From 018118d41e27ba00f28a2f8ab4dbc62233ffb4f3 Mon Sep 17 00:00:00 2001
From: Guillaume Martres <smarter@ubuntu.com>
Date: Wed, 7 Jun 2017 16:43:41 +0200
Subject: [PATCH] Fix #2680: Backend generates useless companion class for
 inner objects

`isTopLevelModuleClass` was incorrect and returned true for all static
module classes.
---
 .../src/dotty/tools/backend/jvm/DottyBackendInterface.scala  | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/compiler/src/dotty/tools/backend/jvm/DottyBackendInterface.scala b/compiler/src/dotty/tools/backend/jvm/DottyBackendInterface.scala
index 709ce4616f9b..942c3f1fc071 100644
--- a/compiler/src/dotty/tools/backend/jvm/DottyBackendInterface.scala
+++ b/compiler/src/dotty/tools/backend/jvm/DottyBackendInterface.scala
@@ -746,7 +746,10 @@ class DottyBackendInterface(outputDirectory: AbstractFile, val superCallsMap: Ma
      * True for module classes of package level objects. The backend will generate a mirror class for
      * such objects.
      */
-    def isTopLevelModuleClass: Boolean = sym.isModuleClass && sym.isStatic
+    def isTopLevelModuleClass: Boolean = sym.isModuleClass &&
+      ctx.atPhase(ctx.flattenPhase) { implicit ctx =>
+        toDenot(sym).owner.is(Flags.PackageClass)
+      }
 
     /**
      * This is basically a re-implementation of sym.isStaticOwner, but using the originalOwner chain.