* http://helm.cs.unibo.it/
*)
-exception MetaSubstFailure of string
-exception Uncertain of string
-exception AssertFailure of string
+exception MetaSubstFailure of string Lazy.t
+exception Uncertain of string Lazy.t
+exception AssertFailure of string Lazy.t
exception DeliftingARelWouldCaptureAFreeVariable;;
(* The entry (i,t) in a substitution means that *)