seemingly inconsistent behavior for "kind-indexed" type constraints in GHC 7.6

Nicolas Frisby nicolas.frisby at
Sun Oct 7 06:43:25 CEST 2012

On Sat, Oct 6, 2012 at 12:46 PM, Gábor Lehel <illissius at> wrote:
> What do you use NLong for? I.e. where and how are you taking advantage
> of the knowledge that the list is N long?

OK, some context. I'm experimenting with an augmentation of the
generic-deriving generic programming approach.

Regarding the part of the library that doesn't suffer from the issue
in my original email in this thread, user code using the library
results in more accurate inferred types because of the NLong
constraints. These more accurate inferred types ultimately avoid some
"ambiguous type variable" errors in the user's code.

This new gist demonstrates the
benefits that I get from NLong; it gives an example of it eliminating
an otherwise ambiguous type variable. It also explains the context of
the library a bit more.


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