Add staticcheck tool

vendor/honnef.co/go/tools/staticcheck/sa1011/sa1011.go

@@ -0,0 +1,47 @@
+package sa1011
+
+import (
+	"go/constant"
+	"unicode/utf8"
+
+	"honnef.co/go/tools/analysis/callcheck"
+	"honnef.co/go/tools/analysis/lint"
+	"honnef.co/go/tools/internal/passes/buildir"
+
+	"golang.org/x/tools/go/analysis"
+)
+
+var SCAnalyzer = lint.InitializeAnalyzer(&lint.Analyzer{
+	Analyzer: &analysis.Analyzer{
+		Name:     "SA1011",
+		Requires: []*analysis.Analyzer{buildir.Analyzer},
+		Run:      callcheck.Analyzer(checkUTF8CutsetRules),
+	},
+	Doc: &lint.RawDocumentation{
+		Title:    `Various methods in the \"strings\" package expect valid UTF-8, but invalid input is provided`,
+		Since:    "2017.1",
+		Severity: lint.SeverityError,
+		MergeIf:  lint.MergeIfAny,
+	},
+})
+
+var Analyzer = SCAnalyzer.Analyzer
+
+var checkUTF8CutsetRules = map[string]callcheck.Check{
+	"strings.IndexAny":     check,
+	"strings.LastIndexAny": check,
+	"strings.ContainsAny":  check,
+	"strings.Trim":         check,
+	"strings.TrimLeft":     check,
+	"strings.TrimRight":    check,
+}
+
+func check(call *callcheck.Call) {
+	arg := call.Args[1]
+	if c := callcheck.ExtractConstExpectKind(arg.Value, constant.String); c != nil {
+		s := constant.StringVal(c.Value)
+		if !utf8.ValidString(s) {
+			arg.Invalid("argument is not a valid UTF-8 encoded string")
+		}
+	}
+}