Add support for Dotty projects (#397)

* Abstract over the scala compiler organization

* Support using a locally published compiler

Publishing locally with sbt means publishing ivy-style, which uses
a different naming convention than maven, we now handle both cases.

* Add minimal support for Dotty projects

* Rewrite scalalib.Dep, introduce scalalib.CrossVersion

Instead of Dep being a trait with three cases (Java/Scala/Point), it is
now a case class where the cross field is an instance of the
CrossVersion trait which has three cases (Constant/Binary/Full). This is
more versatile since it allows for non-empty constant suffixes which
will be used to implement withDottyCompat in the next commit. It's
also a cleaner separation of concerns. We also deduplicate various
pieces of codes that computed the artifact name: this is now always handled in
Dep and CrossVersion.

* Add simple way to use Scala 2 deps in a Dotty project

This is similar to the withDottyCompat method in the sbt-dotty plugin.

* Turn off the Dotty test on Java >= 9

1 files changed, 17 insertions, 0 deletions

diff --git a/scalalib/test/resources/hello-dotty/foo/src/Main.scala b/scalalib/test/resources/hello-dotty/foo/src/Main.scala
new file mode 100644
index 00000000..3fe80342
--- /dev/null
+++ b/scalalib/test/resources/hello-dotty/foo/src/Main.scala
@@ -0,0 +1,17 @@
+import cats._, cats.data._, cats.implicits._
+
+trait Context
+
+object Main {
+  def foo(f: implicit Int => Int): Int = {
+    implicit val x: Int = 1
+    f
+  }
+
+  def main(args: Array[String]): Unit = {
+    val x = Applicative[List].pure(1)
+    assert(x == List(1))
+    val value = foo(implicit x => x + 1)
+    assert(value == 2)
+  }
+}