diff -r 64aad1e46f98 -r 97ccf48c2f0c src/Pure/Thy/export_theory.scala
--- a/src/Pure/Thy/export_theory.scala	Fri Mar 27 13:04:15 2020 +0100
+++ b/src/Pure/Thy/export_theory.scala	Fri Mar 27 22:01:27 2020 +0100
@@ -23,7 +23,7 @@
       else None
 
     def theories: List[Theory] =
-      theory_graph.topological_order.flatMap(theory(_))
+      theory_graph.topological_order.flatMap(theory)
   }
 
   def read_session(