| Continuationals.Error s -> "Tactical error: " ^ Lazy.force s
| CicTypeChecker.TypeCheckerFailure msg ->
"Type checking error: " ^ Lazy.force msg
+ | CicTypeChecker.AssertFailure msg ->
+ "Type checking assertion failed: " ^ Lazy.force msg
| exn -> "Uncaught exception: " ^ Printexc.to_string exn