Just going through the sample Scala code on Scala website, but encountered an annoying error when trying to run it.
Here\'s the code: http://www.scala-lang.org/node/
In the worst case - create the project once again with all the imports from the beginning. In my case none of the other options worked. This type of error hints that there is an error in the project settings. I once managed to solve it, but once further developments were done, the error came back. Recreating everything from the beginning helped me understand and optimize some links, and now I am confident it works correctly.