SI-7596 Curtail overloaded symbols during unpickling

In code like:

    object O { val x = A; def x(a: Any) = ... }
    object P extends O.x.A

The unpickler was using an overloaded symbol for `x` in the
parent type of `P`. This led to compilation failures under
separate compilation.

The code that leads to this is in `Unpicklers`:

    def fromName(name: Name) = name.toTermName match {
      case nme.ROOT     => loadingMirror.RootClass
      case nme.ROOTPKG  => loadingMirror.RootPackage
      case _            => adjust(owner.info.decl(name))
    }

This commit filters the overloaded symbol based its stability
unpickling a singleton type. That seemed a slightly safer place
than in `fromName`.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/reflect/scala/reflect/internal/pickling/UnPickler.scala b/src/reflect/scala/reflect/internal/pickling/UnPickler.scala
index 5433bfad60..a35620a994 100644
--- a/src/reflect/scala/reflect/internal/pickling/UnPickler.scala
+++ b/src/reflect/scala/reflect/internal/pickling/UnPickler.scala
@@ -396,7 +396,7 @@ abstract class UnPickler {
         case NOtpe                     => NoType
         case NOPREFIXtpe               => NoPrefix
         case THIStpe                   => ThisType(readSymbolRef())
-        case SINGLEtpe                 => SingleType(readTypeRef(), readSymbolRef())
+        case SINGLEtpe                 => SingleType(readTypeRef(), readSymbolRef().filter(_.isStable)) // SI-7596 account for overloading
         case SUPERtpe                  => SuperType(readTypeRef(), readTypeRef())
         case CONSTANTtpe               => ConstantType(readConstantRef())
         case TYPEREFtpe                => TypeRef(readTypeRef(), readSymbolRef(), readTypes())