Why doesn't the Def.inputTask macro work in Scala 2.11.1?

Question

I'm using Scala 2.11.1 and sbt 0.13.5.

I have an sbt plugin that contains a helper function to create input tasks as follows (the implementation is stripped away as it's irrelevant to the problem):

def register(name: String, description: String): Def.Setting[InputTask[Unit]] = {
    InputKey[Unit](name, description) <<= Def.inputTask { 
        println("test")
    }
}

This function compiles and works just fine in Scala 2.10.4, however once I switch to 2.11.1 it fails with the following error:

can't expand macros compiled by previous versions of Scala

Is the Def.inputTask macro simply broken in Scala 2.11.1, or am I missing some glaring detail?

Right now the above function is residing in the simplest sbt plugin imaginable. There are no dependencies at all, either.

Answer 1

sbt 0.13.x series uses Scala 2.10.x when it loads up, so sbt 0.13.x itself must be compiled against Scala 2.10, and so do all sbt plugins for 0.13.x.

Note: sbt 0.13 can define Scala projects using 2.11.x.

Answer 2

If you're running scala 2.11.x, use this line in your build.sbt file .

libraryDependencies += "org.scalatest" % "scalatest_2.11" % "2.2.4" % "test"