Hi,
this message started appearing all over my files since the latest phpstorm update.
To remove this warning all solutions say to look into : Settings/Preferences | Editor | Inspections | PHP | Undefined | Undefined class, it has "Don't report multiple class declaration potential problems" checkbox.
But mine DOESN'T have the checkbox in there.
It only has an ignore PHPdocs which doesn't change the problem.
What class is it? Try ctrl+click on it to see what classes matches. For me it was some .stub files. So I just set phpstorm to ignore .stub files, and the error was gone.
@Sinnbeck It's literally all my custom models. It's due to the laravel ide helper model file I think, but it was never an issue until the phpstorm upgrade from today.