One last nudge for elidable.

A method with return type Nothing elides into a call to ??? .
It's the role ??? was born for.

7 files changed, 8 insertions, 38 deletions

diff --git a/src/compiler/scala/reflect/internal/Definitions.scala b/src/compiler/scala/reflect/internal/Definitions.scala
index d043230e48..ce5bb3d1c4 100644
--- a/src/compiler/scala/reflect/internal/Definitions.scala
+++ b/src/compiler/scala/reflect/internal/Definitions.scala
@@ -274,6 +274,7 @@ trait Definitions extends reflect.api.StandardDefinitions {
       def Predef_identity = getMember(PredefModule, nme.identity)
       def Predef_conforms = getMember(PredefModule, nme.conforms)
       def Predef_wrapRefArray = getMember(PredefModule, nme.wrapRefArray)
+      def Predef_??? = getMember(PredefModule, nme.???)
       
     /** Is `sym` a member of Predef with the given name?
      *  Note: DON't replace this by sym == Predef_conforms/etc, as Predef_conforms is a `def`
diff --git a/src/compiler/scala/reflect/internal/StdNames.scala b/src/compiler/scala/reflect/internal/StdNames.scala
index f61fe7a457..a78e0cc939 100644
--- a/src/compiler/scala/reflect/internal/StdNames.scala
+++ b/src/compiler/scala/reflect/internal/StdNames.scala
@@ -260,6 +260,8 @@ trait StdNames extends NameManglers { self: SymbolTable =>
       case _  => newTermName("x$" + i)
     }
     
+    val ??? = encode("???")
+    
     val wrapRefArray: NameType     = "wrapRefArray"
     val wrapByteArray: NameType    = "wrapByteArray"
     val wrapShortArray: NameType   = "wrapShortArray"
diff --git a/src/compiler/scala/reflect/internal/TreeGen.scala b/src/compiler/scala/reflect/internal/TreeGen.scala
index cc882ad5ed..8c2a067d4d 100644
--- a/src/compiler/scala/reflect/internal/TreeGen.scala
+++ b/src/compiler/scala/reflect/internal/TreeGen.scala
@@ -250,7 +250,10 @@ abstract class TreeGen {
    *    var x: T = _
    *  which is appropriate to the given Type.
    */
-  def mkZero(tp: Type): Tree = Literal(mkConstantZero(tp)) setType tp
+  def mkZero(tp: Type): Tree = tp.typeSymbol match {
+    case NothingClass => mkMethodCall(Predef_???, Nil) setType NothingClass.tpe
+    case _            => Literal(mkConstantZero(tp)) setType tp
+  }
 
   def mkConstantZero(tp: Type): Constant = tp.typeSymbol match {
     case UnitClass    => Constant(())
diff --git a/src/compiler/scala/tools/nsc/transform/UnCurry.scala b/src/compiler/scala/tools/nsc/transform/UnCurry.scala
index 69bf006036..6a7fcc98c3 100644
--- a/src/compiler/scala/tools/nsc/transform/UnCurry.scala
+++ b/src/compiler/scala/tools/nsc/transform/UnCurry.scala
@@ -508,7 +508,7 @@ abstract class UnCurry extends InfoTransform
         // TODO - settings.noassertions.value temporarily retained to avoid
         // breakage until a reasonable interface is settled upon.
         if ((sym ne null) && (sym.elisionLevel.exists (_ < settings.elidebelow.value || settings.noassertions.value)))
-          super.transform(replaceElidableTree(tree))
+          replaceElidableTree(tree)
         else tree match {
           case dd @ DefDef(mods, name, tparams, vparamss, tpt, rhs) =>
             if (dd.symbol hasAnnotation VarargsClass) saveRepeatedParams(dd)
diff --git a/test/files/neg/elide-to-nothing.check b/test/files/neg/elide-to-nothing.check
deleted file mode 100644
index 3ef05aac9a..0000000000
--- a/test/files/neg/elide-to-nothing.check
+++ /dev/null
@@ -1,4 +0,0 @@
-elide-to-nothing.scala:14: error: Cannot elide where Nothing is required.
-  val b: Nothing = unimplemented()
-                                ^
-one error found
diff --git a/test/files/neg/elide-to-nothing.flags b/test/files/neg/elide-to-nothing.flags
deleted file mode 100644
index 59a512e547..0000000000
--- a/test/files/neg/elide-to-nothing.flags
+++ /dev/null
@@ -1 +0,0 @@
--Xelide-below 500
diff --git a/test/files/neg/elide-to-nothing.scala b/test/files/neg/elide-to-nothing.scala
deleted file mode 100644
index 5008e8bc1d..0000000000
--- a/test/files/neg/elide-to-nothing.scala
+++ /dev/null
@@ -1,31 +0,0 @@
-
-/** Test which should fail compilation */
-class ElysianFailed {
-
-  import ElysianField._
-
-  // fine
-  val a: Int = myInt
-
-  // fine
-  unimplemented()
-
-  // not fine
-  val b: Nothing = unimplemented()
-  
-}
-
-object ElysianField {
-
-  import annotation.elidable
-
-  @elidable(100) def unimplemented(): Nothing = throw new UnsupportedOperationException
-
-  @elidable(100) def myInt: Int = 17
-
-}
-
-
-
-
-