deriving over renamed types

[Ashley Yakeley]

At 2002-04-04 05:57, C T McBride wrote:

>> ...which would be very useful, but would probably have unpleasant
>> consequences for type inference...
> 
>To my mind, this is not a credible objection. The horse has already
>bolted; there's no point in trying to shut the stable door.

Perhaps I should say "type decidability". Currently Haskell can always 
calculate whether one type-constructor is a substitution-instance of 
another, and therefore whether two type-constructors are the same. This 
may not be possible if you have full type lambdas, as in general there is 
no way of calculating whether two functions are the same.

-- 
Ashley Yakeley, Seattle WA