Merge pull request #33 from ohze/cross

Author: dwijnand

.travis.yml

@@ -6,6 +6,7 @@ env: ADOPTOPENJDK=8
 scala:
   - 2.12
   - 2.12.next
+  - 2.13
 script: sbt test
 
 notifications:

build.sbt

@@ -1,15 +1,21 @@
 import _root_.scalafix.sbt.BuildInfo._
 import sbt.librarymanagement.Configurations.CompilerPlugin
 
-def scala213 = "2.13.3"
 def scalametaVersion = "4.3.17"
 
 inThisBuild(List(
   organization := "org.scala-lang",
   licenses := List("Apache-2.0" -> url("https://www.apache.org/licenses/LICENSE-2.0")),
   developers := List(Developer("", "", "", url("https://github.com/scala/scala-rewrites/graphs/contributors"))),
   homepage := Some(url("https://github.com/scala/scala-rewrites")),
-  scalaVersion := scala212,
+  scalaVersion := (sys.env.get("TRAVIS_SCALA_VERSION") match {
+    case Some("2.13")      => scala213
+    case Some("2.12")      => scala212
+    case Some("2.12.next") => scala212 // and then overriden by ScalaNightlyPlugin
+    case None              => scala212
+    case tsv               => sys.error(s"Unknown TRAVIS_SCALA_VERSION $tsv")
+  }),
+  crossScalaVersions := Seq(scala212, scala213),
   publish / skip := true,
 ))
 
@@ -24,10 +30,13 @@ val input = project.enablePlugins(ScalaNightlyPlugin).settings(
   libraryDependencies += "org.scalameta" % "semanticdb-scalac" % scalametaVersion % CompilerPlugin cross CrossVersion.patch,
 )
 
-val output    = project
+val output = project
+
+// This project is used to verify that the output code actually compiles with scala 2.13
 val output213 = output.withId("output213").settings(
   target := file(s"${target.value.getPath}-2.13"),
   scalaVersion := scala213,
+  crossScalaVersions := Seq(scalaVersion.value),
 )
 
 val tests = project.dependsOn(rewrites).enablePlugins(ScalaNightlyPlugin, ScalafixTestkitPlugin).settings(