diff --git a/Lib/test/test_syntax.py b/Lib/test/test_syntax.py
index ce1de4b319f20f..a0f487d4ed76b4 100644
--- a/Lib/test/test_syntax.py
+++ b/Lib/test/test_syntax.py
@@ -51,6 +51,10 @@
 Traceback (most recent call last):
 SyntaxError: cannot assign to __debug__
 
+>>> (__debug__ := 1)
+Traceback (most recent call last):
+SyntaxError: cannot assign to __debug__
+
 >>> f() = 1
 Traceback (most recent call last):
 SyntaxError: cannot assign to function call
diff --git a/Python/ast.c b/Python/ast.c
index 5cef3fdadc9ae9..8482a615035b4d 100644
--- a/Python/ast.c
+++ b/Python/ast.c
@@ -1084,7 +1084,7 @@ set_context(struct compiling *c, expr_ty e, expr_context_ty ctx, const node *n)
                 return 0;
             break;
         case Name_kind:
-            if (ctx == Store) {
+            if (ctx == Store || ctx == NamedStore) {
                 if (forbidden_name(c, e->v.Name.id, n, 0))
                     return 0; /* forbidden_name() calls ast_error() */
             }