1 files changed, 1 insertions, 1 deletions
diff --git a/insns.def b/insns.def
index 85c0a38471..979aa1cc6a 100644
--- a/insns.def
+++ b/insns.def
@@ -866,7 +866,7 @@ trace
     }
 
     EXEC_EVENT_HOOK(th, flag, GET_SELF(), 0, 0 /* id and klass are resolved at callee */,
-		    (flag & RUBY_EVENT_RETURN | RUBY_EVENT_B_RETURN) ? TOPN(0) : Qundef);
+		    (flag & (RUBY_EVENT_RETURN | RUBY_EVENT_B_RETURN)) ? TOPN(0) : Qundef);
 }
 
 /**********************************************************/