title: Rails Simple Form Inspection error 'null' is too big for type inference
body: <p>Not entirely sure if this is an actual problem with my code or if it is potentially a RubyMine bug as it appeared after updating, but not all my forms have the problem. </p>
  
  <p>I have a Simple Form that the entire form is being highlighted with the inspection error: 'null' is too big for type inference. The form works fine and I haven't had it run into any actual errors. Messing with the file the only way I could get the inspection to go away was removing the buttons from the form.</p>
  
  <p>The buttons are a bit convoluted but the functions are:</p>
  
  <ul>
  <li><p>Submit button that overrides validations (only for development)</p></li>
  <li><p>Disabled Fake Submit button (Just for user</p></li>
  <li><p>Hidden Submit button (shown when another button that triggers JS succeeds)</p></li>
  <li><p>Cancel Button</p></li>
  <li><p>There is also another button in the form the just triggers a JS method</p></li>
  </ul>
  
  <p>If I remove all of the buttons the errors clears, but no combination of removing some and leaving some gets rid of the error. Only removing all of them will clear it. Currently the form in HAML, but even after converting to ERB it still gave the same inspection error. </p>
  
  <p>I realize I can just ignore the error since it's just an inspection error and it runs. However, if the inspection is really showing a potential problem I would like to resolve it. And it makes it nearly impossible to see other errors/inspects as it highlights the entire file. Thank you in advance for any help you can provide.</p>
  
  <p><a href="https://i.stack.imgur.com/oUGq3.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/oUGq3.png" alt="Here is the error discription"></a></p>
  
  <pre><code># Button to run JS method
  &lt;%= f.button :button, 'Run Green Sheet Calculations', type: 'button', id: 'run_green_sheet_calc', class: 'calc_btn', data: {disable_with: 'Please Wait'} %&gt;
  
  
  .modal-footer
    # Development Button to submit form without validations
    -if Rails.env.development?
      = f.button :button, 'Submit - No Validations', type: 'submit', class: 'btn btn-success contract_submit_button', id: 'submit_form_no_validate', data: {disable_with: 'Please wait…'}, name: 'no_validate', value: 'no_validate'
  
    # Disabled fake submit, just so user knows they need to do something to submit
    = f.button :submit, type: 'button', readonly: true, id: 'fake_submit', data: {disable_with: 'Run Calculations to Submit'}, value: 'Run Calculations to Submit'
  
    # Hidden Submit button that is shown after JS method succeeds from top button
    = f.button :submit, class: 'btn btn-success contract_submit_button hidden', id: 'submit_form', data: {disable_with: 'Please wait…'}, value: 'Submit'
  
    # Cancel button to dismiss modal
    = link_to 'Cancel', '#', class: 'btn btn-danger', data: {dismiss: 'modal'}, type: 'button'
  </code></pre>
  
  <p>Environment:</p>
  
  <ul>
  <li><p>RubyMine: 2018.1.1</p></li>
  <li><p>Build: #RM-181.4445.97, built on April 11, 2018</p></li>
  <li><p>JRE: 1.8.0_152-release-1136-b27 x86_64</p></li>
  <li><p>JVM: OpenJDK 64-Bit Server VM by JetBrains s.r.o</p></li>
  <li><p>Ruby: 2.3.3</p></li>
  <li><p>Rails: 5.0.0</p></li>
  <li><p>macOS 10.13.4</p></li>
  </ul>