[darcs-devel] GHC and flagging use of a given constant

[Juliusz Chroboczek]

>> Another thing I'd like to be able to do is to flag all uses of a given
>> instance of a method in a type class.  The case in point is that we're
>> using the instance
>> 
>>   show :: Control.Exception.Exception -> String
>> 
>> in quite a lot of places, and most of these are incorrect.

Hmm...  It looks like the DEPRECATED pragma (7.10.1 in the user's
manual) almost does what we need.  It only has two flaws:

  - you cannot put it in a different module -- you need to recompile
    the Ghc libraries;
  - you cannot apply it to a method in an instance.

                                        Juliusz