(".moo file '%s' has been compiled by a different version of matita, "
^^ "please recompile it")
fname
+ | ProofEngineTypes.Fail msg -> "Tactic error: " ^ Lazy.force msg
| Continuationals.Error s -> "Tactical error: " ^ Lazy.force s
| exn -> "Uncaught exception: " ^ Printexc.to_string exn