Often when you are getting error messages you would like to find the place they originate. Failure provides backtraces but not everyone uses failure and tbh it'

Often when you are getting error messages you would like to find the place they originate. Failure provides backtraces but not everyone uses failure and tbh it's quite a heavy dependency, using serde and so on. With try!, you can easily shadow the macro to e.g. emit a panic. This can be done to basically any codebase using try!, even if it's not yours. Migrating it to use failure is much harder :). It would be cool if you just had a compiler flag that invokes an user settable handler function every time Err() gets constructed or something like that. To give concrete examples, I was developing a library to generate certificates [1]. Often you generate a wrong one though and the parser library you use for testing gives you a Err(BadDer). If that's everything you are getting it can be a bit tough to find out the origins. As it was using ? I had to grep for all the places returning a BadDer error and replace them with a panic. Shadowing try! would have been much easier. [1]: https://github.com/est31/rcgen https://github.com/est31/rcgen