Fix overriding a Java method with varargs

If A method like:
  override def foo(x: Object*)
overrides a Java method, it needs to be rewritten as:
  def foo(x: Seq[Object])
  override def foo(x: Array[Object]): Object = foo(Predef.wrapRefArray(x))

This should be handled by ElimRepeated but there were two bugs:
- `addVarArgsBridge` was called at phase `thisTransformer.next`, this is
too late to create the bridge since `T*` has already been rewritten as
`Seq[T]`
- The original method symbol needs to have the `override` flag dropped,
since it doesn't override anything.

Furthermore, RefChecks had to be moved after ElimRepeated, otherwise the
testcase would fail the overriding checks.

1 files changed, 7 insertions, 2 deletions

diff --git a/compiler/src/dotty/tools/dotc/transform/ElimRepeated.scala b/compiler/src/dotty/tools/dotc/transform/ElimRepeated.scala
index 258b7f234..e67b3f114 100644
--- a/compiler/src/dotty/tools/dotc/transform/ElimRepeated.scala
+++ b/compiler/src/dotty/tools/dotc/transform/ElimRepeated.scala
@@ -95,8 +95,8 @@ class ElimRepeated extends MiniPhaseTransform with InfoTransformer with Annotati
     assert(ctx.phase == thisTransformer)
     def overridesJava = tree.symbol.allOverriddenSymbols.exists(_ is JavaDefined)
     if (tree.symbol.info.isVarArgsMethod && overridesJava)
-        addVarArgsBridge(tree)(ctx.withPhase(thisTransformer.next))
-     else
+      addVarArgsBridge(tree)
+    else
       tree
   }
 
@@ -120,6 +120,11 @@ class ElimRepeated extends MiniPhaseTransform with InfoTransformer with Annotati
         .appliedToArgs(vrefs :+ TreeGen.wrapArray(varArgRef, elemtp))
         .appliedToArgss(vrefss1)
     })
+
+    // Drop the override flag on the user-written method, only the added bridge
+    // is a real override.
+    original.copySymDenotation(initFlags = original.flags &~ Override).installAfter(thisTransformer)
+
     Thicket(ddef, bridgeDef)
   }