src/Pure/Concurrent/consumer_thread.scala

--- a/src/Pure/Concurrent/consumer_thread.scala	Sat Aug 07 19:29:41 2021 +0200
+++ b/src/Pure/Concurrent/consumer_thread.scala	Sat Aug 07 19:58:38 2021 +0200
@@ -119,6 +119,6 @@
   def shutdown(): Unit =
   {
     synchronized { if (is_active) { active = false; mailbox.send(None) } }
-    thread.join
+    thread.join()
   }
 }