1 files changed, 16 insertions, 6 deletions
diff --git a/src/main/scala/scala/async/internal/TransformUtils.scala b/src/main/scala/scala/async/internal/TransformUtils.scala
index 90419d3..e15ef1b 100644
--- a/src/main/scala/scala/async/internal/TransformUtils.scala
+++ b/src/main/scala/scala/async/internal/TransformUtils.scala
@@ -38,6 +38,9 @@ private[async] trait TransformUtils {
     def fresh(name: String): String = c.freshName(name)
   }
 
+  def isAsync(fun: Tree) =
+    fun.symbol == defn.Async_async
+
   def isAwait(fun: Tree) =
     fun.symbol == defn.Async_await
 
@@ -164,6 +167,7 @@ private[async] trait TransformUtils {
 
     val NonFatalClass = rootMirror.staticModule("scala.util.control.NonFatal")
     val ThrowableClass = rootMirror.staticClass("java.lang.Throwable")
+    val Async_async   = asyncBase.asyncMethod(c.universe)(c.macroApplication.symbol).ensuring(_ != NoSymbol)
     val Async_await   = asyncBase.awaitMethod(c.universe)(c.macroApplication.symbol).ensuring(_ != NoSymbol)
     val IllegalStateExceptionClass = rootMirror.staticClass("java.lang.IllegalStateException")
   }
@@ -281,6 +285,8 @@ private[async] trait TransformUtils {
 
     override def traverse(tree: Tree) {
       tree match {
+        case _ if isAsync(tree) =>
+          // Under -Ymacro-expand:discard, used in the IDE, nested async blocks will be visible to the outer blocks
         case cd: ClassDef          => nestedClass(cd)
         case md: ModuleDef         => nestedModule(md)
         case dd: DefDef            => nestedMethod(dd)
@@ -398,7 +404,7 @@ private[async] trait TransformUtils {
   final def containsAwaitCached(t: Tree): Tree => Boolean = {
     def treeCannotContainAwait(t: Tree) = t match {
       case _: Ident | _: TypeTree | _: Literal => true
-      case _ => false
+      case _ => isAsync(t)
     }
     def shouldAttach(t: Tree) = !treeCannotContainAwait(t)
     val symtab = c.universe.asInstanceOf[scala.reflect.internal.SymbolTable]
@@ -417,11 +423,15 @@ private[async] trait TransformUtils {
       override def traverse(tree: Tree): Unit = {
         stack ::= tree
         try {
-          if (isAwait(tree))
-            stack.foreach(attachContainsAwait)
-          else
-            attachNoAwait(tree)
-          super.traverse(tree)
+          if (isAsync(tree)) {
+            ;
+          } else {
+            if (isAwait(tree))
+              stack.foreach(attachContainsAwait)
+            else
+              attachNoAwait(tree)
+            super.traverse(tree)
+          }
         } finally stack = stack.tail
       }
     }