I am strongly against this, as sometimes you
do want to use fromJust. For example:
1. Quick and dirty scripting/examples where you don't care about error-proofing your work and just want it to be done quickly. In that context, fromJust is a good function.
2. You know by construction that it is a Just constructor. This is usually not a good design, but sometimes it's useful. Writing an (error "fromJust") is possible, but annoying.
IMHO removing fromJust would be a bad idea; although it may be overused there are certainly times and places where it is useful. In addition, it seems like the real issue is that "error" needs to give better stack traces, so that you do not need to do as Erik suggests and write " fromMaybe (error "Module.functionName : unexpected Nothing") x". But I think that by 7.12 or 7.14 this will happen, as there is work being done in this direction. It may be a good idea to change the documentation of `fromJust` to say something like "please never use this unless you really know you want to".
(That said, I do wish that `head` and `tail` were replaced by `headMay` and `tailMay`, which you could then use with `fromJust` if you wanted to. But that's another discussion for adding things from `safe` to `base`, unrelated...)
Strong -1.