title: IntelliJ thinks package and file path do not match
body: <p>I have imported a sizable enterprise project into IntelliJ but one particular package in one module is experiencing an issue. IntelliJ gives the error "Package name "X" does not correspond to the file path" when opening any class in this package and as a result refuses to acknowledge the classes as existing when I try to import them elsewhere. It has no problem with other packages at the same level in the module, the folder is visible in the project explorer window to the left and using "Show in Explorer" happily brings up the correct place in the file path. IntelliJ's automatic solution suggests setting the file path to "", suggesting it can't see the folder at all</p>
  
  <p>I can temporarily fix the issue by deleting and then reimporting the module, but as soon as I restart IntelliJ the problem is back. This also removes the dependencies on this module from others and as about 25 other modules depend on this one, it is time-consuming to read these so it's not a long term solution. </p>
  
  <p>I have tried using the Invalidate Caches command but with no success.</p>