Suggest strings.ContainsFunc instead of strings.IndexFunc with Go 1.21+

simple/lint.go

@@ -349,6 +349,7 @@ func CheckStringsContains(pass *analysis.Pass) (interface{}, error) {
 			return
 		}
 
+		var opts []report.Option
 		var r ast.Expr
 		switch funIdent.Name {
 		case "IndexRune":
@@ -366,6 +367,12 @@ func CheckStringsContains(pass *analysis.Pass) (interface{}, error) {
 				X:   pkgIdent,
 				Sel: &ast.Ident{Name: "Contains"},
 			}
+		case "IndexFunc":
+			r = &ast.SelectorExpr{
+				X:   pkgIdent,
+				Sel: &ast.Ident{Name: "ContainsFunc"},
+			}
+			opts = append(opts, report.MinimumStdlibVersion(21))
 		default:
 			return
 		}
@@ -381,9 +388,10 @@ func CheckStringsContains(pass *analysis.Pass) (interface{}, error) {
 			}
 		}
 
-		report.Report(pass, node, fmt.Sprintf("should use %s instead", report.Render(pass, r)),
+		opts = append(opts,
 			report.FilterGenerated(),
 			report.Fixes(edit.Fix(fmt.Sprintf("simplify use of %s", report.Render(pass, call.Fun)), edit.ReplaceWithNode(pass.Fset, node, r))))
+		report.Report(pass, node, fmt.Sprintf("should use %s instead", report.Render(pass, r)), opts...)
 	}
 	code.Preorder(pass, fn, (*ast.BinaryExpr)(nil))
 	return nil, nil

simple/lint_test.go

@@ -11,7 +11,11 @@ func TestAll(t *testing.T) {
 		"S1000": {{Dir: "example.com/CheckSingleCaseSelect"}},
 		"S1001": {{Dir: "example.com/CheckLoopCopy"}},
 		"S1002": {{Dir: "example.com/CheckIfBoolCmp"}},
-		"S1003": {{Dir: "example.com/CheckStringsContains"}},
+		"S1003": {
+			{Dir: "example.com/CheckStringsContains"},
+			{Dir: "example.com/CheckStringsContains_go120", Version: "1.20"},
+			{Dir: "example.com/CheckStringsContains_go121", Version: "1.21"},
+		},
 		"S1004": {{Dir: "example.com/CheckBytesCompare"}},
 		"S1005": {
 			{Dir: "example.com/CheckUnnecessaryBlank"},

simple/testdata/src/example.com/CheckStringsContains_go120/contains.go

@@ -0,0 +1,11 @@
+package pkg
+
+import (
+	"bytes"
+	"strings"
+)
+
+func fn() {
+	_ = bytes.IndexFunc(nil, func(r rune) bool { return false }) != -1
+	_ = strings.IndexFunc("", func(r rune) bool { return false }) != -1
+}

simple/testdata/src/example.com/CheckStringsContains_go121/contains.go

@@ -0,0 +1,11 @@
+package pkg
+
+import (
+	"bytes"
+	"strings"
+)
+
+func fn() {
+	_ = bytes.IndexFunc(nil, func(r rune) bool { return false }) != -1  //@ diag(`bytes.ContainsFunc`)
+	_ = strings.IndexFunc("", func(r rune) bool { return false }) != -1 //@ diag(`strings.ContainsFunc`)
+}

simple/testdata/src/example.com/CheckStringsContains_go121/contains.go.golden

@@ -0,0 +1,11 @@
+package pkg
+
+import (
+	"bytes"
+	"strings"
+)
+
+func fn() {
+	_ = bytes.ContainsFunc(nil, func(r rune) bool { return false })  //@ diag(`bytes.ContainsFunc`)
+	_ = strings.ContainsFunc("", func(r rune) bool { return false }) //@ diag(`strings.ContainsFunc`)
+}