Merge pull request #9 from phaller/topic/local-classes

#8 - Clean compilation error when defining local class inside async block

3 files changed, 130 insertions, 1 deletions

diff --git a/src/main/scala/scala/async/ExprBuilder.scala b/src/main/scala/scala/async/ExprBuilder.scala
index 1a3f866..56274ec 100644
--- a/src/main/scala/scala/async/ExprBuilder.scala
+++ b/src/main/scala/scala/async/ExprBuilder.scala
@@ -368,6 +368,14 @@ final class ExprBuilder[C <: Context, FS <: FutureSystem](val c: C, val futureSy
         currState = currState + matchBudget
         stateBuilder = new builder.AsyncStateBuilder(currState, toRename)
 
+      case ClassDef(_, name, _, _) =>
+        // do not allow local class definitions, because of SI-5467 (specific to case classes, though)
+        c.error(stat.pos, s"Local class ${name.decoded} illegal within `async` block")
+
+      case ModuleDef(_, name, _) =>
+        // local object definitions lead to spurious type errors (because of resetAllAttrs?)
+        c.error(stat.pos, s"Local object ${name.decoded} illegal within `async` block")
+
       case _ =>
         checkForUnsupportedAwait(stat)
         stateBuilder += stat
diff --git a/src/test/scala/scala/async/TreeInterrogation.scala b/src/test/scala/scala/async/TreeInterrogation.scala
index 7c277b1..1293bdf 100644
--- a/src/test/scala/scala/async/TreeInterrogation.scala
+++ b/src/test/scala/scala/async/TreeInterrogation.scala
@@ -10,7 +10,7 @@ class TreeInterrogation {
   @Test
   def `a minimal set of vals are lifted to vars`() {
     val cm = reflect.runtime.currentMirror
-    val tb = mkToolbox()
+    val tb = mkToolbox("-cp target/scala-2.10/classes")
     val tree = mkToolbox().parse(
       """| import _root_.scala.async.AsyncId._
         | async {
diff --git a/src/test/scala/scala/async/neg/LocalClasses0Spec.scala b/src/test/scala/scala/async/neg/LocalClasses0Spec.scala
new file mode 100644
index 0000000..7932744
--- /dev/null
+++ b/src/test/scala/scala/async/neg/LocalClasses0Spec.scala
@@ -0,0 +1,121 @@
+package scala.async
+package neg
+
+/**
+ * Copyright (C) 2012 Typesafe Inc. <http://www.typesafe.com>
+ */
+
+import org.junit.runner.RunWith
+import org.junit.runners.JUnit4
+import org.junit.Test
+
+@RunWith(classOf[JUnit4])
+class LocalClasses0Spec {
+
+  @Test
+  def `reject a local class`() {
+    expectError("Local class Person illegal within `async` block", "-cp target/scala-2.10/classes -deprecation -Xfatal-warnings") {
+      """
+        | import scala.concurrent.ExecutionContext.Implicits.global
+        | import scala.async.Async._
+        | 
+        | async {
+        |   case class Person(name: String)
+        | }
+      """.stripMargin
+    }
+  }
+
+  @Test
+  def `reject a local class 2`() {
+    expectError("Local class Person illegal within `async` block", "-cp target/scala-2.10/classes -deprecation -Xfatal-warnings") {
+      """
+        | import scala.concurrent.{Future, ExecutionContext}
+        | import ExecutionContext.Implicits.global
+        | import scala.async.Async._
+        | 
+        | async {
+        |   case class Person(name: String)
+        |   val fut = Future { 5 }
+        |   val x = await(fut)
+        |   x
+        | }
+      """.stripMargin
+    }
+  }
+
+  @Test
+  def `reject a local class 3`() {
+    expectError("Local class Person illegal within `async` block", "-cp target/scala-2.10/classes -deprecation -Xfatal-warnings") {
+      """
+        | import scala.concurrent.{Future, ExecutionContext}
+        | import ExecutionContext.Implicits.global
+        | import scala.async.Async._
+        | 
+        | async {
+        |   val fut = Future { 5 }
+        |   val x = await(fut)
+        |   case class Person(name: String)
+        |   x
+        | }
+      """.stripMargin
+    }
+  }
+
+  @Test
+  def `reject a local class with symbols in its name`() {
+    expectError("Local class :: illegal within `async` block", "-cp target/scala-2.10/classes -deprecation -Xfatal-warnings") {
+      """
+        | import scala.concurrent.{Future, ExecutionContext}
+        | import ExecutionContext.Implicits.global
+        | import scala.async.Async._
+        | 
+        | async {
+        |   val fut = Future { 5 }
+        |   val x = await(fut)
+        |   case class ::(name: String)
+        |   x
+        | }
+      """.stripMargin
+    }
+  }
+
+  @Test
+  def `reject a nested local class`() {
+    expectError("Local class Person illegal within `async` block", "-cp target/scala-2.10/classes -deprecation -Xfatal-warnings") {
+      """
+        | import scala.concurrent.{Future, ExecutionContext}
+        | import ExecutionContext.Implicits.global
+        | import scala.async.Async._
+        | 
+        | async {
+        |   val fut = Future { 5 }
+        |   val x = 2 + 2
+        |   var y = 0
+        |   if (x > 0) {
+        |     case class Person(name: String)
+        |     y = await(fut)
+        |   } else {
+        |     y = x
+        |   }
+        |   y
+        | }
+      """.stripMargin
+    }
+  }
+
+  @Test
+  def `reject a local singleton object`() {
+    expectError("Local object Person illegal within `async` block", "-cp target/scala-2.10/classes -deprecation -Xfatal-warnings") {
+      """
+        | import scala.concurrent.ExecutionContext.Implicits.global
+        | import scala.async.Async._
+        | 
+        | async {
+        |   object Person { val name = "Joe" }
+        | }
+      """.stripMargin
+    }
+  }
+
+}