I'm currently giving the IntelliJ Scala plugin a spin and one thing is bugging me a wee-bit. I get 3 warnings when compiling.
Warning: scala: Recompiling 4 files
Warning: scala: there were 1 deprecation warnings; re-run with -deprecation for details
In IntelliJ 14:
Intellij IDEA > Preferencesor
cmd + ,
Scala Compiler. Alternatively, it's under
Build, Execution, Deployment > Compiler > Scala Compiler
Rebuild your project!