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, 34 insertions, 0 deletions

diff --git a/src/test/scala/scala/async/run/lazyval/LazyValSpec.scala b/src/test/scala/scala/async/run/lazyval/LazyValSpec.scala
new file mode 100644
index 0000000..6214b43
--- /dev/null
+++ b/src/test/scala/scala/async/run/lazyval/LazyValSpec.scala
@@ -0,0 +1,34 @@
+/*
+ * Copyright (C) 2012-2014 Typesafe Inc. <http://www.typesafe.com>
+ */
+
+package scala.async
+package run
+package lazyval
+
+import scala.async.run.noawait
+
+import scala.async.internal.AsyncId
+import scala.async.internal.AsyncId
+import AsyncId._
+import org.junit.Test
+import scala.async.internal.AsyncId._
+
+class LazyValSpec {
+  @Test
+  def lazyValAllowed() {
+    val result = async {
+      var x = 0
+      lazy val y = { x += 1; 42 }
+      assert(x == 0, x)
+      val z = await(1)
+      val result = y + x
+      assert(x == 1, x)
+      identity(y)
+      assert(x == 1, x)
+      result
+    }
+    result mustBe 43
+  }
+}
+