Support caching of next method in for-of and built-in methods. (#3939)

JerryScript-DCO-1.0-Signed-off-by: Zoltan Herczeg zherczeg.u-szeged@partner.samsung.com

jerry-core/ecma/builtin-objects/ecma-builtin-array.c

@@ -153,7 +153,8 @@ ecma_builtin_array_object_from (ecma_value_t this_arg, /**< 'this' argument */
     ecma_object_t *array_obj_p = ecma_get_object_from_value (array);
 
     /* 6.d */
-    ecma_value_t iterator = ecma_op_get_iterator (items, using_iterator, NULL);
+    ecma_value_t next_method;
+    ecma_value_t iterator = ecma_op_get_iterator (items, using_iterator, &next_method);
     ecma_free_value (using_iterator);
 
     /* 6.e */
@@ -170,7 +171,7 @@ ecma_builtin_array_object_from (ecma_value_t this_arg, /**< 'this' argument */
     while (true)
     {
       /* 6.g.ii */
-      ecma_value_t next = ecma_op_iterator_step (iterator);
+      ecma_value_t next = ecma_op_iterator_step (iterator, next_method);
 
       /* 6.g.iii */
       if (ECMA_IS_VALUE_ERROR (next))
@@ -196,6 +197,7 @@ ecma_builtin_array_object_from (ecma_value_t this_arg, /**< 'this' argument */
         }
 
         ecma_free_value (iterator);
+        ecma_free_value (next_method);
         /* 6.g.iv.3 */
         return array;
       }
@@ -254,6 +256,7 @@ ecma_builtin_array_object_from (ecma_value_t this_arg, /**< 'this' argument */
 
 iterator_cleanup:
     ecma_free_value (iterator);
+    ecma_free_value (next_method);
     ecma_free_value (array);
 
     return ret_value;

jerry-core/ecma/builtin-objects/ecma-builtin-promise.c

@@ -126,6 +126,7 @@ ecma_builtin_promise_resolve (ecma_value_t this_arg, /**< 'this' argument */
  */
 inline static ecma_value_t
 ecma_builtin_promise_perform_race (ecma_value_t iterator, /**< the iterator for race */
+                                   ecma_value_t next_method, /**< next method */
                                    ecma_value_t capability, /**< PromiseCapability record */
                                    ecma_value_t ctor, /**< Constructor value */
                                    bool *done_p) /**< [out] iteratorRecord[[done]] */
@@ -138,7 +139,7 @@ ecma_builtin_promise_perform_race (ecma_value_t iterator, /**< the iterator for
   while (true)
   {
     /* a. */
-    ecma_value_t next = ecma_op_iterator_step (iterator);
+    ecma_value_t next = ecma_op_iterator_step (iterator, next_method);
     /* b, c. */
     if (ECMA_IS_VALUE_ERROR (next))
     {
@@ -321,8 +322,9 @@ ecma_builtin_promise_all_handler (const ecma_value_t function, /**< the function
  */
 inline static ecma_value_t
 ecma_builtin_promise_perform_all (ecma_value_t iterator, /**< iteratorRecord */
-                                  ecma_value_t ctor, /**< the caller of Promise.race */
+                                  ecma_value_t next_method, /**< next method */
                                   ecma_value_t capability,  /**< PromiseCapability record */
+                                  ecma_value_t ctor, /**< the caller of Promise.race */
                                   bool *done_p) /**< [out] iteratorRecord[[done]] */
 {
   /* 1. - 2. */
@@ -350,7 +352,7 @@ ecma_builtin_promise_perform_all (ecma_value_t iterator, /**< iteratorRecord */
   while (true)
   {
     /* a. */
-    ecma_value_t next = ecma_op_iterator_step (iterator);
+    ecma_value_t next = ecma_op_iterator_step (iterator, next_method);
     /* b. - c. */
     if (ECMA_IS_VALUE_ERROR (next))
     {
@@ -527,9 +529,9 @@ ecma_builtin_promise_race_or_all (ecma_value_t this_arg, /**< 'this' argument */
     return capability;
   }
 
-  ecma_value_t iterator;
+  ecma_value_t next_method;
-  iterator = ecma_builtin_promise_reject_abrupt (ecma_op_get_iterator (iterable, ECMA_VALUE_SYNC_ITERATOR, NULL),
+  ecma_value_t iterator = ecma_op_get_iterator (iterable, ECMA_VALUE_SYNC_ITERATOR, &next_method);
-                                                 capability);
+  iterator = ecma_builtin_promise_reject_abrupt (iterator, capability);
 
   if (ECMA_IS_VALUE_ERROR (iterator))
   {
@@ -543,11 +545,11 @@ ecma_builtin_promise_race_or_all (ecma_value_t this_arg, /**< 'this' argument */
 
   if (is_race)
   {
-    ret = ecma_builtin_promise_perform_race (iterator, capability, constructor_value, &is_done);
+    ret = ecma_builtin_promise_perform_race (iterator, next_method, capability, constructor_value, &is_done);
   }
   else
   {
-    ret = ecma_builtin_promise_perform_all (iterator, constructor_value, capability, &is_done);
+    ret = ecma_builtin_promise_perform_all (iterator, next_method, capability, constructor_value, &is_done);
   }
 
   ecma_free_value (constructor_value);
@@ -563,6 +565,7 @@ ecma_builtin_promise_race_or_all (ecma_value_t this_arg, /**< 'this' argument */
   }
 
   ecma_free_value (iterator);
+  ecma_free_value (next_method);
   ecma_free_value (capability);
 
   return ret;

jerry-core/ecma/operations/ecma-container-object.c

@@ -439,22 +439,23 @@ ecma_op_container_create (const ecma_value_t *arguments_list_p, /**< arguments l
 
   ecma_object_t *adder_func_p = ecma_get_object_from_value (result);
 
-  result = ecma_op_get_iterator (iterable, ECMA_VALUE_SYNC_ITERATOR, NULL);
+  ecma_value_t next_method;
+  result = ecma_op_get_iterator (iterable, ECMA_VALUE_SYNC_ITERATOR, &next_method);
 
   if (ECMA_IS_VALUE_ERROR (result))
   {
     goto cleanup_adder;
   }
 
-  const ecma_value_t iter = result;
+  const ecma_value_t iterator = result;
 
   while (true)
   {
-    result = ecma_op_iterator_step (iter);
+    result = ecma_op_iterator_step (iterator, next_method);
 
     if (ECMA_IS_VALUE_ERROR (result))
     {
-      goto cleanup_iter;
+      goto cleanup_iterator;
     }
 
     if (ecma_is_value_false (result))
@@ -468,7 +469,7 @@ ecma_op_container_create (const ecma_value_t *arguments_list_p, /**< arguments l
 
     if (ECMA_IS_VALUE_ERROR (result))
     {
-      goto cleanup_iter;
+      goto cleanup_iterator;
     }
 
     if (lit_id == LIT_MAGIC_STRING_SET_UL || lit_id == LIT_MAGIC_STRING_WEAKSET_UL)
@@ -486,9 +487,9 @@ ecma_op_container_create (const ecma_value_t *arguments_list_p, /**< arguments l
       {
         ecma_free_value (result);
         ecma_raise_type_error (ECMA_ERR_MSG ("Iterator value is not an object."));
-        result = ecma_op_iterator_close (iter);
+        result = ecma_op_iterator_close (iterator);
         JERRY_ASSERT (ECMA_IS_VALUE_ERROR (result));
-        goto cleanup_iter;
+        goto cleanup_iterator;
       }
 
       ecma_object_t *next_object_p = ecma_get_object_from_value (result);
@@ -498,8 +499,8 @@ ecma_op_container_create (const ecma_value_t *arguments_list_p, /**< arguments l
       if (ECMA_IS_VALUE_ERROR (result))
       {
         ecma_deref_object (next_object_p);
-        ecma_op_iterator_close (iter);
+        ecma_op_iterator_close (iterator);
-        goto cleanup_iter;
+        goto cleanup_iterator;
       }
 
       const ecma_value_t key = result;
@@ -510,8 +511,8 @@ ecma_op_container_create (const ecma_value_t *arguments_list_p, /**< arguments l
       {
         ecma_deref_object (next_object_p);
         ecma_free_value (key);
-        ecma_op_iterator_close (iter);
+        ecma_op_iterator_close (iterator);
-        goto cleanup_iter;
+        goto cleanup_iterator;
       }
 
       const ecma_value_t value = result;
@@ -525,19 +526,19 @@ ecma_op_container_create (const ecma_value_t *arguments_list_p, /**< arguments l
 
     if (ECMA_IS_VALUE_ERROR (result))
     {
-      ecma_op_iterator_close (iter);
+      ecma_op_iterator_close (iterator);
-      goto cleanup_iter;
+      goto cleanup_iterator;
     }
 
     ecma_free_value (result);
   }
 
-  ecma_free_value (iter);
+  ecma_ref_object (object_p);
-  ecma_deref_object (adder_func_p);
+  result = ecma_make_object_value (object_p);
-  return ecma_make_object_value (object_p);
 
-cleanup_iter:
+cleanup_iterator:
-  ecma_free_value (iter);
+  ecma_free_value (iterator);
+  ecma_free_value (next_method);
 cleanup_adder:
   ecma_deref_object (adder_func_p);
 cleanup_object:

jerry-core/ecma/operations/ecma-iterator-object.c

@@ -579,10 +579,20 @@ ecma_op_iterator_close (ecma_value_t iterator) /**< iterator value */
  *         raised error - otherwise
  */
 ecma_value_t
-ecma_op_iterator_step (ecma_value_t iterator) /**< iterator value */
+ecma_op_iterator_step (ecma_value_t iterator, /**< iterator value */
+                       ecma_value_t next_method) /**< next method */
 {
   /* 1. */
-  ecma_value_t result = ecma_op_iterator_next_old (iterator, ECMA_VALUE_EMPTY);
+  ecma_value_t result;
+  if (next_method == ECMA_VALUE_EMPTY)
+  {
+    /* TODO: EMPTY support should be removed after all functions support next method caching. */
+    result = ecma_op_iterator_next_old (iterator, ECMA_VALUE_EMPTY);
+  }
+  else
+  {
+    result = ecma_op_iterator_next (iterator, next_method, ECMA_VALUE_EMPTY);
+  }
 
   /* 2. */
   if (ECMA_IS_VALUE_ERROR (result))

jerry-core/ecma/operations/ecma-iterator-object.h

@@ -66,7 +66,7 @@ ecma_value_t
 ecma_op_iterator_close (ecma_value_t iterator);
 
 ecma_value_t
-ecma_op_iterator_step (ecma_value_t iterator);
+ecma_op_iterator_step (ecma_value_t iterator, ecma_value_t next_method);
 
 ecma_value_t
 ecma_op_iterator_do (ecma_iterator_command_type_t command, ecma_value_t iterator,

jerry-core/ecma/operations/ecma-typedarray-object.c

@@ -777,7 +777,8 @@ ecma_op_typedarray_from (ecma_value_t items_val, /**< the source array-like obje
   if (!ecma_is_value_undefined (using_iterator))
   {
     /* 8.a */
-    ecma_value_t iterator = ecma_op_get_iterator (items_val, using_iterator, NULL);
+    ecma_value_t next_method;
+    ecma_value_t iterator = ecma_op_get_iterator (items_val, using_iterator, &next_method);
     ecma_free_value (using_iterator);
 
     /* 8.b */
@@ -794,7 +795,7 @@ ecma_op_typedarray_from (ecma_value_t items_val, /**< the source array-like obje
     while (true)
     {
       /* 8.e.i */
-      ecma_value_t next = ecma_op_iterator_step (iterator);
+      ecma_value_t next = ecma_op_iterator_step (iterator, next_method);
 
       /* 8.e.ii */
       if (ECMA_IS_VALUE_ERROR (next))
@@ -822,6 +823,7 @@ ecma_op_typedarray_from (ecma_value_t items_val, /**< the source array-like obje
     }
 
     ecma_free_value (iterator);
+    ecma_free_value (next_method);
 
     if (ECMA_IS_VALUE_ERROR (ret_value))
     {

jerry-core/parser/js/byte-code.h

@@ -194,8 +194,8 @@
 #define PARSER_FINALLY_CONTEXT_STACK_ALLOCATION 2
 /* PARSER_FOR_IN_CONTEXT_STACK_ALLOCATION must be <= 4 */
 #define PARSER_FOR_IN_CONTEXT_STACK_ALLOCATION 4
-/* PARSER_FOR_OF_CONTEXT_STACK_ALLOCATION must be <= 3 */
+/* PARSER_FOR_OF_CONTEXT_STACK_ALLOCATION must be <= 4 */
-#define PARSER_FOR_OF_CONTEXT_STACK_ALLOCATION 3
+#define PARSER_FOR_OF_CONTEXT_STACK_ALLOCATION 4
 /* PARSER_WITH_CONTEXT_STACK_ALLOCATION must be <= 4 */
 #define PARSER_WITH_CONTEXT_STACK_ALLOCATION 1
 /* PARSER_BLOCK_CONTEXT_STACK_ALLOCATION must be <= 3 */

jerry-core/vm/opcodes.c

@@ -339,13 +339,14 @@ opfunc_append_to_spread_array (ecma_value_t *stack_top_p, /**< current stack top
       ecma_value_t ret_value = ECMA_VALUE_ERROR;
       ecma_value_t spread_value = stack_top_p[i];
 
-      ecma_value_t iterator = ecma_op_get_iterator (spread_value, ECMA_VALUE_SYNC_ITERATOR, NULL);
+      ecma_value_t next_method;
+      ecma_value_t iterator = ecma_op_get_iterator (spread_value, ECMA_VALUE_SYNC_ITERATOR, &next_method);
 
       if (!ECMA_IS_VALUE_ERROR (iterator))
       {
         while (true)
         {
-          ecma_value_t next_value = ecma_op_iterator_step (iterator);
+          ecma_value_t next_value = ecma_op_iterator_step (iterator, next_method);
 
           if (ECMA_IS_VALUE_ERROR (next_value))
           {
@@ -380,6 +381,7 @@ opfunc_append_to_spread_array (ecma_value_t *stack_top_p, /**< current stack top
       }
 
       ecma_free_value (iterator);
+      ecma_free_value (next_method);
       ecma_free_value (spread_value);
 
       if (ECMA_IS_VALUE_ERROR (ret_value))
@@ -432,13 +434,14 @@ opfunc_spread_arguments (ecma_value_t *stack_top_p, /**< pointer to the current
     ecma_value_t spread_value = *stack_top_p++;
     i++;
 
-    ecma_value_t iterator = ecma_op_get_iterator (spread_value, ECMA_VALUE_SYNC_ITERATOR, NULL);
+    ecma_value_t next_method;
+    ecma_value_t iterator = ecma_op_get_iterator (spread_value, ECMA_VALUE_SYNC_ITERATOR, &next_method);
 
     if (!ECMA_IS_VALUE_ERROR (iterator))
     {
       while (true)
       {
-        ecma_value_t next_value = ecma_op_iterator_step (iterator);
+        ecma_value_t next_value = ecma_op_iterator_step (iterator, next_method);
 
         if (ECMA_IS_VALUE_ERROR (next_value))
         {
@@ -465,6 +468,7 @@ opfunc_spread_arguments (ecma_value_t *stack_top_p, /**< pointer to the current
     }
 
     ecma_free_value (iterator);
+    ecma_free_value (next_method);
     ecma_free_value (spread_value);
 
     if (ECMA_IS_VALUE_ERROR (ret_value))

jerry-core/vm/vm-stack.c

@@ -81,6 +81,8 @@ vm_stack_context_abort (vm_frame_ctx_t *frame_ctx_p, /**< frame context */
     case VM_CONTEXT_FOR_OF:
     {
       ecma_value_t iterator = vm_stack_top_p[-3];
+      ecma_free_value (vm_stack_top_p[-2]);
+      ecma_free_value (vm_stack_top_p[-4]);
 
       if (context_info & VM_CONTEXT_CLOSE_ITERATOR)
       {
@@ -88,7 +90,6 @@ vm_stack_context_abort (vm_frame_ctx_t *frame_ctx_p, /**< frame context */
       }
       ecma_free_value (iterator);
 
-      ecma_free_value (vm_stack_top_p[-2]);
       VM_MINUS_EQUAL_U16 (frame_ctx_p->context_depth, PARSER_FOR_OF_CONTEXT_STACK_ALLOCATION);
       vm_stack_top_p -= PARSER_FOR_OF_CONTEXT_STACK_ALLOCATION;
       break;
@@ -339,7 +340,8 @@ vm_get_context_value_offsets (ecma_value_t *context_item_p) /**< any item of a c
     }
     case VM_CONTEXT_FOR_OF:
     {
-      return ((3 << (VM_CONTEXT_OFFSET_SHIFT * 2))
+      return ((4 << (VM_CONTEXT_OFFSET_SHIFT * 3))
+              | (3 << (VM_CONTEXT_OFFSET_SHIFT * 2))
               | (2 << (VM_CONTEXT_OFFSET_SHIFT))
               | PARSER_FOR_OF_CONTEXT_STACK_ALLOCATION);
     }

jerry-core/vm/vm.c

@@ -2055,7 +2055,7 @@ vm_loop (vm_frame_ctx_t *frame_ctx_p) /**< frame context */
         {
           JERRY_ASSERT (opcode >= CBC_EXT_ITERATOR_STEP && opcode <= CBC_EXT_ITERATOR_STEP_3);
           const uint8_t index = (uint8_t) (1 + (opcode - CBC_EXT_ITERATOR_STEP));
-          result = ecma_op_iterator_step (stack_top_p[-index]);
+          result = ecma_op_iterator_step (stack_top_p[-index], ECMA_VALUE_EMPTY);
 
           if (ECMA_IS_VALUE_ERROR (result))
           {
@@ -2113,7 +2113,7 @@ vm_loop (vm_frame_ctx_t *frame_ctx_p) /**< frame context */
 
           while (true)
           {
-            result = ecma_op_iterator_step (iterator);
+            result = ecma_op_iterator_step (iterator, ECMA_VALUE_EMPTY);
 
             if (ECMA_IS_VALUE_ERROR (result))
             {
@@ -3786,7 +3786,8 @@ vm_loop (vm_frame_ctx_t *frame_ctx_p) /**< frame context */
 
           JERRY_ASSERT (VM_GET_REGISTERS (frame_ctx_p) + register_end + frame_ctx_p->context_depth == stack_top_p);
 
-          ecma_value_t iterator = ecma_op_get_iterator (value, ECMA_VALUE_SYNC_ITERATOR, NULL);
+          ecma_value_t next_method;
+          ecma_value_t iterator = ecma_op_get_iterator (value, ECMA_VALUE_SYNC_ITERATOR, &next_method);
 
           ecma_free_value (value);
 
@@ -3796,22 +3797,34 @@ vm_loop (vm_frame_ctx_t *frame_ctx_p) /**< frame context */
             goto error;
           }
 
-          ecma_value_t next_value = ecma_op_iterator_step (iterator);
+          result = ecma_op_iterator_step (iterator, next_method);
 
-          if (ECMA_IS_VALUE_ERROR (next_value))
+          if (ECMA_IS_VALUE_ERROR (result))
           {
             ecma_free_value (iterator);
-            result = next_value;
+            ecma_free_value (next_method);
             goto error;
           }
 
-          if (ecma_is_value_false (next_value))
+          if (ecma_is_value_false (result))
           {
             ecma_free_value (iterator);
+            ecma_free_value (next_method);
             byte_code_p = byte_code_start_p + branch_offset;
             continue;
           }
 
+          ecma_value_t next_value = ecma_op_iterator_value (result);
+          ecma_free_value (result);
+
+          if (ECMA_IS_VALUE_ERROR (next_value))
+          {
+            result = next_value;
+            ecma_free_value (iterator);
+            ecma_free_value (next_method);
+            goto error;
+          }
+
           branch_offset += (int32_t) (byte_code_start_p - frame_ctx_p->byte_code_start_p);
 
           VM_PLUS_EQUAL_U16 (frame_ctx_p->context_depth, PARSER_FOR_OF_CONTEXT_STACK_ALLOCATION);
@@ -3819,6 +3832,7 @@ vm_loop (vm_frame_ctx_t *frame_ctx_p) /**< frame context */
           stack_top_p[-1] = VM_CREATE_CONTEXT (VM_CONTEXT_FOR_OF, branch_offset) | VM_CONTEXT_CLOSE_ITERATOR;
           stack_top_p[-2] = next_value;
           stack_top_p[-3] = iterator;
+          stack_top_p[-4] = next_method;
 
           if (byte_code_p[0] == CBC_EXT_OPCODE && byte_code_p[1] == CBC_EXT_CLONE_CONTEXT)
           {
@@ -3832,22 +3846,33 @@ vm_loop (vm_frame_ctx_t *frame_ctx_p) /**< frame context */
           ecma_value_t *context_top_p = VM_GET_REGISTERS (frame_ctx_p) + register_end + frame_ctx_p->context_depth;
           JERRY_ASSERT (VM_GET_CONTEXT_TYPE (context_top_p[-1]) == VM_CONTEXT_FOR_OF);
 
-          ecma_value_t next_value = ecma_op_iterator_value (context_top_p[-2]);
+          *stack_top_p++ = context_top_p[-2];
-
+          context_top_p[-2] = ECMA_VALUE_UNDEFINED;
-          if (ECMA_IS_VALUE_ERROR (next_value))
-          {
-            result = next_value;
-            goto error;
-          }
-
-          *stack_top_p++ = next_value;
           continue;
         }
         case VM_OC_FOR_OF_HAS_NEXT:
         {
           JERRY_ASSERT (VM_GET_REGISTERS (frame_ctx_p) + register_end + frame_ctx_p->context_depth == stack_top_p);
 
-          ecma_value_t next_value = ecma_op_iterator_step (stack_top_p[-3]);
+          result = ecma_op_iterator_step (stack_top_p[-3], stack_top_p[-4]);
+
+          if (ECMA_IS_VALUE_ERROR (result))
+          {
+            goto error;
+          }
+
+          if (ecma_is_value_false (result))
+          {
+            ecma_free_value (stack_top_p[-2]);
+            ecma_free_value (stack_top_p[-3]);
+            ecma_free_value (stack_top_p[-4]);
+            VM_MINUS_EQUAL_U16 (frame_ctx_p->context_depth, PARSER_FOR_OF_CONTEXT_STACK_ALLOCATION);
+            stack_top_p -= PARSER_FOR_OF_CONTEXT_STACK_ALLOCATION;
+            continue;
+          }
+
+          ecma_value_t next_value = ecma_op_iterator_value (result);
+          ecma_free_value (result);
 
           if (ECMA_IS_VALUE_ERROR (next_value))
           {
@@ -3855,18 +3880,9 @@ vm_loop (vm_frame_ctx_t *frame_ctx_p) /**< frame context */
             goto error;
           }
 
-          if (!ecma_is_value_false (next_value))
+          JERRY_ASSERT (stack_top_p[-2] == ECMA_VALUE_UNDEFINED);
-          {
+          stack_top_p[-2] = next_value;
-            ecma_free_value (stack_top_p[-2]);
+          byte_code_p = byte_code_start_p + branch_offset;
-            stack_top_p[-2] = next_value;
-            byte_code_p = byte_code_start_p + branch_offset;
-            continue;
-          }
-
-          ecma_free_value (stack_top_p[-2]);
-          ecma_free_value (stack_top_p[-3]);
-          VM_MINUS_EQUAL_U16 (frame_ctx_p->context_depth, PARSER_FOR_OF_CONTEXT_STACK_ALLOCATION);
-          stack_top_p -= PARSER_FOR_OF_CONTEXT_STACK_ALLOCATION;
           continue;
         }
 #endif /* ENABLED (JERRY_ESNEXT) */

tests/jerry/es.next/for-of.js

@@ -119,3 +119,41 @@ var i = 0;
 for (var a of obj) {
   assert (a === i++);
 }
+
+var status = 0;
+i = 0;
+
+function yieldNext() {
+  ++status
+  assert(status === 3 || status === 6 || status === 9)
+  return {
+    get value() {
+      ++status
+      assert(status === 4 || status === 7)
+      return "Res"
+    },
+    done: ++i >= 3
+  }
+}
+
+obj = {
+  [Symbol.iterator]() {
+    assert(++status === 1)
+    return {
+      get next() {
+        assert(++status === 2)
+        return yieldNext
+      }
+    }
+  }
+}
+
+function getX() {
+  ++status
+  assert(status === 5 || status === 8)
+  return { x:0 }
+}
+
+for (getX().x of obj)
+  ;
+assert(status == 9)

tests/test262-es6-excludelist.xml

@@ -360,6 +360,7 @@
   <test id="language/statements/continue/simple-and-labeled.js"><reason></reason></test>
   <test id="language/statements/for-of/body-dstr-assign-error.js"><reason></reason></test>
   <test id="language/statements/for-of/body-dstr-assign.js"><reason></reason></test>
+  <test id="language/statements/for-of/iterator-next-reference.js"><reason>ES spec change: next method must be cached</reason></test>
   <test id="language/statements/for/S12.6.3_A9.1.js"><reason></reason></test>
   <test id="language/statements/for/S12.6.3_A9.js"><reason></reason></test>
   <test id="language/statements/generators/has-instance.js"><reason></reason></test>