How do I fix the unused variable's error which I used?

Phoenix Forum Questions / Help
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1

In my controller, I improved and prevent dirty code in my project, for example, I was trying to put my params in variable like this:

Original codes :

def create_cms_post(conn, %{ 
      "title" => title, 
      "status" => status, 
      "post_type" => post_type, 
      "download_ext_link" => download_ext_link, 
      "price" => price, 
      "pic_x1_link" => pic_x1_link, 
      "pic_x2_link" => pic_x2_link, 
      "pic_x3_link" => pic_x3_link, 
      "group_acl" => group_acl, 
      "description" => description, 
      "changelog" => changelog, 
      "changelog_category" => changelog_category, 
      "plugin" => plugin, 
      "plugin_category" => plugin_category, 
      ....
      ....
      ....
    }) do

      create_cms_posts = case PostQuery.insert_post(title, status, post_type, **.... and more ...**) do

when I have done it my code was clear.

Edited codes :

def create_cms_post(conn, %{ 
      "title" => title, 
      "status" => status, 
      "post_type" => post_type, 
      "download_ext_link" => download_ext_link, 
      "price" => price, 
      "pic_x1_link" => pic_x1_link, 
      "pic_x2_link" => pic_x2_link, 
      ....
      ....
      ....
    } = allreq) do
      create_cms_posts = case PostQuery.insert_post(allreq) do

I have put params in one variable and I was putting in my function which I needed.

Now my codes works for me without any problems. but I have many the unused errors when I’m compiling my project.

  1. first question, does the errors have a bad efect on me ?
  2. and second , how can I fix this not to show me?

Thanks.

2

They are warnings, if they were errors they had the bad effect of failing the compilation.

Unused variable warnings are emitted during compiletime and should be a hint to you as the developer, that you might have forgotten to actually process a value that you have bound to a name. Thats the main reason for the warning.

It does not affect runtime behaviour off your application (well, maybe stack size is increased because of that, but I am not 100% sure on this as we have a lot of optimizer passes in between).

  1. Use the variables you bound
  2. Prefix the variables with an understcore (eg. _example) while binding
  3. Do not bind at all.
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