diff -r d3de24c50b08 -r 6a078c80eab6 src/Pure/Tools/build_job.scala
--- a/src/Pure/Tools/build_job.scala	Sun Jan 15 20:00:44 2023 +0100
+++ b/src/Pure/Tools/build_job.scala	Sun Jan 15 20:20:59 2023 +0100
@@ -592,7 +592,7 @@
 
     val heap_digest =
       if (result2.ok && do_store && store.output_heap(session_name).is_file)
-        Some(Sessions.write_heap_digest(store.output_heap(session_name)))
+        Some(ML_Heap.write_digest(store.output_heap(session_name)))
       else None
 
     (result2, heap_digest)