diff -r 696d87036f04 -r f8d164ab0dc1 src/Doc/Tutorial/Protocol/Message.thy
--- a/src/Doc/Tutorial/Protocol/Message.thy	Thu Mar 19 17:25:57 2015 +0100
+++ b/src/Doc/Tutorial/Protocol/Message.thy	Thu Mar 19 22:30:57 2015 +0100
@@ -856,7 +856,7 @@
      (EVERY 
       [  (*push in occurrences of X...*)
        (REPEAT o CHANGED)
-           (res_inst_tac ctxt [(("x", 1), "X")] (insert_commute RS ssubst) 1),
+           (res_inst_tac ctxt [((("x", 1), Position.none), "X")] (insert_commute RS ssubst) 1),
        (*...allowing further simplifications*)
        simp_tac ctxt 1,
        REPEAT (FIRSTGOAL (resolve_tac ctxt [allI,impI,notI,conjI,iffI])),