diff --git a/src/main/scala/scala/async/internal/AsyncAnalysis.scala b/src/main/scala/scala/async/internal/AsyncAnalysis.scala index ffbc04db..6540bdbe 100644 --- a/src/main/scala/scala/async/internal/AsyncAnalysis.scala +++ b/src/main/scala/scala/async/internal/AsyncAnalysis.scala @@ -60,9 +60,8 @@ trait AsyncAnalysis { super.traverse(tree) case Return(_) => c.abort(tree.pos, "return is illegal within a async block") - case ValDef(mods, _, _, _) if mods.hasFlag(Flag.LAZY) => - // TODO lift this restriction - c.abort(tree.pos, "lazy vals are illegal within an async block") + case DefDef(mods, _, _, _, _, _) if mods.hasFlag(Flag.LAZY) && containsAwait => + reportUnsupportedAwait(tree, "lazy val initializer") case CaseDef(_, guard, _) if guard exists isAwait => // TODO lift this restriction reportUnsupportedAwait(tree, "pattern guard") diff --git a/src/main/scala/scala/async/internal/AsyncTransform.scala b/src/main/scala/scala/async/internal/AsyncTransform.scala index cf9dd1cc..aca8c7e2 100644 --- a/src/main/scala/scala/async/internal/AsyncTransform.scala +++ b/src/main/scala/scala/async/internal/AsyncTransform.scala @@ -57,8 +57,7 @@ trait AsyncTransform { val template = Template(List(tryToUnit, typeOf[() => Unit]).map(TypeTree(_)), emptyValDef, body) val t = ClassDef(NoMods, name.stateMachineT, Nil, template) - typingTransform(atPos(macroPos)(Block(t :: Nil, Literal(Constant(())))))((tree, api) => api.typecheck(tree)) - t + typecheckClassDef(t) } val stateMachineClass = stateMachine.symbol @@ -211,4 +210,12 @@ trait AsyncTransform { } result } + + def typecheckClassDef(cd: ClassDef): ClassDef = { + val Block(cd1 :: Nil, _) = typingTransform(atPos(macroPos)(Block(cd :: Nil, Literal(Constant(())))))( + (tree, api) => + api.typecheck(tree) + ) + cd1.asInstanceOf[ClassDef] + } } diff --git a/src/test/scala/scala/async/neg/NakedAwait.scala b/src/test/scala/scala/async/neg/NakedAwait.scala index 9778c723..2af691ff 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 initializer") { """ | 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 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 00000000..701d5d6c --- /dev/null +++ b/src/test/scala/scala/async/run/lazyval/LazyValSpec.scala @@ -0,0 +1,29 @@ +/* + * Copyright (C) 2012-2014 Typesafe Inc. + */ + +package scala.async +package run +package lazyval + +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 + } +} +