Rails: Can't render error messages - ruby-on-rails

Question

I'm trying to render errors messages that arise from model validation but I end up with this error:
First argument in form cannot contain nil or be empty
Hopefully the provided code with be of assistance... I was able to at least get the pages to load when I used :comment instead of #comment, but then I didn't know how to then render the errors partial because it was a symbol and not an actual object. Now that I have changed it to an instance variable of an object, I get the error.
Error messages partial
<% if object.errors.any? %>
<div id="error_explanation">
<div class="alert alert-danger">
The form contains <%= pluralize(object.errors.count, "error") %>
</div>
<ul>
<% object.errors.full_messages.each do |msg| %>
<li><%= msg %></li>
<% end %>
</ul>
</div>
<% end %>
Comment form
<%= form_for #comment, url: comments_path do |f| %>
<%= render 'shared/error_messages', object: f.object %>
<%= f.hidden_field :user_id, value: current_user.id %>
<%= f.hidden_field :post_id, value: post.id %>
<%= f.text_area :content, size: "60x2", placeholder: "Comment on this post..." %>
<%= f.submit "Comment" %>
Post form
<%= form_for [#user, #post] do |f| %>
<%= render 'shared/error_messages', object: f.object %>
<%= f.text_area :content, size: "60x12", placeholder: "What do you want to say?" %>
<%= f.submit "Post" %>
<% end %>
class CommentsController < ApplicationController
def index
#comments = Comment.all
end
def new
#comment = Comment.new
#user = User.find(params[:user_id])
end
def create
#user = current_user
##post = Post.find(params[:post_id])
#comment = #user.comments.build(comment_params)
if #comment.save
flash[:success] = "Comment Posted!"
redirect_back(fallback_location: root_path)
else
flash[:notice] = "Could not post comment"
redirect_back(fallback_location: root_path)
end
end
private
def comment_params
params.require(:comment).permit(:content, :user_id, :post_id)
end
end
class PostsController < ApplicationController
def index
#posts = Post.all
#user = User.find(params[:user_id])
end
def new
#post = Post.new
#user = User.find(params[:user_id])
end
def create
#post = current_user.posts.build(post_params)
if #post.save
flash[:success] = "Posted!"
redirect_to user_path(current_user)
else
flash[:notice] = "Post could not be submitted"
redirect_to users_path
end
end
private
def post_params
params.require(:post).permit(:content)
end
end

Answer 1

I was able to get it by declaring an #comment variable in my posts#index action because that is where the view is being rendered from