Fix warnings in 2.13 and keep scala.collection.Seq for the api

.github/workflows/ci.yml

@@ -37,14 +37,6 @@ jobs:
         with:
           java-version: adopt@1.11
       - run: sbt ci-213
-  windows_212:
-    name: Windows/scala_2.12 tests
-    runs-on: windows-latest
-    steps:
-      - uses: actions/checkout@v2
-      - uses: olafurpg/setup-scala@v7
-      - run: sbt ci-212-windows
-        shell: bash
 
   windows_213:
     name: Windows/scala_2.13 tests

build.sbt

@@ -63,7 +63,8 @@ lazy val core = project
       scalameta,
       googleDiff,
       "com.geirsson" %% "metaconfig-typesafe-config" % metaconfigV,
-      "org.scala-lang" % "scala-reflect" % scalaVersion.value % Provided
+      "org.scala-lang" % "scala-reflect" % scalaVersion.value % Provided,
+      collectionCompat
     )
   )
   .enablePlugins(BuildInfoPlugin)
@@ -73,7 +74,10 @@ lazy val rules = project
   .settings(
     moduleName := "scalafix-rules",
     description := "Built-in Scalafix rules",
-    libraryDependencies += "org.scalameta" % "semanticdb-scalac-core" % scalametaV cross CrossVersion.full
+    libraryDependencies ++= List(
+      "org.scalameta" % "semanticdb-scalac-core" % scalametaV cross CrossVersion.full,
+      collectionCompat
+    )
   )
   .dependsOn(core)
 

project/Dependencies.scala

@@ -24,6 +24,7 @@ object Dependencies {
   def scalatest = "org.scalatest" %% "scalatest" % "3.0.8"
   def bijectionCore = "com.twitter" %% "bijection-core" % "0.9.7"
   def scalacheck = "org.scalacheck" %% "scalacheck" % "1.14.3"
+  def collectionCompat = "org.scala-lang.modules" %% "scala-collection-compat" % "2.1.6"
 
   def testsDeps = List(
     // integration property tests

project/ScalafixBuild.scala

@@ -201,11 +201,6 @@ object ScalafixBuild extends AutoPlugin with GhpagesKeys {
         "unit/test" ::
         s
     },
-    commands += Command.command("ci-212-windows") { s =>
-      s"++$scala212" ::
-        s"unit/testOnly -- -l scalafix.internal.tests.utils.SkipWindows" ::
-        s
-    },
     commands += Command.command("ci-213-windows") { s =>
       s"++$scala213" ::
         s"unit/testOnly -- -l scalafix.internal.tests.utils.SkipWindows" ::

scalafix-cli/src/main/scala/scalafix/internal/interfaces/ScalafixArgumentsImpl.scala

@@ -9,7 +9,7 @@ import java.util
 import java.util.Optional
 import metaconfig.Conf
 import metaconfig.Configured
-import scala.collection.JavaConverters._
+import scala.jdk.CollectionConverters._
 import scala.meta.io.AbsolutePath
 import scala.meta.io.Classpath
 import scala.util.control.NoStackTrace

scalafix-cli/src/main/scala/scalafix/internal/jgit/JGitDiff.scala

@@ -23,7 +23,7 @@ import org.eclipse.jgit.treewalk.FileTreeIterator
 import org.eclipse.jgit.util.io.NullOutputStream
 import org.eclipse.jgit.lib.Constants.DOT_GIT
 
-import scala.collection.JavaConverters._
+import scala.jdk.CollectionConverters._
 
 import metaconfig.{ConfError, Configured}
 

scalafix-cli/src/main/scala/scalafix/internal/v1/Args.scala

@@ -19,7 +19,6 @@ import metaconfig.internal.ConfGet
 import metaconfig.typesafeconfig.typesafeConfigMetaconfigParser
 import pprint.TPrint
 import scala.annotation.StaticAnnotation
-import scala.language.higherKinds
 import scala.meta.internal.io.PathIO
 import scala.meta.internal.symtab.SymbolTable
 import scala.meta.io.AbsolutePath

scalafix-cli/src/main/scala/scalafix/internal/v1/CompletionsOps.scala

@@ -14,7 +14,7 @@ object CompletionsOps {
     if (setting.isHidden) Nil
     else setting.name :: setting.alternativeNames.filter(_.length == 1)
 
-  private def toZshOption(setting: Setting): scala.Seq[String] = {
+  private def toZshOption(setting: Setting): scala.collection.Seq[String] = {
     if (setting.isHidden) Nil
     else {
       // See https://github.com/zsh-users/zsh-completions/blob/master/zsh-completions-howto.org#writing-completion-functions-using-_arguments

scalafix-cli/src/main/scala/scalafix/internal/v1/MainOps.scala

@@ -19,12 +19,10 @@ import metaconfig.generic.Settings
 import metaconfig.internal.Case
 import org.typelevel.paiges.{Doc => D}
 import scala.annotation.tailrec
-import scala.collection.mutable.ArrayBuffer
 import scala.collection.mutable.ListBuffer
 import scala.meta.Tree
 import scala.meta.inputs.Input
 import scala.meta.internal.semanticdb.TextDocument
-import scala.meta.internal.tokenizers.PlatformTokenizerCache
 import scala.meta.io.AbsolutePath
 import scala.meta.parsers.ParseException
 import scala.util.control.NoStackTrace
@@ -81,7 +79,7 @@ object MainOps {
   def files(args: ValidatedArgs): collection.Seq[AbsolutePath] =
     args.args.ls match {
       case Ls.Find =>
-        val buf = ArrayBuffer.empty[AbsolutePath]
+        val buf =  Vector.newBuilder[AbsolutePath]
         val visitor = new SimpleFileVisitor[Path] {
           override def visitFile(
               file: Path,
@@ -273,7 +271,6 @@ object MainOps {
 
   def handleFile(args: ValidatedArgs, file: AbsolutePath): ExitStatus = {
     try {
-      PlatformTokenizerCache.megaCache.clear()
       unsafeHandleFile(args, file)
     } catch {
       case e: ParseException =>

scalafix-core/src/main/scala-2.11/scalafix/util/Compat.scala

@@ -5,4 +5,5 @@ import scala.collection.immutable.IndexedSeq
 object Compat {
   type View[T] = collection.SeqView[T, IndexedSeq[T]]
   type SeqView[T] = collection.SeqView[T, IndexedSeq[T]]
+
 }

scalafix-core/src/main/scala-2.12/scalafix/util/Compat.scala

@@ -5,4 +5,5 @@ import scala.collection.immutable.IndexedSeq
 object Compat {
   type View[T] = collection.SeqView[T, IndexedSeq[T]]
   type SeqView[T] = collection.Seq[T]
+
 }

scalafix-core/src/main/scala-2.13/scalafix/util/Compat.scala

@@ -3,4 +3,5 @@ package scalafix.util
 object Compat {
   type View[T] = collection.View[T]
   type SeqView[T] = collection.SeqView[T]
-}
+
+}

scalafix-core/src/main/scala/org/langmeta/internal/ScalametaInternals.scala

@@ -1,13 +1,13 @@
 package scala.meta.internal
 
-import scala.compat.Platform.EOL
 import scala.meta._
 import scala.meta.internal.semanticdb.Scala.Descriptor
 import scala.meta.internal.semanticdb.Scala.DescriptorParser
 import scala.meta.internal.trees.Origin
 import scala.meta.internal.{semanticdb => s}
 
 object ScalametaInternals {
+  private val EOL = System.lineSeparator()
 
   def symbolOwnerAndDescriptor(symbol: String): (String, Descriptor) = {
     val (desc, owner) = DescriptorParser(symbol)

scalafix-core/src/main/scala/scalafix/internal/diff/DiffUtils.scala

@@ -1,7 +1,7 @@
 package scalafix.internal.diff
 
 import difflib.{DiffUtils => DU}
-import scala.collection.JavaConverters._
+import scala.jdk.CollectionConverters._
 
 object DiffUtils {
   def unifiedDiff(

scalafix-core/src/main/scala/scalafix/internal/patch/EscapeHatch.scala

@@ -18,6 +18,7 @@ import scalafix.patch.Patch.internal._
 import scalafix.rule.RuleName
 import scalafix.util.TreeExtractors.Mods
 import scalafix.v0._
+import scala.collection.compat._ // used for cross-compilation.
 
 /** EscapeHatch is an algorithm to selectively disable rules. There
  * are two mechanisms to do so: anchored comments and the
@@ -171,7 +172,7 @@ object EscapeHatch {
       if (isEmpty) (true, None)
       else {
         val escapesUpToPos =
-          escapeTree.to(EscapeOffset(position)).valuesIterator.flatten
+          escapeTree.rangeTo(EscapeOffset(position)).valuesIterator.flatten
         escapesUpToPos
           .collectFirst {
             case f @ EscapeFilter(_, _, _, Some(end))
@@ -316,7 +317,7 @@ object EscapeHatch {
       if (disabling.isEmpty) (true, None)
       else {
         val disables =
-          disabling.to(EscapeOffset(position)).valuesIterator.flatten
+          disabling.rangeTo(EscapeOffset(position)).valuesIterator.flatten
         loop(disables.toList, None)
       }
     }

scalafix-core/src/main/scala/scalafix/internal/patch/ImportPatchOps.scala

@@ -161,7 +161,7 @@ object ImportPatchOps {
         .sortBy(_.ref.syntax)
         .map(is => ctx.addRight(editToken, s"\nimport ${is.syntax}"))
     val isRemovedImporter =
-      allImporters.toIterator
+      allImporters.iterator
         .filter(_.importees.forall(isRemovedImportee))
         .toSet
     def removeSpaces(tokens: Iterable[Token]): Patch = {

scalafix-core/src/main/scala/scalafix/internal/patch/LegacyPatchOps.scala

@@ -70,9 +70,9 @@ trait LegacyPatchOps extends PatchOps {
     Patch.replaceSymbols(toReplace: _*)
   @deprecated(DeprecationMessage, "0.6.0")
   final def replaceSymbols(
-      toReplace: Seq[(String, String)]
+      toReplace: scala.collection.Seq[(String, String)]
   )(implicit noop: DummyImplicit, index: SemanticdbIndex): Patch =
-    Patch.replaceSymbols(toReplace: _*)
+    Patch.replaceSymbols(toReplace.toSeq: _*)
   @deprecated(DeprecationMessage, "0.6.0")
   final def renameSymbol(fromSymbol: Symbol.Global, toName: String)(
       implicit index: SemanticdbIndex

scalafix-core/src/main/scala/scalafix/internal/patch/PatchInternals.scala

@@ -115,7 +115,7 @@ object PatchInternals {
     val patchMap = patches
       .groupBy(x => TokenOps.hash(x.tok))
       .mapValues(_.reduce(merge).newTok)
-    ctx.tokens.toIterator
+    ctx.tokens.iterator
       .map(tok => patchMap.getOrElse(TokenOps.hash(tok), tok.syntax))
       .mkString
   }

scalafix-core/src/main/scala/scalafix/internal/patch/ReplaceSymbolOps.scala

@@ -23,7 +23,7 @@ object ReplaceSymbolOps {
   )(implicit ctx: RuleCtx, index: SemanticdbIndex): Patch = {
     if (moveSymbols.isEmpty) return Patch.empty
     val moves: Map[String, Symbol.Global] =
-      moveSymbols.toIterator.flatMap {
+      moveSymbols.iterator.flatMap {
         case ReplaceSymbol(
             term @ Symbol.Global(_, Signature.Method(_, _)),
             to
@@ -67,7 +67,7 @@ object ReplaceSymbolOps {
     }
     object Move {
       def unapply(name: Name): Option[Symbol.Global] = {
-        val result = name.symbol.toIterator
+        val result = name.symbol.iterator
           .flatMap {
             case Symbol.Multi(syms) => syms
             case els => els :: Nil

scalafix-core/src/main/scala/scalafix/internal/util/FileOps.scala

@@ -19,7 +19,7 @@ object FileOps {
     } else {
       def listFilesIter(s: File): Iterable[String] = {
         val (dirs, files) = Option(s.listFiles()).toIterable
-          .flatMap(_.toIterator)
+          .flatMap(_.iterator)
           .partition(_.isDirectory)
         files.map(_.getPath) ++ dirs.flatMap(listFilesIter)
       }

scalafix-core/src/main/scala/scalafix/internal/util/Pretty.scala

@@ -180,6 +180,7 @@ object Pretty {
             Doc.intercalate(Doc.comma, parameterList.map(prettyTermParameter))
           }
           val paramss = Doc.intercalate(`)` + `(`, params)
+
           `(` + paramss + `)`
         }
       val returnType = pretty(t.returnType)

scalafix-core/src/main/scala/scalafix/internal/v0/LegacyCodePrinter.scala

@@ -160,9 +160,9 @@ class LegacyCodePrinter(doc: SemanticDocument) {
       case s.IntConstant(value) =>
         text.append(value)
       case s.LongConstant(value) =>
-        text.append(value + "L")
+        text.append(s"${value}L")
       case s.FloatConstant(value) =>
-        text.append(value + "f")
+        text.append(s"${value}f")
       case s.DoubleConstant(value) =>
         text.append(value)
       case s.StringConstant(value) =>

scalafix-core/src/main/scala/scalafix/internal/v1/Rules.scala

@@ -96,7 +96,7 @@ object Rules {
     all(Thread.currentThread.getContextClassLoader)
   }
   def all(classLoader: ClassLoader): List[Rule] = {
-    import scala.collection.JavaConverters._
+    import scala.jdk.CollectionConverters._
     ServiceLoader
       .load(classOf[Rule], classLoader)
       .iterator()

scalafix-core/src/main/scala/scalafix/patch/PatchOps.scala

@@ -132,6 +132,6 @@ trait PatchOps {
    * to differentiate from replaceSymbols((String, String)*) after type erasure
    */
   def replaceSymbols(
-      toReplace: Seq[(String, String)]
+      toReplace: scala.collection.Seq[(String, String)]
   )(implicit noop: DummyImplicit, index: SemanticdbIndex): Patch
 }

scalafix-core/src/main/scala/scalafix/syntax/package.scala

@@ -1,13 +1,13 @@
 package scalafix
 
-import scala.compat.Platform.EOL
 import scala.meta._
 import scala.meta.internal.scalafix.ScalafixScalametaHacks
 import scalafix.internal.util.DenotationOps
 import scalafix.internal.util.SymbolOps
 import scalafix.util.SymbolMatcher
 import scalafix.util.TreeOps
 import scalafix.v0.Symbol
+import scala.collection.compat.immutable.LazyList
 
 package object syntax {
   implicit class XtensionRefSymbolOpt(tree: Tree)(
@@ -40,7 +40,7 @@ package object syntax {
   implicit class XtensionTreeScalafix(tree: Tree) {
     def matches(matcher: SymbolMatcher): Boolean =
       matcher.matches(tree)
-    def parents: Stream[Tree] = TreeOps.parents(tree)
+    def parents: LazyList[Tree] = TreeOps.parents(tree)
     def input: Input = tree.tokens.headOption.map(_.input).getOrElse(Input.None)
   }
   implicit class XtensionInputScalafix(input: Input) {
@@ -49,7 +49,7 @@ package object syntax {
       case inputs.Input.VirtualFile(label, _) => label
       case _ =>
         s"Input.${input.productPrefix}('<${input.chars.take(10).mkString}...>')"
-          .replaceAllLiterally(EOL, "")
+          .replace(System.lineSeparator(), "")
     }
   }
 }

scalafix-core/src/main/scala/scalafix/util/TokenList.scala

@@ -7,10 +7,10 @@ import scala.meta.tokens.Tokens
 /** Helper to traverse tokens as a doubly linked list.  */
 final class TokenList private (tokens: Tokens) {
   def trailing(token: Token): View[Token] =
-    tokens.view(tok2idx(token) + 1, tokens.length)
+    tokens.view.slice(tok2idx(token) + 1, tokens.length)
 
   def leading(token: Token): View[Token] =
-    tokens.view(0, tok2idx(token)).reverse
+    tokens.view.slice(0, tok2idx(token)).reverse
 
   private[this] val tok2idx = {
     val map = Map.newBuilder[Token, Int]
@@ -29,7 +29,7 @@ final class TokenList private (tokens: Tokens) {
     tokens.drop(tok2idx(start)).find(p)
 
   def slice(from: Token, to: Token): SeqView[Token] =
-    tokens.view(tok2idx(from), tok2idx(to))
+    tokens.view.slice(tok2idx(from), tok2idx(to))
 
   /** Returns the next/trailing token or the original token if none exists.
    *

scalafix-core/src/main/scala/scalafix/util/TreeOps.scala

@@ -1,6 +1,7 @@
 package scalafix.util
 
 import scala.meta._
+import scala.collection.compat.immutable.LazyList
 import scalafix.v1.Symbol
 import scala.meta.internal.semanticdb.Scala.Symbols
 import scala.meta.internal.semanticdb.Scala.Descriptor
@@ -101,9 +102,9 @@ object TreeOps {
     }
     result.map(Symbol(_))
   }
-  def parents(tree: Tree): Stream[Tree] =
-    tree #:: (tree.parent match {
+  def parents(tree: Tree): LazyList[Tree] =
+    tree +: (tree.parent match {
       case Some(x) => parents(x)
-      case _ => Stream.empty
+      case _ => LazyList.empty
     })
 }

scalafix-core/src/main/scala/scalafix/v0/Database.scala

@@ -1,6 +1,5 @@
 package scalafix.v0
 
-import scala.compat.Platform.EOL
 import scala.meta.internal.io.PathIO
 
 final case class Database(documents: Seq[Document]) {
@@ -10,6 +9,7 @@ final case class Database(documents: Seq[Document]) {
   lazy val synthetics: Seq[Synthetic] = documents.flatMap(_.synthetics)
 
   def syntax: String = {
+    val EOL = System.lineSeparator
     val s_entries = documents.map { attrs =>
       val s_input = PathIO.toUnix(attrs.input.syntax)
       val separator = EOL + "-" * s_input.toString.length + EOL

scalafix-core/src/main/scala/scalafix/v0/Document.scala

@@ -1,6 +1,5 @@
 package scalafix.v0
 
-import scala.compat.Platform.EOL
 import scala.math.Ordering
 import scala.meta.inputs._
 
@@ -27,7 +26,7 @@ final case class Document(
     appendSection("Messages", messages.sorted.map(_.syntax))
     appendSection("Symbols", symbols.sorted.map(_.syntax))
     appendSection("Synthetics", synthetics.sorted.map(_.syntax))
-    lines.mkString(EOL)
+    lines.mkString(System.lineSeparator)
   }
 
   private implicit def positionOrder: Ordering[Position] =