haskell@gentoo.org
Gentoo Haskell
In the presence of GADTs, sometimes a proof is
needed that two types are equal. This package
contains an equality type for this purpose, plus its
properties (reflexive, symmetric, transitive) and
some useful operations (substitution, congruence,
coercion/cast). It also contains a type class for
producing equality proofs, providing some form of
decidable equality on types.
hesselink/type-equality