Add staticcheck tool

vendor/honnef.co/go/tools/staticcheck/sa9002/sa9002.go

@@ -0,0 +1,63 @@
+package sa9002
+
+import (
+	"fmt"
+	"go/ast"
+	"strconv"
+
+	"honnef.co/go/tools/analysis/code"
+	"honnef.co/go/tools/analysis/edit"
+	"honnef.co/go/tools/analysis/lint"
+	"honnef.co/go/tools/analysis/report"
+	"honnef.co/go/tools/go/types/typeutil"
+
+	"golang.org/x/tools/go/analysis"
+	"golang.org/x/tools/go/analysis/passes/inspect"
+)
+
+var SCAnalyzer = lint.InitializeAnalyzer(&lint.Analyzer{
+	Analyzer: &analysis.Analyzer{
+		Name:     "SA9002",
+		Run:      run,
+		Requires: []*analysis.Analyzer{inspect.Analyzer},
+	},
+	Doc: &lint.RawDocumentation{
+		Title:    `Using a non-octal \'os.FileMode\' that looks like it was meant to be in octal.`,
+		Since:    "2017.1",
+		Severity: lint.SeverityWarning,
+		MergeIf:  lint.MergeIfAny,
+	},
+})
+
+var Analyzer = SCAnalyzer.Analyzer
+
+func run(pass *analysis.Pass) (any, error) {
+	fn := func(node ast.Node) {
+		call := node.(*ast.CallExpr)
+		for _, arg := range call.Args {
+			lit, ok := arg.(*ast.BasicLit)
+			if !ok {
+				continue
+			}
+			if !typeutil.IsTypeWithName(pass.TypesInfo.TypeOf(lit), "os.FileMode") &&
+				!typeutil.IsTypeWithName(pass.TypesInfo.TypeOf(lit), "io/fs.FileMode") {
+				continue
+			}
+			if len(lit.Value) == 3 &&
+				lit.Value[0] != '0' &&
+				lit.Value[0] >= '0' && lit.Value[0] <= '7' &&
+				lit.Value[1] >= '0' && lit.Value[1] <= '7' &&
+				lit.Value[2] >= '0' && lit.Value[2] <= '7' {
+
+				v, err := strconv.ParseInt(lit.Value, 10, 64)
+				if err != nil {
+					continue
+				}
+				report.Report(pass, arg, fmt.Sprintf("file mode '%s' evaluates to %#o; did you mean '0%s'?", lit.Value, v, lit.Value),
+					report.Fixes(edit.Fix("Fix octal literal", edit.ReplaceWithString(arg, "0"+lit.Value))))
+			}
+		}
+	}
+	code.Preorder(pass, fn, (*ast.CallExpr)(nil))
+	return nil, nil
+}