diff --git a/package/PikaStdLib/PikaStdData_List.c b/package/PikaStdLib/PikaStdData_List.c
index 59c96a582..7007d20c5 100644
--- a/package/PikaStdLib/PikaStdData_List.c
+++ b/package/PikaStdLib/PikaStdData_List.c
@@ -41,8 +41,7 @@ void PikaStdData_List_set(PikaObj* self, Arg* arg, int i) {
 
 Arg* PikaStdData_List___iter__(PikaObj* self) {
     obj_setInt(self, "__iter_i", 0);
-    /* use weak ref to void loop ref */
-    return arg_setWeakRefObj(NULL, "", self);
+    return arg_setRefObj(NULL, "", self);
 }
 
 Arg* PikaStdData_List___next__(PikaObj* self) {
diff --git a/port/linux/.vscode/launch.json b/port/linux/.vscode/launch.json
index 8ed8e9ecc..1bd4f2ff6 100644
--- a/port/linux/.vscode/launch.json
+++ b/port/linux/.vscode/launch.json
@@ -11,7 +11,8 @@
             "program": "${workspaceFolder}/build/test/pikascript_test",
             // "program": "${workspaceFolder}/build/boot/demo06-pikamain/pikascript_demo06-pikamain",
             "args": [
-                "--gtest_filter=gc.*",
+                "--gtest_filter=pikaMain.list_iter",
+                // "--gtest_filter=gc.*",
                 // "--gtest_filter=parser.bytes_iteral",
                 // "--gtest_filter=parser.list_init_fun",
                 // "--gtest_filter=args.heap_struct_override",
diff --git a/port/linux/package/pikascript/pikascript-lib/PikaStdLib/PikaStdData_List.c b/port/linux/package/pikascript/pikascript-lib/PikaStdLib/PikaStdData_List.c
index 59c96a582..7007d20c5 100644
--- a/port/linux/package/pikascript/pikascript-lib/PikaStdLib/PikaStdData_List.c
+++ b/port/linux/package/pikascript/pikascript-lib/PikaStdLib/PikaStdData_List.c
@@ -41,8 +41,7 @@ void PikaStdData_List_set(PikaObj* self, Arg* arg, int i) {
 
 Arg* PikaStdData_List___iter__(PikaObj* self) {
     obj_setInt(self, "__iter_i", 0);
-    /* use weak ref to void loop ref */
-    return arg_setWeakRefObj(NULL, "", self);
+    return arg_setRefObj(NULL, "", self);
 }
 
 Arg* PikaStdData_List___next__(PikaObj* self) {
diff --git a/port/linux/test/pikaMain-test.cpp b/port/linux/test/pikaMain-test.cpp
index 6e68bfbd4..c253c2e4b 100644
--- a/port/linux/test/pikaMain-test.cpp
+++ b/port/linux/test/pikaMain-test.cpp
@@ -279,7 +279,7 @@ TEST(pikaMain, PikaStdData) {
     EXPECT_EQ(pikaMemNow(), 0);
 }
 
-TEST(pikaMain, iter) {
+TEST(pikaMain, list_method) {
     /* init */
     pikaMemInfo.heapUsedMax = 0;
     PikaObj* pikaMain = newRootObj((char*)"pikaMain", New_PikaMain);
@@ -291,6 +291,23 @@ TEST(pikaMain, iter) {
         "len = list.len()\n"
         "a1 = list.get(0)\n"
         "a2 = list.get(1)\n"
+        "\n"
+        );
+    /* collect */
+    /* assert */
+    /* deinit */
+    // obj_deinit(globals);
+    obj_deinit(pikaMain);
+    EXPECT_EQ(pikaMemNow(), 0);
+}
+
+TEST(pikaMain, list_iter) {
+    /* init */
+    pikaMemInfo.heapUsedMax = 0;
+    PikaObj* pikaMain = newRootObj((char*)"pikaMain", New_PikaMain);
+    /* run */
+    obj_runDirect(pikaMain, (char*)
+        "list = PikaStdData.List()\n"
         "res = iter(list)\n"
         "\n"
         );