diff -r 64751a7abfa6 -r 97d3485028b6 src/Pure/PIDE/headless.scala
--- a/src/Pure/PIDE/headless.scala	Mon Sep 30 21:01:08 2019 +0200
+++ b/src/Pure/PIDE/headless.scala	Tue Oct 01 11:29:03 2019 +0200
@@ -318,7 +318,7 @@
 
       def check_state(beyond_limit: Boolean = false)
       {
-        val state = session.current_state()
+        val state = session.get_state()
         for (version <- state.stable_tip_version) {
           val (load_theories, share_common_data) =
             use_theories_state.change_result(_.check(state, version, beyond_limit))