Add staticcheck tool

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
+	}
+}