Lumen 为何不能够像 Laravel 一样在 function 中就根据主键自动实例化出 EloquentModel 实例?

像laravel public function like(Comment $comment, CommentService $service) 这样你route中{comment}主键ID, 你后面程序中就会自动获取到$comment这个Eloquent实例, 不存在这个ID就会抛出异常, 而在lumen中为何这种形式就不行了必须把$comment= Comment::find($comment) 再去查找一遍, 这样让我不爽, 有没有像laravel这样去实现的方法.
laravel :

public function like(Comment $comment, CommentService $service)
    {
        return DB::transaction(function () use ($comment, $service) {
            $like = CommentLike::where(['create_user_id' => auth()->user()->id, 'comment_id' => $comment->id])->first();

            if ($like != null) {
                //已存在点赞, 执行取消点赞
                $comment->decrement('like');
                $comment->decrement('hot', $service->getIncrementHotValue());
                $like->delete();
            } else {
                $comment->increment('like');
                $comment->increment('hot', $service->getIncrementHotValue());

                CommentLike::create([
                    'article_id' => $comment->article_id,
                    'create_user_id' => auth()->user()->id,
                    'comment_id' => $comment->id
                ]);
            }

            return responseSuccess($service->getSingleComment($comment, auth()->user(), false));
        });
    }

Lumen:

 public function like($comment, CommentService $service)
    {
        //Lumen无法在进入这个方法的时候直接根据ID注入生成我需要的对象
        $comment = Comment::where(['id' => $comment])->firstOrFail();

        return DB::transaction(function () use ($comment, $service) {
            $like = CommentLike::where(['create_user_id' => auth()->user()->id, 'comment_id' => $comment->id])->first();

            if ($like != null) {
                //已存在点赞, 执行取消点赞
                $comment->decrement('like');
                $comment->decrement('hot', $service->getIncrementHotValue());
                $like->delete();
            } else {
                $comment->increment('like');
                $comment->increment('hot', $service->getIncrementHotValue());

                CommentLike::create([
                    'article_id' => $comment->article_id,
                    'create_user_id' => auth()->user()->id,
                    'comment_id' => $comment->id
                ]);
            }

            return responseSuccess($service->getSingleComment($comment, auth()->user(), false));
        });
    }