Fix InnerClass / EnclosingMethod for closures nested in value classes

Members of value classes are moved over to the companion object early.
This change ensures that closure classes nested in value classes
appear that way to Java reflection.

This commit also changes the EnclosingMethod attribute for classes
(and anonymous functions) nested in anonymous function bodies. Before,
the enclosing method was in some cases the function's apply method.
Not always though:
  () => { class C ... val a = { class D ...} }
The class C used to be nested in the function's apply method, but not
D, because the value definition for a was lifted out of the apply.

After this commit, we uniformly set the enclosing method of classes
nested in function bodies to `null`. This is consistent with the
source-level view of the code.

Note that under delambdafy:method, closures never appear as enclosing
classes (this didn't change in this commit).

1 files changed, 4 insertions, 0 deletions

diff --git a/src/compiler/scala/tools/nsc/transform/UnCurry.scala b/src/compiler/scala/tools/nsc/transform/UnCurry.scala
index 3544dc9966..e1cf53059a 100644
--- a/src/compiler/scala/tools/nsc/transform/UnCurry.scala
+++ b/src/compiler/scala/tools/nsc/transform/UnCurry.scala
@@ -225,6 +225,10 @@ abstract class UnCurry extends InfoTransform
           if (inlineFunctionExpansion || !canUseDelamdafyMethod) {
             val parents = addSerializable(abstractFunctionForFunctionType(fun.tpe))
             val anonClass = fun.symbol.owner newAnonymousFunctionClass(fun.pos, inConstructorFlag) addAnnotation SerialVersionUIDAnnotation
+            // The original owner is used in the backend for the EnclosingMethod attribute. If fun is
+            // nested in a value-class method, its owner was already changed to the extension method.
+            // Saving the original owner allows getting the source structure from the class symbol.
+            defineOriginalOwner(anonClass, fun.symbol.originalOwner)
             anonClass setInfo ClassInfoType(parents, newScope, anonClass)
 
             val applyMethodDef = mkMethod(anonClass, nme.apply)