diff --git a/compiler/ccgtypes.nim b/compiler/ccgtypes.nim
index 492e1f1812ff..23e1a5867a88 100644
--- a/compiler/ccgtypes.nim
+++ b/compiler/ccgtypes.nim
@@ -39,7 +39,7 @@ proc mangleName(m: BModule; s: PSym): Rope =
   result = s.loc.r
   if result == nil:
     result = s.name.s.mangle.rope
-    result.add "_"
+    result.add "__"
     result.add m.g.graph.ifaces[s.itemId.module].uniqueName
     result.add "_"
     result.add rope s.itemId.item