src/Pure/PIDE/resources.scala

--- a/src/Pure/PIDE/resources.scala	Mon Mar 01 20:12:09 2021 +0100
+++ b/src/Pure/PIDE/resources.scala	Mon Mar 01 22:22:12 2021 +0100
@@ -278,7 +278,7 @@
       consolidate: List[Document.Node.Name]): Session.Change =
     Thy_Syntax.parse_change(resources, reparse_limit, previous, doc_blobs, edits, consolidate)
 
-  def commit(change: Session.Change) { }
+  def commit(change: Session.Change): Unit = {}
 
 
   /* theory and file dependencies */