Add staticcheck tool

vendor/honnef.co/go/tools/staticcheck/sa1028/sa1028.go

@@ -0,0 +1,57 @@
+package sa1028
+
+import (
+	"fmt"
+	"go/types"
+
+	"honnef.co/go/tools/analysis/callcheck"
+	"honnef.co/go/tools/analysis/lint"
+	"honnef.co/go/tools/go/ir"
+	"honnef.co/go/tools/internal/passes/buildir"
+
+	"golang.org/x/tools/go/analysis"
+)
+
+var SCAnalyzer = lint.InitializeAnalyzer(&lint.Analyzer{
+	Analyzer: &analysis.Analyzer{
+		Name:     "SA1028",
+		Requires: []*analysis.Analyzer{buildir.Analyzer},
+		Run:      callcheck.Analyzer(rules),
+	},
+	Doc: &lint.RawDocumentation{
+		Title:    `\'sort.Slice\' can only be used on slices`,
+		Text:     `The first argument of \'sort.Slice\' must be a slice.`,
+		Since:    "2020.1",
+		Severity: lint.SeverityError,
+		MergeIf:  lint.MergeIfAny,
+	},
+})
+
+var Analyzer = SCAnalyzer.Analyzer
+
+var rules = map[string]callcheck.Check{
+	"sort.Slice":         check,
+	"sort.SliceIsSorted": check,
+	"sort.SliceStable":   check,
+}
+
+func check(call *callcheck.Call) {
+	c := call.Instr.Common().StaticCallee()
+	arg := call.Args[0]
+
+	T := arg.Value.Value.Type().Underlying()
+	switch T.(type) {
+	case *types.Interface:
+		// we don't know.
+		// TODO(dh): if the value is a phi node we can look at its edges
+		if k, ok := arg.Value.Value.(*ir.Const); ok && k.Value == nil {
+			// literal nil, e.g. sort.Sort(nil, ...)
+			arg.Invalid(fmt.Sprintf("cannot call %s on nil literal", c))
+		}
+	case *types.Slice:
+		// this is fine
+	default:
+		// this is not fine
+		arg.Invalid(fmt.Sprintf("%s must only be called on slices, was called on %s", c, T))
+	}
+}