class.c: const_missing do not have to be in the backtrace; ref #5528

src/class.c

@@ -2460,6 +2460,7 @@ mrb_mod_const_missing(mrb_state *mrb, mrb_value mod)
   mrb_sym sym;
 
   mrb_get_args(mrb, "n", &sym);
+  mrb->c->ci->mid = 0;
 
   if (mrb_class_real(mrb_class_ptr(mod)) != mrb->object_class) {
     mrb_name_error(mrb, sym, "uninitialized constant %v::%n", mod, sym);