Add scalafix migration rule.

Copied from https://github.com/scala/collection-strawman

Author: julienrf

scalafix/build.sbt

@@ -0,0 +1,43 @@
+def scalafixVersion = _root_.scalafix.Versions.version
+inScope(Global)(
+  List(
+    scalaVersion := _root_.scalafix.Versions.scala212
+  )
+)
+
+lazy val root = project
+  .in(file("."))
+  .aggregate(
+    rules, input, output, tests
+  )
+
+lazy val rules = project.settings(
+  libraryDependencies += "ch.epfl.scala" %% "scalafix-core" % scalafixVersion
+)
+
+lazy val input = project
+  .settings(
+    scalafixSourceroot := sourceDirectory.in(Compile).value
+  )
+
+lazy val output = project
+  .settings(
+    resolvers += "scala-pr" at "https://scala-ci.typesafe.com/artifactory/scala-integration/",
+    scalaVersion := "2.13.0-M4-pre-20d3c21"
+  )
+
+lazy val tests = project
+  .settings(
+    libraryDependencies += "ch.epfl.scala" % "scalafix-testkit" % scalafixVersion % Test cross CrossVersion.full,
+    buildInfoPackage := "fix",
+    buildInfoKeys := Seq[BuildInfoKey](
+      "inputSourceroot" ->
+        sourceDirectory.in(input, Compile).value,
+      "outputSourceroot" ->
+        sourceDirectory.in(output, Compile).value,
+      "inputClassdirectory" ->
+        classDirectory.in(input, Compile).value
+    )
+  )
+  .dependsOn(input, rules)
+  .enablePlugins(BuildInfoPlugin)

scalafix/input/src/main/scala/fix/Collectionstrawman_v0_Stream.scala

@@ -0,0 +1,14 @@
+/*
+rule = "scala:fix.Collectionstrawman_v0"
+ */
+package fix
+
+object Collectionstrawman_v0_Stream {
+  val s = Stream(1, 2, 3)
+  s.append(List(4, 5, 6))
+  1 #:: 2 #:: 3 #:: Stream.Empty
+  val isEmpty: Stream[_] => Boolean = {
+    case Stream.Empty => true
+    case x #:: xs     => false
+  }
+}

scalafix/input/src/main/scala/fix/Collectionstrawman_v0_Traversable.scala

@@ -0,0 +1,13 @@
+/*
+rule = "scala:fix.Collectionstrawman_v0"
+ */
+package fix
+
+object Collectionstrawman_v0_Traversable {
+  def foo(xs: Traversable[(Int, String)], ys: List[Int]): Unit = {
+    xs.to[List]
+    xs.to[Set]
+    xs.toIterator
+    ys.iterator
+  }
+}

scalafix/input/src/main/scala/fix/Collectionstrawman_v0_TupleNZipped.scala

@@ -0,0 +1,36 @@
+/*
+rule = "scala:fix.Collectionstrawman_v0"
+ */
+package fix
+
+import scala.language.postfixOps
+object Collectionstrawman_v0_Tuple2Zipped {
+  def zipped(xs: List[Int], ys: List[Int]): Unit = {
+    (xs, ys).zipped
+    (xs,ys).zipped
+    ((xs, ys) zipped)
+    (((xs)    ,    (ys)).zipped)
+    (xs, // foo
+      ys).zipped
+    /* a */(/* b */ xs /* c */, /* d */ ys /* e */)/* f */./* g */zipped/* h */
+    (coll(1), coll(2)).zipped
+    (List(1, 2, 3), Stream.from(1)).zipped
+  }
+  def coll(x: Int): List[Int] = ???
+}
+
+object Collectionstrawman_v0_Tuple3Zipped {
+  def zipped(xs: List[Int], ys: List[Int], zs: List[Int]): Unit = {
+    (xs, ys, zs).zipped
+    (xs,ys,zs).zipped
+    ((xs, ys, zs) zipped)
+    (((xs)    ,    (ys)    ,    (zs)).zipped)
+    (xs, // foo
+      ys, // bar
+      zs).zipped
+    /* a */(/* b */ xs /* c */, /* d */ ys /* e */, /* f */ zs /* g */)/* h */./* i */zipped/* j */
+    (coll(1), coll(2), coll(3)).zipped
+    (List(1, 2, 3), Set(1, 2, 3), Stream.from(1)).zipped
+  }
+  def coll(x: Int): List[Int] = ???
+}

scalafix/input/src/main/scala/fix/Collectionstrawman_v0_copyToBuffer.scala

@@ -0,0 +1,13 @@
+/*
+rule = "scala:fix.Collectionstrawman_v0"
+ */
+package fix
+
+import scala.collection.mutable
+
+class Collectionstrawman_v0_copyToBuffer(xs: List[Int], b: mutable.Buffer[Int]) {
+
+  xs.copyToBuffer(b)
+  (xs ++ xs).copyToBuffer(b)
+
+}

scalafix/output/src/main/scala/fix/Collectionstrawman_v0_Stream.scala

@@ -0,0 +1,11 @@
+package fix
+
+object Collectionstrawman_v0_Stream {
+  val s = LazyList(1, 2, 3)
+  s.lazyAppendAll(List(4, 5, 6))
+  1 #:: 2 #:: 3 #:: LazyList.Empty
+  val isEmpty: LazyList[_] => Boolean = {
+    case LazyList.Empty => true
+    case x #:: xs     => false
+  }
+}

scalafix/output/src/main/scala/fix/Collectionstrawman_v0_Traversable.scala

@@ -0,0 +1,10 @@
+package fix
+
+object Collectionstrawman_v0_Traversable {
+  def foo(xs: Iterable[(Int, String)], ys: List[Int]): Unit = {
+    xs.to(List)
+    xs.to(Set)
+    xs.iterator()
+    ys.iterator()
+  }
+}

scalafix/output/src/main/scala/fix/Collectionstrawman_v0_TupleNZipped.scala

@@ -0,0 +1,33 @@
+package fix
+
+import scala.language.postfixOps
+object Collectionstrawman_v0_Tuple2Zipped {
+  def zipped(xs: List[Int], ys: List[Int]): Unit = {
+    xs.lazyZip(ys)
+    xs.lazyZip(ys)
+    (xs.lazyZip(ys) )
+    ((xs).lazyZip((ys)))
+    xs.lazyZip(// foo
+      ys)
+    /* a *//* b */ xs /* c */.lazyZip(/* d */ ys /* e */)/* f *//* g *//* h */
+    coll(1).lazyZip(coll(2))
+    List(1, 2, 3).lazyZip(LazyList.from(1))
+  }
+  def coll(x: Int): List[Int] = ???
+}
+
+object Collectionstrawman_v0_Tuple3Zipped {
+  def zipped(xs: List[Int], ys: List[Int], zs: List[Int]): Unit = {
+    xs.lazyZip(ys).lazyZip(zs)
+    xs.lazyZip(ys).lazyZip(zs)
+    (xs.lazyZip(ys).lazyZip(zs) )
+    ((xs).lazyZip((ys)).lazyZip((zs)))
+    xs.lazyZip(// foo
+      ys).lazyZip(// bar
+      zs)
+    /* a *//* b */ xs /* c */.lazyZip(/* d */ ys /* e */).lazyZip(/* f */ zs /* g */)/* h *//* i *//* j */
+    coll(1).lazyZip(coll(2)).lazyZip(coll(3))
+    List(1, 2, 3).lazyZip(Set(1, 2, 3)).lazyZip(LazyList.from(1))
+  }
+  def coll(x: Int): List[Int] = ???
+}

scalafix/output/src/main/scala/fix/Collectionstrawman_v0_copyToBuffer.scala

@@ -0,0 +1,10 @@
+package fix
+
+import scala.collection.mutable
+
+class Collectionstrawman_v0_copyToBuffer(xs: List[Int], b: mutable.Buffer[Int]) {
+
+  b ++= xs
+  b ++= xs ++ xs
+
+}

scalafix/project/build.properties

@@ -0,0 +1 @@
+sbt.version=0.13.16