Ruby on Rails: undefined method `user' for nil:NilClassのNoMethodErrorについて

Question

show.html.erbにイイね機能とコメント機能を付けたのち、以下のようなエラーが出てしまいました。

関連あるようなコードは以下のように乗っけていきます。

class User < ApplicationRecord
  # Include default devise modules. Others available are:
  # :confirmable, :lockable, :timeoutable, :trackable and :omniauthable
  devise :database_authenticatable, :registerable,
         :recoverable, :rememberable, :validatable

  has_many :articles, dependent: :destroy
  has_many :comments
  has_many :comments, dependent: :destroy
  has_many :likes
  has_many :likes, dependent: :destroy
  has_many :liked_articles, through: :likes, source: :article

  def already_liked?(article)
    self.likes.exists?(article_id: article.id)
  end

end

class Article < ApplicationRecord
    belongs_to :user
    has_many :likes, dependent: :destroy
    has_many :liked_users, through: :likes, source: :user
    has_many :comments, dependent: :destroy
end

class Comment < ApplicationRecord
    belongs_to :article
    belongs_to :user
end

class ArticlesController < ApplicationController
    before_action :authenticate_user!

    def index
        @articles = Article.all
    end

    def new
        @articles = Article.new
    end

    def create
        @articles = Article.new(article_params)

        @articles.user_id = current_user.id

        if @articles.save
          redirect_to :action => "index"
        else
          redirect_to :action => "new"
        end
    end

    def show
        @article = Article.find(params[:id])
        @like = Like.new
        @comments = @article.comments
        @comment = Comment.new 
    end 
    
    private
    def article_params
        params.require(:article).permit(:title,:content,:category)
    end

end

class LikesController < ApplicationController
    def create
      @like = current_user.likes.create(article_id: params[:article_id])
      redirect_back(fallback_location: root_path)
    end
  
    def destroy
      @like = Like.find_by(article_id: params[:article_id], user_id: current_user.id)
      @like.destroy
      redirect_back(fallback_location: root_path)
    end
end

class CommentsController < ApplicationController
    before_action :authenticate_user!
  
    def create
      article = Article.find(params[:article_id])
      comment = article.comments.build(comment_params) #buildを使い、contentとtweet_idの二つを同時に代入
      comment.user_id = current_user.id
      if comment.save
        flash[:success] = "コメントしました"
        redirect_back(fallback_location: root_path)
      else
        flash[:success] = "コメントできませんでした"
        redirect_back(fallback_location: root_path)
      end
    end
  
    private
  
    def comment_params
        params.require(:comment).permit(:content)
    end
end

問題が起きているshow.html.erb

<h4>し か く　 ちゃんねる</h4>
<h1>資格い頻道</h1>

<div class="article">
  <p><%= @articles.user.email %></p>
  <h3><%= @articles.content %></h3>
  <p><%= @articles.created_at %></p>

  <h3>いいね件数: <%= @articles.likes.count %></h3>
  <% if current_user.already_liked?(@article) %>
    <%=link_to article_like_path(@article), method: :delete do%>
        <i class="fas fa-heart"></i>
　　　<%end%>
  <% else %>
    <%=link_to article_likes_path(@article), method: :post do%>
        <i class="fas fa-heart"></i>
　　  <%end%>
  <% end %>

</div>

<h2>いいねしたユーザー</h2>
<% @article.liked_users.each do |user| %>
  <li><%= user.email %></li>
<% end %>

<div class="comment-wrapper">
  <p>コメント一覧</p>
  <% @comments.each do |c| %>
    <div>
      <%= c.user.email unless c.user.blank? %>
      <br>
      <%= c.content %>
    </div>
      <br>
  <% end %>

  <% if user_signed_in? %>
    <%= form_with(model: [@article, @comment], local: true) do |f| %>
      <%= f.text_area :content %>
      <%= button_tag type: "submit" do %>
        <i class="far fa-comments"></i> コメントする
      <% end %>
    <% end %>
  <% end %>
</div>

<%= link_to "編集する", edit_article_path(@article.id) %>
<%= link_to "一覧に戻る", articles_path %>

routes.rb

Rails.application.routes.draw do
  devise_for :users
  # For details on the DSL available within this file, see https://guides.rubyonrails.org/routing.html

  resources :articles do 
    resources :likes, only: [:create, :destroy]
    resources :comments, only: [:create]
  end
  root 'articles#index'

  get 'articles/top'   => 'article#top'
  get 'articles/intro' => 'article#intro'

end

Answer 1

@articlesがnilになってしまっているため、`user'がないぞ！とおっしゃってます。

そこらへんをしらべてみては。