: 26 December 2012 02:48
To: Conal Elliott
Cc: glasgow-haskell-bugs@haskell.org; GHC Users Mailing List
Subject: Re: Fundeps and type equality
Hello Conal,
GHC implementation of functional dependencies is incomplete: it will use
functional dependencies during type inference (i.e., to determine
Hi Iavor,
Thanks much for the explanation.
Before this experiment with FDs, I was using a type family. I tried
switching to FDs, because I wanted the compiler to know that the family is
injective in order to assist type-checking. Can we declare type families to
be injective? Now I see that I ran
Hello Conal,
GHC implementation of functional dependencies is incomplete: it will use
functional dependencies during type inference (i.e., to determine the
values of free type variables), but it will not use them in proofs, which
is what is needed in examples like the one you posted. The reason
