Add staticcheck tool

vendor/honnef.co/go/tools/staticcheck/sa1026/sa1026.go

@@ -0,0 +1,77 @@
+package sa1026
+
+import (
+	"fmt"
+	"go/types"
+
+	"honnef.co/go/tools/analysis/callcheck"
+	"honnef.co/go/tools/analysis/lint"
+	"honnef.co/go/tools/internal/passes/buildir"
+	"honnef.co/go/tools/staticcheck/fakejson"
+	"honnef.co/go/tools/staticcheck/fakexml"
+
+	"golang.org/x/tools/go/analysis"
+)
+
+var SCAnalyzer = lint.InitializeAnalyzer(&lint.Analyzer{
+	Analyzer: &analysis.Analyzer{
+		Name:     "SA1026",
+		Requires: []*analysis.Analyzer{buildir.Analyzer},
+		Run:      callcheck.Analyzer(rules),
+	},
+	Doc: &lint.RawDocumentation{
+		Title:    `Cannot marshal channels or functions`,
+		Since:    "2019.2",
+		Severity: lint.SeverityError,
+		MergeIf:  lint.MergeIfAny,
+	},
+})
+
+var Analyzer = SCAnalyzer.Analyzer
+
+var rules = map[string]callcheck.Check{
+	"encoding/json.Marshal":           checkJSON,
+	"encoding/xml.Marshal":            checkXML,
+	"(*encoding/json.Encoder).Encode": checkJSON,
+	"(*encoding/xml.Encoder).Encode":  checkXML,
+}
+
+func checkJSON(call *callcheck.Call) {
+	arg := call.Args[0]
+	T := arg.Value.Value.Type()
+	if err := fakejson.Marshal(T); err != nil {
+		typ := types.TypeString(err.Type, types.RelativeTo(call.Parent.Pkg.Pkg))
+		if err.Path == "x" {
+			arg.Invalid(fmt.Sprintf("trying to marshal unsupported type %s", typ))
+		} else {
+			arg.Invalid(fmt.Sprintf("trying to marshal unsupported type %s, via %s", typ, err.Path))
+		}
+	}
+}
+
+func checkXML(call *callcheck.Call) {
+	arg := call.Args[0]
+	T := arg.Value.Value.Type()
+	if err := fakexml.Marshal(T); err != nil {
+		switch err := err.(type) {
+		case *fakexml.UnsupportedTypeError:
+			typ := types.TypeString(err.Type, types.RelativeTo(call.Parent.Pkg.Pkg))
+			if err.Path == "x" {
+				arg.Invalid(fmt.Sprintf("trying to marshal unsupported type %s", typ))
+			} else {
+				arg.Invalid(fmt.Sprintf("trying to marshal unsupported type %s, via %s", typ, err.Path))
+			}
+		case *fakexml.CyclicTypeError:
+			typ := types.TypeString(err.Type, types.RelativeTo(call.Parent.Pkg.Pkg))
+			if err.Path == "x" {
+				arg.Invalid(fmt.Sprintf("trying to marshal cyclic type %s", typ))
+			} else {
+				arg.Invalid(fmt.Sprintf("trying to marshal cyclic type %s, via %s", typ, err.Path))
+			}
+		case *fakexml.TagPathError:
+			// Vet does a better job at reporting this error, because it can flag the actual struct tags, not just the call to Marshal
+		default:
+			// These errors get reported by SA5008 instead, which can flag the actual fields, independently of calls to xml.Marshal
+		}
+	}
+}