Allow await in applications with multiple argument lists

Before, we levied an implementation restriction to prevent
this. As it turned out, that needlessly prevented use of
`await` in the receiver of a multi-param-list application.

This commit lifts the restriction altogether, and treats
such applications holistically, being careful to preserve the
left-to-right evaluation order of arguments in the translated
code.

 - use `TreeInfo.Applied` and `Type#paramss` from `reflect.internal`
   to get the info we need
 - use the parameter name for the lifted argument val, rather than
   `argN`
 - encapsulate handling of by-name-ness and parameter names
   in `mapArgumentss`
 - test for evaluation order preservation

1 files changed, 7 insertions, 10 deletions

diff --git a/src/test/scala/scala/async/TreeInterrogation.scala b/src/test/scala/scala/async/TreeInterrogation.scala
index 4d611e5..deaee03 100644
--- a/src/test/scala/scala/async/TreeInterrogation.scala
+++ b/src/test/scala/scala/async/TreeInterrogation.scala
@@ -71,17 +71,14 @@ object TreeInterrogation extends App {
     val tb = mkToolbox("-cp target/scala-2.10/classes -Xprint:flatten")
     import scala.async.Async._
     val tree = tb.parse(
-      """ import scala.async.AsyncId._
-        | async {
-        |   val x = 1
-        |   val opt = Some("")
-        |   await(0)
-        |   val o @ Some(y) = opt
-        |
-        |   {
-        |     val o @ Some(y) = Some(".")
-        |   }
+      """ import _root_.scala.async.AsyncId.{async, await}
+        | def foo[T](a0: Int)(b0: Int*) = s"a0 = $a0, b0 = ${b0.head}"
+        | val res = async {
+        |   var i = 0
+        |   def get = async {i += 1; i}
+        |   foo[Int](await(get))(await(get) :: Nil : _*)
         | }
+        | res
         | """.stripMargin)
     println(tree)
     val tree1 = tb.typeCheck(tree.duplicate)