revert r73361
diff --git a/Python/ast.c b/Python/ast.c
index 8e1c530..2cc41b2 100644
--- a/Python/ast.c
+++ b/Python/ast.c
@@ -2120,6 +2120,10 @@
         for (i = 0; i < NCH(n) - 2; i += 2) {
             expr_ty e;
             node *ch = CHILD(n, i);
+            if (TYPE(ch) == yield_expr) {
+                ast_error(ch, "assignment to yield expression not possible");
+                return NULL;
+            }
             e = ast_for_testlist(c, ch);
 
             /* set context to assign */