Enable Scala 2.13.0 in the linker and all the other artifacts.

Partest is not yet unabled in this commit, because a dependency of
`partest` 2.13.0, namely `testkit`, was not published. See
scala/bug#11529 upstream.

Jenkinsfile

@@ -420,7 +420,7 @@ def allJavaVersions = otherJavaVersions.clone()
 allJavaVersions << mainJavaVersion
 
 def mainScalaVersion = "2.12.8"
-def mainScalaVersions = ["2.11.12", "2.12.8"]
+def mainScalaVersions = ["2.11.12", "2.12.8", "2.13.0"]
 def otherScalaVersions = [
   "2.11.0",
   "2.11.1",
@@ -440,7 +440,6 @@ def otherScalaVersions = [
   "2.12.6",
   "2.12.7"
 ]
-def noToolsScalaVersions = ["2.13.0"]
 
 // The 'quick' matrix
 def quickMatrix = []
@@ -456,11 +455,6 @@ mainScalaVersions.each { scalaVersion ->
   quickMatrix.add([task: "partest-fastopt", scala: scalaVersion, java: mainJavaVersion])
 }
 quickMatrix.add([task: "test-suite-ecma-script5-force-polyfills", scala: mainScalaVersion, java: mainJavaVersion, testSuite: "testSuite"])
-noToolsScalaVersions.each { scalaVersion ->
-  quickMatrix.add([task: "main", scala: scalaVersion, java: mainJavaVersion])
-  quickMatrix.add([task: "test-suite-ecma-script2015", scala: scalaVersion, java: mainJavaVersion, testSuite: "testSuite"])
-  quickMatrix.add([task: "test-suite-ecma-script5", scala: scalaVersion, java: mainJavaVersion, testSuite: "testSuite"])
-}
 allJavaVersions.each { javaVersion ->
   quickMatrix.add([task: "tools-sbtplugin", scala: "2.12.8", sbt_version_override: "", java: javaVersion])
   quickMatrix.add([task: "tools", scala: "2.10.7", java: javaVersion])

js-envs-test-kit/src/main/scala/org/scalajs/jsenv/test/JSEnvSuite.scala

@@ -14,7 +14,6 @@ package org.scalajs.jsenv.test
 
 import org.scalajs.jsenv.JSEnv
 
-import scala.collection.JavaConverters._
 import scala.reflect.ClassTag
 
 import org.junit.runner.Runner
@@ -40,7 +39,7 @@ abstract class JSEnvSuite(private[test] val config: JSEnvSuiteConfig)
 
 /** Runner for a [[JSEnvSuite]]. May only be used on subclasses of [[JSEnvSuite]]. */
 final class JSEnvSuiteRunner(root: Class[_], config: JSEnvSuiteConfig)
-    extends Suite(root, JSEnvSuiteRunner.getRunners(config).asJava) {
+    extends Suite(root, JSEnvSuiteRunner.getRunners(config)) {
 
   /** Constructor for reflective instantiation via `@RunWith`. */
   def this(suite: Class[_ <: JSEnvSuite]) =
@@ -56,16 +55,19 @@ private object JSEnvSuiteRunner {
       .map { case (name, value) => s"$name = $value" }
       .mkString("[", ", ", "]")
 
-    val paramValues = config +: params.map(_._2)
+    val paramValues = new java.util.LinkedList[AnyRef]
+    paramValues.add(config)
+    for (param <- params)
+      paramValues.add(param._2)
 
     new BlockJUnit4ClassRunnerWithParameters(
-        new TestWithParameters(name, new TestClass(t.runtimeClass), paramValues.asJava))
+        new TestWithParameters(name, new TestClass(t.runtimeClass), paramValues))
   }
 
-  private def getRunners(config: JSEnvSuiteConfig): List[Runner] = {
+  private def getRunners(config: JSEnvSuiteConfig): java.util.List[Runner] = {
     import java.lang.Boolean.{TRUE, FALSE}
 
-    List(
+    java.util.Arrays.asList(
         r[RunTests](config, "withCom" -> FALSE),
         r[RunTests](config, "withCom" -> TRUE),
         r[TimeoutRunTests](config, "withCom" -> FALSE),

linker/jvm/src/main/scala/org/scalajs/linker/backend/closure/ClosureLinkerBackend.scala

@@ -12,7 +12,6 @@
 
 package org.scalajs.linker.backend.closure
 
-import scala.collection.JavaConverters._
 import scala.concurrent._
 
 import java.io._
@@ -92,7 +91,7 @@ final class ClosureLinkerBackend(config: LinkerBackendImpl.Config)
     }
 
     // Compile the module
-    val closureExterns = List(
+    val closureExterns = java.util.Arrays.asList(
         ClosureSource.fromCode("ScalaJSExterns.js", ClosureLinkerBackend.ScalaJSExterns),
         ClosureSource.fromCode("ScalaJSGlobalRefs.js", makeExternsForGlobalRefs(globalRefs)),
         ClosureSource.fromCode("ScalaJSExportExterns.js", makeExternsForExports(topLevelVarDeclarations, unit)))
@@ -101,7 +100,7 @@ final class ClosureLinkerBackend(config: LinkerBackendImpl.Config)
 
     val result = logger.time("Closure: Compiler pass") {
       compiler.compileModules(
-          closureExterns.asJava, List(module).asJava, options)
+          closureExterns, java.util.Arrays.asList(module), options)
     }
 
     if (!result.success) {

linker/jvm/src/main/scala/org/scalajs/linker/backend/closure/ClosureModuleBuilder.scala

@@ -30,7 +30,7 @@ private[closure] class ClosureModuleBuilder(
     relativizeBaseURI: Option[URI] = None) extends JSBuilder {
 
   private val transformer = new ClosureAstTransformer(relativizeBaseURI)
-  private val treeBuf = mutable.ListBuffer.empty[Node]
+  private val treeBuf = List.newBuilder[Node]
 
   def addJSTree(tree: Tree): Unit = {
     /* Top-level `js.Block`s must be explicitly flattened here.
@@ -54,8 +54,9 @@ private[closure] class ClosureModuleBuilder(
   def result(): JSModule = {
     val module = new JSModule("Scala.js")
 
-    if (treeBuf.nonEmpty) {
-      val root = transformer.setNodePosition(IR.script(treeBuf: _*), NoPosition)
+    val trees = treeBuf.result()
+    if (trees.nonEmpty) {
+      val root = transformer.setNodePosition(IR.script(trees: _*), NoPosition)
       val ast = new ClosureModuleBuilder.ScalaJSSourceAst(root)
       module.add(new CompilerInput(ast, ast.getInputId(), false))
     }

linker/jvm/src/main/scala/org/scalajs/linker/frontend/optimizer/ParIncOptimizer.scala

@@ -41,6 +41,9 @@ final class ParIncOptimizer(config: CommonPhaseConfig)
     def emptyParIterable[V]: ParIterable[V] = ParArray.empty
 
     // Operations on ParMap
+    def isEmpty[K, V](map: ParMap[K, V]): Boolean = map.isEmpty
+    def forceGet[K, V](map: ParMap[K, V], k: K): V = map(k)
+    def get[K, V](map: ParMap[K, V], k: K): Option[V] = map.get(k)
     def put[K, V](map: ParMap[K, V], k: K, v: V): Unit = map.put(k, v)
     def remove[K, V](map: ParMap[K, V], k: K): Option[V] = map.remove(k)
 
@@ -51,16 +54,19 @@ final class ParIncOptimizer(config: CommonPhaseConfig)
       }
     }
 
+    def valuesForeach[K, V, U](map: ParMap[K, V])(f: V => U): Unit =
+      map.values.foreach(f)
+
     // Operations on AccMap
     def acc[K, V](map: AccMap[K, V], k: K, v: V): Unit =
       map.getOrPut(k, AtomicAcc.empty) += v
 
-    def getAcc[K, V](map: AccMap[K, V], k: K): GenIterable[V] =
+    def getAcc[K, V](map: AccMap[K, V], k: K): ParIterable[V] =
       map.get(k).fold[Iterable[V]](Nil)(_.removeAll()).toParArray
 
     def parFlatMapKeys[A, B](map: AccMap[A, _])(
-        f: A => GenTraversableOnce[B]): GenIterable[B] =
-      map.keys.flatMap(f).toParArray
+        f: A => Option[B]): ParIterable[B] =
+      map.keys.flatMap(f(_)).toParArray
 
     // Operations on ParIterable
     def prepAdd[V](it: ParIterable[V]): Addable[V] =
@@ -71,6 +77,12 @@ final class ParIncOptimizer(config: CommonPhaseConfig)
 
     def finishAdd[V](addable: Addable[V]): ParIterable[V] =
       addable.removeAll().toParArray
+
+    def foreach[V, U](it: ParIterable[V])(f: V => U): Unit =
+      it.foreach(f)
+
+    def filter[V](it: ParIterable[V])(f: V => Boolean): ParIterable[V] =
+      it.filter(f)
   }
 
   private val _interfaces = TrieMap.empty[String, InterfaceType]

linker/shared/src/main/scala/org/scalajs/linker/CollectionsCompat.scala

@@ -0,0 +1,32 @@
+/*
+ * Scala.js (https://www.scala-js.org/)
+ *
+ * Copyright EPFL.
+ *
+ * Licensed under Apache License 2.0
+ * (https://www.apache.org/licenses/LICENSE-2.0).
+ *
+ * See the NOTICE file distributed with this work for
+ * additional information regarding copyright ownership.
+ */
+
+package org.scalajs.linker
+
+import scala.collection.mutable
+
+private[linker] object CollectionsCompat {
+  implicit class MutableMapCompatOps[K, V](val __self: mutable.Map[K, V])
+      extends AnyVal {
+
+    // filterInPlace replaces retain
+    def filterInPlace(p: (K, V) => Boolean): Unit = {
+      // Believe it or not, this is the implementation of `retain` in 2.12.x:
+
+      // scala/bug#7269 toList avoids ConcurrentModificationException
+      for ((k, v) <- __self.toList) {
+        if (!p(k, v))
+        __self -= k
+      }
+    }
+  }
+}

linker/shared/src/main/scala/org/scalajs/linker/analyzer/Analysis.scala

@@ -33,7 +33,7 @@ trait Analysis {
   import Analysis._
 
   def classInfos: scala.collection.Map[String, ClassInfo]
-  def errors: Seq[Error]
+  def errors: scala.collection.Seq[Error]
 }
 
 object Analysis {
@@ -62,8 +62,8 @@ object Analysis {
     def encodedName: String
     def kind: ClassKind
     def superClass: Option[ClassInfo]
-    def interfaces: Seq[ClassInfo]
-    def ancestors: Seq[ClassInfo]
+    def interfaces: scala.collection.Seq[ClassInfo]
+    def ancestors: scala.collection.Seq[ClassInfo]
     def nonExistent: Boolean
     /** For a Scala class, it is instantiated with a `New`; for a JS class,
      *  its constructor is accessed with a `JSLoadConstructor` or because it
@@ -74,8 +74,8 @@ object Analysis {
     def isModuleAccessed: Boolean
     def areInstanceTestsUsed: Boolean
     def isDataAccessed: Boolean
-    def linkedFrom: Seq[From]
-    def instantiatedFrom: Seq[From]
+    def linkedFrom: scala.collection.Seq[From]
+    def instantiatedFrom: scala.collection.Seq[From]
     def methodInfos(
         namespace: MemberNamespace): scala.collection.Map[String, MethodInfo]
 
@@ -97,8 +97,8 @@ object Analysis {
     def isExported: Boolean
     def isReflProxy: Boolean
     def isReachable: Boolean
-    def calledFrom: Seq[From]
-    def instantiatedSubclasses: Seq[ClassInfo]
+    def calledFrom: scala.collection.Seq[From]
+    def instantiatedSubclasses: scala.collection.Seq[ClassInfo]
     def nonExistent: Boolean
     def syntheticKind: MethodSyntheticKind
 

linker/shared/src/main/scala/org/scalajs/linker/analyzer/Analyzer.scala

@@ -55,7 +55,7 @@ private final class Analyzer(config: CommonPhaseConfig,
 
   def classInfos: scala.collection.Map[String, Analysis.ClassInfo] = _loadedClassInfos
 
-  def errors: Seq[Error] = _errors
+  def errors: scala.collection.Seq[Error] = _errors
 
   def computeReachability(): Future[Unit] = {
     require(_classInfos.isEmpty, "Cannot run the same Analyzer multiple times")
@@ -1150,7 +1150,7 @@ object Analyzer {
   }
 
   trait InputProvider {
-    def classesWithEntryPoints(): TraversableOnce[String]
+    def classesWithEntryPoints(): Iterable[String]
 
     def loadInfo(encodedName: String)(implicit ec: ExecutionContext): Option[Future[Infos.ClassInfo]]
   }

linker/shared/src/main/scala/org/scalajs/linker/analyzer/Infos.scala

@@ -136,7 +136,7 @@ object Infos {
       this
     }
 
-    def addInterfaces(interfaces: TraversableOnce[String]): this.type = {
+    def addInterfaces(interfaces: List[String]): this.type = {
       this.interfaces ++= interfaces
       this
     }
@@ -319,7 +319,7 @@ object Infos {
     def result(): MethodInfo = {
       def toMapOfLists[A](
           m: mutable.Map[String, mutable.Set[A]]): Map[String, List[A]] = {
-        m.mapValues(_.toList).toMap
+        m.map(kv => kv._1 -> kv._2.toList).toMap
       }
 
       MethodInfo(

linker/shared/src/main/scala/org/scalajs/linker/backend/emitter/Emitter.scala

@@ -25,6 +25,7 @@ import org.scalajs.logging._
 import org.scalajs.linker._
 import org.scalajs.linker.standard._
 import org.scalajs.linker.backend.javascript.{Trees => js, _}
+import org.scalajs.linker.CollectionsCompat.MutableMapCompatOps
 
 import GlobalRefUtils._
 
@@ -402,7 +403,7 @@ final class Emitter private (config: CommonPhaseConfig,
     logger.debug(
         s"Emitter: Method tree cache stats: resued: $statsMethodsReused -- "+
         s"invalidated: $statsMethodsInvalidated")
-    classCaches.retain((_, c) => c.cleanAfterRun())
+    classCaches.filterInPlace((_, c) => c.cleanAfterRun())
   }
 
   /** Generates all the desugared classes.
@@ -658,7 +659,7 @@ final class Emitter private (config: CommonPhaseConfig,
 
   private def mergeVersions(v1: Option[String],
       v2: Option[String]): Option[String] = {
-    v1.flatMap(s1 => v2.map(s2 => s1.length + "-" + s1 + s2))
+    v1.flatMap(s1 => v2.map(s2 => "" + s1.length + "-" + s1 + s2))
   }
 
   private def getClassTreeCache(linkedClass: LinkedClass): DesugaredClassCache =
@@ -722,7 +723,7 @@ final class Emitter private (config: CommonPhaseConfig,
     }
 
     def cleanAfterRun(): Boolean = {
-      _methodCaches.foreach(_.retain((_, c) => c.cleanAfterRun()))
+      _methodCaches.foreach(_.filterInPlace((_, c) => c.cleanAfterRun()))
 
       if (_constructorCache.exists(!_.cleanAfterRun()))
         _constructorCache = None
@@ -837,9 +838,9 @@ private object Emitter {
         cond(!coreSpec.esFeatures.allowBigIntsForLongs) {
           multiple(
               instanceTests(LongImpl.RuntimeLongClass),
-              instantiateClass(LongImpl.RuntimeLongClass, LongImpl.AllConstructors),
-              callMethods(LongImpl.RuntimeLongClass, LongImpl.AllMethods),
-              callOnModule(LongImpl.RuntimeLongModuleClass, LongImpl.AllModuleMethods)
+              instantiateClass(LongImpl.RuntimeLongClass, LongImpl.AllConstructors.toList),
+              callMethods(LongImpl.RuntimeLongClass, LongImpl.AllMethods.toList),
+              callOnModule(LongImpl.RuntimeLongModuleClass, LongImpl.AllModuleMethods.toList)
           )
         }
     )

linker/shared/src/main/scala/org/scalajs/linker/backend/emitter/KnowledgeGuardian.scala

@@ -20,6 +20,7 @@ import org.scalajs.ir.Types.Type
 
 import org.scalajs.linker._
 import org.scalajs.linker.standard._
+import org.scalajs.linker.CollectionsCompat.MutableMapCompatOps
 
 private[emitter] final class KnowledgeGuardian(config: CommonPhaseConfig) {
   import KnowledgeGuardian._
@@ -73,7 +74,7 @@ private[emitter] final class KnowledgeGuardian(config: CommonPhaseConfig) {
     }
 
     // Garbage collection
-    classes.retain((_, cls) => cls.testAndResetIsAlive())
+    classes.filterInPlace((_, cls) => cls.testAndResetIsAlive())
 
     val invalidateAll = !firstRun && {
       newIsParentDataAccessed != isParentDataAccessed

linker/shared/src/main/scala/org/scalajs/linker/checker/IRChecker.scala

@@ -453,7 +453,7 @@ private final class IRChecker(unit: LinkingUnit, logger: Logger) {
       val initialEnv = Env.fromSignature(NoType, classDef.jsClassCaptures,
           params, NoType, isConstructor = true)
 
-      val preparedEnv = (initialEnv /: prepStats) { (prevEnv, stat) =>
+      val preparedEnv = prepStats.foldLeft(initialEnv) { (prevEnv, stat) =>
         typecheckStat(stat, prevEnv)
       }
 
@@ -601,7 +601,7 @@ private final class IRChecker(unit: LinkingUnit, logger: Logger) {
         env
 
       case Block(stats) =>
-        (env /: stats) { (prevEnv, stat) =>
+        stats.foldLeft(env) { (prevEnv, stat) =>
           typecheckStat(stat, prevEnv)
         }
         env
@@ -718,7 +718,7 @@ private final class IRChecker(unit: LinkingUnit, logger: Logger) {
 
       case Block(statsAndExpr) =>
         val stats :+ expr = statsAndExpr
-        val envAfterStats = (env /: stats) { (prevEnv, stat) =>
+        val envAfterStats = stats.foldLeft(env) { (prevEnv, stat) =>
           typecheckStat(stat, prevEnv)
         }
         typecheckExpr(expr, envAfterStats)
@@ -1321,7 +1321,7 @@ private final class IRChecker(unit: LinkingUnit, logger: Logger) {
       val ancestors: Set[String],
       val hasInstances: Boolean,
       val jsNativeLoadSpec: Option[JSNativeLoadSpec],
-      _fields: TraversableOnce[CheckedField])(
+      _fields: List[CheckedField])(
       implicit ctx: ErrorContext) {
 
     val fields = _fields.filter(!_.flags.namespace.isStatic).map(f => f.name -> f).toMap