I am using intellij 14 with scala 2.11.6 installed using home brew and symlink using
ln -s /usr/local/Cellar/scala/2.11.6/libexec/src /usr/local/Cellar/scala/2.1
To fix the problem go to project structure in intellij and go to global libraries It should be like this
After that remove all the scala SDKs by hitting the - mark
Next, click the + and choose your Scala SDK version to add
After that please make sure to apply the changes and re-run the program