Error when delete comment Ruby on Rails

When I delete comment I see

undefined method 'each' for nil:NilClass

Also, the user cannot delete his account if has posted... It makes the error.

This is code

<p id="notice"><%= notice %></p>

<h1>Comments</h1>

<table>
  <thead>
    <tr>
      <th>Link</th>
      <th>Body</th>
      <th>User</th>
      <th colspan="3"></th>
    </tr>
  </thead>

  <tbody>
    <% @comments.each do |comment| %>
      <tr>
        <td><%= comment.link_id %></td>
        <td><%= comment.body %></td>
        <td><%= comment.user %></td>
        <td><%= link_to 'Show', comment %></td>
        <td><%= link_to 'Edit', edit_comment_path(comment) %></td>
        <td><%= link_to 'Destroy', comment, method: :delete, data: { confirm: 'Are you sure?' } %></td>
      </tr>
    <% end %>
  </tbody>
</table>

<br>

<%= link_to 'New Comment', new_comment_path %>