ConstantSwitch %s", relName(s.Tag, s))
+	for _, cond := range s.Conds {
+		fmt.Fprintf(&b, " %s", relName(cond, s))
+	}
+	fmt.Fprint(&b, " →")
+	for _, succ := range s.block.Succs {
+		fmt.Fprintf(&b, " b%d", succ.Index)
+	}
+	return b.String()
+}
+
+func (v *CompositeValue) String() string {
+	var b bytes.Buffer
+	from := v.Parent().pkg()
+	fmt.Fprintf(&b, "CompositeValue <%s>", relType(v.Type(), from))
+	if v.NumSet >= len(v.Values) {
+		// All values provided
+		fmt.Fprint(&b, " [all]")
+	} else if v.Bitmap.BitLen() == 0 {
+		// No values provided
+		fmt.Fprint(&b, " [none]")
+	} else {
+		// Some values provided
+		bits := fmt.Appendf(nil, "%0*b", len(v.Values), &v.Bitmap)
+		for i := 0; i < len(bits)/2; i++ {
+			o := len(bits) - 1 - i
+			bits[i], bits[o] = bits[o], bits[i]
+		}
+		fmt.Fprintf(&b, " [%s]", bits)
+	}
+	for _, vv := range v.Values {
+		fmt.Fprintf(&b, " %s", relName(vv, v))
+	}
+	return b.String()
+}
+
+func (s *TypeSwitch) String() string {
+	from := s.Parent().pkg()
+	var b bytes.Buffer
+	fmt.Fprintf(&b, "TypeSwitch <%s> %s", relType(s.typ, from), relName(s.Tag, s))
+	for _, cond := range s.Conds {
+		fmt.Fprintf(&b, " %q", relType(cond, s.block.parent.pkg()))
+	}
+	return b.String()
+}
+
+func (s *Go) String() string {
+	return printCall(&s.Call, "Go", s)
+}
+
+func (s *Panic) String() string {
+	// Be robust against malformed CFG.
+	block := -1
+	if s.block != nil && len(s.block.Succs) == 1 {
+		block = s.block.Succs[0].Index
+	}
+	return fmt.Sprintf("Panic %s → b%d", relName(s.X, s), block)
+}
+
+func (s *Return) String() string {
+	var b bytes.Buffer
+	b.WriteString("Return")
+	for _, r := range s.Results {
+		b.WriteString(" ")
+		b.WriteString(relName(r, s))
+	}
+	return b.String()
+}
+
+func (*RunDefers) String() string {
+	return "RunDefers"
+}
+
+func (s *Send) String() string {
+	return fmt.Sprintf("Send %s %s", relName(s.Chan, s), relName(s.X, s))
+}
+
+func (recv *Recv) String() string {
+	from := recv.Parent().pkg()
+	return fmt.Sprintf("Recv <%s> %s", relType(recv.Type(), from), relName(recv.Chan, recv))
+}
+
+func (s *Defer) String() string {
+	prefix := "Defer "
+	if s._DeferStack != nil {
+		prefix += "[" + relName(s._DeferStack, s) + "] "
+	}
+	c := printCall(&s.Call, prefix, s)
+	return c
+}
+
+func (s *Select) String() string {
+	var b bytes.Buffer
+	for i, st := range s.States {
+		if i > 0 {
+			b.WriteString(", ")
+		}
+		if st.Dir == types.RecvOnly {
+			b.WriteString("<-")
+			b.WriteString(relName(st.Chan, s))
+		} else {
+			b.WriteString(relName(st.Chan, s))
+			b.WriteString("<-")
+			b.WriteString(relName(st.Send, s))
+		}
+	}
+	non := ""
+	if !s.Blocking {
+		non = "Non"
+	}
+	from := s.Parent().pkg()
+	return fmt.Sprintf("Select%sBlocking <%s> [%s]", non, relType(s.Type(), from), b.String())
+}
+
+func (s *Store) String() string {
+	return fmt.Sprintf("Store {%s} %s %s",
+		s.Val.Type(), relName(s.Addr, s), relName(s.Val, s))
+}
+
+func (s *BlankStore) String() string {
+	return fmt.Sprintf("BlankStore %s", relName(s.Val, s))
+}
+
+func (s *MapUpdate) String() string {
+	return fmt.Sprintf("MapUpdate %s %s %s", relName(s.Map, s), relName(s.Key, s), relName(s.Value, s))
+}
+
+func (s *DebugRef) String() string {
+	p := s.Parent().Prog.Fset.Position(s.Pos())
+	var descr any
+	if s.object != nil {
+		descr = s.object // e.g. "var x int"
+	} else {
+		descr = reflect.TypeOf(s.Expr) // e.g. "*ast.CallExpr"
+	}
+	var addr string
+	if s.IsAddr {
+		addr = "address of "
+	}
+	return fmt.Sprintf("; %s%s @ %d:%d is %s", addr, descr, p.Line, p.Column, s.X.Name())
+}
+
+func (p *Package) String() string {
+	return "package " + p.Pkg.Path()
+}
+
+var _ io.WriterTo = (*Package)(nil) // *Package implements io.Writer
+
+func (p *Package) WriteTo(w io.Writer) (int64, error) {
+	var buf bytes.Buffer
+	WritePackage(&buf, p)
+	n, err := w.Write(buf.Bytes())
+	return int64(n), err
+}
+
+// WritePackage writes to buf a human-readable summary of p.
+func WritePackage(buf *bytes.Buffer, p *Package) {
+	fmt.Fprintf(buf, "%s:\n", p)
+
+	var names []string
+	maxname := 0
+	for name := range p.Members {
+		if l := len(name); l > maxname {
+			maxname = l
+		}
+		names = append(names, name)
+	}
+
+	from := p.Pkg
+	sort.Strings(names)
+	for _, name := range names {
+		switch mem := p.Members[name].(type) {
+		case *NamedConst:
+			fmt.Fprintf(buf, "  const %-*s %s = %s\n",
+				maxname, name, mem.Name(), mem.Value.RelString(from))
+
+		case *Function:
+			fmt.Fprintf(buf, "  func  %-*s %s\n",
+				maxname, name, relType(mem.Type(), from))
+
+		case *Type:
+			fmt.Fprintf(buf, "  type  %-*s %s\n",
+				maxname, name, relType(mem.Type().Underlying(), from))
+			for _, meth := range typeutil.IntuitiveMethodSet(mem.Type(), &p.Prog.MethodSets) {
+				fmt.Fprintf(buf, "    %s\n", types.SelectionString(meth, types.RelativeTo(from)))
+			}
+
+		case *Global:
+			fmt.Fprintf(buf, "  var   %-*s %s\n",
+				maxname, name, relType(mem.Type().(*types.Pointer).Elem(), from))
+		}
+	}
+
+	fmt.Fprintf(buf, "\n")
+}
+
+func (v *MultiConvert) String() string {
+	from := v.Parent().Pkg.Pkg
+
+	var b strings.Builder
+	b.WriteString(printConv("MultiConvert", v, v.X))
+	b.WriteString(" [")
+	for i, s := range v.from.Terms {
+		for j, d := range v.to.Terms {
+			if i != 0 || j != 0 {
+				b.WriteString(" | ")
+			}
+			fmt.Fprintf(&b, "%s -> %s", relTerm(s, from), relTerm(d, from))
+		}
+	}
+	b.WriteString("]")
+	return b.String()
+}

vendor/honnef.co/go/tools/go/ir/sanity.go

@@ -0,0 +1,546 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package ir
+
+// An optional pass for sanity-checking invariants of the IR representation.
+// Currently it checks CFG invariants but little at the instruction level.
+
+import (
+	"bytes"
+	"fmt"
+	"go/ast"
+	"go/types"
+	"io"
+	"os"
+	"slices"
+	"strings"
+
+	"honnef.co/go/tools/go/types/typeutil"
+)
+
+type sanity struct {
+	reporter io.Writer
+	fn       *Function
+	block    *BasicBlock
+	instrs   map[Instruction]struct{}
+	insane   bool
+}
+
+// sanityCheck performs integrity checking of the IR representation
+// of the function fn and returns true if it was valid.  Diagnostics
+// are written to reporter if non-nil, os.Stderr otherwise.  Some
+// diagnostics are only warnings and do not imply a negative result.
+//
+// Sanity-checking is intended to facilitate the debugging of code
+// transformation passes.
+func sanityCheck(fn *Function, reporter io.Writer) bool {
+	if reporter == nil {
+		reporter = os.Stderr
+	}
+	return (&sanity{reporter: reporter}).checkFunction(fn)
+}
+
+// mustSanityCheck is like sanityCheck but panics instead of returning
+// a negative result.
+func mustSanityCheck(fn *Function, reporter io.Writer) {
+	if !sanityCheck(fn, reporter) {
+		fn.WriteTo(os.Stderr)
+		panic("SanityCheck failed")
+	}
+}
+
+func (s *sanity) diagnostic(prefix, format string, args ...any) {
+	fmt.Fprintf(s.reporter, "%s: function %s", prefix, s.fn)
+	if s.block != nil {
+		fmt.Fprintf(s.reporter, ", block %s", s.block)
+	}
+	io.WriteString(s.reporter, ": ")
+	fmt.Fprintf(s.reporter, format, args...)
+	io.WriteString(s.reporter, "\n")
+}
+
+func (s *sanity) errorf(format string, args ...any) {
+	s.insane = true
+	s.diagnostic("Error", format, args...)
+}
+
+func (s *sanity) warnf(format string, args ...any) {
+	s.diagnostic("Warning", format, args...)
+}
+
+// findDuplicate returns an arbitrary basic block that appeared more
+// than once in blocks, or nil if all were unique.
+func findDuplicate(blocks []*BasicBlock) *BasicBlock {
+	if len(blocks) < 2 {
+		return nil
+	}
+	if blocks[0] == blocks[1] {
+		return blocks[0]
+	}
+	// Slow path:
+	m := make(map[*BasicBlock]bool)
+	for _, b := range blocks {
+		if m[b] {
+			return b
+		}
+		m[b] = true
+	}
+	return nil
+}
+
+func (s *sanity) checkInstr(idx int, instr Instruction) {
+	switch instr := instr.(type) {
+	case *If, *Jump, *Return, *Panic, *Unreachable, *ConstantSwitch:
+		s.errorf("control flow instruction not at end of block")
+	case *Sigma:
+		if idx > 0 {
+			prev := s.block.Instrs[idx-1]
+			if _, ok := prev.(*Sigma); !ok {
+				s.errorf("Sigma instruction follows a non-Sigma: %T", prev)
+			}
+		}
+	case *Phi:
+		if idx == 0 {
+			// It suffices to apply this check to just the first phi node.
+			if dup := findDuplicate(s.block.Preds); dup != nil {
+				s.errorf("phi node in block with duplicate predecessor %s", dup)
+			}
+		} else {
+			prev := s.block.Instrs[idx-1]
+			switch prev.(type) {
+			case *Phi, *Sigma:
+			default:
+				s.errorf("Phi instruction follows a non-Phi, non-Sigma: %T", prev)
+			}
+		}
+		if ne, np := len(instr.Edges), len(s.block.Preds); ne != np {
+			s.errorf("phi node has %d edges but %d predecessors", ne, np)
+
+		} else {
+			for i, e := range instr.Edges {
+				if e == nil {
+					s.errorf("phi node '%s' has no value for edge #%d from %s", instr.Comment(), i, s.block.Preds[i])
+				}
+			}
+		}
+
+	case *Alloc:
+		if !instr.Heap && !slices.Contains(s.fn.Locals, instr) {
+			s.errorf("local alloc %s = %s does not appear in Function.Locals", instr.Name(), instr)
+		}
+
+	case *BinOp:
+	case *Call:
+	case *ChangeInterface:
+	case *ChangeType:
+	case *SliceToArrayPointer:
+	case *SliceToArray:
+	case *Convert:
+		tsetInstrX := typeutil.NewTypeSet(instr.X.Type().Underlying())
+		tsetInstr := typeutil.NewTypeSet(instr.Type().Underlying())
+		ok1 := tsetInstr.Any(func(term *types.Term) bool { _, ok := term.Type().Underlying().(*types.Basic); return ok })
+		ok2 := tsetInstrX.Any(func(term *types.Term) bool { _, ok := term.Type().Underlying().(*types.Basic); return ok })
+		if !ok1 && !ok2 {
+			s.errorf("convert %s -> %s: at least one type set must contain basic type", instr.X.Type(), instr.Type())
+		}
+
+	case *MultiConvert:
+	case *Defer:
+	case *Extract:
+	case *Field:
+	case *FieldAddr:
+	case *Go:
+	case *Index:
+	case *IndexAddr:
+	case *MapLookup:
+	case *StringLookup:
+	case *MakeChan:
+	case *MakeClosure:
+		numFree := len(instr.Fn.(*Function).FreeVars)
+		numBind := len(instr.Bindings)
+		if numFree != numBind {
+			s.errorf("MakeClosure has %d Bindings for function %s with %d free vars",
+				numBind, instr.Fn, numFree)
+
+		}
+		if recv := instr.Type().(*types.Signature).Recv(); recv != nil {
+			s.errorf("MakeClosure's type includes receiver %s", recv.Type())
+		}
+
+	case *MakeInterface:
+	case *MakeMap:
+	case *MakeSlice:
+	case *MapUpdate:
+	case *Next:
+	case *Range:
+	case *RunDefers:
+	case *Select:
+	case *Send:
+	case *Slice:
+	case *Store:
+	case *TypeAssert:
+	case *UnOp:
+	case *DebugRef:
+	case *BlankStore:
+	case *Load:
+	case *Parameter:
+	case *Const:
+	case *AggregateConst:
+	case *ArrayConst:
+	case *GenericConst:
+	case *Recv:
+	case *TypeSwitch:
+	case *CompositeValue:
+	default:
+		panic(fmt.Sprintf("Unknown instruction type: %T", instr))
+	}
+
+	if call, ok := instr.(CallInstruction); ok {
+		if call.Common().Signature() == nil {
+			s.errorf("nil signature: %s", call)
+		}
+	}
+
+	// Check that value-defining instructions have valid types
+	// and a valid referrer list.
+	if v, ok := instr.(Value); ok {
+		t := v.Type()
+		if t == nil {
+			s.errorf("no type: %s = %s", v.Name(), v)
+		} else if b, ok := t.Underlying().(*types.Basic); ok && b.Info()&types.IsUntyped != 0 {
+			if _, ok := v.(*Const); !ok {
+				s.errorf("instruction has 'untyped' result: %s = %s : %s", v.Name(), v, t)
+			}
+		}
+		s.checkReferrerList(v)
+	}
+
+	// Untyped constants are legal as instruction Operands(),
+	// for example:
+	//   _ = "foo"[0]
+	// or:
+	//   if wordsize==64 {...}
+
+	// All other non-Instruction Values can be found via their
+	// enclosing Function or Package.
+}
+
+func (s *sanity) checkFinalInstr(instr Instruction) {
+	switch instr := instr.(type) {
+	case *If:
+		if nsuccs := len(s.block.Succs); nsuccs != 2 {
+			s.errorf("If-terminated block has %d successors; expected 2", nsuccs)
+			return
+		}
+		if s.block.Succs[0] == s.block.Succs[1] {
+			s.errorf("If-instruction has same True, False target blocks: %s", s.block.Succs[0])
+			return
+		}
+
+	case *Jump:
+		if nsuccs := len(s.block.Succs); nsuccs != 1 {
+			s.errorf("Jump-terminated block has %d successors; expected 1", nsuccs)
+			return
+		}
+
+	case *Return:
+		if nsuccs := len(s.block.Succs); nsuccs != 0 {
+			s.errorf("Return-terminated block has %d successors; expected none", nsuccs)
+			return
+		}
+		if na, nf := len(instr.Results), s.fn.Signature.Results().Len(); nf != na {
+			s.errorf("%d-ary return in %d-ary function", na, nf)
+		}
+
+	case *Panic:
+		if nsuccs := len(s.block.Succs); nsuccs != 1 {
+			s.errorf("Panic-terminated block has %d successors; expected one", nsuccs)
+			return
+		}
+
+	case *Unreachable:
+		if nsuccs := len(s.block.Succs); nsuccs != 1 {
+			s.errorf("Unreachable-terminated block has %d successors; expected one", nsuccs)
+			return
+		}
+
+	case *ConstantSwitch:
+
+	default:
+		s.errorf("non-control flow instruction at end of block")
+	}
+}
+
+func (s *sanity) checkBlock(b *BasicBlock, index int) {
+	s.block = b
+
+	if b.Index != index {
+		s.errorf("block has incorrect Index %d", b.Index)
+	}
+	if b.parent != s.fn {
+		s.errorf("block has incorrect parent %s", b.parent)
+	}
+
+	// Check all blocks are reachable.
+	// (The entry block is always implicitly reachable, the exit block may be unreachable.)
+	if index > 1 && len(b.Preds) == 0 {
+		s.warnf("unreachable block")
+		if b.Instrs == nil {
+			// Since this block is about to be pruned,
+			// tolerating transient problems in it
+			// simplifies other optimizations.
+			return
+		}
+	}
+
+	// Check predecessor and successor relations are dual,
+	// and that all blocks in CFG belong to same function.
+	for _, a := range b.Preds {
+		if !slices.Contains(a.Succs, b) {
+			s.errorf("expected successor edge in predecessor %s; found only: %s", a, a.Succs)
+		}
+		if a.parent != s.fn {
+			s.errorf("predecessor %s belongs to different function %s", a, a.parent)
+		}
+	}
+	for _, c := range b.Succs {
+		if !slices.Contains(c.Preds, b) {
+			s.errorf("expected predecessor edge in successor %s; found only: %s", c, c.Preds)
+		}
+		if c.parent != s.fn {
+			s.errorf("successor %s belongs to different function %s", c, c.parent)
+		}
+	}
+
+	// Check each instruction is sane.
+	n := len(b.Instrs)
+	if n == 0 {
+		s.errorf("basic block contains no instructions")
+	}
+	var rands [10]*Value // reuse storage
+	for j, instr := range b.Instrs {
+		if instr == nil {
+			s.errorf("nil instruction at index %d", j)
+			continue
+		}
+		if b2 := instr.Block(); b2 == nil {
+			s.errorf("nil Block() for instruction at index %d", j)
+			continue
+		} else if b2 != b {
+			s.errorf("wrong Block() (%s) for instruction at index %d ", b2, j)
+			continue
+		}
+		if j < n-1 {
+			s.checkInstr(j, instr)
+		} else {
+			s.checkFinalInstr(instr)
+		}
+
+		// Check Instruction.Operands.
+	operands:
+		for i, op := range instr.Operands(rands[:0]) {
+			if op == nil {
+				s.errorf("nil operand pointer %d of %s", i, instr)
+				continue
+			}
+			val := *op
+			if val == nil {
+				continue // a nil operand is ok
+			}
+
+			// Check that "untyped" types only appear on constant operands.
+			if _, ok := (*op).(*Const); !ok {
+				if basic, ok := types.Unalias((*op).Type()).(*types.Basic); ok {
+					if basic.Info()&types.IsUntyped != 0 {
+						s.errorf("operand #%d of %s is untyped: %s", i, instr, basic)
+					}
+				}
+			}
+
+			// Check that Operands that are also Instructions belong to same function.
+			// TODO(adonovan): also check their block dominates block b.
+			if val, ok := val.(Instruction); ok {
+				if val.Block() == nil {
+					s.errorf("operand %d of %s is an instruction (%s) that belongs to no block", i, instr, val)
+				} else if val.Parent() != s.fn {
+					s.errorf("operand %d of %s is an instruction (%s) from function %s", i, instr, val, val.Parent())
+				}
+			}
+
+			// Check that each function-local operand of
+			// instr refers back to instr.  (NB: quadratic)
+			switch val := val.(type) {
+			case *Const, *Global, *Builtin:
+				continue // not local
+			case *Function:
+				if val.parent == nil {
+					continue // only anon functions are local
+				}
+			}
+
+			// TODO(adonovan): check val.Parent() != nil <=> val.Referrers() is defined.
+
+			if refs := val.Referrers(); refs != nil {
+				for _, ref := range *refs {
+					if ref == instr {
+						continue operands
+					}
+				}
+				s.errorf("operand %d of %s (%s) does not refer to us", i, instr, val)
+			} else {
+				s.errorf("operand %d of %s (%s) has no referrers", i, instr, val)
+			}
+		}
+	}
+}
+
+func (s *sanity) checkReferrerList(v Value) {
+	refs := v.Referrers()
+	if refs == nil {
+		s.errorf("%s has missing referrer list", v.Name())
+		return
+	}
+	for i, ref := range *refs {
+		if _, ok := s.instrs[ref]; !ok {
+			if val, ok := ref.(Value); ok {
+				s.errorf("%s.Referrers()[%d] = %s = %s is not an instruction belonging to this function", v.Name(), i, val.Name(), val)
+			} else {
+				s.errorf("%s.Referrers()[%d] = %s is not an instruction belonging to this function", v.Name(), i, ref)
+			}
+		}
+	}
+}
+
+func (s *sanity) checkFunction(fn *Function) bool {
+	// TODO(adonovan): check Function invariants:
+	// - check params match signature
+	// - check transient fields are nil
+	// - warn if any fn.Locals do not appear among block instructions.
+	s.fn = fn
+	if fn.Prog == nil {
+		s.errorf("nil Prog")
+	}
+
+	var buf bytes.Buffer
+	_ = fn.String()            // must not crash
+	_ = fn.RelString(fn.pkg()) // must not crash
+	WriteFunction(&buf, fn)    // must not crash
+
+	// All functions have a package, except delegates (which are
+	// shared across packages, or duplicated as weak symbols in a
+	// separate-compilation model), and error.Error.
+	if fn.Pkg == nil {
+		switch fn.Synthetic {
+		case SyntheticWrapper, SyntheticBound, SyntheticThunk, SyntheticGeneric:
+		default:
+			if !strings.HasSuffix(fn.name, "Error") {
+				s.errorf("nil Pkg")
+			}
+		}
+	}
+	if syn, src := fn.Synthetic == 0, fn.source != nil; src != syn {
+		if _, ok := fn.source.(*ast.RangeStmt); !ok || fn.Synthetic != SyntheticRangeOverFuncYield {
+			// Only range-over-func yield functions are synthetic and have syntax
+			s.errorf("got fromSource=%t, hasSyntax=%t; want same values", src, syn)
+		}
+	}
+	for i, l := range fn.Locals {
+		if l.Parent() != fn {
+			s.errorf("Local %s at index %d has wrong parent", l.Name(), i)
+		}
+		if l.Heap {
+			s.errorf("Local %s at index %d has Heap flag set", l.Name(), i)
+		}
+	}
+	// Build the set of valid referrers.
+	s.instrs = make(map[Instruction]struct{})
+	for _, b := range fn.Blocks {
+		for _, instr := range b.Instrs {
+			s.instrs[instr] = struct{}{}
+		}
+	}
+	for i, p := range fn.Params {
+		if p.Parent() != fn {
+			s.errorf("Param %s at index %d has wrong parent", p.Name(), i)
+		}
+		// Check common suffix of Signature and Params match type.
+		if sig := fn.Signature; sig != nil {
+			j := i - len(fn.Params) + sig.Params().Len() // index within sig.Params
+			if j < 0 {
+				continue
+			}
+			if !types.Identical(p.Type(), sig.Params().At(j).Type()) {
+				s.errorf("Param %s at index %d has wrong type (%s, versus %s in Signature)", p.Name(), i, p.Type(), sig.Params().At(j).Type())
+
+			}
+		}
+
+		s.checkReferrerList(p)
+	}
+	for i, fv := range fn.FreeVars {
+		if fv.Parent() != fn {
+			s.errorf("FreeVar %s at index %d has wrong parent", fv.Name(), i)
+		}
+		s.checkReferrerList(fv)
+	}
+
+	if fn.Blocks != nil && len(fn.Blocks) == 0 {
+		// Function _had_ blocks (so it's not external) but
+		// they were "optimized" away, even the entry block.
+		s.errorf("Blocks slice is non-nil but empty")
+	}
+	for i, b := range fn.Blocks {
+		if b == nil {
+			s.warnf("nil *BasicBlock at f.Blocks[%d]", i)
+			continue
+		}
+		s.checkBlock(b, i)
+	}
+
+	s.block = nil
+	for i, anon := range fn.AnonFuncs {
+		if anon.Parent() != fn {
+			s.errorf("AnonFuncs[%d]=%s but %s.Parent()=%s", i, anon, anon, anon.Parent())
+		}
+	}
+	s.fn = nil
+	return !s.insane
+}
+
+// sanityCheckPackage checks invariants of packages upon creation.
+// It does not require that the package is built.
+// Unlike sanityCheck (for functions), it just panics at the first error.
+func sanityCheckPackage(pkg *Package) {
+	if pkg.Pkg == nil {
+		panic(fmt.Sprintf("Package %s has no Object", pkg))
+	}
+	_ = pkg.String() // must not crash
+
+	for name, mem := range pkg.Members {
+		if name != mem.Name() {
+			panic(fmt.Sprintf("%s: %T.Name() = %s, want %s",
+				pkg.Pkg.Path(), mem, mem.Name(), name))
+		}
+		obj := mem.Object()
+		if obj == nil {
+			// This check is sound because fields
+			// {Global,Function}.object have type
+			// types.Object.  (If they were declared as
+			// *types.{Var,Func}, we'd have a non-empty
+			// interface containing a nil pointer.)
+
+			continue // not all members have typechecker objects
+		}
+		if obj.Name() != name {
+			if obj.Name() == "init" && strings.HasPrefix(mem.Name(), "init#") {
+				// Ok.  The name of a declared init function varies between
+				// its types.Func ("init") and its ir.Function ("init#%d").
+			} else {
+				panic(fmt.Sprintf("%s: %T.Object().Name() = %s, want %s",
+					pkg.Pkg.Path(), mem, obj.Name(), name))
+			}
+		}
+	}
+}

vendor/honnef.co/go/tools/go/ir/source.go

@@ -0,0 +1,263 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package ir
+
+// This file defines utilities for working with source positions
+// or source-level named entities ("objects").
+
+// TODO(adonovan): test that {Value,Instruction}.Pos() positions match
+// the originating syntax, as specified.
+
+import (
+	"go/ast"
+	"go/token"
+	"go/types"
+)
+
+// EnclosingFunction returns the function that contains the syntax
+// node denoted by path.
+//
+// Syntax associated with package-level variable specifications is
+// enclosed by the package's init() function.
+//
+// Returns nil if not found; reasons might include:
+//   - the node is not enclosed by any function.
+//   - the node is within an anonymous function (FuncLit) and
+//     its IR function has not been created yet
+//     (pkg.Build() has not yet been called).
+func EnclosingFunction(pkg *Package, path []ast.Node) *Function {
+	// Start with package-level function...
+	fn := findEnclosingPackageLevelFunction(pkg, path)
+	if fn == nil {
+		return nil // not in any function
+	}
+
+	// ...then walk down the nested anonymous functions.
+	n := len(path)
+outer:
+	for i := range path {
+		if lit, ok := path[n-1-i].(*ast.FuncLit); ok {
+			for _, anon := range fn.AnonFuncs {
+				if anon.Pos() == lit.Type.Func {
+					fn = anon
+					continue outer
+				}
+			}
+			// IR function not found:
+			// - package not yet built, or maybe
+			// - builder skipped FuncLit in dead block
+			//   (in principle; but currently the Builder
+			//   generates even dead FuncLits).
+			return nil
+		}
+	}
+	return fn
+}
+
+// HasEnclosingFunction returns true if the AST node denoted by path
+// is contained within the declaration of some function or
+// package-level variable.
+//
+// Unlike EnclosingFunction, the behaviour of this function does not
+// depend on whether IR code for pkg has been built, so it can be
+// used to quickly reject check inputs that will cause
+// EnclosingFunction to fail, prior to IR building.
+func HasEnclosingFunction(pkg *Package, path []ast.Node) bool {
+	return findEnclosingPackageLevelFunction(pkg, path) != nil
+}
+
+// findEnclosingPackageLevelFunction returns the Function
+// corresponding to the package-level function enclosing path.
+func findEnclosingPackageLevelFunction(pkg *Package, path []ast.Node) *Function {
+	if n := len(path); n >= 2 { // [... {Gen,Func}Decl File]
+		switch decl := path[n-2].(type) {
+		case *ast.GenDecl:
+			if decl.Tok == token.VAR && n >= 3 {
+				// Package-level 'var' initializer.
+				return pkg.init
+			}
+
+		case *ast.FuncDecl:
+			// Declared function/method.
+			fn := findNamedFunc(pkg, decl.Pos())
+			if fn == nil && decl.Recv == nil && decl.Name.Name == "init" {
+				// Hack: return non-nil when IR is not yet
+				// built so that HasEnclosingFunction works.
+				return pkg.init
+			}
+			return fn
+		}
+	}
+	return nil // not in any function
+}
+
+// findNamedFunc returns the named function whose FuncDecl.Ident is at
+// position pos.
+func findNamedFunc(pkg *Package, pos token.Pos) *Function {
+	for _, fn := range pkg.Functions {
+		if fn.Pos() == pos {
+			return fn
+		}
+	}
+	return nil
+}
+
+// ValueForExpr returns the IR Value that corresponds to non-constant
+// expression e.
+//
+// It returns nil if no value was found, e.g.
+//   - the expression is not lexically contained within f;
+//   - f was not built with debug information; or
+//   - e is a constant expression.  (For efficiency, no debug
+//     information is stored for constants. Use
+//     go/types.Info.Types[e].Value instead.)
+//   - e is a reference to nil or a built-in function.
+//   - the value was optimised away.
+//
+// If e is an addressable expression used in an lvalue context,
+// value is the address denoted by e, and isAddr is true.
+//
+// The types of e (or &e, if isAddr) and the result are equal
+// (modulo "untyped" bools resulting from comparisons).
+//
+// (Tip: to find the ir.Value given a source position, use
+// astutil.PathEnclosingInterval to locate the ast.Node, then
+// EnclosingFunction to locate the Function, then ValueForExpr to find
+// the ir.Value.)
+func (f *Function) ValueForExpr(e ast.Expr) (value Value, isAddr bool) {
+	if f.debugInfo() { // (opt)
+		e = unparen(e)
+		for _, b := range f.Blocks {
+			for _, instr := range b.Instrs {
+				if ref, ok := instr.(*DebugRef); ok {
+					if ref.Expr == e {
+						return ref.X, ref.IsAddr
+					}
+				}
+			}
+		}
+	}
+	return
+}
+
+// --- Lookup functions for source-level named entities (types.Objects) ---
+
+// Package returns the IR Package corresponding to the specified
+// type-checker package object.
+// It returns nil if no such IR package has been created.
+func (prog *Program) Package(obj *types.Package) *Package {
+	return prog.packages[obj]
+}
+
+// packageLevelValue returns the package-level value corresponding to
+// the specified named object, which may be a package-level const
+// (*Const), var (*Global) or func (*Function) of some package in
+// prog.  It returns nil if the object is not found.
+func (prog *Program) packageLevelValue(obj types.Object) Value {
+	if pkg, ok := prog.packages[obj.Pkg()]; ok {
+		return pkg.values[obj]
+	}
+	return nil
+}
+
+// FuncValue returns the concrete Function denoted by the source-level
+// named function obj, or nil if obj denotes an interface method.
+//
+// TODO(adonovan): check the invariant that obj.Type() matches the
+// result's Signature, both in the params/results and in the receiver.
+func (prog *Program) FuncValue(obj *types.Func) *Function {
+	obj = obj.Origin()
+	fn, _ := prog.packageLevelValue(obj).(*Function)
+	return fn
+}
+
+// ConstValue returns the IR Value denoted by the source-level named
+// constant obj.
+func (prog *Program) ConstValue(obj *types.Const) *Const {
+	// TODO(adonovan): opt: share (don't reallocate)
+	// Consts for const objects and constant ast.Exprs.
+
+	// Universal constant? {true,false,nil}
+	if obj.Parent() == types.Universe {
+		return NewConst(obj.Val(), obj.Type(), nil)
+	}
+	// Package-level named constant?
+	if v := prog.packageLevelValue(obj); v != nil {
+		return v.(*Const)
+	}
+	return NewConst(obj.Val(), obj.Type(), nil)
+}
+
+// VarValue returns the IR Value that corresponds to a specific
+// identifier denoting the source-level named variable obj.
+//
+// VarValue returns nil if a local variable was not found, perhaps
+// because its package was not built, the debug information was not
+// requested during IR construction, or the value was optimized away.
+//
+// ref is the path to an ast.Ident (e.g. from PathEnclosingInterval),
+// and that ident must resolve to obj.
+//
+// pkg is the package enclosing the reference.  (A reference to a var
+// always occurs within a function, so we need to know where to find it.)
+//
+// If the identifier is a field selector and its base expression is
+// non-addressable, then VarValue returns the value of that field.
+// For example:
+//
+//	func f() struct {x int}
+//	f().x  // VarValue(x) returns a *Field instruction of type int
+//
+// All other identifiers denote addressable locations (variables).
+// For them, VarValue may return either the variable's address or its
+// value, even when the expression is evaluated only for its value; the
+// situation is reported by isAddr, the second component of the result.
+//
+// If !isAddr, the returned value is the one associated with the
+// specific identifier.  For example,
+//
+//	var x int    // VarValue(x) returns Const 0 here
+//	x = 1        // VarValue(x) returns Const 1 here
+//
+// It is not specified whether the value or the address is returned in
+// any particular case, as it may depend upon optimizations performed
+// during IR code generation, such as registerization, constant
+// folding, avoidance of materialization of subexpressions, etc.
+func (prog *Program) VarValue(obj *types.Var, pkg *Package, ref []ast.Node) (value Value, isAddr bool) {
+	// All references to a var are local to some function, possibly init.
+	fn := EnclosingFunction(pkg, ref)
+	if fn == nil {
+		return // e.g. def of struct field; IR not built?
+	}
+
+	id := ref[0].(*ast.Ident)
+
+	// Defining ident of a parameter?
+	if id.Pos() == obj.Pos() {
+		for _, param := range fn.Params {
+			if param.Object() == obj {
+				return param, false
+			}
+		}
+	}
+
+	// Other ident?
+	for _, b := range fn.Blocks {
+		for _, instr := range b.Instrs {
+			if dr, ok := instr.(*DebugRef); ok {
+				if dr.Pos() == id.Pos() {
+					return dr.X, dr.IsAddr
+				}
+			}
+		}
+	}
+
+	// Defining ident of package-level var?
+	if v := prog.packageLevelValue(obj); v != nil {
+		return v.(*Global), true
+	}
+
+	return // e.g. debug info not requested, or var optimized away
+}

vendor/honnef.co/go/tools/go/ir/util.go

@@ -0,0 +1,162 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package ir
+
+// This file defines a number of miscellaneous utility functions.
+
+import (
+	"fmt"
+	"go/ast"
+	"go/token"
+	"go/types"
+	"io"
+	"os"
+
+	"honnef.co/go/tools/go/ast/astutil"
+	"honnef.co/go/tools/go/types/typeutil"
+
+	"golang.org/x/exp/typeparams"
+)
+
+//// AST utilities
+
+func unparen(e ast.Expr) ast.Expr { return astutil.Unparen(e) }
+
+// isBlankIdent returns true iff e is an Ident with name "_".
+// They have no associated types.Object, and thus no type.
+func isBlankIdent(e ast.Expr) bool {
+	id, ok := e.(*ast.Ident)
+	return ok && id.Name == "_"
+}
+
+//// Type utilities.  Some of these belong in go/types.
+
+// isPointer returns true for types whose underlying type is a pointer,
+// and for type parameters whose core type is a pointer.
+func isPointer(typ types.Type) bool {
+	if ctyp := typeutil.CoreType(typ); ctyp != nil {
+		_, ok := ctyp.(*types.Pointer)
+		return ok
+	}
+	_, ok := typ.Underlying().(*types.Pointer)
+	return ok
+}
+
+// deref returns a pointer's element type; otherwise it returns typ.
+func deref(typ types.Type) types.Type {
+	orig := typ
+	typ = types.Unalias(typ)
+
+	if t, ok := typ.(*types.TypeParam); ok {
+		if ctyp := typeutil.CoreType(t); ctyp != nil {
+			// This can happen, for example, with len(T) where T is a
+			// type parameter whose core type is a pointer to array.
+			typ = ctyp
+		}
+	}
+	if p, ok := typ.Underlying().(*types.Pointer); ok {
+		return p.Elem()
+	}
+	return orig
+}
+
+// recvType returns the receiver type of method obj.
+func recvType(obj *types.Func) types.Type {
+	return obj.Type().(*types.Signature).Recv().Type()
+}
+
+// logStack prints the formatted "start" message to stderr and
+// returns a closure that prints the corresponding "end" message.
+// Call using 'defer logStack(...)()' to show builder stack on panic.
+// Don't forget trailing parens!
+func logStack(format string, args ...any) func() {
+	msg := fmt.Sprintf(format, args...)
+	io.WriteString(os.Stderr, msg)
+	io.WriteString(os.Stderr, "\n")
+	return func() {
+		io.WriteString(os.Stderr, msg)
+		io.WriteString(os.Stderr, " end\n")
+	}
+}
+
+// newVar creates a 'var' for use in a types.Tuple.
+func newVar(name string, typ types.Type) *types.Var {
+	return types.NewParam(token.NoPos, nil, name, typ)
+}
+
+// anonVar creates an anonymous 'var' for use in a types.Tuple.
+func anonVar(typ types.Type) *types.Var {
+	return newVar("", typ)
+}
+
+var lenResults = types.NewTuple(anonVar(tInt))
+
+// makeLen returns the len builtin specialized to type func(T)int.
+func makeLen(T types.Type) *Builtin {
+	lenParams := types.NewTuple(anonVar(T))
+	return &Builtin{
+		name: "len",
+		sig:  types.NewSignatureType(nil, nil, nil, lenParams, lenResults, false),
+	}
+}
+
+type StackMap struct {
+	m []map[Value]Value
+}
+
+func (m *StackMap) Push() {
+	m.m = append(m.m, map[Value]Value{})
+}
+
+func (m *StackMap) Pop() {
+	m.m = m.m[:len(m.m)-1]
+}
+
+func (m *StackMap) Get(key Value) (Value, bool) {
+	for i := len(m.m) - 1; i >= 0; i-- {
+		if v, ok := m.m[i][key]; ok {
+			return v, true
+		}
+	}
+	return nil, false
+}
+
+func (m *StackMap) Set(k Value, v Value) {
+	m.m[len(m.m)-1][k] = v
+}
+
+// Unwrap recursively unwraps Sigma and Copy nodes.
+func Unwrap(v Value) Value {
+	for {
+		switch vv := v.(type) {
+		case *Sigma:
+			v = vv.X
+		case *Copy:
+			v = vv.X
+		default:
+			return v
+		}
+	}
+}
+
+func assert(x bool) {
+	if !x {
+		panic("failed assertion")
+	}
+}
+
+// BlockMap is a mapping from basic blocks (identified by their indices) to values.
+type BlockMap[T any] []T
+
+// isBasic reports whether t is a basic type.
+func isBasic(t types.Type) bool {
+	_, ok := t.(*types.Basic)
+	return ok
+}
+
+// isNonTypeParamInterface reports whether t is an interface type but not a type parameter.
+func isNonTypeParamInterface(t types.Type) bool {
+	return !typeparams.IsTypeParam(t) && types.IsInterface(t)
+}

vendor/honnef.co/go/tools/go/ir/wrappers.go

@@ -0,0 +1,342 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package ir
+
+// This file defines synthesis of Functions that delegate to declared
+// methods; they come in three kinds:
+//
+// (1) wrappers: methods that wrap declared methods, performing
+//     implicit pointer indirections and embedded field selections.
+//
+// (2) thunks: funcs that wrap declared methods.  Like wrappers,
+//     thunks perform indirections and field selections. The thunk's
+//     first parameter is used as the receiver for the method call.
+//
+// (3) bounds: funcs that wrap declared methods.  The bound's sole
+//     free variable, supplied by a closure, is used as the receiver
+//     for the method call.  No indirections or field selections are
+//     performed since they can be done before the call.
+
+import (
+	"fmt"
+	"go/types"
+)
+
+// -- wrappers -----------------------------------------------------------
+
+// makeWrapper returns a synthetic method that delegates to the
+// declared method denoted by meth.Obj(), first performing any
+// necessary pointer indirections or field selections implied by meth.
+//
+// The resulting method's receiver type is meth.Recv().
+//
+// This function is versatile but quite subtle!  Consider the
+// following axes of variation when making changes:
+//   - optional receiver indirection
+//   - optional implicit field selections
+//   - meth.Obj() may denote a concrete or an interface method
+//   - the result may be a thunk or a wrapper.
+//
+// EXCLUSIVE_LOCKS_REQUIRED(prog.methodsMu)
+func makeWrapper(prog *Program, sel *types.Selection) *Function {
+	obj := sel.Obj().(*types.Func)       // the declared function
+	sig := sel.Type().(*types.Signature) // type of this wrapper
+
+	var recv *types.Var // wrapper's receiver or thunk's params[0]
+	name := obj.Name()
+	var description Synthetic
+	var start int // first regular param
+	if sel.Kind() == types.MethodExpr {
+		name += "$thunk"
+		description = SyntheticThunk
+		recv = sig.Params().At(0)
+		start = 1
+	} else {
+		description = SyntheticWrapper
+		recv = sig.Recv()
+	}
+
+	if prog.mode&LogSource != 0 {
+		defer logStack("make %s to (%s)", description, recv.Type())()
+	}
+	fn := &Function{
+		name:         name,
+		method:       sel,
+		object:       obj,
+		Signature:    sig,
+		Synthetic:    description,
+		Prog:         prog,
+		functionBody: new(functionBody),
+	}
+	fn.initHTML(prog.PrintFunc)
+	fn.startBody()
+	fn.addSpilledParam(recv, nil)
+	createParams(fn, start)
+
+	indices := sel.Index()
+
+	var v Value = fn.Locals[0] // spilled receiver
+	if isPointer(sel.Recv()) {
+		v = emitLoad(fn, v, nil)
+
+		// For simple indirection wrappers, perform an informative nil-check:
+		// "value method (T).f called using nil *T pointer"
+		if len(indices) == 1 && !isPointer(recvType(obj)) {
+			var c Call
+			c.Call.Value = &Builtin{
+				name: "ir:wrapnilchk",
+				sig: types.NewSignatureType(nil, nil, nil,
+					types.NewTuple(anonVar(sel.Recv()), anonVar(tString), anonVar(tString)),
+					types.NewTuple(anonVar(sel.Recv())), false),
+			}
+			c.Call.Args = []Value{
+				v,
+				emitConst(fn, stringConst(deref(sel.Recv()).String(), nil)),
+				emitConst(fn, stringConst(sel.Obj().Name(), nil)),
+			}
+			c.setType(v.Type())
+			v = fn.emit(&c, nil)
+		}
+	}
+
+	// Invariant: v is a pointer, either
+	//   value of *A receiver param, or
+	// address of  A spilled receiver.
+
+	// We use pointer arithmetic (FieldAddr possibly followed by
+	// Load) in preference to value extraction (Field possibly
+	// preceded by Load).
+
+	v = emitImplicitSelections(fn, v, indices[:len(indices)-1], nil)
+
+	// Invariant: v is a pointer, either
+	//   value of implicit *C field, or
+	// address of implicit  C field.
+
+	var c Call
+	if r := recvType(obj); !types.IsInterface(r) { // concrete method
+		if !isPointer(r) {
+			v = emitLoad(fn, v, nil)
+		}
+		c.Call.Value = prog.declaredFunc(obj)
+		c.Call.Args = append(c.Call.Args, v)
+	} else {
+		c.Call.Method = obj
+		c.Call.Value = emitLoad(fn, v, nil)
+	}
+	for _, arg := range fn.Params[1:] {
+		c.Call.Args = append(c.Call.Args, arg)
+	}
+	emitTailCall(fn, &c, nil)
+	fn.finishBody()
+	return fn
+}
+
+// createParams creates parameters for wrapper method fn based on its
+// Signature.Params, which do not include the receiver.
+// start is the index of the first regular parameter to use.
+func createParams(fn *Function, start int) {
+	tparams := fn.Signature.Params()
+	for i, n := start, tparams.Len(); i < n; i++ {
+		fn.addParamVar(tparams.At(i), nil)
+	}
+}
+
+// -- bounds -----------------------------------------------------------
+
+// makeBound returns a bound method wrapper (or "bound"), a synthetic
+// function that delegates to a concrete or interface method denoted
+// by obj.  The resulting function has no receiver, but has one free
+// variable which will be used as the method's receiver in the
+// tail-call.
+//
+// Use MakeClosure with such a wrapper to construct a bound method
+// closure.  e.g.:
+//
+//	type T int          or:  type T interface { meth() }
+//	func (t T) meth()
+//	var t T
+//	f := t.meth
+//	f() // calls t.meth()
+//
+// f is a closure of a synthetic wrapper defined as if by:
+//
+//	f := func() { return t.meth() }
+//
+// Unlike makeWrapper, makeBound need perform no indirection or field
+// selections because that can be done before the closure is
+// constructed.
+//
+// EXCLUSIVE_LOCKS_ACQUIRED(meth.Prog.methodsMu)
+func makeBound(prog *Program, obj *types.Func) *Function {
+	prog.methodsMu.Lock()
+	defer prog.methodsMu.Unlock()
+	if prog.mode&LogSource != 0 {
+		defer logStack("%s", SyntheticBound)()
+	}
+	fn := &Function{
+		name:         obj.Name() + "$bound",
+		object:       obj,
+		Signature:    changeRecv(obj.Type().(*types.Signature), nil), // drop receiver
+		Synthetic:    SyntheticBound,
+		Prog:         prog,
+		functionBody: new(functionBody),
+	}
+	fn.initHTML(prog.PrintFunc)
+
+	fv := &FreeVar{name: "recv", typ: recvType(obj), parent: fn}
+	fn.FreeVars = []*FreeVar{fv}
+	fn.startBody()
+	createParams(fn, 0)
+	var c Call
+
+	if !types.IsInterface(recvType(obj)) { // concrete
+		c.Call.Value = prog.declaredFunc(obj)
+		c.Call.Args = []Value{fv}
+	} else {
+		c.Call.Value = fv
+		c.Call.Method = obj
+	}
+	for _, arg := range fn.Params {
+		c.Call.Args = append(c.Call.Args, arg)
+	}
+	emitTailCall(fn, &c, nil)
+	fn.finishBody()
+	return fn
+}
+
+// -- thunks -----------------------------------------------------------
+
+// makeThunk returns a thunk, a synthetic function that delegates to a
+// concrete or interface method denoted by sel.Obj().  The resulting
+// function has no receiver, but has an additional (first) regular
+// parameter.
+//
+// Precondition: sel.Kind() == types.MethodExpr.
+//
+//	type T int          or:  type T interface { meth() }
+//	func (t T) meth()
+//	f := T.meth
+//	var t T
+//	f(t) // calls t.meth()
+//
+// f is a synthetic wrapper defined as if by:
+//
+//	f := func(t T) { return t.meth() }
+//
+// EXCLUSIVE_LOCKS_ACQUIRED(meth.Prog.methodsMu)
+func makeThunk(prog *Program, sel *types.Selection) *Function {
+	if sel.Kind() != types.MethodExpr {
+		panic(sel)
+	}
+
+	prog.methodsMu.Lock()
+	defer prog.methodsMu.Unlock()
+
+	fn := makeWrapper(prog, sel)
+	if fn.Signature.Recv() != nil {
+		panic(fn) // unexpected receiver
+	}
+	return fn
+}
+
+func changeRecv(s *types.Signature, recv *types.Var) *types.Signature {
+	return types.NewSignatureType(recv, nil, nil, s.Params(), s.Results(), s.Variadic())
+}
+
+// makeInstance creates a wrapper function with signature sig that calls the generic function fn.
+// If targs is not nil, fn is a function and targs describes the concrete type arguments.
+// If targs is nil, fn is a method and the type arguments are derived from the receiver.
+func makeInstance(prog *Program, fn *Function, sig *types.Signature, targs *types.TypeList) *Function {
+	if sig.Recv() != nil {
+		assert(targs == nil)
+		// Methods don't have their own type parameters, but the receiver does
+		targs = types.Unalias(deref(sig.Recv().Type())).(*types.Named).TypeArgs()
+	} else {
+		assert(targs != nil)
+	}
+
+	wrapper := fn.generics.At(targs)
+	if wrapper != nil {
+		return wrapper
+	}
+
+	var name string
+	if sig.Recv() != nil {
+		name = fn.name
+	} else {
+		name = fmt.Sprintf("%s$generic#%d", fn.name, fn.generics.Len())
+	}
+	w := &Function{
+		name:         name,
+		object:       fn.object,
+		Signature:    sig,
+		Synthetic:    SyntheticGeneric,
+		Prog:         prog,
+		functionBody: new(functionBody),
+	}
+	w.initHTML(prog.PrintFunc)
+	w.startBody()
+	if sig.Recv() != nil {
+		w.addParamVar(sig.Recv(), nil)
+	}
+	createParams(w, 0)
+	var c Call
+	c.Call.Value = fn
+	tresults := fn.Signature.Results()
+	if tresults.Len() == 1 {
+		c.typ = tresults.At(0).Type()
+	} else {
+		c.typ = tresults
+	}
+
+	changeType := func(v Value, typ types.Type) Value {
+		if types.Identical(v.Type(), typ) {
+			return v
+		}
+		var c ChangeType
+		c.X = v
+		c.typ = typ
+		return w.emit(&c, nil)
+	}
+
+	for i, arg := range w.Params {
+		if sig.Recv() != nil {
+			if i == 0 {
+				c.Call.Args = append(c.Call.Args, changeType(w.Params[0], fn.Signature.Recv().Type()))
+			} else {
+				c.Call.Args = append(c.Call.Args, changeType(arg, fn.Signature.Params().At(i-1).Type()))
+			}
+		} else {
+			c.Call.Args = append(c.Call.Args, changeType(arg, fn.Signature.Params().At(i).Type()))
+		}
+	}
+	for arg := range targs.Types() {
+		c.Call.TypeArgs = append(c.Call.TypeArgs, arg)
+	}
+	results := w.emit(&c, nil)
+	var ret Return
+	switch tresults.Len() {
+	case 0:
+	case 1:
+		ret.Results = []Value{changeType(results, sig.Results().At(0).Type())}
+	default:
+		for i := 0; i < tresults.Len(); i++ {
+			v := emitExtract(w, results, i, nil)
+			ret.Results = append(ret.Results, changeType(v, sig.Results().At(i).Type()))
+		}
+	}
+
+	w.Exit = w.newBasicBlock("exit")
+	emitJump(w, w.Exit, nil)
+	w.currentBlock = w.Exit
+	w.emit(&ret, nil)
+	w.currentBlock = nil
+
+	w.finishBody()
+
+	fn.generics.Set(targs, w)
+	return w
+}

vendor/honnef.co/go/tools/go/ir/write.go

@@ -0,0 +1,5 @@
+package ir
+
+func NewJump(parent *BasicBlock) *Jump {
+	return &Jump{anInstruction{block: parent}}
+}

vendor/honnef.co/go/tools/go/loader/hash.go

@@ -0,0 +1,98 @@
+package loader
+
+import (
+	"fmt"
+	"runtime"
+	"sort"
+	"strings"
+
+	"honnef.co/go/tools/go/buildid"
+	"honnef.co/go/tools/lintcmd/cache"
+)
+
+// computeHash computes a package's hash. The hash is based on all Go
+// files that make up the package, as well as the hashes of imported
+// packages.
+func computeHash(c *cache.Cache, pkg *PackageSpec) (cache.ActionID, error) {
+	key := c.NewHash("package " + pkg.PkgPath)
+	fmt.Fprintf(key, "goos %s goarch %s\n", runtime.GOOS, runtime.GOARCH)
+	fmt.Fprintf(key, "import %q\n", pkg.PkgPath)
+
+	// Compute the hashes of all files making up the package. As an
+	// optimization, we use the build ID that Go already computed for us,
+	// because it is virtually identical to hashing all CompiledGoFiles. It is
+	// also sensitive to the Go version declared in go.mod.
+	success := false
+	if pkg.ExportFile != "" {
+		id, err := getBuildid(pkg.ExportFile)
+		if err == nil {
+			if idx := strings.IndexRune(id, '/'); idx > -1 {
+				fmt.Fprintf(key, "files %s\n", id[:idx])
+				success = true
+			}
+		}
+	}
+	if !success {
+		for _, f := range pkg.CompiledGoFiles {
+			h, err := cache.FileHash(f)
+			if err != nil {
+				return cache.ActionID{}, err
+			}
+			fmt.Fprintf(key, "file %s %x\n", f, h)
+		}
+		if pkg.Module != nil && pkg.Module.GoMod != "" {
+			// The go.mod file specifies the language version, which affects how
+			// packages are analyzed.
+			h, err := cache.FileHash(pkg.Module.GoMod)
+			if err != nil {
+				// TODO(dh): this doesn't work for tests because the go.mod file doesn't
+				// exist on disk and is instead provided via an overlay. However, we're
+				// unlikely to get here in the first place, as reading the build ID from
+				// the export file is likely to succeed.
+				return cache.ActionID{}, fmt.Errorf("couldn't hash go.mod: %w", err)
+			} else {
+				fmt.Fprintf(key, "file %s %x\n", pkg.Module.GoMod, h)
+			}
+		}
+	}
+
+	imps := make([]*PackageSpec, 0, len(pkg.Imports))
+	for _, v := range pkg.Imports {
+		imps = append(imps, v)
+	}
+	sort.Slice(imps, func(i, j int) bool {
+		return imps[i].PkgPath < imps[j].PkgPath
+	})
+
+	for _, dep := range imps {
+		if dep.ExportFile == "" {
+			fmt.Fprintf(key, "import %s \n", dep.PkgPath)
+		} else {
+			id, err := getBuildid(dep.ExportFile)
+			if err == nil {
+				fmt.Fprintf(key, "import %s %s\n", dep.PkgPath, id)
+			} else {
+				fh, err := cache.FileHash(dep.ExportFile)
+				if err != nil {
+					return cache.ActionID{}, err
+				}
+				fmt.Fprintf(key, "import %s %x\n", dep.PkgPath, fh)
+			}
+		}
+	}
+	return key.Sum(), nil
+}
+
+var buildidCache = map[string]string{}
+
+func getBuildid(f string) (string, error) {
+	if h, ok := buildidCache[f]; ok {
+		return h, nil
+	}
+	h, err := buildid.ReadFile(f)
+	if err != nil {
+		return "", err
+	}
+	buildidCache[f] = h
+	return h, nil
+}

vendor/honnef.co/go/tools/go/loader/loader.go

@@ -0,0 +1,379 @@
+package loader
+
+import (
+	"errors"
+	"fmt"
+	"go/ast"
+	"go/build"
+	"go/parser"
+	"go/scanner"
+	"go/token"
+	"go/types"
+	"os"
+	"time"
+
+	"honnef.co/go/tools/config"
+	"honnef.co/go/tools/lintcmd/cache"
+
+	"golang.org/x/tools/go/gcexportdata"
+	"golang.org/x/tools/go/packages"
+)
+
+const MaxFileSize = 50 * 1024 * 1024 // 50 MB
+
+var errMaxFileSize = errors.New("file exceeds max file size")
+
+type PackageSpec struct {
+	ID      string
+	Name    string
+	PkgPath string
+	// Errors that occurred while building the import graph. These will
+	// primarily be parse errors or failure to resolve imports, but
+	// may also be other errors.
+	Errors          []packages.Error
+	GoFiles         []string
+	CompiledGoFiles []string
+	OtherFiles      []string
+	ExportFile      string
+	Imports         map[string]*PackageSpec
+	TypesSizes      types.Sizes
+	Hash            cache.ActionID
+	Module          *packages.Module
+
+	Config config.Config
+}
+
+func (spec *PackageSpec) String() string {
+	return spec.ID
+}
+
+type Package struct {
+	*PackageSpec
+
+	// Errors that occurred while loading the package. These will
+	// primarily be parse or type errors, but may also be lower-level
+	// failures such as file-system ones.
+	Errors    []packages.Error
+	Types     *types.Package
+	Fset      *token.FileSet
+	Syntax    []*ast.File
+	TypesInfo *types.Info
+}
+
+// Graph resolves patterns and returns packages with all the
+// information required to later load type information, and optionally
+// syntax trees.
+//
+// The provided config can set any setting with the exception of Mode.
+func Graph(c *cache.Cache, cfg *packages.Config, patterns ...string) ([]*PackageSpec, error) {
+	var dcfg packages.Config
+	if cfg != nil {
+		dcfg = *cfg
+	}
+	dcfg.Mode = packages.NeedName |
+		packages.NeedImports |
+		packages.NeedDeps |
+		packages.NeedExportFile |
+		packages.NeedFiles |
+		packages.NeedCompiledGoFiles |
+		packages.NeedTypesSizes |
+		packages.NeedModule
+	pkgs, err := packages.Load(&dcfg, patterns...)
+	if err != nil {
+		return nil, err
+	}
+
+	m := map[*packages.Package]*PackageSpec{}
+	packages.Visit(pkgs, nil, func(pkg *packages.Package) {
+		spec := &PackageSpec{
+			ID:              pkg.ID,
+			Name:            pkg.Name,
+			PkgPath:         pkg.PkgPath,
+			Errors:          pkg.Errors,
+			GoFiles:         pkg.GoFiles,
+			CompiledGoFiles: pkg.CompiledGoFiles,
+			OtherFiles:      pkg.OtherFiles,
+			ExportFile:      pkg.ExportFile,
+			Imports:         map[string]*PackageSpec{},
+			TypesSizes:      pkg.TypesSizes,
+			Module:          pkg.Module,
+		}
+		for path, imp := range pkg.Imports {
+			spec.Imports[path] = m[imp]
+		}
+		if cdir := config.Dir(pkg.GoFiles); cdir != "" {
+			cfg, err := config.Load(cdir)
+			if err != nil {
+				spec.Errors = append(spec.Errors, convertError(err)...)
+			}
+			spec.Config = cfg
+		} else {
+			spec.Config = config.DefaultConfig
+		}
+		spec.Hash, err = computeHash(c, spec)
+		if err != nil {
+			spec.Errors = append(spec.Errors, convertError(err)...)
+		}
+		m[pkg] = spec
+	})
+	out := make([]*PackageSpec, 0, len(pkgs))
+	for _, pkg := range pkgs {
+		if len(pkg.CompiledGoFiles) == 0 && len(pkg.Errors) == 0 && pkg.PkgPath != "unsafe" {
+			// If a package consists only of test files, then
+			// go/packages incorrectly(?) returns an empty package for
+			// the non-test variant. Get rid of those packages. See
+			// #646.
+			//
+			// Do not, however, skip packages that have errors. Those,
+			// too, may have no files, but we want to print the
+			// errors.
+			continue
+		}
+		out = append(out, m[pkg])
+	}
+
+	return out, nil
+}
+
+type program struct {
+	fset     *token.FileSet
+	packages map[string]*types.Package
+	options  *Options
+}
+
+type Stats struct {
+	Source time.Duration
+	Export map[*PackageSpec]time.Duration
+}
+
+type Options struct {
+	// The Go language version to use for the type checker. If unset, or if set
+	// to "module", it will default to the Go version specified in the module;
+	// if there is no module, it will default to the version of Go the
+	// executable was built with.
+	GoVersion string
+}
+
+// Load loads the package described in spec. Imports will be loaded
+// from export data, while the package itself will be loaded from
+// source.
+//
+// An error will only be returned for system failures, such as failure
+// to read export data from disk. Syntax and type errors, among
+// others, will only populate the returned package's Errors field.
+func Load(spec *PackageSpec, opts *Options) (*Package, Stats, error) {
+	if opts == nil {
+		opts = &Options{}
+	}
+	if opts.GoVersion == "" {
+		opts.GoVersion = "module"
+	}
+	prog := &program{
+		fset:     token.NewFileSet(),
+		packages: map[string]*types.Package{},
+		options:  opts,
+	}
+
+	stats := Stats{
+		Export: map[*PackageSpec]time.Duration{},
+	}
+	for _, imp := range spec.Imports {
+		if imp.PkgPath == "unsafe" {
+			continue
+		}
+		t := time.Now()
+		_, err := prog.loadFromExport(imp)
+		stats.Export[imp] = time.Since(t)
+		if err != nil {
+			return nil, stats, err
+		}
+	}
+	t := time.Now()
+	pkg, err := prog.loadFromSource(spec)
+	if err == errMaxFileSize {
+		pkg, err = prog.loadFromExport(spec)
+	}
+	stats.Source = time.Since(t)
+	return pkg, stats, err
+}
+
+// loadFromExport loads a package from export data.
+func (prog *program) loadFromExport(spec *PackageSpec) (*Package, error) {
+	// log.Printf("Loading package %s from export", spec)
+	if spec.ExportFile == "" {
+		return nil, fmt.Errorf("no export data for %q", spec.ID)
+	}
+	f, err := os.Open(spec.ExportFile)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+
+	r, err := gcexportdata.NewReader(f)
+	if err != nil {
+		return nil, err
+	}
+	tpkg, err := gcexportdata.Read(r, prog.fset, prog.packages, spec.PkgPath)
+	if err != nil {
+		return nil, err
+	}
+	pkg := &Package{
+		PackageSpec: spec,
+		Types:       tpkg,
+		Fset:        prog.fset,
+	}
+	// runtime.SetFinalizer(pkg, func(pkg *Package) {
+	// 	log.Println("Unloading package", pkg.PkgPath)
+	// })
+	return pkg, nil
+}
+
+// loadFromSource loads a package from source. All of its dependencies
+// must have been loaded already.
+func (prog *program) loadFromSource(spec *PackageSpec) (*Package, error) {
+	if len(spec.Errors) > 0 {
+		panic("LoadFromSource called on package with errors")
+	}
+
+	pkg := &Package{
+		PackageSpec: spec,
+		Types:       types.NewPackage(spec.PkgPath, spec.Name),
+		Syntax:      make([]*ast.File, len(spec.CompiledGoFiles)),
+		Fset:        prog.fset,
+		TypesInfo: &types.Info{
+			Types:        make(map[ast.Expr]types.TypeAndValue),
+			Defs:         make(map[*ast.Ident]types.Object),
+			Uses:         make(map[*ast.Ident]types.Object),
+			Implicits:    make(map[ast.Node]types.Object),
+			Scopes:       make(map[ast.Node]*types.Scope),
+			Selections:   make(map[*ast.SelectorExpr]*types.Selection),
+			Instances:    make(map[*ast.Ident]types.Instance),
+			FileVersions: make(map[*ast.File]string),
+		},
+	}
+	// runtime.SetFinalizer(pkg, func(pkg *Package) {
+	// 	log.Println("Unloading package", pkg.PkgPath)
+	// })
+
+	// OPT(dh): many packages have few files, much fewer than there
+	// are CPU cores. Additionally, parsing each individual file is
+	// very fast. A naive parallel implementation of this loop won't
+	// be faster, and tends to be slower due to extra scheduling,
+	// bookkeeping and potentially false sharing of cache lines.
+	for i, file := range spec.CompiledGoFiles {
+		f, err := os.Open(file)
+		if err != nil {
+			return nil, err
+		}
+		fi, err := f.Stat()
+		if err != nil {
+			return nil, err
+		}
+		if fi.Size() >= MaxFileSize {
+			return nil, errMaxFileSize
+		}
+		af, err := parser.ParseFile(prog.fset, file, f, parser.ParseComments|parser.SkipObjectResolution)
+		f.Close()
+		if err != nil {
+			pkg.Errors = append(pkg.Errors, convertError(err)...)
+			return pkg, nil
+		}
+		pkg.Syntax[i] = af
+	}
+	importer := func(path string) (*types.Package, error) {
+		if path == "unsafe" {
+			return types.Unsafe, nil
+		}
+		if path == "C" {
+			// go/packages doesn't tell us that cgo preprocessing
+			// failed. When we subsequently try to parse the package,
+			// we'll encounter the raw C import.
+			return nil, errors.New("cgo preprocessing failed")
+		}
+		ispecpkg := spec.Imports[path]
+		if ispecpkg == nil {
+			return nil, fmt.Errorf("trying to import %q in the context of %q returned nil PackageSpec", path, spec)
+		}
+		ipkg := prog.packages[ispecpkg.PkgPath]
+		if ipkg == nil {
+			return nil, fmt.Errorf("trying to import %q (%q) in the context of %q returned nil PackageSpec", ispecpkg.PkgPath, path, spec)
+		}
+		return ipkg, nil
+	}
+	tc := &types.Config{
+		Importer: importerFunc(importer),
+		Error: func(err error) {
+			pkg.Errors = append(pkg.Errors, convertError(err)...)
+		},
+	}
+	if prog.options.GoVersion == "module" {
+		if spec.Module != nil && spec.Module.GoVersion != "" {
+			tc.GoVersion = "go" + spec.Module.GoVersion
+		} else {
+			tags := build.Default.ReleaseTags
+			tc.GoVersion = tags[len(tags)-1]
+		}
+	} else {
+		tc.GoVersion = prog.options.GoVersion
+	}
+	// Note that the type-checker can return a non-nil error even though the Go
+	// compiler has already successfully built this package (which is an
+	// invariant of getting to this point), for example because of the Go
+	// version passed to the type checker.
+	err := types.NewChecker(tc, pkg.Fset, pkg.Types, pkg.TypesInfo).Files(pkg.Syntax)
+	return pkg, err
+}
+
+func convertError(err error) []packages.Error {
+	var errs []packages.Error
+	// taken from go/packages
+	switch err := err.(type) {
+	case packages.Error:
+		// from driver
+		errs = append(errs, err)
+
+	case *os.PathError:
+		// from parser
+		errs = append(errs, packages.Error{
+			Pos:  err.Path + ":1",
+			Msg:  err.Err.Error(),
+			Kind: packages.ParseError,
+		})
+
+	case scanner.ErrorList:
+		// from parser
+		for _, err := range err {
+			errs = append(errs, packages.Error{
+				Pos:  err.Pos.String(),
+				Msg:  err.Msg,
+				Kind: packages.ParseError,
+			})
+		}
+
+	case types.Error:
+		// from type checker
+		errs = append(errs, packages.Error{
+			Pos:  err.Fset.Position(err.Pos).String(),
+			Msg:  err.Msg,
+			Kind: packages.TypeError,
+		})
+
+	case config.ParseError:
+		errs = append(errs, packages.Error{
+			Pos:  fmt.Sprintf("%s:%d:%d", err.Filename, err.Position.Line, err.Position.Col),
+			Msg:  fmt.Sprintf("%s (last key parsed: %q)", err.Message, err.LastKey),
+			Kind: packages.ParseError,
+		})
+	default:
+		errs = append(errs, packages.Error{
+			Pos:  "-",
+			Msg:  err.Error(),
+			Kind: packages.UnknownError,
+		})
+	}
+	return errs
+}
+
+type importerFunc func(path string) (*types.Package, error)
+
+func (f importerFunc) Import(path string) (*types.Package, error) { return f(path) }

vendor/honnef.co/go/tools/go/types/typeutil/ext.go

@@ -0,0 +1,27 @@
+package typeutil
+
+import (
+	"fmt"
+	"go/types"
+)
+
+type Iterator struct {
+	elem types.Type
+}
+
+func (t *Iterator) Underlying() types.Type { return t }
+func (t *Iterator) String() string         { return fmt.Sprintf("iterator(%s)", t.elem) }
+func (t *Iterator) Elem() types.Type       { return t.elem }
+
+func NewIterator(elem types.Type) *Iterator {
+	return &Iterator{elem: elem}
+}
+
+type DeferStack struct{}
+
+func (t *DeferStack) Underlying() types.Type { return t }
+func (t *DeferStack) String() string         { return "deferStack" }
+
+func NewDeferStack() *DeferStack {
+	return &DeferStack{}
+}

vendor/honnef.co/go/tools/go/types/typeutil/typeparams.go

@@ -0,0 +1,106 @@
+package typeutil
+
+import (
+	"errors"
+	"go/types"
+	"slices"
+
+	"golang.org/x/exp/typeparams"
+)
+
+type TypeSet struct {
+	Terms []*types.Term
+	empty bool
+}
+
+func NewTypeSet(typ types.Type) TypeSet {
+	terms, err := typeparams.NormalTerms(typ)
+	if err != nil {
+		if errors.Is(err, typeparams.ErrEmptyTypeSet) {
+			return TypeSet{nil, true}
+		} else {
+			// We couldn't determine the type set. Assume it's all types.
+			return TypeSet{nil, false}
+		}
+	}
+	return TypeSet{terms, false}
+}
+
+// CoreType returns the type set's core type, or nil if it has none.
+// The function only looks at type terms and may thus return core types for some empty type sets, such as
+// 'interface { map[int]string; foo() }'
+func (ts TypeSet) CoreType() types.Type {
+	if len(ts.Terms) == 0 {
+		// Either the type set is empty, or it isn't constrained. Either way it doesn't have a core type.
+		return nil
+	}
+	typ := ts.Terms[0].Type().Underlying()
+	for _, term := range ts.Terms[1:] {
+		ut := term.Type().Underlying()
+		if types.Identical(typ, ut) {
+			continue
+		}
+
+		ch1, ok := typ.(*types.Chan)
+		if !ok {
+			return nil
+		}
+		ch2, ok := ut.(*types.Chan)
+		if !ok {
+			return nil
+		}
+		if ch1.Dir() == types.SendRecv {
+			// typ is currently a bidirectional channel. The term's type is either also bidirectional, or
+			// unidirectional. Use the term's type.
+			typ = ut
+		} else if ch2.Dir() == types.SendRecv {
+			// typ is currently a unidirectional channel and the term's type is bidirectional, which means it has no
+			// effect.
+			continue
+		} else if ch1.Dir() != ch2.Dir() {
+			// typ is not bidirectional and typ and term disagree about the direction
+			return nil
+		}
+	}
+	return typ
+}
+
+// CoreType is a wrapper for NewTypeSet(typ).CoreType()
+func CoreType(typ types.Type) types.Type {
+	return NewTypeSet(typ).CoreType()
+}
+
+// All calls fn for each term in the type set and reports whether all invocations returned true.
+// If the type set is empty or unconstrained, All immediately returns false.
+func (ts TypeSet) All(fn func(*types.Term) bool) bool {
+	if len(ts.Terms) == 0 {
+		return false
+	}
+	for _, term := range ts.Terms {
+		if !fn(term) {
+			return false
+		}
+	}
+	return true
+}
+
+// Any calls fn for each term in the type set and reports whether any invocation returned true.
+// It stops after the first call that returned true.
+func (ts TypeSet) Any(fn func(*types.Term) bool) bool {
+	return slices.ContainsFunc(ts.Terms, fn)
+}
+
+// All is a wrapper for NewTypeSet(typ).All(fn).
+func All(typ types.Type, fn func(*types.Term) bool) bool {
+	return NewTypeSet(typ).All(fn)
+}
+
+// Any is a wrapper for NewTypeSet(typ).Any(fn).
+func Any(typ types.Type, fn func(*types.Term) bool) bool {
+	return NewTypeSet(typ).Any(fn)
+}
+
+func IsSlice(term *types.Term) bool {
+	_, ok := term.Type().Underlying().(*types.Slice)
+	return ok
+}

vendor/honnef.co/go/tools/go/types/typeutil/upstream.go

@@ -0,0 +1,52 @@
+package typeutil
+
+import (
+	"go/ast"
+	"go/types"
+	_ "unsafe"
+
+	"golang.org/x/tools/go/types/typeutil"
+)
+
+type MethodSetCache = typeutil.MethodSetCache
+type Hasher = typeutil.Hasher
+
+func Callee(info *types.Info, call *ast.CallExpr) types.Object {
+	return typeutil.Callee(info, call)
+}
+
+func IntuitiveMethodSet(T types.Type, msets *MethodSetCache) []*types.Selection {
+	return typeutil.IntuitiveMethodSet(T, msets)
+}
+
+func MakeHasher() Hasher {
+	return typeutil.MakeHasher()
+}
+
+type Map[V any] struct {
+	m typeutil.Map
+}
+
+func (m *Map[V]) Delete(key types.Type) bool { return m.m.Delete(key) }
+func (m *Map[V]) At(key types.Type) (V, bool) {
+	v := m.m.At(key)
+	if v == nil {
+		var zero V
+		return zero, false
+	} else {
+		return v.(V), true
+	}
+}
+func (m *Map[V]) Set(key types.Type, value V) { m.m.Set(key, value) }
+func (m *Map[V]) Len() int                    { return m.m.Len() }
+func (m *Map[V]) Iterate(f func(key types.Type, value V)) {
+	ff := func(key types.Type, value any) {
+		f(key, value.(V))
+	}
+	m.m.Iterate(ff)
+
+}
+func (m *Map[V]) Keys() []types.Type          { return m.m.Keys() }
+func (m *Map[V]) String() string              { return m.m.String() }
+func (m *Map[V]) KeysString() string          { return m.m.KeysString() }
+func (m *Map[V]) SetHasher(h typeutil.Hasher) { m.m.SetHasher(h) }

vendor/honnef.co/go/tools/go/types/typeutil/util.go

@@ -0,0 +1,211 @@
+package typeutil
+
+import (
+	"bytes"
+	"go/types"
+	"strings"
+	"sync"
+
+	"golang.org/x/exp/typeparams"
+)
+
+var bufferPool = &sync.Pool{
+	New: func() any {
+		buf := bytes.NewBuffer(nil)
+		buf.Grow(64)
+		return buf
+	},
+}
+
+func FuncName(f *types.Func) string {
+	// We don't care about aliases in this function because we use FuncName to check calls
+	// to known methods, and method receivers are determined by the method declaration,
+	// not the call. Thus, even if a user does 'type Alias = *sync.Mutex' and calls
+	// Alias.Lock, we'll still see it as (*sync.Mutex).Lock.
+
+	buf := bufferPool.Get().(*bytes.Buffer)
+	buf.Reset()
+	if f.Type() != nil {
+		sig := f.Type().(*types.Signature)
+		if recv := sig.Recv(); recv != nil {
+			buf.WriteByte('(')
+			if _, ok := recv.Type().(*types.Interface); ok {
+				// gcimporter creates abstract methods of
+				// named interfaces using the interface type
+				// (not the named type) as the receiver.
+				// Don't print it in full.
+				buf.WriteString("interface")
+			} else {
+				types.WriteType(buf, recv.Type(), nil)
+			}
+			buf.WriteByte(')')
+			buf.WriteByte('.')
+		} else if f.Pkg() != nil {
+			writePackage(buf, f.Pkg())
+		}
+	}
+	buf.WriteString(f.Name())
+	s := buf.String()
+	bufferPool.Put(buf)
+	return s
+}
+
+func writePackage(buf *bytes.Buffer, pkg *types.Package) {
+	if pkg == nil {
+		return
+	}
+	s := pkg.Path()
+	if s != "" {
+		buf.WriteString(s)
+		buf.WriteByte('.')
+	}
+}
+
+// Dereference returns a pointer's element type; otherwise it returns
+// T.
+func Dereference(T types.Type) types.Type {
+	if p, ok := T.Underlying().(*types.Pointer); ok {
+		return p.Elem()
+	}
+	return T
+}
+
+// DereferenceR returns a pointer's element type; otherwise it returns
+// T. If the element type is itself a pointer, DereferenceR will be
+// applied recursively.
+func DereferenceR(T types.Type) types.Type {
+	if p, ok := T.Underlying().(*types.Pointer); ok {
+		return DereferenceR(p.Elem())
+	}
+	return T
+}
+
+func IsObject(obj types.Object, name string) bool {
+	var path string
+	if pkg := obj.Pkg(); pkg != nil {
+		path = pkg.Path() + "."
+	}
+	return path+obj.Name() == name
+}
+
+// IsTypeName reports whether obj represents the qualified name. If obj is a type alias,
+// IsTypeName checks both the alias and the aliased type, if the aliased type has a type
+// name.
+func IsTypeName(obj *types.TypeName, name string) bool {
+	var qf string
+	if idx := strings.LastIndex(name, "."); idx != -1 {
+		qf = name[:idx]
+		name = name[idx+1:]
+	}
+	if obj.Name() == name &&
+		((qf == "" && obj.Pkg() == nil) || (obj.Pkg() != nil && obj.Pkg().Path() == qf)) {
+		return true
+	}
+
+	if !obj.IsAlias() {
+		return false
+	}
+
+	// FIXME(dh): we should peel away one layer of alias at a time; this is blocked on
+	// github.com/golang/go/issues/66559
+	if typ, ok := types.Unalias(obj.Type()).(interface{ Obj() *types.TypeName }); ok {
+		return IsTypeName(typ.Obj(), name)
+	}
+
+	return false
+}
+
+func IsPointerToTypeWithName(typ types.Type, name string) bool {
+	ptr, ok := types.Unalias(typ).(*types.Pointer)
+	if !ok {
+		return false
+	}
+	return IsTypeWithName(ptr.Elem(), name)
+}
+
+// IsTypeWithName reports whether typ represents a type with the qualified name, If typ is
+// a type alias, IsTypeWithName checks both the alias and the aliased type. The following
+// types can have names: Basic, Named, Alias.
+func IsTypeWithName(typ types.Type, name string) bool {
+	switch typ := typ.(type) {
+	case *types.Basic:
+		return typ.Name() == name
+	case *types.Named:
+		return IsTypeName(typ.Obj(), name)
+	case *types.Alias:
+		// FIXME(dh): we should peel away one layer of alias at a time; this is blocked on
+		// github.com/golang/go/issues/66559
+
+		// IsTypeName already handles aliases to other aliases or named types; our
+		// fallback is required for aliases to basic types.
+		return IsTypeName(typ.Obj(), name) || IsTypeWithName(types.Unalias(typ), name)
+	default:
+		return false
+	}
+}
+
+// IsPointerLike returns true if type T is like a pointer. This returns true for all nillable types,
+// unsafe.Pointer, and type sets where at least one term is pointer-like.
+func IsPointerLike(T types.Type) bool {
+	switch T := T.Underlying().(type) {
+	case *types.Interface:
+		if T.IsMethodSet() {
+			return true
+		} else {
+			terms, err := typeparams.NormalTerms(T)
+			if err != nil {
+				return false
+			}
+			for _, term := range terms {
+				if IsPointerLike(term.Type()) {
+					return true
+				}
+			}
+			return false
+		}
+	case *types.Chan, *types.Map, *types.Signature, *types.Pointer, *types.Slice:
+		return true
+	case *types.Basic:
+		return T.Kind() == types.UnsafePointer
+	}
+	return false
+}
+
+type Field struct {
+	Var  *types.Var
+	Tag  string
+	Path []int
+}
+
+// FlattenFields recursively flattens T and embedded structs,
+// returning a list of fields. If multiple fields with the same name
+// exist, all will be returned.
+func FlattenFields(T *types.Struct) []Field {
+	return flattenFields(T, nil, nil)
+}
+
+func flattenFields(T *types.Struct, path []int, seen map[types.Type]bool) []Field {
+	if seen == nil {
+		seen = map[types.Type]bool{}
+	}
+	if seen[T] {
+		return nil
+	}
+	seen[T] = true
+	var out []Field
+	for i := 0; i < T.NumFields(); i++ {
+		field := T.Field(i)
+		tag := T.Tag(i)
+		np := append(path[:len(path):len(path)], i)
+		if field.Anonymous() {
+			if s, ok := Dereference(field.Type()).Underlying().(*types.Struct); ok {
+				out = append(out, flattenFields(s, np, seen)...)
+			} else {
+				out = append(out, Field{field, tag, np})
+			}
+		} else {
+			out = append(out, Field{field, tag, np})
+		}
+	}
+	return out
+}

vendor/honnef.co/go/tools/internal/analysisinternal/typeindex/typeindex.go

@@ -0,0 +1,33 @@
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package typeindex defines an analyzer that provides a
+// [golang.org/x/tools/internal/typesinternal/typeindex.Index].
+//
+// Like [golang.org/x/tools/go/analysis/passes/inspect], it is
+// intended to be used as a helper by other analyzers; it reports no
+// diagnostics of its own.
+package typeindex
+
+import (
+	"reflect"
+
+	"golang.org/x/tools/go/analysis"
+	"golang.org/x/tools/go/analysis/passes/inspect"
+	"golang.org/x/tools/go/ast/inspector"
+	"honnef.co/go/tools/internal/typesinternal/typeindex"
+)
+
+var Analyzer = &analysis.Analyzer{
+	Name: "typeindex",
+	Doc:  "indexes of type information for later passes",
+	URL:  "https://pkg.go.dev/golang.org/x/tools/internal/analysisinternal/typeindex",
+	Run: func(pass *analysis.Pass) (any, error) {
+		inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+		return typeindex.New(inspect, pass.Pkg, pass.TypesInfo), nil
+	},
+	RunDespiteErrors: true,
+	Requires:         []*analysis.Analyzer{inspect.Analyzer},
+	ResultType:       reflect.TypeFor[*typeindex.Index](),
+}

vendor/honnef.co/go/tools/internal/passes/buildir/buildir.go

@@ -0,0 +1,101 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package buildir defines an Analyzer that constructs the IR
+// of an error-free package and returns the set of all
+// functions within it. It does not report any diagnostics itself but
+// may be used as an input to other analyzers.
+//
+// THIS INTERFACE IS EXPERIMENTAL AND MAY BE SUBJECT TO INCOMPATIBLE CHANGE.
+package buildir
+
+import (
+	"go/types"
+	"reflect"
+
+	"honnef.co/go/tools/go/ir"
+
+	"golang.org/x/tools/go/analysis"
+	"golang.org/x/tools/go/analysis/passes/ctrlflow"
+)
+
+var Debug = struct {
+	Mode ir.BuilderMode
+}{}
+
+var Analyzer = &analysis.Analyzer{
+	Name:       "buildir",
+	Doc:        "build IR for later passes",
+	Run:        run,
+	ResultType: reflect.TypeFor[*IR](),
+	Requires:   []*analysis.Analyzer{ctrlflow.Analyzer},
+}
+
+// IR provides intermediate representation for all the
+// source functions in the current package.
+type IR struct {
+	Pkg      *ir.Package
+	SrcFuncs []*ir.Function
+}
+
+func run(pass *analysis.Pass) (any, error) {
+	cfgs := pass.ResultOf[ctrlflow.Analyzer].(*ctrlflow.CFGs)
+
+	// Plundered from ssautil.BuildPackage.
+
+	// We must create a new Program for each Package because the
+	// analysis API provides no place to hang a Program shared by
+	// all Packages. Consequently, IR Packages and Functions do not
+	// have a canonical representation across an analysis session of
+	// multiple packages. This is unlikely to be a problem in
+	// practice because the analysis API essentially forces all
+	// packages to be analysed independently, so any given call to
+	// Analysis.Run on a package will see only IR objects belonging
+	// to a single Program.
+
+	mode := ir.GlobalDebug
+	if Debug.Mode != 0 {
+		mode = Debug.Mode
+	}
+
+	prog := ir.NewProgram(pass.Fset, mode)
+
+	prog.SetNoReturn(cfgs.NoReturn)
+
+	// Create IR packages for all imports.
+	// Order is not significant.
+	created := make(map[*types.Package]bool)
+	var createAll func(pkgs []*types.Package)
+	createAll = func(pkgs []*types.Package) {
+		for _, p := range pkgs {
+			if !created[p] {
+				created[p] = true
+				prog.CreatePackage(p, nil, nil, true)
+				createAll(p.Imports())
+			}
+		}
+	}
+	createAll(pass.Pkg.Imports())
+
+	// Create and build the primary package.
+	irpkg := prog.CreatePackage(pass.Pkg, pass.Files, pass.TypesInfo, false)
+	irpkg.Build()
+
+	// Compute list of source functions, including literals,
+	// in source order.
+	var addAnons func(f *ir.Function)
+	funcs := make([]*ir.Function, len(irpkg.Functions))
+	copy(funcs, irpkg.Functions)
+	addAnons = func(f *ir.Function) {
+		for _, anon := range f.AnonFuncs {
+			funcs = append(funcs, anon)
+			addAnons(anon)
+		}
+	}
+	for _, fn := range irpkg.Functions {
+		addAnons(fn)
+	}
+
+	return &IR{Pkg: irpkg, SrcFuncs: funcs}, nil
+}

vendor/honnef.co/go/tools/internal/renameio/UPSTREAM

@@ -0,0 +1,2 @@
+This package is a copy of cmd/go/internal/renameio.
+The upstream package no longer exists, as the Go project replaced all of its uses with the lockedfile package.

vendor/honnef.co/go/tools/internal/renameio/renameio.go

@@ -0,0 +1,93 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package renameio writes files atomically by renaming temporary files.
+package renameio
+
+import (
+	"bytes"
+	"io"
+	"math/rand"
+	"os"
+	"path/filepath"
+	"strconv"
+
+	"honnef.co/go/tools/internal/robustio"
+)
+
+const patternSuffix = ".tmp"
+
+// Pattern returns a glob pattern that matches the unrenamed temporary files
+// created when writing to filename.
+func Pattern(filename string) string {
+	return filepath.Join(filepath.Dir(filename), filepath.Base(filename)+patternSuffix)
+}
+
+// WriteFile is like ioutil.WriteFile, but first writes data to an arbitrary
+// file in the same directory as filename, then renames it atomically to the
+// final name.
+//
+// That ensures that the final location, if it exists, is always a complete file.
+func WriteFile(filename string, data []byte, perm os.FileMode) (err error) {
+	return WriteToFile(filename, bytes.NewReader(data), perm)
+}
+
+// WriteToFile is a variant of WriteFile that accepts the data as an io.Reader
+// instead of a slice.
+func WriteToFile(filename string, data io.Reader, perm os.FileMode) (err error) {
+	f, err := tempFile(filepath.Dir(filename), filepath.Base(filename), perm)
+	if err != nil {
+		return err
+	}
+	defer func() {
+		// Only call os.Remove on f.Name() if we failed to rename it: otherwise,
+		// some other process may have created a new file with the same name after
+		// that.
+		if err != nil {
+			f.Close()
+			os.Remove(f.Name())
+		}
+	}()
+
+	if _, err := io.Copy(f, data); err != nil {
+		return err
+	}
+	// Sync the file before renaming it: otherwise, after a crash the reader may
+	// observe a 0-length file instead of the actual contents.
+	// See https://golang.org/issue/22397#issuecomment-380831736.
+	if err := f.Sync(); err != nil {
+		return err
+	}
+	if err := f.Close(); err != nil {
+		return err
+	}
+
+	return robustio.Rename(f.Name(), filename)
+}
+
+// ReadFile is like ioutil.ReadFile, but on Windows retries spurious errors that
+// may occur if the file is concurrently replaced.
+//
+// Errors are classified heuristically and retries are bounded, so even this
+// function may occasionally return a spurious error on Windows.
+// If so, the error will likely wrap one of:
+//   - syscall.ERROR_ACCESS_DENIED
+//   - syscall.ERROR_FILE_NOT_FOUND
+//   - internal/syscall/windows.ERROR_SHARING_VIOLATION
+func ReadFile(filename string) ([]byte, error) {
+	return robustio.ReadFile(filename)
+}
+
+// tempFile creates a new temporary file with given permission bits.
+func tempFile(dir, prefix string, perm os.FileMode) (f *os.File, err error) {
+	for range 10000 {
+		name := filepath.Join(dir, prefix+strconv.Itoa(rand.Intn(1000000000))+patternSuffix)
+		f, err = os.OpenFile(name, os.O_RDWR|os.O_CREATE|os.O_EXCL, perm)
+		if os.IsExist(err) {
+			continue
+		}
+		break
+	}
+	return
+}

vendor/honnef.co/go/tools/internal/robustio/UPSTREAM

@@ -0,0 +1,6 @@
+This package is a copy of cmd/go/internal/robustio.
+It is mostly in sync with upstream according to the last commit we've looked at,
+with the exception of still using I/O functions that work with older Go versions.
+
+The last upstream commit we've looked at was:
+dc04f3ba1f25313bc9c97e728620206c235db9ee

vendor/honnef.co/go/tools/internal/robustio/robustio.go

@@ -0,0 +1,53 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package robustio wraps I/O functions that are prone to failure on Windows,
+// transparently retrying errors up to an arbitrary timeout.
+//
+// Errors are classified heuristically and retries are bounded, so the functions
+// in this package do not completely eliminate spurious errors. However, they do
+// significantly reduce the rate of failure in practice.
+//
+// If so, the error will likely wrap one of:
+// The functions in this package do not completely eliminate spurious errors,
+// but substantially reduce their rate of occurrence in practice.
+package robustio
+
+// Rename is like os.Rename, but on Windows retries errors that may occur if the
+// file is concurrently read or overwritten.
+//
+// (See golang.org/issue/31247 and golang.org/issue/32188.)
+func Rename(oldpath, newpath string) error {
+	return rename(oldpath, newpath)
+}
+
+// ReadFile is like os.ReadFile, but on Windows retries errors that may
+// occur if the file is concurrently replaced.
+//
+// (See golang.org/issue/31247 and golang.org/issue/32188.)
+func ReadFile(filename string) ([]byte, error) {
+	return readFile(filename)
+}
+
+// RemoveAll is like os.RemoveAll, but on Windows retries errors that may occur
+// if an executable file in the directory has recently been executed.
+//
+// (See golang.org/issue/19491.)
+func RemoveAll(path string) error {
+	return removeAll(path)
+}
+
+// IsEphemeralError reports whether err is one of the errors that the functions
+// in this package attempt to mitigate.
+//
+// Errors considered ephemeral include:
+//   - syscall.ERROR_ACCESS_DENIED
+//   - syscall.ERROR_FILE_NOT_FOUND
+//   - internal/syscall/windows.ERROR_SHARING_VIOLATION
+//
+// This set may be expanded in the future; programs must not rely on the
+// non-ephemerality of any given error.
+func IsEphemeralError(err error) bool {
+	return isEphemeralError(err)
+}

vendor/honnef.co/go/tools/internal/robustio/robustio_darwin.go

@@ -0,0 +1,21 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package robustio
+
+import (
+	"errors"
+	"syscall"
+)
+
+const errFileNotFound = syscall.ENOENT
+
+// isEphemeralError returns true if err may be resolved by waiting.
+func isEphemeralError(err error) bool {
+	var errno syscall.Errno
+	if errors.As(err, &errno) {
+		return errno == errFileNotFound
+	}
+	return false
+}

vendor/honnef.co/go/tools/internal/robustio/robustio_flaky.go

@@ -0,0 +1,91 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build windows || darwin
+
+package robustio
+
+import (
+	"errors"
+	"math/rand"
+	"os"
+	"syscall"
+	"time"
+)
+
+const arbitraryTimeout = 2000 * time.Millisecond
+
+// retry retries ephemeral errors from f up to an arbitrary timeout
+// to work around filesystem flakiness on Windows and Darwin.
+func retry(f func() (err error, mayRetry bool)) error {
+	var (
+		bestErr     error
+		lowestErrno syscall.Errno
+		start       time.Time
+		nextSleep   time.Duration = 1 * time.Millisecond
+	)
+	for {
+		err, mayRetry := f()
+		if err == nil || !mayRetry {
+			return err
+		}
+
+		var errno syscall.Errno
+		if errors.As(err, &errno) && (lowestErrno == 0 || errno < lowestErrno) {
+			bestErr = err
+			lowestErrno = errno
+		} else if bestErr == nil {
+			bestErr = err
+		}
+
+		if start.IsZero() {
+			start = time.Now()
+		} else if d := time.Since(start) + nextSleep; d >= arbitraryTimeout {
+			break
+		}
+		time.Sleep(nextSleep)
+		nextSleep += time.Duration(rand.Int63n(int64(nextSleep)))
+	}
+
+	return bestErr
+}
+
+// rename is like os.Rename, but retries ephemeral errors.
+//
+// On Windows it wraps os.Rename, which (as of 2019-06-04) uses MoveFileEx with
+// MOVEFILE_REPLACE_EXISTING.
+//
+// Windows also provides a different system call, ReplaceFile,
+// that provides similar semantics, but perhaps preserves more metadata. (The
+// documentation on the differences between the two is very sparse.)
+//
+// Empirical error rates with MoveFileEx are lower under modest concurrency, so
+// for now we're sticking with what the os package already provides.
+func rename(oldpath, newpath string) (err error) {
+	return retry(func() (err error, mayRetry bool) {
+		err = os.Rename(oldpath, newpath)
+		return err, isEphemeralError(err)
+	})
+}
+
+// readFile is like os.ReadFile, but retries ephemeral errors.
+func readFile(filename string) ([]byte, error) {
+	var b []byte
+	err := retry(func() (err error, mayRetry bool) {
+		b, err = os.ReadFile(filename)
+
+		// Unlike in rename, we do not retry errFileNotFound here: it can occur
+		// as a spurious error, but the file may also genuinely not exist, so the
+		// increase in robustness is probably not worth the extra latency.
+		return err, isEphemeralError(err) && !errors.Is(err, errFileNotFound)
+	})
+	return b, err
+}
+
+func removeAll(path string) error {
+	return retry(func() (err error, mayRetry bool) {
+		err = os.RemoveAll(path)
+		return err, isEphemeralError(err)
+	})
+}

vendor/honnef.co/go/tools/internal/robustio/robustio_other.go

@@ -0,0 +1,27 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build !windows && !darwin
+
+package robustio
+
+import (
+	"os"
+)
+
+func rename(oldpath, newpath string) error {
+	return os.Rename(oldpath, newpath)
+}
+
+func readFile(filename string) ([]byte, error) {
+	return os.ReadFile(filename)
+}
+
+func removeAll(path string) error {
+	return os.RemoveAll(path)
+}
+
+func isEphemeralError(err error) bool {
+	return false
+}