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"

Answer 3

This is what I have just tried and it works with scalaVersion of 2.11.6
The code is checked in on github, in case you want to check

I have sbt version as

$ sbt --version
sbt launcher version 0.13.8

My project settings looks like

object LearningScalaBuild extends Build {
  lazy val commonSettings = Seq(
    organization := "com.learner",
    version := "0.1.0",
    scalaVersion := "2.11.6",
    libraryDependencies += "org.scalatest" % "scalatest_2.11" % "2.2.4" % "test"
  )

  lazy val root = project.in(file(".")).aggregate(s99, ahka)
  lazy val s99 = project.in(file("s99"))
  .settings(commonSettings: _*)

  lazy val ahka = project.in(file("ahka"))
    .settings(commonSettings: _*)
    .settings(libraryDependencies += "com.typesafe.akka" %% "akka-actor" % "2.3.9")
}

I ran it on Travis CI and it seems to work well

[info] Resolving org.scalatest#scalatest_2.11;2.2.4 ...
[info] Resolving org.scala-lang#scala-reflect;2.11.2 ...
[info] Resolving org.scala-lang.modules#scala-xml_2.11;1.0.2 ...
[info] Resolving org.scala-lang#scala-compiler;2.11.6 ...
[info] Resolving org.scala-lang#scala-reflect;2.11.6 ...
[info] Resolving org.scala-lang.modules#scala-xml_2.11;1.0.3 ...
[info] Resolving org.scala-lang.modules#scala-parser-combinators_2.11;1.0.3 ...
[info] Resolving jline#jline;2.12.1 ...
[info] downloading https://repo1.maven.org/maven2/com/typesafe/akka/akka-actor_2.11/2.3.9/akka-actor_2.11-2.3.9.jar ...
[info]  [SUCCESSFUL ] com.typesafe.akka#akka-actor_2.11;2.3.9!akka-actor_2.11.jar (253ms)
[info] downloading https://repo1.maven.org/maven2/com/typesafe/config/1.2.1/config-1.2.1.jar ...
[info]  [SUCCESSFUL ] com.typesafe#config;1.2.1!config.jar(bundle) (170ms)
[info] Done updating.
[info] 'compiler-interface' not yet compiled for Scala 2.11.6. Compiling...
[info] Run completed in 13 milliseconds.
[info] Total number of tests run: 0
[info] Suites: completed 0, aborted 0
[info] Tests: succeeded 0, failed 0, canceled 0, ignored 0, pending 0
[info] No tests were executed.
[info]   Compilation completed in 18.159 s
[info] Compiling 1 Scala source to /home/travis/build/hhimanshu/learningScala/s99/target/scala-2.11/test-classes...
[info] P01Spec:
[info] [Dummy Test] A List
[info] - must return true when provided empty list
[info] Run completed in 259 milliseconds.
[info] Total number of tests run: 1
[info] Suites: completed 1, aborted 0
[info] Tests: succeeded 1, failed 0, canceled 0, ignored 0, pending 0
[info] All tests passed.
[success] Total time: 28 s, completed May 30, 2015 3:41:26 AM
The command "sbt ++2.11.6 test" exited with 0.
Done. Your build exited with 0.

Answer 4

I changed the build.sbt file. Now its working for me. Below is the change

scalaVersion := "2.11.6"

scalacOptions += "-deprecation"

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