Method flash not found in Gears\Session

[osc2nuke]

Using phpStorm i get a notice in my controller:

"Method flash not found in \Gears\Session.
Referenced Method is not found in subject class"

in my controller:
Session::flash('message', $product->getName() . ' added to cart');
in my View:
@if ($flash = Session::get('message')) <div class="alert alert-success alert-dismissible fade show"><button type="button" class="close" data-dismiss="alert">&times;</button>{{$flash}}</div> @endif

But the call works:
https://www.youtube.com/watch?v=WtJbyb7TgCk