More uniform treatment of package objects

  - Introduce `Symbol#packageObject` and `Type#packageObject`
    to lookup the member package object of a package class/module,
    and use this far and wide.
  - Replace the overly complicated (and still buggy) implementation
    of `Context#isInPackageObject` with a one liner. The simplifying
    insight is that if we select a symbol from a package prefix
    that does not own that symbol, it *must* have really been
    selected from the package object.
  - Change implicit search to use the cache in
    `ModuleSymbol#implicitMembers` via `Type#implicitMembers`,
    which lets the client code read more naturally.

Fixes a bug with `adapt::insertApply` that Adriaan spotted in a feat
of lateral thinking. This is tested in t8862b.scala. alladin763.scala
adds the test case from the bug originally remedied by `insertApply`
to check we haven't regressed.

1 files changed, 5 insertions, 1 deletions

diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
index 422b940cd3..fe6038bc00 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Typers.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
@@ -538,7 +538,11 @@ trait Typers extends Adaptations with Tags with TypersTracking with PatternTyper
         }
         val qual = typedQualifier { atPos(tree.pos.makeTransparent) {
           tree match {
-            case Ident(_) => Ident(rootMirror.getPackageObjectWithMember(pre, sym))
+            case Ident(_) =>
+              val packageObject =
+                if (sym.owner.isModuleClass) sym.owner.sourceModule // historical optimization, perhaps no longer needed
+                else pre.typeSymbol.packageObject
+              Ident(packageObject)
             case Select(qual, _) => Select(qual, nme.PACKAGEkw)
             case SelectFromTypeTree(qual, _) => Select(qual, nme.PACKAGEkw)
           }