is_free_in_any_child checks children of nested comprehensions

Author: iritkatriel

Lib/test/test_listcomps.py

@@ -512,6 +512,44 @@ def test_nested_references_super(self):
         """
         self._check_in_scopes(code, outputs={"res": [[super]]})
 
+    def test_nested_inlined_super_does_not_require_class_cell(self):
+        # Nested inlined comps compile super/__class__ as global lookups.
+        # They must not inject __classcell__ the way a nested function would.
+        class Meta(type):
+            def __new__(mcls, name, bases, ns):
+                ns.pop('__classcell__', None)
+                return type.__new__(mcls, name, bases, ns)
+
+        cases = [
+            ("[[super for _ in (0,)] for _ in (0,)]", [[super]]),
+            ("[{super for _ in (0,)} for _ in (0,)]", [{super}]),
+            ("{0: {1: super for _ in (0,)} for _ in (0,)}", {0: {1: super}}),
+        ]
+        for expr, expected in cases:
+            with self.subTest(expr=expr):
+                ns = {"Meta": Meta}
+                exec(f"class C(metaclass=Meta):\n    result = {expr}", ns)
+                self.assertEqual(ns["C"].result, expected)
+
+    def test_nested_inlined_lambda_class_ref_requires_class_cell(self):
+        class Meta(type):
+            def __new__(mcls, name, bases, ns):
+                ns.pop('__classcell__', None)
+                return type.__new__(mcls, name, bases, ns)
+
+        exprs = [
+            "[[lambda: __class__ for _ in (0,)] for _ in (0,)]",
+            "[{lambda: __class__ for _ in (0,)} for _ in (0,)]",
+            "{0: {1: (lambda: __class__) for _ in (0,)} for _ in (0,)}",
+        ]
+        for expr in exprs:
+            with self.subTest(expr=expr):
+                with self.assertRaisesRegex(
+                        RuntimeError,
+                        r"__class__ not set.*__classcell__ propagated"):
+                    exec(f"class C(metaclass=Meta):\n    result = {expr}",
+                         {"Meta": Meta})
+
     def test_nested_2(self):
         code = """
             l = [1, 2, 3]

Python/symtable.c

@@ -805,6 +805,14 @@ is_free_in_any_child(PySTEntryObject *entry, PyObject *key)
     for (Py_ssize_t i = 0; i < PyList_GET_SIZE(entry->ste_children); i++) {
         PySTEntryObject *child_ste = (PySTEntryObject *)PyList_GET_ITEM(
             entry->ste_children, i);
+        if (child_ste->ste_type == InlinedComprehensionBlock) {
+            /* this is the same scope, so we check its children */
+            int nested = is_free_in_any_child(child_ste, key);
+            if (nested != 0) {
+                return nested;
+            }
+            continue;
+        }
         long scope = _PyST_GetScope(child_ste, key);
         if (scope < 0) {
             return -1;