Eliminated the accumulated feature warnings.

No, this isn't busywork, how dare you suggest
such a thing. I intend my tombstone to say

           HERE LIES EXTEMPORE,
  WHO ELIMINATED A LOT OF SIP-18 WARNINGS
             REST IN PEACE

3 files changed, 9 insertions, 7 deletions

diff --git a/src/library/scala/collection/Searching.scala b/src/library/scala/collection/Searching.scala
index 03eb4283ad..8957771988 100644
--- a/src/library/scala/collection/Searching.scala
+++ b/src/library/scala/collection/Searching.scala
@@ -8,6 +8,7 @@
 
 package scala.collection
 
+import scala.language.implicitConversions
 import scala.annotation.tailrec
 import scala.collection.generic.IsSeqLike
 import scala.math.Ordering
@@ -50,7 +51,7 @@ object Searching {
       *         sequence, or the `InsertionPoint` where the element would be inserted if
       *         the element is not in the sequence.
       */
-    final def search[B >: A](elem: B)(implicit ord: Ordering[B]): SearchResult = 
+    final def search[B >: A](elem: B)(implicit ord: Ordering[B]): SearchResult =
       coll match {
         case _: IndexedSeq[A] => binarySearch(elem, -1, coll.length)(ord)
         case _ => linearSearch(coll.view, elem, 0)(ord)
@@ -77,7 +78,7 @@ object Searching {
       *         the element is not in the sequence.
       */
     final def search[B >: A](elem: B, from: Int, to: Int)
-    (implicit ord: Ordering[B]): SearchResult = 
+    (implicit ord: Ordering[B]): SearchResult =
       coll match {
         case _: IndexedSeq[A] => binarySearch(elem, from-1, to)(ord)
         case _ => linearSearch(coll.view(from, to), elem, from)(ord)
diff --git a/src/library/scala/concurrent/duration/Duration.scala b/src/library/scala/concurrent/duration/Duration.scala
index 6c6155279d..cbc31a7eed 100644
--- a/src/library/scala/concurrent/duration/Duration.scala
+++ b/src/library/scala/concurrent/duration/Duration.scala
@@ -10,6 +10,7 @@ package scala.concurrent.duration
 
 import java.lang.{ Double => JDouble, Long => JLong }
 import scala.language.implicitConversions
+import scala.language.postfixOps
 
 object Duration {
 
diff --git a/src/library/scala/concurrent/impl/ExecutionContextImpl.scala b/src/library/scala/concurrent/impl/ExecutionContextImpl.scala
index e4a0f464f9..ed04293e0d 100644
--- a/src/library/scala/concurrent/impl/ExecutionContextImpl.scala
+++ b/src/library/scala/concurrent/impl/ExecutionContextImpl.scala
@@ -30,7 +30,7 @@ private[scala] class ExecutionContextImpl private[impl] (es: Executor, reporter:
   }
 
   // Implement BlockContext on FJP threads
-  class DefaultThreadFactory(daemonic: Boolean) extends ThreadFactory with ForkJoinPool.ForkJoinWorkerThreadFactory { 
+  class DefaultThreadFactory(daemonic: Boolean) extends ThreadFactory with ForkJoinPool.ForkJoinWorkerThreadFactory {
     def wire[T <: Thread](thread: T): T = {
       thread.setDaemon(daemonic)
       thread.setUncaughtExceptionHandler(uncaughtExceptionHandler)
@@ -72,7 +72,7 @@ private[scala] class ExecutionContextImpl private[impl] (es: Executor, reporter:
       getInt("scala.concurrent.context.maxThreads", _.toInt))
 
     val threadFactory = new DefaultThreadFactory(daemonic = true)
-    
+
     try {
       new ForkJoinPool(
         desiredParallelism,
@@ -98,13 +98,13 @@ private[scala] class ExecutionContextImpl private[impl] (es: Executor, reporter:
 
   def execute(runnable: Runnable): Unit = executor match {
     case fj: ForkJoinPool =>
-      val fjt = runnable match {
+      val fjt: ForkJoinTask[_] = runnable match {
         case t: ForkJoinTask[_] => t
-        case r => new ExecutionContextImpl.AdaptedForkJoinTask(r)
+        case r                  => new ExecutionContextImpl.AdaptedForkJoinTask(r)
       }
       Thread.currentThread match {
         case fjw: ForkJoinWorkerThread if fjw.getPool eq fj => fjt.fork()
-        case _ => fj execute fjt
+        case _                                              => fj execute fjt
       }
     case generic => generic execute runnable
   }