Merge branch '2.10.x' into topic/name-implicits

16 files changed, 268 insertions, 254 deletions

diff --git a/src/library/scala/StringContext.scala b/src/library/scala/StringContext.scala
index f400f18dab..f11dfb72ae 100644
--- a/src/library/scala/StringContext.scala
+++ b/src/library/scala/StringContext.scala
@@ -8,7 +8,7 @@
 
 package scala
 
-import collection.mutable.ArrayBuffer
+import language.experimental.macros
 
 /** A class to support string interpolation.
  *  This class supports string interpolation as outlined in Scala SIP-11.
@@ -42,7 +42,7 @@ case class StringContext(parts: String*) {
    *  @throws A `StringContext.InvalidEscapeException` if if a `parts` string contains a backslash (`\`) character
    *          that does not start a valid escape sequence.
    */
-  def s(args: Any*) = {
+  def s(args: Any*): String = {
     checkLengths(args: _*)
     val pi = parts.iterator
     val ai = args.iterator
@@ -82,38 +82,8 @@ case class StringContext(parts: String*) {
    *      string literally. This is achieved by replacing each such occurrence by the
    *      format specifier `%%`.
    */
-  def f(args: Any*) = {
-    checkLengths(args: _*)
-    val pi = parts.iterator
-    val bldr = new java.lang.StringBuilder
-    def copyString(first: Boolean): Unit = {
-      val str = treatEscapes(pi.next())
-      val strIsEmpty = str.length == 0
-      var start = 0
-      var idx = 0
-      if (!first) {
-        if (strIsEmpty || (str charAt 0) != '%')
-          bldr append "%s"
-        idx = 1
-      }
-      if (!strIsEmpty) {
-        val len = str.length
-        while (idx < len) {
-          if (str(idx) == '%') {
-            bldr append (str substring (start, idx)) append "%%"
-            start = idx + 1
-          }
-          idx += 1
-        }
-        bldr append (str substring (start, idx))
-      }
-    }
-    copyString(first = true)
-    while (pi.hasNext) {
-      copyString(first = false)
-    }
-    bldr.toString format (args: _*)
-  }
+  // The implementation is magically hardwired into `scala.tools.reflect.MacroImplementations.macro_StringInterpolation_f`
+  def f(args: Any*): String = macro ???
 }
 
 object StringContext {
diff --git a/src/library/scala/collection/MapLike.scala b/src/library/scala/collection/MapLike.scala
index 55d482f6c8..ed2a877631 100644
--- a/src/library/scala/collection/MapLike.scala
+++ b/src/library/scala/collection/MapLike.scala
@@ -301,11 +301,11 @@ self =>
   def ++[B1 >: B](xs: GenTraversableOnce[(A, B1)]): Map[A, B1] =
     ((repr: Map[A, B1]) /: xs.seq) (_ + _)
 
-  /** Returns a new map with all key/value pairs for which the predicate
+  /** Returns a new map obtained by removing all key/value pairs for which the predicate
    *  `p` returns `true`.
    *
-   *  '''Note:'''    This method works by successively removing elements fro which the
-   *           predicate is false from this set.
+   *  '''Note:'''    This method works by successively removing elements for which the
+   *           predicate is true from this set.
    *           If removal is slow, or you expect that most elements of the set
    *           will be removed, you might consider using `filter`
    *           with a negated predicate instead.
diff --git a/src/library/scala/collection/convert/Wrappers.scala b/src/library/scala/collection/convert/Wrappers.scala
index 8c603dc91b..75707b69b0 100644
--- a/src/library/scala/collection/convert/Wrappers.scala
+++ b/src/library/scala/collection/convert/Wrappers.scala
@@ -467,4 +467,5 @@ private[collection] trait Wrappers {
   }
 }
 
-object Wrappers extends Wrappers
+@SerialVersionUID(0 - 5857859809262781311L)
+object Wrappers extends Wrappers with Serializable
diff --git a/src/library/scala/collection/parallel/TaskSupport.scala b/src/library/scala/collection/parallel/TaskSupport.scala
index 2eaa861429..3d27f619bb 100644
--- a/src/library/scala/collection/parallel/TaskSupport.scala
+++ b/src/library/scala/collection/parallel/TaskSupport.scala
@@ -48,7 +48,7 @@ extends TaskSupport with AdaptiveWorkStealingThreadPoolTasks
  *  By default, parallel collections are parametrized with this task support object, so parallel collections
  *  share the same execution context backend as the rest of the `scala.concurrent` package.
  */
-class ExecutionContextTaskSupport(val environment: ExecutionContext = scala.concurrent.defaultExecutionContext)
+class ExecutionContextTaskSupport(val environment: ExecutionContext = scala.concurrent.ExecutionContext.global)
 extends TaskSupport with ExecutionContextTasks
 
 
diff --git a/src/library/scala/concurrent/BlockContext.scala b/src/library/scala/concurrent/BlockContext.scala
new file mode 100644
index 0000000000..a5b878c546
--- /dev/null
+++ b/src/library/scala/concurrent/BlockContext.scala
@@ -0,0 +1,81 @@
+/*                     __                                               *\
+**     ________ ___   / /  ___     Scala API                            **
+**    / __/ __// _ | / /  / _ |    (c) 2003-2012, LAMP/EPFL             **
+**  __\ \/ /__/ __ |/ /__/ __ |    http://scala-lang.org/               **
+** /____/\___/_/ |_/____/_/ | |                                         **
+**                          |/                                          **
+\*                                                                      */
+
+package scala.concurrent
+
+import java.lang.Thread
+import scala.concurrent.util.Duration
+
+/**
+ * A context to be notified by `scala.concurrent.blocking()` when
+ * a thread is about to block. In effect this trait provides
+ * the implementation for `scala.concurrent.blocking()`. `scala.concurrent.blocking()`
+ * locates an instance of `BlockContext` by first looking for one
+ * provided through `BlockContext.withBlockContext()` and failing that,
+ * checking whether `Thread.currentThread` is an instance of `BlockContext`.
+ * So a thread pool can have its `java.lang.Thread` instances implement
+ * `BlockContext`. There's a default `BlockContext` used if the thread
+ * doesn't implement `BlockContext`.
+ *
+ * Typically, you'll want to chain to the previous `BlockContext`,
+ * like this:
+ * {{{
+ *  val oldContext = BlockContext.current
+ *  val myContext = new BlockContext {
+ *    override def internalBlockingCall[T](awaitable: Awaitable[T], atMost: Duration): T = {
+ *      // you'd have code here doing whatever you need to do
+ *      // when the thread is about to block.
+ *      // Then you'd chain to the previous context:
+ *      oldContext.internalBlockingCall(awaitable, atMost)
+ *    }
+ *  }
+ *  BlockContext.withBlockContext(myContext) {
+ *    // then this block runs with myContext as the handler
+ *    // for scala.concurrent.blocking
+ *  }
+ *  }}}
+ */
+trait BlockContext {
+
+  /** Used internally by the framework; blocks execution for at most
+   * `atMost` time while waiting for an `awaitable` object to become ready.
+   *
+   * Clients should use `scala.concurrent.blocking` instead; this is
+   * the implementation of `scala.concurrent.blocking`, generally
+   * provided by a `scala.concurrent.ExecutionContext` or `java.util.concurrent.Executor`.
+   */
+  def internalBlockingCall[T](awaitable: Awaitable[T], atMost: Duration): T
+}
+
+object BlockContext {
+  private object DefaultBlockContext extends BlockContext {
+    override def internalBlockingCall[T](awaitable: Awaitable[T], atMost: Duration): T =
+      awaitable.result(atMost)(Await.canAwaitEvidence)
+  }
+
+  private val contextLocal = new ThreadLocal[BlockContext]() {
+    override def initialValue = Thread.currentThread match {
+      case ctx: BlockContext => ctx
+      case _ => DefaultBlockContext
+    }
+  }
+
+  /** Obtain the current thread's current `BlockContext`. */
+  def current: BlockContext = contextLocal.get
+
+  /** Pushes a current `BlockContext` while executing `body`. */
+  def withBlockContext[T](blockContext: BlockContext)(body: => T): T = {
+    val old = contextLocal.get
+    try {
+      contextLocal.set(blockContext)
+      body
+    } finally {
+      contextLocal.set(old)
+    }
+  }
+}
diff --git a/src/library/scala/concurrent/ConcurrentPackageObject.scala b/src/library/scala/concurrent/ConcurrentPackageObject.scala
index 330a2f0e25..86a86966ef 100644
--- a/src/library/scala/concurrent/ConcurrentPackageObject.scala
+++ b/src/library/scala/concurrent/ConcurrentPackageObject.scala
@@ -17,23 +17,6 @@ import language.implicitConversions
 /** This package object contains primitives for concurrent and parallel programming.
  */
 abstract class ConcurrentPackageObject {
-  /** A global execution environment for executing lightweight tasks.
-   */
-  lazy val defaultExecutionContext: ExecutionContext with Executor = impl.ExecutionContextImpl.fromExecutor(null: Executor)
-
-  val currentExecutionContext = new ThreadLocal[ExecutionContext]
-  
-  val handledFutureException: PartialFunction[Throwable, Throwable] = {
-    case t: Throwable if isFutureThrowable(t) => t
-  }
-
-  // TODO rename appropriately and make public
-  private[concurrent] def isFutureThrowable(t: Throwable) = t match {
-    case e: Error                               => false
-    case t: scala.util.control.ControlThrowable => false
-    case i: InterruptedException                => false
-    case _                                      => true
-  }
 
   /* concurrency constructs */
 
@@ -46,8 +29,7 @@ abstract class ConcurrentPackageObject {
    *  @param execctx  the execution context on which the future is run
    *  @return         the `Future` holding the result of the computation
    */
-  def future[T](body: =>T)(implicit execctx: ExecutionContext = defaultExecutionContext): Future[T] =
-    Future[T](body)
+  def future[T](body: =>T)(implicit execctx: ExecutionContext): Future[T] = Future[T](body)
 
   /** Creates a promise object which can be completed with a value.
    *  
@@ -55,8 +37,7 @@ abstract class ConcurrentPackageObject {
    *  @param execctx  the execution context on which the promise is created on
    *  @return         the newly created `Promise` object
    */
-  def promise[T]()(implicit execctx: ExecutionContext = defaultExecutionContext): Promise[T] =
-    Promise[T]()
+  def promise[T]()(implicit execctx: ExecutionContext): Promise[T] = Promise[T]()
 
   /** Used to block on a piece of code which potentially blocks.
    *
@@ -67,8 +48,7 @@ abstract class ConcurrentPackageObject {
    *  - InterruptedException - in the case that a wait within the blockable object was interrupted
    *  - TimeoutException - in the case that the blockable object timed out
    */
-  def blocking[T](body: =>T): T =
-    blocking(impl.Future.body2awaitable(body), Duration.Inf)
+  def blocking[T](body: =>T): T = blocking(impl.Future.body2awaitable(body), Duration.Inf)
 
   /** Blocks on an awaitable object.
    *
@@ -79,12 +59,8 @@ abstract class ConcurrentPackageObject {
    *  - InterruptedException - in the case that a wait within the blockable object was interrupted
    *  - TimeoutException - in the case that the blockable object timed out
    */
-  def blocking[T](awaitable: Awaitable[T], atMost: Duration): T = {
-    currentExecutionContext.get match {
-      case null => awaitable.result(atMost)(Await.canAwaitEvidence)
-      case ec => ec.internalBlockingCall(awaitable, atMost)
-    }
-  }
+  def blocking[T](awaitable: Awaitable[T], atMost: Duration): T =
+    BlockContext.current.internalBlockingCall(awaitable, atMost)
 
   @inline implicit final def int2durationops(x: Int): DurationOps = new DurationOps(x)
 }
diff --git a/src/library/scala/concurrent/DelayedLazyVal.scala b/src/library/scala/concurrent/DelayedLazyVal.scala
index 96a66d83b6..91e41748f5 100644
--- a/src/library/scala/concurrent/DelayedLazyVal.scala
+++ b/src/library/scala/concurrent/DelayedLazyVal.scala
@@ -23,7 +23,7 @@ package scala.concurrent
  *  @author  Paul Phillips
  *  @version 2.8
  */
-class DelayedLazyVal[T](f: () => T, body: => Unit) {
+class DelayedLazyVal[T](f: () => T, body: => Unit){
   @volatile private[this] var _isDone = false
   private[this] lazy val complete = f()
 
@@ -39,7 +39,8 @@ class DelayedLazyVal[T](f: () => T, body: => Unit) {
    */
   def apply(): T = if (isDone) complete else f()
 
-  // TODO replace with scala.concurrent.future { ... }
+  // FIXME need to take ExecutionContext in constructor
+  import ExecutionContext.Implicits.global
   future {
     body
     _isDone = true
diff --git a/src/library/scala/concurrent/ExecutionContext.scala b/src/library/scala/concurrent/ExecutionContext.scala
index 436a17a33b..b486e5269e 100644
--- a/src/library/scala/concurrent/ExecutionContext.scala
+++ b/src/library/scala/concurrent/ExecutionContext.scala
@@ -9,58 +9,80 @@
 package scala.concurrent
 
 
-
-import java.util.concurrent.atomic.{ AtomicInteger }
-import java.util.concurrent.{ Executors, Future => JFuture, Callable, ExecutorService, Executor }
+import java.util.concurrent.{ ExecutorService, Executor }
 import scala.concurrent.util.Duration
-import scala.concurrent.forkjoin.{ ForkJoinPool, RecursiveTask => FJTask, RecursiveAction, ForkJoinWorkerThread }
-import scala.collection.generic.CanBuildFrom
-import collection._
-
-
+import scala.annotation.implicitNotFound
 
+/**
+ * An `ExecutionContext` is an abstraction over an entity that can execute program logic.
+ */
+@implicitNotFound("Cannot find an implicit ExecutionContext, either require one yourself or import ExecutionContext.Implicits.global")
 trait ExecutionContext {
   
   /** Runs a block of code on this execution context.
    */
   def execute(runnable: Runnable): Unit
   
-  /** Used internally by the framework - blocks execution for at most `atMost` time while waiting
-   *  for an `awaitable` object to become ready.
-   *  
-   *  Clients should use `scala.concurrent.blocking` instead.
-   */
-  def internalBlockingCall[T](awaitable: Awaitable[T], atMost: Duration): T
-  
   /** Reports that an asynchronous computation failed.
    */
   def reportFailure(t: Throwable): Unit
   
 }
 
+/**
+ * Union interface since Java does not support union types
+ */
+trait ExecutionContextExecutor extends ExecutionContext with Executor
+
+/**
+ * Union interface since Java does not support union types
+ */
+trait ExecutionContextExecutorService extends ExecutionContextExecutor with ExecutorService
+
 
 /** Contains factory methods for creating execution contexts.
  */
 object ExecutionContext {
-  
-  implicit def defaultExecutionContext: ExecutionContext = scala.concurrent.defaultExecutionContext
-  
+  /**
+   * The `ExecutionContext` associated with the current `Thread`
+   */
+  val currentExecutionContext: ThreadLocal[ExecutionContext] = new ThreadLocal //FIXME might want to set the initial value to an executionContext that throws an exception on execute and warns that it's not set
+
+  /**
+   * This is the explicit global ExecutionContext,
+   * call this when you want to provide the global ExecutionContext explicitly
+   */
+  def global: ExecutionContextExecutor = Implicits.global
+
+  object Implicits {
+    /**
+     * This is the implicit global ExecutionContext,
+     * import this when you want to provide the global ExecutionContext implicitly
+     */
+    implicit lazy val global: ExecutionContextExecutor = impl.ExecutionContextImpl.fromExecutor(null: Executor)
+  }
+    
   /** Creates an `ExecutionContext` from the given `ExecutorService`.
    */
-  def fromExecutorService(e: ExecutorService, reporter: Throwable => Unit = defaultReporter): ExecutionContext with ExecutorService =
+  def fromExecutorService(e: ExecutorService, reporter: Throwable => Unit): ExecutionContextExecutorService =
     impl.ExecutionContextImpl.fromExecutorService(e, reporter)
+
+  /** Creates an `ExecutionContext` from the given `ExecutorService` with the default Reporter.
+   */
+  def fromExecutorService(e: ExecutorService): ExecutionContextExecutorService = fromExecutorService(e, defaultReporter)
   
   /** Creates an `ExecutionContext` from the given `Executor`.
    */
-  def fromExecutor(e: Executor, reporter: Throwable => Unit = defaultReporter): ExecutionContext with Executor =
+  def fromExecutor(e: Executor, reporter: Throwable => Unit): ExecutionContextExecutor =
     impl.ExecutionContextImpl.fromExecutor(e, reporter)
+
+  /** Creates an `ExecutionContext` from the given `Executor` with the default Reporter.
+   */
+  def fromExecutor(e: Executor): ExecutionContextExecutor = fromExecutor(e, defaultReporter)
   
-  def defaultReporter: Throwable => Unit = {
-    // re-throwing `Error`s here causes an exception handling test to fail.
-    //case e: Error => throw e
-    case t => t.printStackTrace()
-  }
-  
+  /** The default reporter simply prints the stack trace of the `Throwable` to System.err.
+   */
+  def defaultReporter: Throwable => Unit = { case t => t.printStackTrace() }
 }
 
 
diff --git a/src/library/scala/concurrent/Future.scala b/src/library/scala/concurrent/Future.scala
index 2de0c57253..75a83d6ef8 100644
--- a/src/library/scala/concurrent/Future.scala
+++ b/src/library/scala/concurrent/Future.scala
@@ -8,7 +8,7 @@
 
 package scala.concurrent
 
-
+import language.higherKinds
 
 import java.util.concurrent.{ ConcurrentLinkedQueue, TimeUnit, Callable }
 import java.util.concurrent.TimeUnit.{ NANOSECONDS => NANOS, MILLISECONDS ⇒ MILLIS }
@@ -23,11 +23,9 @@ import scala.Option
 import scala.util.{Try, Success, Failure}
 
 import scala.annotation.tailrec
-import scala.collection.mutable.Stack
 import scala.collection.mutable.Builder
 import scala.collection.generic.CanBuildFrom
 import scala.reflect.ClassTag
-import language.higherKinds
 
 
 
@@ -138,7 +136,7 @@ trait Future[+T] extends Awaitable[T] {
    *  $callbackInContext
    */
   def onFailure[U](callback: PartialFunction[Throwable, U])(implicit executor: ExecutionContext): Unit = onComplete {
-    case Left(t) if (isFutureThrowable(t) && callback.isDefinedAt(t)) => callback(t)
+    case Left(t) if (impl.Future.isFutureThrowable(t) && callback.isDefinedAt(t)) => callback(t)
     case _ =>
   }(executor)
 
@@ -580,6 +578,20 @@ object Future {
     classOf[Double]  -> classOf[jl.Double],
     classOf[Unit]    -> classOf[scala.runtime.BoxedUnit]
   )
+
+  /** Creates an already completed Future with the specified exception.
+   *  
+   *  @tparam T       the type of the value in the future
+   *  @return         the newly created `Future` object
+   */
+  def failed[T](exception: Throwable): Future[T] = Promise.failed(exception).future
+
+  /** Creates an already completed Future with the specified result.
+   *  
+   *  @tparam T       the type of the value in the future
+   *  @return         the newly created `Future` object
+   */
+  def successful[T](result: T): Future[T] = Promise.successful(result).future
   
   /** Starts an asynchronous computation and returns a `Future` object with the result of that computation.
   *
@@ -710,5 +722,12 @@ object Future {
   }
 }
 
-
+/** A marker indicating that a `java.lang.Runnable` provided to `scala.concurrent.ExecutionContext`
+ * wraps a callback provided to `Future.onComplete`.
+ * All callbacks provided to a `Future` end up going through `onComplete`, so this allows an
+ * `ExecutionContext` to special-case callbacks that were executed by `Future` if desired.
+ */
+trait OnCompleteRunnable {
+  self: Runnable =>
+}
 
diff --git a/src/library/scala/concurrent/Promise.scala b/src/library/scala/concurrent/Promise.scala
index 578642966f..5d1b2c00b6 100644
--- a/src/library/scala/concurrent/Promise.scala
+++ b/src/library/scala/concurrent/Promise.scala
@@ -34,6 +34,15 @@ trait Promise[T] {
    */
   def future: Future[T]
 
+  /** Returns whether the promise has already been completed with
+   *  a value or an exception.
+   *
+   *  $nonDeterministic
+   *
+   *  @return    `true` if the promise is already completed, `false` otherwise
+   */
+  def isCompleted: Boolean
+
   /** Completes the promise with either an exception or a value.
    *
    *  @param result     Either the value or the exception to complete the promise with.
diff --git a/src/library/scala/concurrent/SyncVar.scala b/src/library/scala/concurrent/SyncVar.scala
index 5a6d95c2ed..292014706d 100644
--- a/src/library/scala/concurrent/SyncVar.scala
+++ b/src/library/scala/concurrent/SyncVar.scala
@@ -53,6 +53,8 @@ class SyncVar[A] {
     value
   }
 
+  /** Waits for this SyncVar to become defined and returns
+   *  the result */
   def take(): A = synchronized {
     try get
     finally unsetVal()
@@ -64,7 +66,8 @@ class SyncVar[A] {
    *  the SyncVar.
    *
    *  @param timeout     the amount of milliseconds to wait, 0 means forever
-   *  @return            `None` if variable is undefined after `timeout`, `Some(value)` otherwise
+   *  @return            the value or a throws an exception if the timeout occurs
+   *  @throws NoSuchElementException on timeout
    */
   def take(timeout: Long): A = synchronized {
     try get(timeout).get
@@ -72,25 +75,28 @@ class SyncVar[A] {
   }
 
   // TODO: this method should be private
-  // [Heather] the reason why: it doesn't take into consideration 
+  // [Heather] the reason why: it doesn't take into consideration
   // whether or not the SyncVar is already defined. So, set has been
   // deprecated in order to eventually be able to make "setting" private
   @deprecated("Use `put` instead, as `set` is potentionally error-prone", "2.10.0")
   def set(x: A): Unit = setVal(x)
 
+  /** Places a value in the SyncVar. If the SyncVar already has a stored value,
+   * it waits until another thread takes it */
   def put(x: A): Unit = synchronized {
     while (isDefined) wait()
     setVal(x)
   }
 
+  /** Checks whether a value is stored in the synchronized variable */
   def isSet: Boolean = synchronized {
     isDefined
   }
 
   // TODO: this method should be private
-  // [Heather] the reason why: it doesn't take into consideration 
+  // [Heather] the reason why: it doesn't take into consideration
   // whether or not the SyncVar is already defined. So, unset has been
-  // deprecated in order to eventually be able to make "unsetting" private  
+  // deprecated in order to eventually be able to make "unsetting" private
   @deprecated("Use `take` instead, as `unset` is potentionally error-prone", "2.10.0")
   def unset(): Unit = synchronized {
     isDefined = false
@@ -98,7 +104,7 @@ class SyncVar[A] {
     notifyAll()
   }
 
-  // `setVal` exists so as to retroactively deprecate `set` without 
+  // `setVal` exists so as to retroactively deprecate `set` without
   // deprecation warnings where we use `set` internally. The
   // implementation of `set` was moved to `setVal` to achieve this
   private def setVal(x: A): Unit = synchronized {
@@ -107,13 +113,13 @@ class SyncVar[A] {
     notifyAll()
   }
 
-  // `unsetVal` exists so as to retroactively deprecate `unset` without 
+  // `unsetVal` exists so as to retroactively deprecate `unset` without
   // deprecation warnings where we use `unset` internally. The
   // implementation of `unset` was moved to `unsetVal` to achieve this
   private def unsetVal(): Unit = synchronized {
     isDefined = false
     value = None
-    notifyAll()    
+    notifyAll()
   }
 
 }
diff --git a/src/library/scala/concurrent/impl/ExecutionContextImpl.scala b/src/library/scala/concurrent/impl/ExecutionContextImpl.scala
index 4c6347dce0..551a444425 100644
--- a/src/library/scala/concurrent/impl/ExecutionContextImpl.scala
+++ b/src/library/scala/concurrent/impl/ExecutionContextImpl.scala
@@ -13,34 +13,34 @@ package scala.concurrent.impl
 import java.util.concurrent.{ Callable, Executor, ExecutorService, Executors, ThreadFactory, TimeUnit }
 import java.util.Collection
 import scala.concurrent.forkjoin._
-import scala.concurrent.{ ExecutionContext, Awaitable }
+import scala.concurrent.{ BlockContext, ExecutionContext, Awaitable, ExecutionContextExecutor, ExecutionContextExecutorService }
 import scala.concurrent.util.Duration
 import scala.util.control.NonFatal
 
 
 
-private[scala] class ExecutionContextImpl private[impl] (es: Executor, reporter: Throwable => Unit) extends ExecutionContext with Executor {
+private[scala] class ExecutionContextImpl private[impl] (es: Executor, reporter: Throwable => Unit) extends ExecutionContextExecutor {
 
   val executor: Executor = es match {
     case null => createExecutorService
     case some => some
   }
-  
-  // to ensure that the current execution context thread local is properly set
-  def executorsThreadFactory = new ThreadFactory {
-    def newThread(r: Runnable) = new Thread(new Runnable {
-      override def run() {
-        scala.concurrent.currentExecutionContext.set(ExecutionContextImpl.this)
-        r.run()
-      }
-    })
-  }
-  
-  // to ensure that the current execution context thread local is properly set
+
+  // Implement BlockContext on FJP threads
   def forkJoinPoolThreadFactory = new ForkJoinPool.ForkJoinWorkerThreadFactory {
-    def newThread(fjp: ForkJoinPool) = new ForkJoinWorkerThread(fjp) {
-      override def onStart() {
-        scala.concurrent.currentExecutionContext.set(ExecutionContextImpl.this)
+    def newThread(fjp: ForkJoinPool) = new ForkJoinWorkerThread(fjp) with BlockContext {
+      override def internalBlockingCall[T](awaitable: Awaitable[T], atMost: Duration): T = {
+        var result: T = null.asInstanceOf[T]
+        ForkJoinPool.managedBlock(new ForkJoinPool.ManagedBlocker {
+          @volatile var isdone = false
+          def block(): Boolean = {
+            result = awaitable.result(atMost)(scala.concurrent.Await.canAwaitEvidence) // FIXME what happens if there's an exception thrown here?
+            isdone = true
+            true
+          }
+          def isReleasable = isdone
+        })
+        result
       }
     }
   }
@@ -68,7 +68,7 @@ private[scala] class ExecutionContextImpl private[impl] (es: Executor, reporter:
     case NonFatal(t) =>
       System.err.println("Failed to create ForkJoinPool for the default ExecutionContext, falling back to Executors.newCachedThreadPool")
       t.printStackTrace(System.err)
-      Executors.newCachedThreadPool(executorsThreadFactory) //FIXME use the same desired parallelism here too?
+      Executors.newCachedThreadPool() //FIXME use the same desired parallelism here too?
   }
 
   def execute(runnable: Runnable): Unit = executor match {
@@ -84,27 +84,6 @@ private[scala] class ExecutionContextImpl private[impl] (es: Executor, reporter:
     case generic => generic execute runnable
   }
 
-  def internalBlockingCall[T](awaitable: Awaitable[T], atMost: Duration): T = {
-    Future.releaseStack(this)
-    
-    executor match {
-      case fj: ForkJoinPool =>
-        var result: T = null.asInstanceOf[T]
-        ForkJoinPool.managedBlock(new ForkJoinPool.ManagedBlocker { 
-          @volatile var isdone = false
-          def block(): Boolean = {
-            result = awaitable.result(atMost)(scala.concurrent.Await.canAwaitEvidence) // FIXME what happens if there's an exception thrown here?
-            isdone = true
-            true
-          }
-          def isReleasable = isdone
-        })
-        result
-      case _ =>
-        awaitable.result(atMost)(scala.concurrent.Await.canAwaitEvidence)
-    }
-  }
-
   def reportFailure(t: Throwable) = reporter(t)
 }
 
@@ -112,8 +91,8 @@ private[scala] class ExecutionContextImpl private[impl] (es: Executor, reporter:
 private[concurrent] object ExecutionContextImpl {
 
   def fromExecutor(e: Executor, reporter: Throwable => Unit = ExecutionContext.defaultReporter): ExecutionContextImpl = new ExecutionContextImpl(e, reporter)
-  def fromExecutorService(es: ExecutorService, reporter: Throwable => Unit = ExecutionContext.defaultReporter): ExecutionContextImpl with ExecutorService =
-    new ExecutionContextImpl(es, reporter) with ExecutorService {
+  def fromExecutorService(es: ExecutorService, reporter: Throwable => Unit = ExecutionContext.defaultReporter): ExecutionContextImpl with ExecutionContextExecutorService =
+    new ExecutionContextImpl(es, reporter) with ExecutionContextExecutorService {
       final def asExecutorService: ExecutorService = executor.asInstanceOf[ExecutorService]
       override def execute(command: Runnable) = executor.execute(command)
       override def shutdown() { asExecutorService.shutdown() }
diff --git a/src/library/scala/concurrent/impl/Future.scala b/src/library/scala/concurrent/impl/Future.scala
index 8012ea6a93..073e6c4c9f 100644
--- a/src/library/scala/concurrent/impl/Future.scala
+++ b/src/library/scala/concurrent/impl/Future.scala
@@ -46,11 +46,19 @@ private[concurrent] object Future {
   
   def boxedType(c: Class[_]): Class[_] = if (c.isPrimitive) toBoxed(c) else c
 
-  private[impl] class PromiseCompletingTask[T](override val executor: ExecutionContext, body: => T)
-    extends Task {
+  // TODO rename appropriately and make public
+  private[concurrent] def isFutureThrowable(t: Throwable) = t match {
+    case e: Error                               => false
+    case t: scala.util.control.ControlThrowable => false
+    case i: InterruptedException                => false
+    case _                                      => true
+  }
+
+  private[impl] class PromiseCompletingRunnable[T](body: => T)
+    extends Runnable {
     val promise = new Promise.DefaultPromise[T]()
 
-    protected override def task() = {
+    override def run() = {
       promise complete {
         try Right(body) catch {
           case NonFatal(e) =>
@@ -63,90 +71,8 @@ private[concurrent] object Future {
   }
 
   def apply[T](body: =>T)(implicit executor: ExecutionContext): Future[T] = {
-    val task = new PromiseCompletingTask(executor, body)
-    task.dispatch()
-
-    task.promise.future
-  }
-
-  private[impl] val throwableId: Throwable => Throwable = identity _
-
-  // an optimization for batching futures
-  // TODO we should replace this with a public queue,
-  // so that it can be stolen from
-  // OR: a push to the local task queue should be so cheap that this is
-  // not even needed, but stealing is still possible
-
-  private[impl] case class TaskStack(stack: Stack[Task], executor: ExecutionContext)
-
-  private val _taskStack = new ThreadLocal[TaskStack]()
-
-  private[impl] trait Task extends Runnable {
-    def executor: ExecutionContext
-
-    // run the original callback (no dispatch)
-    protected def task(): Unit
-
-    // we implement Runnable to avoid creating
-    // an extra object. run() runs ourselves with
-    // a TaskStack pushed, and then runs any
-    // other tasks that show up in the stack.
-    final override def run() = {
-      try {
-        val taskStack = TaskStack(Stack[Task](this), executor)
-        _taskStack set taskStack
-        while (taskStack.stack.nonEmpty) {
-          val next = taskStack.stack.pop()
-          require(next.executor eq executor)
-          try next.task() catch { case NonFatal(e) => executor reportFailure e }
-        }
-      } finally {
-        _taskStack.remove()
-      }
-    }
-
-    // send the task to the running executor.execute() via
-    // _taskStack, or start a new executor.execute()
-    def dispatch(force: Boolean = false): Unit =
-      _taskStack.get match {
-        case stack if (stack ne null) && (executor eq stack.executor) && !force => stack.stack push this
-        case _ => executor.execute(this)
-      }
-  }
-
-  private[impl] class ReleaseTask(override val executor: ExecutionContext, val elems: List[Task])
-    extends Task {
-    protected override def task() = {
-      _taskStack.get.stack.elems = elems
-    }
-  }
-
-  private[impl] def releaseStack(executor: ExecutionContext): Unit =
-    _taskStack.get match {
-      case stack if (stack ne null) && stack.stack.nonEmpty =>
-        val tasks = stack.stack.elems
-        stack.stack.clear()
-        _taskStack.remove()
-        val release = new ReleaseTask(executor, tasks)
-        release.dispatch(force=true)
-      case null =>
-        // do nothing - there is no local batching stack anymore
-      case _ =>
-        _taskStack.remove()
-    }
-
-  private[impl] class OnCompleteTask[T](override val executor: ExecutionContext, val onComplete: (Either[Throwable, T]) => Any)
-    extends Task {
-    private var value: Either[Throwable, T] = null
-
-    protected override def task() = {
-      require(value ne null) // dispatch(value) must be called before dispatch()
-      onComplete(value)
-    }
-
-    def dispatch(value: Either[Throwable, T]): Unit = {
-      this.value = value
-      dispatch()
-    }
+    val runnable = new PromiseCompletingRunnable(body)
+    executor.execute(runnable)
+    runnable.promise.future
   }
 }
diff --git a/src/library/scala/concurrent/impl/Promise.scala b/src/library/scala/concurrent/impl/Promise.scala
index c5060a2368..3ac34bef8a 100644
--- a/src/library/scala/concurrent/impl/Promise.scala
+++ b/src/library/scala/concurrent/impl/Promise.scala
@@ -11,11 +11,12 @@ package scala.concurrent.impl
 
 
 import java.util.concurrent.TimeUnit.{ NANOSECONDS, MILLISECONDS }
-import scala.concurrent.{ Awaitable, ExecutionContext, blocking, CanAwait, TimeoutException, ExecutionException }
+import scala.concurrent.{ Awaitable, ExecutionContext, blocking, CanAwait, OnCompleteRunnable, TimeoutException, ExecutionException }
 //import scala.util.continuations._
 import scala.concurrent.util.Duration
 import scala.util
 import scala.annotation.tailrec
+import scala.util.control.NonFatal
 //import scala.concurrent.NonDeterministic
 
 
@@ -24,6 +25,21 @@ private[concurrent] trait Promise[T] extends scala.concurrent.Promise[T] with Fu
   def future: this.type = this
 }
 
+private class CallbackRunnable[T](val executor: ExecutionContext, val onComplete: (Either[Throwable, T]) => Any) extends Runnable with OnCompleteRunnable {
+  // must be filled in before running it
+  var value: Either[Throwable, T] = null
+
+  override def run() = {
+    require(value ne null) // must set value to non-null before running!
+    try onComplete(value) catch { case NonFatal(e) => executor reportFailure e }
+  }
+
+  def executeWithValue(v: Either[Throwable, T]): Unit = {
+    require(value eq null) // can't complete it twice
+    value = v
+    executor.execute(this)
+  }
+}
 
 object Promise {
 
@@ -94,10 +110,10 @@ object Promise {
       val resolved = resolveEither(value)
       (try {
         @tailrec
-        def tryComplete(v: Either[Throwable, T]): List[Future.OnCompleteTask[T]] = {
+        def tryComplete(v: Either[Throwable, T]): List[CallbackRunnable[T]] = {
           getState match {
             case raw: List[_] =>
-              val cur = raw.asInstanceOf[List[Future.OnCompleteTask[T]]]
+              val cur = raw.asInstanceOf[List[CallbackRunnable[T]]]
               if (updateState(cur, v)) cur else tryComplete(v)
             case _ => null
           }
@@ -107,19 +123,19 @@ object Promise {
         synchronized { notifyAll() } //Notify any evil blockers
       }) match {
         case null             => false
-        case cs if cs.isEmpty => true
-        case cs               => cs.foreach(c => c.dispatch(resolved)); true
+        case rs if rs.isEmpty => true
+        case rs               => rs.foreach(r => r.executeWithValue(resolved)); true
       }
     }
 
     def onComplete[U](func: Either[Throwable, T] => U)(implicit executor: ExecutionContext): Unit = {
-      val bound = new Future.OnCompleteTask[T](executor, func)
+      val runnable = new CallbackRunnable[T](executor, func)
 
       @tailrec //Tries to add the callback, if already completed, it dispatches the callback to be executed
       def dispatchOrAddCallback(): Unit =
         getState match {
-          case r: Either[_, _]    => bound.dispatch(r.asInstanceOf[Either[Throwable, T]])
-          case listeners: List[_] => if (updateState(listeners, bound :: listeners)) () else dispatchOrAddCallback()
+          case r: Either[_, _]    => runnable.executeWithValue(r.asInstanceOf[Either[Throwable, T]])
+          case listeners: List[_] => if (updateState(listeners, runnable :: listeners)) () else dispatchOrAddCallback()
         }
       dispatchOrAddCallback()
     }
@@ -139,7 +155,7 @@ object Promise {
 
     def onComplete[U](func: Either[Throwable, T] => U)(implicit executor: ExecutionContext): Unit = {
       val completedAs = value.get
-      (new Future.OnCompleteTask(executor, func)).dispatch(completedAs)
+      (new CallbackRunnable(executor, func)).executeWithValue(completedAs)
     }
 
     def ready(atMost: Duration)(implicit permit: CanAwait): this.type = this
diff --git a/src/library/scala/package.scala b/src/library/scala/package.scala
index c4a8585563..5f90c32e22 100644
--- a/src/library/scala/package.scala
+++ b/src/library/scala/package.scala
@@ -9,6 +9,7 @@
 
 /**
  * Core Scala types. They are always available without an explicit import.
+ * @contentDiagram hideNodes "scala.Serializable"
  */
 package object scala {
   type Throwable = java.lang.Throwable
diff --git a/src/library/scala/util/control/NonFatal.scala b/src/library/scala/util/control/NonFatal.scala
index 9da2f63307..5137f0f2f5 100644
--- a/src/library/scala/util/control/NonFatal.scala
+++ b/src/library/scala/util/control/NonFatal.scala
@@ -23,16 +23,23 @@ package scala.util.control
  *     // dangerous stuff
  *   } catch {
  *     case NonFatal(e) => log.error(e, "Something not that bad.")
+ *    // or
+ *     case e if NonFatal(e) => log.error(e, "Something not that bad.")
  *   }
  * }}}
  */
 object NonFatal {
-
-  def unapply(t: Throwable): Option[Throwable] = t match {
-    case e: StackOverflowError ⇒ Some(e) // StackOverflowError ok even though it is a VirtualMachineError
-    // VirtualMachineError includes OutOfMemoryError and other fatal errors
-    case _: VirtualMachineError | _: ThreadDeath | _: InterruptedException | _: LinkageError | _: ControlThrowable | _: NotImplementedError => None
-    case e ⇒ Some(e)
-  }
-
+   /**
+    * Returns true if the provided `Throwable` is to be considered non-fatal, or false if it is to be considered fatal
+    */
+   def apply(t: Throwable): Boolean = t match {
+     case _: StackOverflowError => true // StackOverflowError ok even though it is a VirtualMachineError
+     // VirtualMachineError includes OutOfMemoryError and other fatal errors
+     case _: VirtualMachineError | _: ThreadDeath | _: InterruptedException | _: LinkageError | _: ControlThrowable | _: NotImplementedError => false
+     case _ => true
+   }
+  /**
+   * Returns Some(t) if NonFatal(t) == true, otherwise None
+   */
+  def unapply(t: Throwable): Option[Throwable] = if (apply(t)) Some(t) else None
 }