Invalid binary version conflict warnings with a custom configuration

[eed3si9n]

steps

$ cat build.sbt
lazy val TheDude = config("dude")

lazy val rootProj = (project in file(".")).
  configs(TheDude).
  settings(inConfig(TheDude)(Defaults.compileSettings): _*).
  settings(
    name := "hello",
    version := "0.1.0-SNAPSHOT",
    scalaVersion := "2.11.1",
    libraryDependencies += "org.scala-lang" % "scala-library" % "2.10.4" % TheDude
  )
$ sbt
hello> clean
hello> dude:compile

problem

hello> dude:compile
[info] Updating {file:/Users/eugene/work/quick-test/minimal-scala/}rootProj...
[warn] Binary version (2.10) for dependency org.scala-lang#scala-library;2.10.4
[warn]  in hello#hello_2.11;0.1.0-SNAPSHOT differs from Scala binary version in project (2.11).
[info] Resolving jline#jline;2.11 ...
[info] Done updating.

TheDude configuration is independent from Compile, so the fact the warning is incorrect there.

expectation

Should we allow scalaVersion to be set on custom configurations? If so does that change the behavior of %%? Probably not because you could have more than one config like default->@;runtime,test->runtime. So that means, each configuration should use scala-library's version to be the basis on checking for binary version conflicts.