Use @uncheckedBounds to avoid introducing refchecks errors …

build.sbt

@@ -1,7 +1,10 @@
-scalaVersion := "2.10.2"
+scalaVersion := "2.10.3-RC1"
 
 organization := "org.typesafe.async" // TODO new org name under scala-lang.
 
+// Uncomment to test with a locally built copy of Scala.
+// scalaHome := Some(file("/code/scala2/build/pack"))
+
 name := "scala-async"
 
 version := "1.0.0-SNAPSHOT"
@@ -15,18 +18,30 @@ libraryDependencies <++= (scalaVersion) {
 
 libraryDependencies += "junit" % "junit-dep" % "4.10" % "test"
 
-libraryDependencies += "com.novocode" % "junit-interface" % "0.10-M2" % "test"
+libraryDependencies += "com.novocode" % "junit-interface" % "0.10" % "test"
 
 testOptions += Tests.Argument(TestFrameworks.JUnit, "-q", "-v", "-s")
 
 parallelExecution in Global := false
 
 autoCompilerPlugins := true
 
-libraryDependencies <<= (scalaVersion, libraryDependencies) {
-  (ver, deps) =>
-    deps :+ compilerPlugin("org.scala-lang.plugins" % "continuations" % ver)
-}
+scalacOptions ++= (scalaHome.value match {
+  case Some(sh) =>
+    // Use continuations plugin from the local scala instance
+    val continuationsJar = sh / "misc" / "scala-devel" / "plugins" / "continuations.jar"
+    ("-Xplugin:" + continuationsJar.getAbsolutePath) :: Nil
+  case None =>
+    Nil
+})
+
+libraryDependencies ++= (scalaHome.value match {
+  case Some(sh) =>
+    Nil
+  case None =>
+    // Use continuations plugin from the published artifact.
+    compilerPlugin("org.scala-lang.plugins" % "continuations" % scalaVersion.value) :: Nil
+})
 
 scalacOptions += "-P:continuations:enable"
 

project/build.properties

@@ -1 +1 @@
-sbt.version=0.12.4
+sbt.version=0.13.0-RC5

src/main/scala/scala/async/internal/AnfTransform.scala

@@ -119,8 +119,8 @@ private[async] trait AnfTransform {
       }
 
       private def defineVar(prefix: String, tp: Type, pos: Position): ValDef = {
-        val sym = currOwner.newTermSymbol(name.fresh(prefix), pos, MUTABLE | SYNTHETIC).setInfo(tp)
-        ValDef(sym, gen.mkZero(tp)).setType(NoType).setPos(pos)
+        val sym = currOwner.newTermSymbol(name.fresh(prefix), pos, MUTABLE | SYNTHETIC).setInfo(uncheckedBounds(tp))
+        ValDef(sym, gen.mkZero(uncheckedBounds(tp))).setType(NoType).setPos(pos)
       }
     }
 
@@ -145,7 +145,7 @@ private[async] trait AnfTransform {
     }
 
     private def defineVal(prefix: String, lhs: Tree, pos: Position): ValDef = {
-      val sym = currOwner.newTermSymbol(name.fresh(prefix), pos, SYNTHETIC).setInfo(lhs.tpe)
+      val sym = currOwner.newTermSymbol(name.fresh(prefix), pos, SYNTHETIC).setInfo(uncheckedBounds(lhs.tpe))
       changeOwner(lhs, currentOwner, sym)
       ValDef(sym, changeOwner(lhs, currentOwner, sym)).setType(NoType).setPos(pos)
     }

src/main/scala/scala/async/internal/AsyncId.scala

@@ -41,7 +41,7 @@ object IdentityFutureSystem extends FutureSystem {
     def execContextType: Type = weakTypeOf[Unit]
 
     def createProm[A: WeakTypeTag]: Expr[Prom[A]] = reify {
-      new Prom()
+      new Prom[A]()
     }
 
     def promiseToFuture[A: WeakTypeTag](prom: Expr[Prom[A]]) = reify {

src/main/scala/scala/async/internal/AsyncTransform.scala

@@ -6,7 +6,12 @@ trait AsyncTransform {
   import global._
 
   def asyncTransform[T](body: Tree, execContext: Tree, cpsFallbackEnabled: Boolean)
-                       (implicit resultType: WeakTypeTag[T]): Tree = {
+                       (resultType: WeakTypeTag[T]): Tree = {
+
+    // We annotate the type of the whole expression as `T @uncheckedBounds` so as not to introduce
+    // warnings about non-conformant LUBs. See SI-7694
+    // This implicit propatages the annotated type in the type tag.
+    implicit val uncheckedBoundsResultTag: WeakTypeTag[T] = WeakTypeTag[T](rootMirror, FixedMirrorTypeCreator(rootMirror, uncheckedBounds(resultType.tpe)))
 
     reportUnsupportedAwaits(body, report = !cpsFallbackEnabled)
 
@@ -22,12 +27,12 @@ trait AsyncTransform {
       DefDef(NoMods, name.apply, Nil, applyVParamss, TypeTree(definitions.UnitTpe), Literal(Constant(())))
     }
 
-    val stateMachineType = applied("scala.async.StateMachine", List(futureSystemOps.promType[T], futureSystemOps.execContextType))
+    val stateMachineType = applied("scala.async.StateMachine", List(futureSystemOps.promType[T](uncheckedBoundsResultTag), futureSystemOps.execContextType))
 
     val stateMachine: ClassDef = {
       val body: List[Tree] = {
         val stateVar = ValDef(Modifiers(Flag.MUTABLE | Flag.PRIVATE | Flag.LOCAL), name.state, TypeTree(definitions.IntTpe), Literal(Constant(0)))
-        val result = ValDef(NoMods, name.result, TypeTree(futureSystemOps.promType[T]), futureSystemOps.createProm[T].tree)
+        val result = ValDef(NoMods, name.result, TypeTree(futureSystemOps.promType[T](uncheckedBoundsResultTag)), futureSystemOps.createProm[T](uncheckedBoundsResultTag).tree)
         val execContextValDef = ValDef(NoMods, name.execContext, TypeTree(), execContext)
 
         val apply0DefDef: DefDef = {

src/main/scala/scala/async/internal/ExprBuilder.scala

@@ -284,7 +284,7 @@ trait ExprBuilder {
 
     def onCompleteHandler[T: WeakTypeTag]: Tree
 
-    def resumeFunTree[T]: DefDef
+    def resumeFunTree[T: WeakTypeTag]: DefDef
   }
 
   case class SymLookup(stateMachineClass: Symbol, applyTrParam: Symbol) {
@@ -303,12 +303,12 @@ trait ExprBuilder {
     new AsyncBlock {
       def asyncStates = blockBuilder.asyncStates.toList
 
-      def mkCombinedHandlerCases[T]: List[CaseDef] = {
+      def mkCombinedHandlerCases[T: WeakTypeTag]: List[CaseDef] = {
         val caseForLastState: CaseDef = {
           val lastState = asyncStates.last
           val lastStateBody = Expr[T](lastState.body)
           val rhs = futureSystemOps.completeProm(
-            Expr[futureSystem.Prom[T]](symLookup.memberRef(name.result)), reify(scala.util.Success(lastStateBody.splice)))
+            Expr[futureSystem.Prom[T]](symLookup.memberRef(name.result)), reify(scala.util.Success[T](lastStateBody.splice)))
           mkHandlerCase(lastState.state, rhs.tree)
         }
         asyncStates.toList match {
@@ -337,7 +337,7 @@ trait ExprBuilder {
        * }
        * }
        */
-      def resumeFunTree[T]: DefDef =
+      def resumeFunTree[T: WeakTypeTag]: DefDef =
         DefDef(Modifiers(), name.resume, Nil, List(Nil), Ident(definitions.UnitClass),
           Try(
             Match(symLookup.memberRef(name.state), mkCombinedHandlerCases[T]),

src/main/scala/scala/async/internal/TransformUtils.scala

@@ -244,8 +244,19 @@ private[async] trait TransformUtils {
   // Attributed version of `TreeGen#mkCastPreservingAnnotations`
   def mkAttributedCastPreservingAnnotations(tree: Tree, tp: Type): Tree = {
     atPos(tree.pos) {
-      val casted = gen.mkAttributedCast(tree, tp.withoutAnnotations.dealias)
+      val casted = gen.mkAttributedCast(tree, uncheckedBounds(tp.withoutAnnotations).dealias)
       Typed(casted, TypeTree(tp)).setType(tp)
     }
   }
+
+  // =====================================
+  // Copy/Pasted from Scala 2.10.3. See SI-7694.
+  private lazy val UncheckedBoundsClass = {
+    global.rootMirror.getClassIfDefined("scala.reflect.internal.annotations.uncheckedBounds")
+  }
+  final def uncheckedBounds(tp: Type): Type = {
+    if (tp.typeArgs.isEmpty || UncheckedBoundsClass == NoSymbol) tp
+    else tp.withAnnotation(AnnotationInfo marker UncheckedBoundsClass.tpe)
+  }
+  // =====================================
 }

src/test/scala/scala/async/TreeInterrogation.scala

@@ -4,14 +4,11 @@
 
 package scala.async
 
-import org.junit.runner.RunWith
-import org.junit.runners.JUnit4
 import org.junit.Test
 import scala.async.internal.AsyncId
 import AsyncId._
 import tools.reflect.ToolBox
 
-@RunWith(classOf[JUnit4])
 class TreeInterrogation {
   @Test
   def `a minimal set of vals are lifted to vars`() {

src/test/scala/scala/async/neg/LocalClasses0Spec.scala

@@ -5,12 +5,9 @@
 package scala.async
 package neg
 
-import org.junit.runner.RunWith
-import org.junit.runners.JUnit4
 import org.junit.Test
 import scala.async.internal.AsyncId
 
-@RunWith(classOf[JUnit4])
 class LocalClasses0Spec {
   @Test
   def localClassCrashIssue16() {

src/test/scala/scala/async/neg/NakedAwait.scala

@@ -5,11 +5,8 @@
 package scala.async
 package neg
 
-import org.junit.runner.RunWith
-import org.junit.runners.JUnit4
 import org.junit.Test
 
-@RunWith(classOf[JUnit4])
 class NakedAwait {
   @Test
   def `await only allowed in async neg`() {

src/test/scala/scala/async/neg/SampleNegSpec.scala

@@ -5,11 +5,8 @@
 package scala.async
 package neg
 
-import org.junit.runner.RunWith
-import org.junit.runners.JUnit4
 import org.junit.Test
 
-@RunWith(classOf[JUnit4])
 class SampleNegSpec {
   @Test
   def `missing symbol`() {

src/test/scala/scala/async/run/anf/AnfTransformSpec.scala

@@ -11,8 +11,6 @@ import scala.concurrent.{Future, ExecutionContext, future, Await}
 import scala.concurrent.duration._
 import scala.async.Async.{async, await}
 import org.junit.Test
-import org.junit.runner.RunWith
-import org.junit.runners.JUnit4
 import scala.async.internal.AsyncId
 
 
@@ -70,7 +68,6 @@ object State {
   @volatile var result: Int = 0
 }
 
-@RunWith(classOf[JUnit4])
 class AnfTransformSpec {
 
   @Test

src/test/scala/scala/async/run/await0/Await0Spec.scala

@@ -15,8 +15,6 @@ import language.{reflectiveCalls, postfixOps}
 import scala.concurrent.{Future, ExecutionContext, future, Await}
 import scala.concurrent.duration._
 import scala.async.Async.{async, await}
-import org.junit.runner.RunWith
-import org.junit.runners.JUnit4
 import org.junit.Test
 
 class Await0Class {
@@ -63,7 +61,6 @@ class Await0Class {
   }
 }
 
-@RunWith(classOf[JUnit4])
 class Await0Spec {
 
   @Test

src/test/scala/scala/async/run/block0/AsyncSpec.scala

@@ -11,8 +11,6 @@ import scala.concurrent.{Future, ExecutionContext, future, Await}
 import scala.concurrent.duration._
 import scala.async.Async.{async, await}
 import org.junit.Test
-import org.junit.runner.RunWith
-import org.junit.runners.JUnit4
 
 
 class Test1Class {
@@ -39,7 +37,6 @@ class Test1Class {
 }
 
 
-@RunWith(classOf[JUnit4])
 class AsyncSpec {
 
   @Test

src/test/scala/scala/async/run/block1/block1.scala

@@ -11,8 +11,6 @@ import scala.concurrent.{Future, ExecutionContext, future, Await}
 import scala.concurrent.duration._
 import scala.async.Async.{async, await}
 import org.junit.Test
-import org.junit.runner.RunWith
-import org.junit.runners.JUnit4
 
 
 class Test1Class {
@@ -32,7 +30,6 @@ class Test1Class {
   }
 }
 
-@RunWith(classOf[JUnit4])
 class Block1Spec {
 
   @Test def `support a simple await`() {

src/test/scala/scala/async/run/cps/CPSSpec.scala

@@ -11,11 +11,8 @@ import scala.concurrent.duration._
 import scala.async.continuations.CPSBasedAsync._
 import scala.util.continuations._
 
-import org.junit.runner.RunWith
-import org.junit.runners.JUnit4
 import org.junit.Test
 
-@RunWith(classOf[JUnit4])
 class CPSSpec {
 
   import ExecutionContext.Implicits.global

src/test/scala/scala/async/run/exceptions/ExceptionsSpec.scala

@@ -14,10 +14,7 @@ import scala.concurrent.duration._
 import scala.reflect.ClassTag
 
 import org.junit.Test
-import org.junit.runner.RunWith
-import org.junit.runners.JUnit4
 
-@RunWith(classOf[JUnit4])
 class ExceptionsSpec {
 
   @Test

src/test/scala/scala/async/run/futures/FutureSpec.scala

@@ -18,10 +18,7 @@ import scala.util.{Try,Success,Failure}
 import scala.async.Async.{async, await}
 
 import org.junit.Test
-import org.junit.runner.RunWith
-import org.junit.runners.JUnit4
 
-@RunWith(classOf[JUnit4])
 class FutureSpec {
 
   /* some utils */

src/test/scala/scala/async/run/hygiene/Hygiene.scala

@@ -7,11 +7,8 @@ package run
 package hygiene
 
 import org.junit.Test
-import org.junit.runner.RunWith
-import org.junit.runners.JUnit4
 import scala.async.internal.AsyncId
 
-@RunWith(classOf[JUnit4])
 class HygieneSpec {
 
   import AsyncId.{async, await}

src/test/scala/scala/async/run/ifelse0/IfElse0.scala

@@ -10,8 +10,6 @@ import language.{reflectiveCalls, postfixOps}
 import scala.concurrent.{Future, ExecutionContext, future, Await}
 import scala.concurrent.duration._
 import scala.async.Async.{async, await}
-import org.junit.runner.RunWith
-import org.junit.runners.JUnit4
 import org.junit.Test
 import scala.async.internal.AsyncId
 
@@ -39,7 +37,6 @@ class TestIfElseClass {
 }
 
 
-@RunWith(classOf[JUnit4])
 class IfElseSpec {
 
   @Test def `support await in a simple if-else expression`() {

src/test/scala/scala/async/run/ifelse0/WhileSpec.scala

@@ -6,12 +6,9 @@ package scala.async
 package run
 package ifelse0
 
-import org.junit.runner.RunWith
-import org.junit.runners.JUnit4
 import org.junit.Test
 import scala.async.internal.AsyncId
 
-@RunWith(classOf[JUnit4])
 class WhileSpec {
 
   @Test

src/test/scala/scala/async/run/ifelse1/IfElse1.scala

@@ -10,8 +10,6 @@ import language.{reflectiveCalls, postfixOps}
 import scala.concurrent.{Future, ExecutionContext, future, Await}
 import scala.concurrent.duration._
 import scala.async.Async.{async, await}
-import org.junit.runner.RunWith
-import org.junit.runners.JUnit4
 import org.junit.Test
 
 
@@ -91,7 +89,6 @@ class TestIfElse1Class {
   }
 }
 
-@RunWith(classOf[JUnit4])
 class IfElse1Spec {
 
   @Test

src/test/scala/scala/async/run/ifelse2/ifelse2.scala

@@ -10,8 +10,6 @@ import language.{reflectiveCalls, postfixOps}
 import scala.concurrent.{Future, ExecutionContext, future, Await}
 import scala.concurrent.duration._
 import scala.async.Async.{async, await}
-import org.junit.runner.RunWith
-import org.junit.runners.JUnit4
 import org.junit.Test
 
 
@@ -37,7 +35,6 @@ class TestIfElse2Class {
   }
 }
 
-@RunWith(classOf[JUnit4])
 class IfElse2Spec {
 
   @Test