Check stack size before accessing env stack; fix
MODIFY
src/vm.c
src/vm.c
@@ -2156,7 +2156,8 @@ RETRY_TRY_BLOCK:
else {
struct REnv *e = uvenv(mrb, lv-1);
if (!e || e->cioff == 0 ||
- (!MRB_ENV_STACK_SHARED_P(e) && e->cxt.mid == 0)) {
+ (!MRB_ENV_STACK_SHARED_P(e) && e->cxt.mid == 0) ||
+ MRB_ENV_STACK_LEN(e) <= m1+r+m2+1) {
localjump_error(mrb, LOCALJUMP_ERROR_YIELD);
goto L_RAISE;
}

Check stack size before accessing env stack; fix #3727