src/Pure/System/scala.ML

--- a/src/Pure/System/scala.ML	Thu Aug 06 17:51:37 2020 +0200
+++ b/src/Pure/System/scala.ML	Thu Aug 06 22:43:40 2020 +0200
@@ -33,7 +33,6 @@
 
 fun promise_function name arg =
   let
-    val _ = if Resources.is_pide () then () else raise Fail "PIDE session required";
     val id = new_id ();
     fun abort () = Output.protocol_message (Markup.cancel_scala id) [];
     val promise = Future.promise_name "invoke_scala" abort : string future;