The hashable major version was bumped because two Hashable instances changed their behvior to be consistent with the corresponding Eq instances (changelog):
hashing Arg values no longer hashes the second component
for floating point numbers, hashing -0 and 0 produces the same result.
The vault package only uses its own Hashable instance for its Unique type, so relaxing the bound is safe.
There is a recent major release of hashable which has been causing trouble for cabal-install to find viable installation plans, e.g. for lambdabot (https://github.com/lambdabot/lambdabot/issues/183), but also for just hoogle.
I've asked the vault maintainer to relax the
hashable
bound two weeks ago, but unfortunately with no response so far: https://github.com/HeinrichApfelmus/vault/issues/28Does this fall under the policies for relaxing constraints?
Background on the hashable version bump
The hashable major version was bumped because two
Hashable
instances changed their behvior to be consistent with the correspondingEq
instances (changelog):Arg
values no longer hashes the second component-0
and0
produces the same result.The vault package only uses its own
Hashable
instance for itsUnique
type, so relaxing the bound is safe.