diff --git a/Python/ast.c b/Python/ast.c
index 7edd345fefc8..4e508ebe8809 100644
--- a/Python/ast.c
+++ b/Python/ast.c
@@ -1415,7 +1415,7 @@ ast_for_trailer(struct compiling *c, const node *n, expr_ty left_expr)
             int j;
             slice_ty slc;
             expr_ty e;
-            bool simple;
+            bool simple = true;
             asdl_seq *slices, *elts;
             slices = asdl_seq_new((NCH(n) + 1) / 2, c->c_arena);
             if (!slices)