Enable trampolining of async state execution

This replaces the previous body of an `async` block with a while
loop:

    var task$async: Option[() => Unit] = Some(<future body>)

    while (task$async.nonEmpty) {
      val task = task$async.get
      task$async = None
      task()
    }

This enables executing an `async` block on a single thread by using
a future system that blocks upon `await`. This execution mode can be
very useful for debugging. The introduced trampolining enables this
mode without running into stack overflows.

1 files changed, 3 insertions, 3 deletions

diff --git a/src/test/scala/scala/async/TreeInterrogation.scala b/src/test/scala/scala/async/TreeInterrogation.scala
index deaee03..1eada08 100644
--- a/src/test/scala/scala/async/TreeInterrogation.scala
+++ b/src/test/scala/scala/async/TreeInterrogation.scala
@@ -35,13 +35,13 @@ class TreeInterrogation {
       case f: Function => f
       case t: Template => t
     }
-    functions.size mustBe 1
+    functions.size mustBe 2
 
     val varDefs = tree1.collect {
       case ValDef(mods, name, _, _) if mods.hasFlag(Flag.MUTABLE) => name
     }
-    varDefs.map(_.decoded.trim).toSet mustBe (Set("state$async", "await$1", "await$2"))
-    varDefs.map(_.decoded.trim).toSet mustBe (Set("state$async", "await$1", "await$2"))
+    varDefs.map(_.decoded.trim).toSet mustBe (Set("state$async", "await$1", "await$2", "task$async"))
+    varDefs.map(_.decoded.trim).toSet mustBe (Set("state$async", "await$1", "await$2", "task$async"))
 
     val defDefs = tree1.collect {
       case t: Template =>