Backport 58330:
Fix Coverity #158: Check the correct variable.
diff --git a/Python/ast.c b/Python/ast.c
index c96c503..2c03ad6 100644
--- a/Python/ast.c
+++ b/Python/ast.c
@@ -1445,7 +1445,7 @@
                 tmp_result = BinOp(result, newoperator, tmp, 
 				   LINENO(next_oper), next_oper->n_col_offset,
                                    c->c_arena);
-		if (!tmp) 
+		if (!tmp_result) 
 			return NULL;
 		result = tmp_result;
 	}