Fix executor

src/compiler/scala/tools/nsc/Global.scala

@@ -414,8 +414,7 @@ class Global(var currentSettings: Settings, reporter0: Reporter)
  assertOnMain()
 
  if (isDebugPrintEnabled) inform("[running phase " + name + " on " + currentRun.size + " compilation units]")
-
- implicit val ec: ExecutionContext = createExecutionContext()
+ implicit val ec: ExecutionContextExecutor = createExecutionContext()
 
  try {
  _synchronizeNames = isParallel
@@ -444,6 +443,11 @@ class Global(var currentSettings: Settings, reporter0: Reporter)
  }
  } finally {
  _synchronizeNames = false
+
+ ec match {
+ case ecxs: ExecutionContextExecutorService => ecxs.shutdown()
+ case _ =>
+ }
  }
  }
 
@@ -483,7 +487,7 @@ class Global(var currentSettings: Settings, reporter0: Reporter)
  /* Depending if we are in the parallel phase or not it creates executor with fixed thread pool size or
  * executor which runs everything on the current thread.
  */
- private def createExecutionContext(): ExecutionContext = {
+ private def createExecutionContext(): ExecutionContextExecutor = {
  if (isParallel) {
  val parallelThreads = settings.YparallelThreads.value
  val threadPoolFactory = ThreadPoolFactory(Global.this, this)