diff --git a/builtin_test.go b/builtin_test.go
index d7a3cd56..852934d6 100644
--- a/builtin_test.go
+++ b/builtin_test.go
@@ -407,7 +407,7 @@ func TestContract(t *testing.T) {
 	pkg := NewPackage("", "foo", nil)
 	at := types.NewPackage("foo", "foo")
 	foo := pkg.Import("github.com/goplus/gogen/internal/foo")
-	tfoo := foo.Ref("Foo").Type()
+	tfoo := foo.Ref("Foo5").Type()
 	tarr := types.NewArray(tyInt, 10)
 	testcases := []struct {
 		Contract
@@ -1699,7 +1699,7 @@ func TestAliasTypeMethod(t *testing.T) {
 	pkg := NewPackage("", "foo", nil)
 	at := types.NewPackage("foo", "foo")
 	foo := pkg.Import("github.com/goplus/gogen/internal/foo")
-	tfoo := foo.Ref("Foo").Type()
+	tfoo := foo.Ref("Foo5").Type()
 	testcases := []struct {
 		Contract
 		typ    types.Type
@@ -1737,7 +1737,7 @@ func TestAliasContract(t *testing.T) {
 	pkg := NewPackage("", "foo", nil)
 	at := types.NewPackage("foo", "foo")
 	foo := pkg.Import("github.com/goplus/gogen/internal/foo")
-	tfoo := foo.Ref("Foo").Type()
+	tfoo := foo.Ref("Foo5").Type()
 	tarr := types.NewArray(tyInt, 10)
 	testcases := []struct {
 		Contract
diff --git a/error_msg_test.go b/error_msg_test.go
index 5bccafc1..40d407bd 100644
--- a/error_msg_test.go
+++ b/error_msg_test.go
@@ -396,38 +396,27 @@ func TestErrDefineVar(t *testing.T) {
 }
 
 func TestErrForRange(t *testing.T) {
-	codeErrorTest(t, `./foo.gop:1:17: can't use return/continue/break/goto in for range of udt.XGo_Enum(callback)`,
+	codeErrorTest(t, `./foo.gop:1:17: cannot range over v (type *github.com/goplus/gogen/internal/foo.Foo3)`,
 		func(pkg *gogen.Package) {
 			foo := pkg.Import("github.com/goplus/gogen/internal/foo")
-			bar := foo.Ref("Foo2").Type()
+			bar := foo.Ref("Foo3").Type()
 			v := newParam(pkg, token.NoPos, "v", types.NewPointer(bar))
 			pkg.NewFunc(nil, "foo", types.NewTuple(v), nil, false).BodyStart(pkg).
 				ForRange("a", "b").
 				Val(v, source("v", 1, 9)).
 				RangeAssignThen(position(1, 17)).
-				Return(0).
 				End().
 				End()
 		})
-	codeErrorTest(t, `./foo.gop:1:17: cannot range over v (type *github.com/goplus/gogen/internal/foo.Foo4)`,
+	codeErrorTest(t, `./foo.gop:1:17: cannot range over v (type bool)`,
 		func(pkg *gogen.Package) {
-			foo := pkg.Import("github.com/goplus/gogen/internal/foo")
-			bar := foo.Ref("Foo4").Type()
-			v := newParam(pkg, token.NoPos, "v", types.NewPointer(bar))
+			bar := types.Typ[types.Bool]
+			v := newParam(pkg, token.NoPos, "v", bar)
 			pkg.NewFunc(nil, "foo", types.NewTuple(v), nil, false).BodyStart(pkg).
+				NewVar(bar, "a", "b").
 				ForRange().
-				Val(v, source("v", 1, 9)).
-				RangeAssignThen(position(1, 17)).
-				End().
-				End()
-		})
-	codeErrorTest(t, `./foo.gop:1:17: cannot range over v (type *github.com/goplus/gogen/internal/foo.Foo3)`,
-		func(pkg *gogen.Package) {
-			foo := pkg.Import("github.com/goplus/gogen/internal/foo")
-			bar := foo.Ref("Foo3").Type()
-			v := newParam(pkg, token.NoPos, "v", types.NewPointer(bar))
-			pkg.NewFunc(nil, "foo", types.NewTuple(v), nil, false).BodyStart(pkg).
-				ForRange("a", "b").
+				VarRef("a").
+				VarRef("b").
 				Val(v, source("v", 1, 9)).
 				RangeAssignThen(position(1, 17)).
 				End().
diff --git a/internal/foo/foo.go b/internal/foo/foo.go
index f529c371..83613c73 100644
--- a/internal/foo/foo.go
+++ b/internal/foo/foo.go
@@ -103,22 +103,15 @@ func (p *Bar3) XGo_Enum() barIt3 {
 
 // -----------------------------------------------------------------------------
 
-type Foo struct {
-}
-
-func (p *Foo) XGo_Enum(c func(v string)) {
-}
-
-func (a Foo) XGo_Add(b Foo) Foo {
-	return Foo{}
+type Foo5 struct {
 }
 
-// -----------------------------------------------------------------------------
-
-type Foo2 struct {
+func (p Foo5) XGo_Enum() iter.Seq2[int, string] {
+	return nil
 }
 
-func (p Foo2) XGo_Enum(c func(k int, v string)) {
+func (p Foo5) XGo_Add(b Foo5) Foo5 {
+	return Foo5{}
 }
 
 // -----------------------------------------------------------------------------
@@ -126,26 +119,7 @@ func (p Foo2) XGo_Enum(c func(k int, v string)) {
 type Foo3 struct {
 }
 
-func (p Foo3) XGo_Enum(c func(k int, v string)) int {
-	return 0
-}
-
-// -----------------------------------------------------------------------------
-
-type Foo4 struct {
-}
-
-func (p Foo4) XGo_Enum(c func()) {
-}
-
-// -----------------------------------------------------------------------------
-
-type Foo5 struct {
-}
-
-func (p Foo5) XGo_Enum() iter.Seq2[int, string] {
-	return nil
-}
+func (p Foo3) XGo_Enum(int) {}
 
 // -----------------------------------------------------------------------------
 
diff --git a/stmt.go b/stmt.go
index 85e29853..33eef7a5 100644
--- a/stmt.go
+++ b/stmt.go
@@ -673,28 +673,9 @@ func (p *forRangeStmt) checkUdt(cb *CodeBuilder, o *types.Named) ([]types.Type,
 		params := sig.Params()
 		switch params.Len() {
 		case 0:
+			// fnIter := obj.XGo_Enum() or
 			// iter := obj.XGo_Enum()
 			// key, val, ok := iter.Next()
-		case 1:
-			// obj.XGo_Enum(func(key K, val V) { ... })
-			if enumRet.Len() != 0 {
-				return nil, false
-			}
-			typ := params.At(0).Type()
-			if t, ok := typ.(*types.Signature); ok && t.Results().Len() == 0 {
-				kv := t.Params()
-				n := kv.Len()
-				if n > 0 {
-					p.kvt = []types.Type{kv.At(0).Type(), nil}
-					if n > 1 {
-						n = 2
-						p.kvt[1] = kv.At(1).Type()
-					}
-					p.udt = -n
-					return p.kvt, true
-				}
-			}
-			fallthrough
 		default:
 			return nil, false
 		}
@@ -797,4 +778,4 @@ func (p *forRangeStmt) End(cb *CodeBuilder, src ast.Node) {
 	emitForRangeStmt(cb, p, stmts, flows)
 }
 
-// ----------------------------------------------------------------------------
\ No newline at end of file
+// ----------------------------------------------------------------------------
diff --git a/util_gengo.go b/util_gengo.go
index fb2cca0c..71b0f43b 100644
--- a/util_gengo.go
+++ b/util_gengo.go
@@ -1137,7 +1137,7 @@ func emitForRangeStmt(cb *CodeBuilder, p *forRangeStmt, stmts []ast.Stmt, flows
 		}
 		p.stmt.Body = p.handleFor(&ast.BlockStmt{List: stmts}, 1)
 		cb.emitStmt(p.stmt)
-	} else if n > 0 {
+	} else {
 		cb.stk.Push(p.x)
 		cb.MemberVal(p.enumName, 0).Call(0)
 		callEnum := cb.stk.Pop().Val
@@ -1187,44 +1187,6 @@ func emitForRangeStmt(cb *CodeBuilder, p *forRangeStmt, stmts []ast.Stmt, flows
 			Body: p.handleFor(&ast.BlockStmt{List: body}, 2),
 		}
 		cb.emitStmt(stmt)
-	} else {
-		/*
-			X.XGo_Enum(func(k K, v V) {
-				...
-			})
-		*/
-		if flows != 0 {
-			cb.panicCodeError(p.stmt.For, p.stmt.For, cantUseFlowsInForRange)
-		}
-		n = -n
-		def := p.stmt.Tok == token.DEFINE
-		args := make([]*ast.Field, n)
-		if def {
-			args[0] = &ast.Field{
-				Names: []*ast.Ident{p.stmt.Key.(*ast.Ident)},
-				Type:  toType(cb.pkg, p.kvt[0]),
-			}
-			if n > 1 {
-				args[1] = &ast.Field{
-					Names: []*ast.Ident{p.stmt.Value.(*ast.Ident)},
-					Type:  toType(cb.pkg, p.kvt[1]),
-				}
-			}
-		} else {
-			panic("TODO: for range udt assign")
-		}
-		stmt := &ast.ExprStmt{
-			X: &ast.CallExpr{
-				Fun: &ast.SelectorExpr{X: p.stmt.X, Sel: ident(p.enumName)},
-				Args: []ast.Expr{
-					&ast.FuncLit{
-						Type: &ast.FuncType{Params: &ast.FieldList{List: args}},
-						Body: p.handleFor(&ast.BlockStmt{List: stmts}, -1),
-					},
-				},
-			},
-		}
-		cb.emitStmt(stmt)
 	}
 }
 
diff --git a/xgo_test.go b/xgo_test.go
index f1e6d9fe..028a0ab6 100644
--- a/xgo_test.go
+++ b/xgo_test.go
@@ -794,6 +794,9 @@ func TestForRangeUDT(t *testing.T) {
 	pkg.NewFunc(nil, "bar", types.NewTuple(v), nil, false).BodyStart(pkg).
 		ForRange("_", "val").Val(v).RangeAssignThen(token.NoPos).
 		Val(pkg.Import("fmt").Ref("Println")).Val(ctxRef(pkg, "val")).Call(1).EndStmt().
+		SetBodyHandler(func(body *target.BlockStmt, kind int) {
+			gogen.InsertStmtFront(body, &target.ExprStmt{X: ast.NewIdent("__sched__")})
+		}).
 		End().End()
 	domTest(t, pkg, `package main
 
@@ -804,6 +807,7 @@ import (
 
 func bar(v foo.NodeSet) {
 	for _xgo_it := v.Gop_Enum(); ; {
+		__sched__
 		var _xgo_ok bool
 		_, val, _xgo_ok := _xgo_it.Next()
 		if !_xgo_ok {
@@ -966,59 +970,6 @@ func bar(v foo.NodeSet) {
 `)
 }
 
-func TestForRangeUDT4(t *testing.T) {
-	pkg := newMainPackage()
-	foo := pkg.Import("github.com/goplus/gogen/internal/foo")
-	bar := foo.Ref("Foo").Type()
-	v := newParam(pkg, token.NoPos, "v", types.NewPointer(bar))
-	pkg.NewFunc(nil, "bar", types.NewTuple(v), nil, false).BodyStart(pkg).
-		ForRange("elem").Val(v).RangeAssignThen(token.NoPos).
-		Val(pkg.Import("fmt").Ref("Println")).Val(ctxRef(pkg, "elem")).Call(1).EndStmt().
-		SetBodyHandler(func(body *target.BlockStmt, kind int) {
-			gogen.InsertStmtFront(body, &target.ExprStmt{X: ast.NewIdent("__sched__")})
-		}).
-		End().End()
-	domTest(t, pkg, `package main
-
-import (
-	"fmt"
-	"github.com/goplus/gogen/internal/foo"
-)
-
-func bar(v *foo.Foo) {
-	v.XGo_Enum(func(elem string) {
-		__sched__
-		fmt.Println(elem)
-	})
-}
-`)
-}
-
-func TestForRangeUDT5(t *testing.T) {
-	pkg := newMainPackage()
-	foo := pkg.Import("github.com/goplus/gogen/internal/foo")
-	bar := foo.Ref("Foo2").Type()
-	v := newParam(pkg, token.NoPos, "v", types.NewPointer(bar))
-	pkg.NewFunc(nil, "bar", types.NewTuple(v), nil, false).BodyStart(pkg).
-		ForRange("key", "elem").Val(v).RangeAssignThen(token.NoPos).
-		Val(pkg.Import("fmt").Ref("Println")).Val(ctxRef(pkg, "key")).Val(ctxRef(pkg, "elem")).
-		Call(2).EndStmt().
-		End().End()
-	domTest(t, pkg, `package main
-
-import (
-	"fmt"
-	"github.com/goplus/gogen/internal/foo"
-)
-
-func bar(v *foo.Foo2) {
-	v.XGo_Enum(func(key int, elem string) {
-		fmt.Println(key, elem)
-	})
-}
-`)
-}
-
 func TestForRangeUDT6(t *testing.T) {
 	pkg := newMainPackage()
 	os := pkg.Import("os")