--- a/src/Pure/PIDE/document.ML Wed Nov 02 16:13:29 2022 +0100
+++ b/src/Pure/PIDE/document.ML Thu Nov 03 12:50:53 2022 +0100
@@ -594,7 +594,7 @@
val assign_update_empty: assign_update = Inttab.empty;
fun assign_update_defined (tab: assign_update) command_id = Inttab.defined tab command_id;
-fun assign_update_change entry (tab: assign_update) = Inttab.update entry tab;
+fun assign_update_change entry (tab: assign_update) : assign_update = Inttab.update entry tab;
fun assign_update_apply (tab: assign_update) node = Inttab.fold assign_entry tab node;
fun assign_update_new upd (tab: assign_update) =