Integrate 2.13.x branch into master

Use version-specific source directories where necessary.

Author: lrytz

.travis.yml

@@ -1,9 +1,9 @@
 language: scala
 
 scala:
-  # note that 2.13 is on the 2.13.x branch instead
-  - 2.11.12
+  - 2.13.0
   - 2.12.8
+  - 2.11.12
 
 env:
   global:

README.md

@@ -161,7 +161,7 @@ as the collection can (in some cases) be built in parallel.
 
 Because the wrappers are invoked based on the static type of the collection, there are also cases where parallelization
 is inefficient when interfacing with Java 8 Streams (e.g. when a collection is typed as `Seq[String]` so might have linear
-access like `List`, but actually is a `WrappedArray[String]` that can be efficiently parallelized) but can be efficient
+access like `List`, but actually is a `WrappedArray[String]` (`ArraySeq` on 2.13) that can be efficiently parallelized) but can be efficient
 with Scala parallel collections.  The `parStream` method is only available when the static type is known to be compatible
 with rapid parallel operation; `seqStream` can be parallelized by using `.parallel`, but may or may not be efficient.
 

build.sbt

@@ -1,8 +1,6 @@
 import ScalaModulePlugin._
 
-// no 2.13 for now in cross-build because of
-// https://github.com/scala/scala-java8-compat/issues/97
-crossScalaVersions in ThisBuild := List("2.12.8", "2.11.12")
+crossScalaVersions in ThisBuild := List("2.13.0", "2.12.8", "2.11.12")
 
 val disableDocs =
   sys.props("nodocs") == "true" ||
@@ -28,7 +26,27 @@ lazy val commonSettings = Seq(
   organization := "org.scala-lang.modules",
   version := "0.9.1-SNAPSHOT",
 
-  scalacOptions ++= Seq("-feature", "-deprecation", "-unchecked")
+  scalacOptions ++= Seq("-feature", "-deprecation", "-unchecked"),
+
+  unmanagedSourceDirectories in Compile ++= {
+    (unmanagedSourceDirectories in Compile).value.flatMap { dir =>
+      CrossVersion.partialVersion(scalaVersion.value) match {
+        case Some((2, 13)) => Seq(file(dir.getPath ++ "-2.13+"))
+        case Some((2, 11)) => Seq(file(dir.getPath ++ "-2.13-"), file(dir.getPath ++ "-2.11"))
+        case _             => Seq(file(dir.getPath ++ "-2.13-"))
+      }
+    }
+  },
+
+  unmanagedSourceDirectories in Test ++= {
+    (unmanagedSourceDirectories in Test).value.flatMap { dir =>
+      CrossVersion.partialVersion(scalaVersion.value) match {
+        case Some((2, 13)) => Seq(file(dir.getPath ++ "-2.13+"))
+        case Some((2, 11)) => Seq(file(dir.getPath ++ "-2.13-"), file(dir.getPath ++ "-2.11"))
+        case _             => Seq(file(dir.getPath ++ "-2.13-"))
+      }
+    }
+  },
 )
 
 lazy val fnGen = (project in file("fnGen")).

fnGen/WrapFnGen.scala

@@ -245,7 +245,7 @@ object WrapFnGen {
           numberedA ++= scalaTargs.map(_.toString).collect{ case An(digits) if (digits.length < 10) => digits.toInt }
           val scalafnTnames = (jfn.pTypes :+ jfn.rType).zipWithIndex.map{
             case (pt, i) if (i < jfn.pTypes.length && pt.isFinalType) || (!pt.isFinalType && jfn.pTypes.take(i).exists(_ == pt)) =>
-              val j = Iterator.from(i).dropWhile(numberedA).next
+              val j = Iterator.from(i).dropWhile(numberedA).next()
               val genericName = TypeName(s"A$j")
               numberedA += j
               evidences += ((genericName, pt.typeSymbol.name.toTypeName))
@@ -309,6 +309,6 @@ object WrapFnGen {
 
   def main(args: Array[String]): Unit = {
     val names = args.iterator.map(x => new java.io.File(x))
-    write(names.next, converterContents)
+    write(names.next(), converterContents)
   }
 }

project/CodeGen.scala

@@ -519,9 +519,9 @@ object CodeGen {
 
     val specialized =
       List("V", "V,IJFD", "V,IJD,IJD").flatMap(specialize).map { case (i, a, sp) =>
-        s"  public static scala.Function$i<$a> procSpecialized(JFunction$i$sp f) { return f; }" } ++
+        s"  public static scala.Function$i<$a> procSpecialized(JFunction$i$sp f) { return (scala.Function$i<$a>)(Object)f; }" } ++
       List("BSIJCFDZ", "ZIFJD,IJFD", "ZIFJD,IJD,IJD").flatMap(specialize).map { case (i, a, sp) =>
-        s"  public static scala.Function$i<$a> funcSpecialized(JFunction$i$sp f) { return f; }" }
+        s"  public static scala.Function$i<$a> funcSpecialized(JFunction$i$sp f) { return (scala.Function$i<$a>)(Object)f; }" }
 
     (blocks.map(_._1) ++ blocks.map(_._2)) :+
       ( "JFunction",