src/Pure/PIDE/session.scala

         if (!global_state.value.defined_command(command.id)) {
           global_state.change(_.define_command(command))
           prover.get.define_command(command)
         }
       }
-      change.doc_edits foreach {
-        case (_, edit) =>
-          edit foreach { case (c1, c2) => c1 foreach id_command; c2 foreach id_command }
+      for { (_, edit) <- change.doc_edits } {
+        edit.foreach({ case (c1, c2) => c1.foreach(id_command); c2.foreach(id_command) })
       }
 
       val assignment = global_state.value.the_assignment(change.previous).check_finished
       global_state.change(_.define_version(change.version, assignment))
       prover.get.update(change.previous.id, change.version.id, change.doc_edits)