src/Pure/Syntax/syntax_ext.ML

--- a/src/Pure/Syntax/syntax_ext.ML	Wed Mar 30 22:00:55 2016 +0200
+++ b/src/Pure/Syntax/syntax_ext.ML	Wed Mar 30 22:35:41 2016 +0200
@@ -190,6 +190,7 @@
 
 fun mfix_to_xprod logical_types (Mfix (sy, typ, const, pris, pri, pos)) =
   let
+    val _ = Position.report pos Markup.language_mixfix;
     val symbs0 = read_mfix sy;
 
     fun err_in_mixfix msg = error (msg ^ " in mixfix annotation" ^ Position.here pos);