Preallocate SystemStackError; ref #3421

src/vm.c

@@ -162,7 +162,7 @@ stack_extend_alloc(mrb_state *mrb, int room, int keep)
      to prevent infinite recursion. However, do this only after resizing the stack, so mrb_raise has stack space to work with. */
   if (size > MRB_STACK_MAX) {
     init_new_stack_space(mrb, room, keep);
-    mrb_raise(mrb, E_SYSSTACK_ERROR, "stack level too deep. (limit=" MRB_STRINGIZE(MRB_STACK_MAX) ")");
+    mrb_exc_raise(mrb, mrb_obj_value(mrb->stack_err));
   }
 }