Quick-fix eclosingMethod attribute generation for t3048.scala

It's a funny interaction between:

    elim-by-name(and erasure specifically);
    lift-static;
    supercalls.

object E extends F2(new B {})

Here we have an anonymous class new B {} that looks like it is created
by erasure.

For some reason this class forgets the link to original anonymous class:
SymDenot(E$annon1).initial.phase == erasure. I guess this is a bug.

Additionally, the owner of E$annon1 is an anonymous method inside E,
that is inSuperCall and thus we have an anonymous nested class that
has enclosingClass be package. This class looks like a top-level
anonymous class breaking a lot of assumptions in shared backend
and taking multiple branches in unexpected ways.

I'm not sure that this is a proper fix. I assume there's a bigger bug
around, but I don't quite understand it right now and I need to work on
other stuff.

Making a quick fix to unblock @odersky.

1 files changed, 3 insertions, 1 deletions

diff --git a/src/dotty/tools/backend/jvm/DottyBackendInterface.scala b/src/dotty/tools/backend/jvm/DottyBackendInterface.scala
index f42a8eee2..30934605b 100644
--- a/src/dotty/tools/backend/jvm/DottyBackendInterface.scala
+++ b/src/dotty/tools/backend/jvm/DottyBackendInterface.scala
@@ -648,12 +648,14 @@ class DottyBackendInterface(outputDirectory: AbstractFile, val superCallsMap: Ma
       originalOwner
     }
     def originalOwner: Symbol = {
+      // used to populate the EnclosingMethod attribute.
+      // it is very tricky in presence of classes(and annonymous classes) defined inside supper calls.
       try {
         if (sym.exists) {
           val original = toDenot(sym).initial
           val validity = original.validFor
           val shiftedContext = ctx.withPhase(validity.phaseId)
-          val r = toDenot(sym)(shiftedContext).maybeOwner.enclosingClass(shiftedContext)
+          val r = toDenot(sym)(shiftedContext).maybeOwner.lexicallyEnclosingClass(shiftedContext)
           r
         } else NoSymbol
       } catch {