IntelliJ IDEA Report Highlighting error when using routes in Controller - intellij-idea

Question

I have a Scala Play project. I'm using Play 2.2.1. I downloaded Scala, Play 2 supported and SBT plugins. Everything is OK, but When I call route on Action in the Controller appear following error(Look screenshots):
I'm using IntelliJ IDEA 12.1.6 Ultimate version. Scala version 2.10.2
Anybody know how to fix this problem?
Thanks in advance!
Edit
When I generate my project to Intellij IDEA via "play idea" command in play console, and I opened project in IDEA project structure was such:
Then I saw answer #millhouse and discussing on this githup([Play 2.2] "play idea" creates not working source mapping in target) and I removed following folders from Sources Folders:
target\scala-2.10\src_managed\main\controllers
target\scala-2.10\src_managed\main\views
and "Report highlighting error" disappeared, but now there is another error:
and
my route:
And I've changed "Sources Folders" as shown below:
But it doesn't help me. And remains "Unspecified value parametrs" error.

Answer 1

millhouse's answer helped me find the right answer. Play 2.2 (and perhaps earlier versions, haven't checked) output a scala version of the routes file to project_dir/target/scala-2.10/src_managed/main So for IntelliJ to get the highlighting right you need to make sure that src_managed/main is added as a source folder. The reverse routes for javascript are for some reason included in project_dir/target/scala-2.10/classes_managed so you'll have to add that as well. (In your screenshot it looks like classes_managed is set to excluded so you'll want to un-exclude it by pressing the x button on the right hand side.)
Here's a screen shot of my project structure:
Update:
In Play 2.3 (or perhaps recent versions of IntelliJ) adding the classes_managed no longer fixes the problem. Instead of adding classes_managed to the project's sources add it to it's dependencies. By doing that IntelliJ should be able to pick up the compiled routes.class.

Answer 2

This is a common problem, it's because IntelliJ needs to be shown where to look for the compiled Scala templates and routes file. Here's how I fixed it on my IntelliJ 12.1 installation:
Go to the Module Settings for your project in IntelliJ (select the top-level, hit F4)
Choose the Modules item in the Project Structure window that appears
Select the projectname item (as opposed to the projectname-build item)
Add the compiler's output directory to the Source Folders items;
For Scala 2.10 it's target/scala-2.10/classes
I personally find the IntelliJ UI for this to be very non-intuitive; you might need to take the target directory and/or one of its subdirectories out of the Excluded Folders first
After applying that change, IntelliJ should see the results of compiling each routes and .scala.html file as just-another source file, so they won't show as "broken" and auto-complete should work for them.