From d193065827c40002de1e56c316eb026907536c17 Mon Sep 17 00:00:00 2001
From: Jason Zaugg <jzaugg@gmail.com>
Date: Fri, 23 Nov 2012 23:30:22 +0100
Subject: Explicitly prohibit await in nested methods.

---
 src/main/scala/scala/async/AsyncAnalysis.scala     |  4 ++++
 src/main/scala/scala/async/TransformUtils.scala    |  4 ++++
 src/test/scala/scala/async/TreeInterrogation.scala |  3 +--
 src/test/scala/scala/async/neg/NakedAwait.scala    | 10 ++++++++++
 4 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/src/main/scala/scala/async/AsyncAnalysis.scala b/src/main/scala/scala/async/AsyncAnalysis.scala
index 9e24130..38fd22f 100644
--- a/src/main/scala/scala/async/AsyncAnalysis.scala
+++ b/src/main/scala/scala/async/AsyncAnalysis.scala
@@ -45,6 +45,10 @@ private[async] final case class AsyncAnalysis[C <: Context](override val c: C) e
       }
     }
 
+    override def nestedMethod(module: DefDef) {
+      reportUnsupportedAwait(module, "nested method")
+    }
+
     override def byNameArgument(arg: Tree) {
       reportUnsupportedAwait(arg, "by-name argument")
     }
diff --git a/src/main/scala/scala/async/TransformUtils.scala b/src/main/scala/scala/async/TransformUtils.scala
index e37f66d..5095875 100644
--- a/src/main/scala/scala/async/TransformUtils.scala
+++ b/src/main/scala/scala/async/TransformUtils.scala
@@ -37,6 +37,9 @@ class TransformUtils[C <: Context](val c: C) {
     def nestedModule(module: ModuleDef) {
     }
 
+    def nestedMethod(module: DefDef) {
+    }
+
     def byNameArgument(arg: Tree) {
     }
 
@@ -47,6 +50,7 @@ class TransformUtils[C <: Context](val c: C) {
       tree match {
         case cd: ClassDef     => nestedClass(cd)
         case md: ModuleDef    => nestedModule(md)
+        case dd: DefDef       => nestedMethod(dd)
         case fun: Function    => function(fun)
         case Apply(fun, args) =>
           val isInByName = isByName(fun)
diff --git a/src/test/scala/scala/async/TreeInterrogation.scala b/src/test/scala/scala/async/TreeInterrogation.scala
index 1212045..08d2c78 100644
--- a/src/test/scala/scala/async/TreeInterrogation.scala
+++ b/src/test/scala/scala/async/TreeInterrogation.scala
@@ -35,8 +35,7 @@ class TreeInterrogation {
     varDefs.map(_.decoded).toSet mustBe(Set("state$async", "onCompleteHandler$async", "await$1", "await$2"))
   }
 
-
-  //@Test
+  @Test
   def sandbox() {
     sys.props("scala.async.debug") = "true"
     val cm = reflect.runtime.currentMirror
diff --git a/src/test/scala/scala/async/neg/NakedAwait.scala b/src/test/scala/scala/async/neg/NakedAwait.scala
index a0c4e4d..61490e2 100644
--- a/src/test/scala/scala/async/neg/NakedAwait.scala
+++ b/src/test/scala/scala/async/neg/NakedAwait.scala
@@ -117,4 +117,14 @@ class NakedAwait {
       """.stripMargin
     }
   }
+
+  @Test
+  def nestedMethod() {
+    expectError("await must not be used under a nested method.") {
+      """
+        | import _root_.scala.async.AsyncId._
+        | async { def foo = await(false) }
+      """.stripMargin
+    }
+  }
 }
-- 
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