diff --git a/tests/threads/ttryrecv.nim b/tests/threads/ttryrecv.nim
index cadf6c550..fcff94e78 100644
--- a/tests/threads/ttryrecv.nim
+++ b/tests/threads/ttryrecv.nim
@@ -1,4 +1,5 @@
 discard """
+  matrix: "--mm:refc"
   outputsub: "channel is empty"
 """