diff -r 421760a1efe7 -r 5ee8004e2151 src/Pure/sign.ML
--- a/src/Pure/sign.ML	Sun Mar 18 13:04:22 2012 +0100
+++ b/src/Pure/sign.ML	Sun Mar 18 13:37:11 2012 +0100
@@ -204,8 +204,7 @@
 val naming_of = Name_Space.naming_of o Context.Theory;
 val map_naming = Context.theory_map o Name_Space.map_naming;
 val restore_naming = map_naming o K o naming_of;
-fun inherit_naming thy =
-  Context.Proof o Context.proof_map (Name_Space.map_naming (K (naming_of thy)));
+fun inherit_naming thy = Name_Space.map_naming (K (naming_of thy)) o Context.Proof;
 
 val full_name = Name_Space.full_name o naming_of;
 fun full_name_path thy path = Name_Space.full_name (Name_Space.add_path path (naming_of thy));