diff --git a/vlib/sync/channels.c.v b/vlib/sync/channels.c.v
index 63f9afe3a9..5fd55647fd 100644
--- a/vlib/sync/channels.c.v
+++ b/vlib/sync/channels.c.v
@@ -415,8 +415,7 @@ fn (mut ch Channel) try_push_priv(src voidptr, no_block bool) ChanState {
 		}
 	}
 	// we should not get here but the V compiler want's to see a return statement
-	assert false
-	return .success
+	panic('unknown `try_push_priv` state')
 }
 
 [inline]
diff --git a/vlib/sync/waitgroup.v b/vlib/sync/waitgroup.c.v
similarity index 100%
rename from vlib/sync/waitgroup.v
rename to vlib/sync/waitgroup.c.v