Allow lazy vals without await in the initializer

We were incorrectly typechecking the `ClassDef` of the state machine
in the macro in a way that discarded the resulting trees, and only
kept around the symbol.

The led to the the macro engine retypechecking
that node, which somehow led to duplicated lazy val initiaializer
`DefDef`-s in the template, which manifest as a `VerifyError`.

This commit:

  - rescues the typechecked `ClassDef` node from the eager
    typechecking by the macro
  - loosens the restriction on lazy vals in async blocks. They are
    still prohibited if they contain an await on the RHS
  - Adds a test that shows evalution is indeed lazy.

Fixes #52

1 files changed, 2 insertions, 2 deletions

diff --git a/src/test/scala/scala/async/neg/NakedAwait.scala b/src/test/scala/scala/async/neg/NakedAwait.scala
index 9778c72..f9264c7 100644
--- a/src/test/scala/scala/async/neg/NakedAwait.scala
+++ b/src/test/scala/scala/async/neg/NakedAwait.scala
@@ -163,10 +163,10 @@ class NakedAwait {
 
   @Test
   def lazyValIllegal() {
-    expectError("lazy vals are illegal") {
+    expectError("await must not be used under a lazy val initalizer") {
       """
         | import _root_.scala.async.internal.AsyncId._
-        | def foo(): Any = async { val x = { lazy val y = 0; y } }
+        | def foo(): Any = async { val x = { lazy val y = await(0); y } }
         | ()
         |
         |""".stripMargin