Merge pull request #14 from karamaru-alpha/update/karamaru/ignore-ren…

…ame-by-default

update: ignore assigning the loop variable to another variable by default / add check-alias option

copyloopvar.go

@@ -10,7 +10,7 @@ import (
 	"golang.org/x/tools/go/ast/inspector"
 )
 
-var ignoreAlias bool
+var checkAlias bool
 
 func NewAnalyzer() *analysis.Analyzer {
 	analyzer := &analysis.Analyzer{
@@ -21,19 +21,15 @@ func NewAnalyzer() *analysis.Analyzer {
 			inspect.Analyzer,
 		},
 	}
-	analyzer.Flags.BoolVar(&ignoreAlias, "ignore-alias", false, "ignore aliasing of loop variables")
+	analyzer.Flags.BoolVar(&checkAlias, "check-alias", false, "check all assigning the loop variable to another variable")
 	return analyzer
 }
 
 func run(pass *analysis.Pass) (any, error) {
-	inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
-
-	nodeFilter := []ast.Node{
+	pass.ResultOf[inspect.Analyzer].(*inspector.Inspector).Preorder([]ast.Node{
 		(*ast.RangeStmt)(nil),
 		(*ast.ForStmt)(nil),
-	}
-
-	inspect.Preorder(nodeFilter, func(n ast.Node) {
+	}, func(n ast.Node) {
 		switch node := n.(type) {
 		case *ast.RangeStmt:
 			checkRangeStmt(pass, node)
@@ -72,7 +68,7 @@ func checkRangeStmt(pass *analysis.Pass, rangeStmt *ast.RangeStmt) {
 			if right.Name != key.Name && (value == nil || right.Name != value.Name) {
 				continue
 			}
-			if ignoreAlias {
+			if !checkAlias {
 				left, ok := assignStmt.Lhs[i].(*ast.Ident)
 				if !ok {
 					continue
@@ -119,7 +115,7 @@ func checkForStmt(pass *analysis.Pass, forStmt *ast.ForStmt) {
 			if _, ok := initVarNameMap[right.Name]; !ok {
 				continue
 			}
-			if ignoreAlias {
+			if !checkAlias {
 				left, ok := assignStmt.Lhs[i].(*ast.Ident)
 				if !ok {
 					continue

copyloopvar_test.go

@@ -13,12 +13,12 @@ func TestAnalyzer(t *testing.T) {
 		analysistest.Run(t, testdata, NewAnalyzer(), "basic")
 	})
 
-	t.Run("ignore-alias", func(t *testing.T) {
+	t.Run("check-alias", func(t *testing.T) {
 		analyzer := NewAnalyzer()
-		if err := analyzer.Flags.Set("ignore-alias", "true"); err != nil {
+		if err := analyzer.Flags.Set("check-alias", "true"); err != nil {
 			t.Error(err)
 		}
 		testdata := testutil.WithModules(t, analysistest.TestData(), nil)
-		analysistest.Run(t, testdata, analyzer, "ignorealias")
+		analysistest.Run(t, testdata, analyzer, "checkalias")
 	})
 }

testdata/src/basic/main.go

@@ -2,31 +2,36 @@ package main
 
 func main() {
 	for i, v := range []int{1, 2, 3} {
-		i := i       // want `The copy of the 'for' variable "i" can be deleted \(Go 1\.22\+\)`
-		_i := i      // want `The copy of the 'for' variable "i" can be deleted \(Go 1\.22\+\)`
-		v := v       // want `The copy of the 'for' variable "v" can be deleted \(Go 1\.22\+\)`
-		_v := v      // want `The copy of the 'for' variable "v" can be deleted \(Go 1\.22\+\)`
-		a, b := 1, i // want `The copy of the 'for' variable "i" can be deleted \(Go 1\.22\+\)`
-		c, d := 1, v // want `The copy of the 'for' variable "v" can be deleted \(Go 1\.22\+\)`
+		i := i // want `The copy of the 'for' variable "i" can be deleted \(Go 1\.22\+\)`
+		_i := i
+		v := v // want `The copy of the 'for' variable "v" can be deleted \(Go 1\.22\+\)`
+		_v := v
+		a, i := 1, i // want `The copy of the 'for' variable "i" can be deleted \(Go 1\.22\+\)`
+		b, _i := 1, i
+		c, v := 1, v // want `The copy of the 'for' variable "v" can be deleted \(Go 1\.22\+\)`
+		d, _v := 1, v
 		e := false
 		_, _, _, _, _, _, _, _, _ = i, _i, v, _v, a, b, c, d, e
 	}
 
 	for i, j := 1, 1; i+j <= 3; i++ {
-		i := i       // want `The copy of the 'for' variable "i" can be deleted \(Go 1\.22\+\)`
-		_i := i      // want `The copy of the 'for' variable "i" can be deleted \(Go 1\.22\+\)`
-		j := j       // want `The copy of the 'for' variable "j" can be deleted \(Go 1\.22\+\)`
-		_j := j      // want `The copy of the 'for' variable "j" can be deleted \(Go 1\.22\+\)`
-		a, b := 1, i // want `The copy of the 'for' variable "i" can be deleted \(Go 1\.22\+\)`
-		c, d := 1, j // want `The copy of the 'for' variable "j" can be deleted \(Go 1\.22\+\)`
+		i := i // want `The copy of the 'for' variable "i" can be deleted \(Go 1\.22\+\)`
+		_i := i
+		j := j // want `The copy of the 'for' variable "j" can be deleted \(Go 1\.22\+\)`
+		_j := j
+		a, i := 1, i // want `The copy of the 'for' variable "i" can be deleted \(Go 1\.22\+\)`
+		b, _i := 1, i
+		c, j := 1, j // want `The copy of the 'for' variable "j" can be deleted \(Go 1\.22\+\)`
+		d, _j := 1, j
 		e := false
 		_, _, _, _, _, _, _, _, _ = i, _i, j, _j, a, b, c, d, e
 	}
 
 	for i := range []int{1, 2, 3} {
-		i := i       // want `The copy of the 'for' variable "i" can be deleted \(Go 1\.22\+\)`
-		_i := i      // want `The copy of the 'for' variable "i" can be deleted \(Go 1\.22\+\)`
-		a, b := 1, i // want `The copy of the 'for' variable "i" can be deleted \(Go 1\.22\+\)`
+		i := i // want `The copy of the 'for' variable "i" can be deleted \(Go 1\.22\+\)`
+		_i := i
+		a, i := 1, i // want `The copy of the 'for' variable "i" can be deleted \(Go 1\.22\+\)`
+		b, _i := 1, i
 		c := false
 		_, _, _, _, _ = i, _i, a, b, c
 	}
@@ -35,6 +40,6 @@ func main() {
 		Bool bool
 	}
 	for _, t.Bool = range []bool{true, false} {
-		_ = t
+		t.Bool = t.Bool // NOTE: ignore
 	}
 }

testdata/src/checkalias/main.go

@@ -0,0 +1,45 @@
+package main
+
+func main() {
+	for i, v := range []int{1, 2, 3} {
+		i := i        // want `The copy of the 'for' variable "i" can be deleted \(Go 1\.22\+\)`
+		_i := i       // want `The copy of the 'for' variable "i" can be deleted \(Go 1\.22\+\)`
+		v := v        // want `The copy of the 'for' variable "v" can be deleted \(Go 1\.22\+\)`
+		_v := v       // want `The copy of the 'for' variable "v" can be deleted \(Go 1\.22\+\)`
+		a, i := 1, i  // want `The copy of the 'for' variable "i" can be deleted \(Go 1\.22\+\)`
+		b, _i := 1, i // want `The copy of the 'for' variable "i" can be deleted \(Go 1\.22\+\)`
+		c, v := 1, v  // want `The copy of the 'for' variable "v" can be deleted \(Go 1\.22\+\)`
+		d, _v := 1, v // want `The copy of the 'for' variable "v" can be deleted \(Go 1\.22\+\)`
+		e := false
+		_, _, _, _, _, _, _, _, _ = i, _i, v, _v, a, b, c, d, e
+	}
+
+	for i, j := 1, 1; i+j <= 3; i++ {
+		i := i        // want `The copy of the 'for' variable "i" can be deleted \(Go 1\.22\+\)`
+		_i := i       // want `The copy of the 'for' variable "i" can be deleted \(Go 1\.22\+\)`
+		j := j        // want `The copy of the 'for' variable "j" can be deleted \(Go 1\.22\+\)`
+		_j := j       // want `The copy of the 'for' variable "j" can be deleted \(Go 1\.22\+\)`
+		a, i := 1, i  // want `The copy of the 'for' variable "i" can be deleted \(Go 1\.22\+\)`
+		b, _i := 1, i // want `The copy of the 'for' variable "i" can be deleted \(Go 1\.22\+\)`
+		c, j := 1, j  // want `The copy of the 'for' variable "j" can be deleted \(Go 1\.22\+\)`
+		d, _j := 1, j // want `The copy of the 'for' variable "j" can be deleted \(Go 1\.22\+\)`
+		e := false
+		_, _, _, _, _, _, _, _, _ = i, _i, j, _j, a, b, c, d, e
+	}
+
+	for i := range []int{1, 2, 3} {
+		i := i        // want `The copy of the 'for' variable "i" can be deleted \(Go 1\.22\+\)`
+		_i := i       // want `The copy of the 'for' variable "i" can be deleted \(Go 1\.22\+\)`
+		a, i := 1, i  // want `The copy of the 'for' variable "i" can be deleted \(Go 1\.22\+\)`
+		b, _i := 1, i // want `The copy of the 'for' variable "i" can be deleted \(Go 1\.22\+\)`
+		c := false
+		_, _, _, _, _ = i, _i, a, b, c
+	}
+
+	var t struct {
+		Bool bool
+	}
+	for _, t.Bool = range []bool{true, false} {
+		t.Bool = t.Bool // NOTE: ignore
+	}
+}