bpo-40769: Allow extra surrounding parentheses for invalid annotated assignment rule (GH-20387)

1 files changed, 10 insertions, 2 deletions

diff --git a/Grammar/python.gram b/Grammar/python.gram
index 652f0db..1cba114 100644
--- a/Grammar/python.gram
+++ b/Grammar/python.gram
@@ -646,8 +646,12 @@ invalid_named_expression:
         RAISE_SYNTAX_ERROR_KNOWN_LOCATION(
             a, "cannot use assignment expressions with %s", _PyPegen_get_expr_name(a)) }
 invalid_assignment:
-    | a=list ':' expression { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "only single target (not list) can be annotated") }
-    | a=tuple ':' expression { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "only single target (not tuple) can be annotated") }
+    | a=invalid_ann_assign_target ':' expression {
+        RAISE_SYNTAX_ERROR_KNOWN_LOCATION(
+            a,
+            "only single target (not %s) can be annotated",
+            _PyPegen_get_expr_name(a)
+        )}
     | a=star_named_expression ',' star_named_expressions* ':' expression {
         RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "only single target (not tuple) can be annotated") }
     | a=expression ':' expression {
@@ -661,6 +665,10 @@ invalid_assignment:
             "'%s' is an illegal expression for augmented assignment",
             _PyPegen_get_expr_name(a)
         )}
+invalid_ann_assign_target[expr_ty]:
+    | list
+    | tuple
+    | '(' a=invalid_ann_assign_target ')' { a }
 invalid_del_stmt:
     | 'del' a=star_expressions {
         RAISE_SYNTAX_ERROR_INVALID_TARGET(DEL_TARGETS, a) }