Merge pull request #84 from retronym/merge/2.10.x-to-master-20140721

Merge 2.10.x to master

7 files changed, 211 insertions, 34 deletions

diff --git a/src/main/scala/scala/async/internal/AsyncTransform.scala b/src/main/scala/scala/async/internal/AsyncTransform.scala
index aca8c7e..66cfb87 100644
--- a/src/main/scala/scala/async/internal/AsyncTransform.scala
+++ b/src/main/scala/scala/async/internal/AsyncTransform.scala
@@ -157,9 +157,10 @@ trait AsyncTransform {
       case ValDef(_, _, _, rhs) if liftedSyms(tree.symbol) =>
         api.atOwner(api.currentOwner) {
           val fieldSym = tree.symbol
-          val set = Assign(gen.mkAttributedStableRef(thisType(fieldSym.owner.asClass), fieldSym), api.recur(rhs))
-          set.changeOwner(tree.symbol, api.currentOwner)
-          api.typecheck(atPos(tree.pos)(set))
+          val lhs = atPos(tree.pos) {
+            gen.mkAttributedStableRef(thisType(fieldSym.owner.asClass), fieldSym)
+          }
+          treeCopy.Assign(tree, lhs, api.recur(rhs)).setType(definitions.UnitTpe).changeOwner(fieldSym, api.currentOwner)
         }
       case _: DefTree if liftedSyms(tree.symbol)           =>
         EmptyTree
diff --git a/src/main/scala/scala/async/internal/Lifter.scala b/src/main/scala/scala/async/internal/Lifter.scala
index bf7bdbd..4242a8e 100644
--- a/src/main/scala/scala/async/internal/Lifter.scala
+++ b/src/main/scala/scala/async/internal/Lifter.scala
@@ -115,8 +115,7 @@ trait Lifter {
             sym.setFlag(MUTABLE | STABLE | PRIVATE | LOCAL)
             sym.setName(name.fresh(sym.name.toTermName))
             sym.setInfo(deconst(sym.info))
-            val zeroRhs = atPos(t.pos)(gen.mkZero(vd.symbol.info))
-            treeCopy.ValDef(vd, Modifiers(sym.flags), sym.name, TypeTree(tpe(sym)).setPos(t.pos), zeroRhs)
+            treeCopy.ValDef(vd, Modifiers(sym.flags), sym.name, TypeTree(tpe(sym)).setPos(t.pos), EmptyTree)
           case dd@DefDef(_, _, tparams, vparamss, tpt, rhs) =>
             sym.setName(this.name.fresh(sym.name.toTermName))
             sym.setFlag(PRIVATE | LOCAL)
diff --git a/src/main/scala/scala/async/internal/LiveVariables.scala b/src/main/scala/scala/async/internal/LiveVariables.scala
index 7f386c8..5b49398 100644
--- a/src/main/scala/scala/async/internal/LiveVariables.scala
+++ b/src/main/scala/scala/async/internal/LiveVariables.scala
@@ -126,14 +126,22 @@ trait LiveVariables {
 
     /** Tests if `state1` is a predecessor of `state2`.
      */
-    def isPred(state1: Int, state2: Int, seen: Set[Int] = Set()): Boolean =
-      if (seen(state1)) false  // breaks cycles in the CFG
-      else cfg get state1 match {
-        case Some(nextStates) =>
-          nextStates.contains(state2) || nextStates.exists(isPred(_, state2, seen + state1))
-        case None =>
-          false
-      }
+    def isPred(state1: Int, state2: Int): Boolean = {
+      val seen = scala.collection.mutable.HashSet[Int]()
+
+      def isPred0(state1: Int, state2: Int): Boolean = 
+        if(state1 == state2) false
+        else if (seen(state1)) false  // breaks cycles in the CFG
+        else cfg get state1 match {
+          case Some(nextStates) =>
+            seen += state1
+            nextStates.contains(state2) || nextStates.exists(isPred0(_, state2))
+          case None =>
+            false
+        }
+
+      isPred0(state1, state2)
+    }
 
     val finalState = asyncStates.find(as => !asyncStates.exists(other => isPred(as.state, other.state))).get
 
@@ -162,12 +170,10 @@ trait LiveVariables {
     LVexit = LVexit + (finalState.state -> noNull)
 
     var currStates = List(finalState)    // start at final state
-    var pred       = List[AsyncState]()  // current predecessor states
-    var hasChanged = true                // if something has changed we need to continue iterating
     var captured: Set[Symbol] = Set()
 
-    while (hasChanged) {
-      hasChanged = false
+    while (!currStates.isEmpty) {
+      var entryChanged: List[AsyncState] = Nil
 
       for (cs <- currStates) {
         val LVentryOld = LVentry(cs.state)
@@ -176,22 +182,23 @@ trait LiveVariables {
         val LVentryNew = LVexit(cs.state) ++ referenced.used
         if (!LVentryNew.sameElements(LVentryOld)) {
           LVentry = LVentry + (cs.state -> LVentryNew)
-          hasChanged = true
+          entryChanged ::= cs
         }
       }
 
-      pred = currStates.flatMap(cs => asyncStates.filter(_.nextStates.contains(cs.state)))
+      val pred = entryChanged.flatMap(cs => asyncStates.filter(_.nextStates.contains(cs.state)))
+      var exitChanged: List[AsyncState] = Nil
 
       for (p <- pred) {
         val LVexitOld = LVexit(p.state)
         val LVexitNew = p.nextStates.flatMap(succ => LVentry(succ)).toSet
         if (!LVexitNew.sameElements(LVexitOld)) {
           LVexit = LVexit + (p.state -> LVexitNew)
-          hasChanged = true
+          exitChanged ::= p
         }
       }
 
-      currStates = pred
+      currStates = exitChanged
     }
 
     for (as <- asyncStates) {
@@ -199,21 +206,29 @@ trait LiveVariables {
       AsyncUtils.vprintln(s"LVexit  at state #${as.state}: ${LVexit(as.state).mkString(", ")}")
     }
 
-    def lastUsagesOf(field: Tree, at: AsyncState, avoid: Set[AsyncState]): Set[Int] =
-      if (avoid(at)) Set()
-      else if (captured(field.symbol)) {
-        Set()
-      }
-      else LVentry get at.state match {
-        case Some(fields) if fields.exists(_ == field.symbol) =>
-          Set(at.state)
-        case _ =>
-          val preds = asyncStates.filter(_.nextStates.contains(at.state)).toSet
-          preds.flatMap(p => lastUsagesOf(field, p, avoid + at))
+    def lastUsagesOf(field: Tree, at: AsyncState): Set[Int] = {
+      val avoid = scala.collection.mutable.HashSet[AsyncState]()
+
+      def lastUsagesOf0(field: Tree, at: AsyncState): Set[Int] = {
+        if (avoid(at)) Set()
+        else if (captured(field.symbol)) {
+          Set()
+        }
+        else LVentry get at.state match {
+          case Some(fields) if fields.exists(_ == field.symbol) =>
+            Set(at.state)
+          case _ =>
+            avoid += at
+            val preds = asyncStates.filter(_.nextStates.contains(at.state)).toSet
+            preds.flatMap(p => lastUsagesOf0(field, p))
+        }
       }
 
+      lastUsagesOf0(field, at)
+    }
+
     val lastUsages: Map[Tree, Set[Int]] =
-      liftables.map(fld => (fld -> lastUsagesOf(fld, finalState, Set()))).toMap
+      liftables.map(fld => (fld -> lastUsagesOf(fld, finalState))).toMap
 
     for ((fld, lastStates) <- lastUsages)
       AsyncUtils.vprintln(s"field ${fld.symbol.name} is last used in states ${lastStates.mkString(", ")}")
diff --git a/src/main/scala/scala/async/internal/TransformUtils.scala b/src/main/scala/scala/async/internal/TransformUtils.scala
index a01a801..665dead 100644
--- a/src/main/scala/scala/async/internal/TransformUtils.scala
+++ b/src/main/scala/scala/async/internal/TransformUtils.scala
@@ -164,11 +164,17 @@ private[async] trait TransformUtils {
       case ld: LabelDef => ld.symbol
     }.toSet
     t.exists {
-      case rt: RefTree => !(labelDefs contains rt.symbol)
+      case rt: RefTree => rt.symbol != null && isLabel(rt.symbol) && !(labelDefs contains rt.symbol)
       case _ => false
     }
   }
 
+  private def isLabel(sym: Symbol): Boolean = {
+    val LABEL = 1L << 17 // not in the public reflection API.
+    (internal.flags(sym).asInstanceOf[Long] & LABEL) != 0L
+  }
+
+
   /** Map a list of arguments to:
     * - A list of argument Trees
     * - A list of auxillary results.
diff --git a/src/test/scala/scala/async/run/ifelse1/IfElse1.scala b/src/test/scala/scala/async/run/ifelse1/IfElse1.scala
index 587aaac..6cbe910 100644
--- a/src/test/scala/scala/async/run/ifelse1/IfElse1.scala
+++ b/src/test/scala/scala/async/run/ifelse1/IfElse1.scala
@@ -87,6 +87,75 @@ class TestIfElse1Class {
     }
     z
   }
+
+  def pred: Future[Boolean] = async(true) 
+
+  def m5: Future[Boolean] = async {
+    if(if(if(if(if(if(if(if(if(if(if(if(if(if(if(if(if(if(if(if(if(await(pred))
+      await(pred)
+    else
+      false)
+      await(pred)
+    else
+      false)
+      await(pred)
+    else
+      false)
+      await(pred)
+    else
+      false)
+      await(pred)
+    else
+      false)
+      await(pred)
+    else
+      false)
+      await(pred)
+    else
+      false)
+      await(pred)
+    else
+      false)
+      await(pred)
+    else
+      false)
+      await(pred)
+    else
+      false)
+      await(pred)
+    else
+      false)
+      await(pred)
+    else
+      false)
+      await(pred)
+    else
+      false)
+      await(pred)
+    else
+      false)
+      await(pred)
+    else
+      false)
+      await(pred)
+    else
+      false)
+      await(pred)
+    else
+      false)
+      await(pred)
+    else
+      false)
+      await(pred)
+    else
+      false)
+      await(pred)
+    else
+      false)
+      await(pred)
+    else
+      false
+  }
 }
 
 class IfElse1Spec {
@@ -124,4 +193,12 @@ class IfElse1Spec {
     val res = Await.result(fut, 2 seconds)
     res mustBe (14)
   }
+
+  @Test
+  def `await in deeply-nested if-else conditions`() {
+    val o = new TestIfElse1Class
+    val fut = o.m5
+    val res = Await.result(fut, 2 seconds)
+    res mustBe true
+  }
 }
diff --git a/src/test/scala/scala/async/run/ifelse4/IfElse4.scala b/src/test/scala/scala/async/run/ifelse4/IfElse4.scala
new file mode 100644
index 0000000..b0ecf13
--- /dev/null
+++ b/src/test/scala/scala/async/run/ifelse4/IfElse4.scala
@@ -0,0 +1,63 @@
+/*
+ * Copyright (C) 2012-2014 Typesafe Inc. <http://www.typesafe.com>
+ */
+
+package scala.async
+package run
+package ifelse4
+
+import language.{reflectiveCalls, postfixOps}
+import scala.concurrent.{Future, ExecutionContext, future, Await}
+import scala.concurrent.duration._
+import scala.async.Async.{async, await}
+import org.junit.Test
+
+
+class TestIfElse4Class {
+
+  import ExecutionContext.Implicits.global
+  
+  class F[A]
+  class S[A](val id: String)
+  trait P
+ 
+  case class K(f: F[_])
+
+  def result[A](f: F[A]) = async {
+    new S[A with P]("foo")
+  }
+    
+  def run(k: K) = async {
+    val res = await(result(k.f))
+    // these triggered a crash with mismatched existential skolems
+    //  found   : S#10272[_$1#10308 with String#137] where type _$1#10308
+    //  required: S#10272[_$1#10311 with String#137] forSome { type _$1#10311 }
+
+    // This variation of the crash could be avoided by fixing the over-eager
+    // generation of states in `If` nodes, which was caused by a bug in label
+    // detection code.
+    if(true) {
+      identity(res)
+    }
+
+    // This variation remained after the aforementioned fix, however.
+    // It was fixed by manually typing the `Assign(liftedField, rhs)` AST,
+    // which is how we avoid these problems through the rest of the ANF transform.
+    if(true) {
+      identity(res)
+      await(result(k.f))
+    }
+    res
+  }
+}
+
+class IfElse4Spec {
+
+  @Test
+  def `await result with complex type containing skolem`() {
+    val o = new TestIfElse4Class
+    val fut = o.run(new o.K(null))
+    val res = Await.result(fut, 2 seconds)
+    res.id mustBe ("foo")
+  }
+}
diff --git a/src/test/scala/scala/async/run/toughtype/ToughType.scala b/src/test/scala/scala/async/run/toughtype/ToughType.scala
index 458157c..54a53c8 100644
--- a/src/test/scala/scala/async/run/toughtype/ToughType.scala
+++ b/src/test/scala/scala/async/run/toughtype/ToughType.scala
@@ -211,6 +211,22 @@ class ToughTypeSpec {
           }(SomeExecutionContext)
         }
     }
+
+  }
+
+  @Test def ticket66Nothing() {
+    import scala.concurrent.Future
+    import scala.concurrent.ExecutionContext.Implicits.global
+    val e = new Exception()
+    val f: Future[Nothing] = Future.failed(e)
+    val f1 = async {
+      await(f)
+    }
+    try {
+      Await.result(f1, 5.seconds)
+    } catch {
+      case `e` =>
+    }
   }
 }