src/Pure/PIDE/command.ML

 local
 
 fun run_process execution_id exec_id process =
   let val group = Future.worker_subgroup () in
     if Execution.running execution_id exec_id [group] then
-      ignore (task_context group Lazy.force_result {strict = true} process)
+      ignore (task_context group (fn () => Lazy.force_result {strict = true} process) ())
     else ()
   end;
 
 fun ignore_process process =
   Lazy.is_running process orelse Lazy.is_finished process;