IntelliJ IDEA 15 Play 2.4 reverse routing method parameter "string cannot be applied to java.lang.String" - playframework-2.4

Question

I use IntelliJ IDEA 15.0.4 to develop a Java Play! 2.4.4 application. Since a few months (I think it was because of an IntelliJ update, but not 100% sure) the following problem occurs:
Whenever I call a reverse route from a controller that takes a String as a parameter, the parameter is displayed as an error with the following message:
methodName (string) in ReverseMyController cannot be applied to (java.lang.String)
Here's a code example:
public Result myAction(String myId) {
// Do something...
// Redirect back to referrer
flash("success", "Action was a success");
if(!myId.isEmpty()) return redirect(controllers.routes.MyController.showItem(myId));
return redirect(controllers.routes.MyController.itemList(1));
}
In this example, the parameter myId passed to the method showItem would be error highlighted, like this.
I already tried fiddling with the Project Structure settings and searched Google, but to no avail. I hope somebody is able to help me with this, my OCD-self would really appreciate having a code base with no error hints again ;)

Answer 1

Accepted answer does not solve the problem that is why I am answering this old question.
I had the same problem with Play 2.5.4 and InteliJ 2016.1.3
I removed the type (String) from route declaration in routes file and InteliJ stopped highlighting it as error.
Change following:
GET /path/:string_arg controllers.MyController.myMethod(string_arg: String)
To
GET /path/:string_arg controllers.MyController.myMethod(string_arg)
and it works fine.

Answer 2

Yes, I meet the same issue as what you said. I think it is a bug of the IDEA 15.0.4, Have you tried to change to the older version before 15.0.4?