CONTRIBUTORS

--- a/CONTRIBUTORS	Thu Jul 02 08:49:04 2020 +0000
+++ b/CONTRIBUTORS	Thu Jul 02 12:10:58 2020 +0000
@@ -20,6 +20,10 @@
 * May 2020: Florian Haftmann
   Generic algebraically founded bit operations NOT, AND, OR, XOR.
 
+* June 2020: Florian Haftmann
+  Simproc defined_all for more aggressive substitution with variables
+  from assumptions.
+
 
 Contributions to Isabelle2020
 -----------------------------