python
diff --git a/‎Python/symtable.c‎
Lines changed: 19 additions & 9 deletions b/‎Python/symtable.c‎
Lines changed: 19 additions & 9 deletions
@@ -1455,6 +1455,7 @@ symtable_enter_existing_block(struct symtable *st, PySTEntryObject* ste, bool ad
 
     if (add_to_children && prev) {
         if (PyList_Append(prev->ste_children, (PyObject *)ste) < 0) {
+            symtable_exit_block(st);
             return 0;
         }
     }
@@ -1466,21 +1467,27 @@ symtable_enter_block(struct symtable *st, identifier name, _Py_block_ty block,
                      void *ast, _Py_SourceLocation loc)
 {
     PySTEntryObject *ste = ste_new(st, name, block, ast, loc);
-    if (ste == NULL)
+    if (ste == NULL) {
         return 0;
+    }
     int result = symtable_enter_existing_block(st, ste, /* add_to_children */true);
     Py_DECREF(ste);
+    if (result == 0) {
+        return 0;
+    }
     if (block == AnnotationBlock || block == TypeVariableBlock || block == TypeAliasBlock) {
         _Py_DECLARE_STR(format, ".format");
         // We need to insert code that reads this "parameter" to the function.
         if (!symtable_add_def(st, &_Py_STR(format), DEF_PARAM, loc)) {
+            symtable_exit_block(st);
             return 0;
         }
         if (!symtable_add_def(st, &_Py_STR(format), USE, loc)) {
+            symtable_exit_block(st);
             return 0;
         }
     }
-    return result;
+    return 1;
 }
 
 static long
@@ -1676,41 +1683,44 @@ symtable_enter_type_param_block(struct symtable *st, identifier name,
     if (current_type == ClassBlock) {
         st->st_cur->ste_can_see_class_scope = 1;
         if (!symtable_add_def(st, &_Py_ID(__classdict__), USE, loc)) {
-            return 0;
+            goto error;
         }
     }
     if (kind == ClassDef_kind) {
         _Py_DECLARE_STR(type_params, ".type_params");
         // It gets "set" when we create the type params tuple and
         // "used" when we build up the bases.
         if (!symtable_add_def(st, &_Py_STR(type_params), DEF_LOCAL, loc)) {
-            return 0;
+            goto error;
         }
         if (!symtable_add_def(st, &_Py_STR(type_params), USE, loc)) {
-            return 0;
+            goto error;
         }
         // This is used for setting the generic base
         _Py_DECLARE_STR(generic_base, ".generic_base");
         if (!symtable_add_def(st, &_Py_STR(generic_base), DEF_LOCAL, loc)) {
-            return 0;
+            goto error;
         }
         if (!symtable_add_def(st, &_Py_STR(generic_base), USE, loc)) {
-            return 0;
+            goto error;
         }
     }
     if (has_defaults) {
         _Py_DECLARE_STR(defaults, ".defaults");
         if (!symtable_add_def(st, &_Py_STR(defaults), DEF_PARAM, loc)) {
-            return 0;
+            goto error;
         }
     }
     if (has_kwdefaults) {
         _Py_DECLARE_STR(kwdefaults, ".kwdefaults");
         if (!symtable_add_def(st, &_Py_STR(kwdefaults), DEF_PARAM, loc)) {
-            return 0;
+            goto error;
         }
     }
     return 1;
+error:
+    symtable_exit_block(st);
+    return 0;
 }
 
 /* VISIT, VISIT_SEQ and VISIT_SEQ_TAIL take an ASDL type as their second argument.
Original file line number	Diff line number	Diff line change
`@@ -1455,6 +1455,7 @@ symtable_enter_existing_block(struct symtable st, PySTEntryObject ste, bool ad`
`1455`	`1455`
`1456`	`1456`	`if (add_to_children && prev) {`
`1457`	`1457`	`if (PyList_Append(prev->ste_children, (PyObject *)ste) < 0) {`
	`1458`	`+ symtable_exit_block(st);`
`1458`	`1459`	`return 0;`
`1459`	`1460`	`}`
`1460`	`1461`	`}`
`@@ -1466,21 +1467,27 @@ symtable_enter_block(struct symtable *st, identifier name, _Py_block_ty block,`
`1466`	`1467`	`void *ast, _Py_SourceLocation loc)`
`1467`	`1468`	`{`
`1468`	`1469`	`PySTEntryObject *ste = ste_new(st, name, block, ast, loc);`
`1469`		`- if (ste == NULL)`
	`1470`	`+ if (ste == NULL) {`
`1470`	`1471`	`return 0;`
	`1472`	`+ }`
`1471`	`1473`	`int result = symtable_enter_existing_block(st, ste, /* add_to_children */true);`
`1472`	`1474`	`Py_DECREF(ste);`
	`1475`	`+ if (result == 0) {`
	`1476`	`+ return 0;`
	`1477`	`+ }`
`1473`	`1478`	`if (block == AnnotationBlock \|\| block == TypeVariableBlock \|\| block == TypeAliasBlock) {`
`1474`	`1479`	`_Py_DECLARE_STR(format, ".format");`
`1475`	`1480`	`// We need to insert code that reads this "parameter" to the function.`
`1476`	`1481`	`if (!symtable_add_def(st, &_Py_STR(format), DEF_PARAM, loc)) {`
	`1482`	`+ symtable_exit_block(st);`
`1477`	`1483`	`return 0;`
`1478`	`1484`	`}`
`1479`	`1485`	`if (!symtable_add_def(st, &_Py_STR(format), USE, loc)) {`
	`1486`	`+ symtable_exit_block(st);`
`1480`	`1487`	`return 0;`
`1481`	`1488`	`}`
`1482`	`1489`	`}`
`1483`		`- return result;`
	`1490`	`+ return 1;`
`1484`	`1491`	`}`
`1485`	`1492`
`1486`	`1493`	`static long`
`@@ -1676,41 +1683,44 @@ symtable_enter_type_param_block(struct symtable *st, identifier name,`
`1676`	`1683`	`if (current_type == ClassBlock) {`
`1677`	`1684`	`st->st_cur->ste_can_see_class_scope = 1;`
`1678`	`1685`	`if (!symtable_add_def(st, &_Py_ID(__classdict__), USE, loc)) {`
`1679`		`- return 0;`
	`1686`	`+ goto error;`
`1680`	`1687`	`}`
`1681`	`1688`	`}`
`1682`	`1689`	`if (kind == ClassDef_kind) {`
`1683`	`1690`	`_Py_DECLARE_STR(type_params, ".type_params");`
`1684`	`1691`	`// It gets "set" when we create the type params tuple and`
`1685`	`1692`	`// "used" when we build up the bases.`
`1686`	`1693`	`if (!symtable_add_def(st, &_Py_STR(type_params), DEF_LOCAL, loc)) {`
`1687`		`- return 0;`
	`1694`	`+ goto error;`
`1688`	`1695`	`}`
`1689`	`1696`	`if (!symtable_add_def(st, &_Py_STR(type_params), USE, loc)) {`
`1690`		`- return 0;`
	`1697`	`+ goto error;`
`1691`	`1698`	`}`
`1692`	`1699`	`// This is used for setting the generic base`
`1693`	`1700`	`_Py_DECLARE_STR(generic_base, ".generic_base");`
`1694`	`1701`	`if (!symtable_add_def(st, &_Py_STR(generic_base), DEF_LOCAL, loc)) {`
`1695`		`- return 0;`
	`1702`	`+ goto error;`
`1696`	`1703`	`}`
`1697`	`1704`	`if (!symtable_add_def(st, &_Py_STR(generic_base), USE, loc)) {`
`1698`		`- return 0;`
	`1705`	`+ goto error;`
`1699`	`1706`	`}`
`1700`	`1707`	`}`
`1701`	`1708`	`if (has_defaults) {`
`1702`	`1709`	`_Py_DECLARE_STR(defaults, ".defaults");`
`1703`	`1710`	`if (!symtable_add_def(st, &_Py_STR(defaults), DEF_PARAM, loc)) {`
`1704`		`- return 0;`
	`1711`	`+ goto error;`
`1705`	`1712`	`}`
`1706`	`1713`	`}`
`1707`	`1714`	`if (has_kwdefaults) {`
`1708`	`1715`	`_Py_DECLARE_STR(kwdefaults, ".kwdefaults");`
`1709`	`1716`	`if (!symtable_add_def(st, &_Py_STR(kwdefaults), DEF_PARAM, loc)) {`
`1710`		`- return 0;`
	`1717`	`+ goto error;`
`1711`	`1718`	`}`
`1712`	`1719`	`}`
`1713`	`1720`	`return 1;`
	`1721`	`+error:`
	`1722`	`+ symtable_exit_block(st);`
	`1723`	`+ return 0;`
`1714`	`1724`	`}`
`1715`	`1725`
`1716`	`1726`	`/* VISIT, VISIT_SEQ and VISIT_SEQ_TAIL take an ASDL type as their second argument.`