diff -r 2852f997bfb5 -r 6973b3f41334 src/Pure/Isar/attrib.ML
--- a/src/Pure/Isar/attrib.ML	Tue Jan 08 16:01:07 2013 +0100
+++ b/src/Pure/Isar/attrib.ML	Tue Jan 08 16:23:07 2013 +0100
@@ -391,7 +391,7 @@
     "rename bound variables in abstractions" #>
   setup (Binding.name "unfolded") unfolded "unfolded definitions" #>
   setup (Binding.name "folded") folded "folded definitions" #>
-  setup (Binding.name "consumes") (Scan.lift (Scan.optional Parse.nat 1) >> Rule_Cases.consumes)
+  setup (Binding.name "consumes") (Scan.lift (Scan.optional Parse.int 1) >> Rule_Cases.consumes)
     "number of consumed facts" #>
   setup (Binding.name "constraints") (Scan.lift Parse.nat >> Rule_Cases.constraints)
     "number of equality constraints" #>