py/vm: "yield from" didn't handle MP_OBJ_STOP_ITERATION optimization.

E.g. crashed when yielding from already stopped generators.

1 files changed, 2 insertions, 1 deletions

diff --git a/py/vm.c b/py/vm.c
index b8d38f78e..bd5bae115 100644
--- a/py/vm.c
+++ b/py/vm.c
@@ -1144,7 +1144,8 @@ yield:
                     if (ret_kind == MP_VM_RETURN_NORMAL) {
                         // Pop exhausted gen
                         sp--;
-                        if (ret_value == MP_OBJ_NULL) {
+                        // TODO: When ret_value can be MP_OBJ_NULL here??
+                        if (ret_value == MP_OBJ_NULL || ret_value == MP_OBJ_STOP_ITERATION) {
                             // Optimize StopIteration
                             // TODO: get StopIteration's value
                             PUSH(mp_const_none);