# HG changeset patch
# User wenzelm
# Date 1273339108 -7200
# Node ID 6e7704471eaa43db44b812ca80882c01e55a7e4b
# Parent  403585a8977247c022039bce29984a06f3b72a65
tuned error message: regular Pretty.string_of instead of raw Pretty.output;

diff -r 403585a89772 -r 6e7704471eaa src/Pure/Isar/class.ML
--- a/src/Pure/Isar/class.ML	Sat May 08 19:14:13 2010 +0200
+++ b/src/Pure/Isar/class.ML	Sat May 08 19:18:28 2010 +0200
@@ -202,7 +202,7 @@
       |> Expression.cert_declaration supexpr I inferred_elems;
     fun check_vars e vs = if null vs
       then error ("No type variable in part of specification element "
-        ^ (Pretty.output NONE o Pretty.chunks) (Element.pretty_ctxt class_ctxt e))
+        ^ (Pretty.string_of o Pretty.chunks) (Element.pretty_ctxt class_ctxt e))
       else ();
     fun check_element (e as Element.Fixes fxs) =
           map (fn (_, SOME T, _) => check_vars e (Term.add_tfreesT T [])) fxs