Our own Alejandro has been proposed

Fine-grained pragmas for classes, families, and instances

His idea is to bring the flexibility of overlaps/overlapping/overlappable pragmas to termination checking, type inference, and constraint solving. Alejandro proposes to introduce the following %-modifiers (as in already accepted #370, https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0370-modifiers.rst):

to liberate conditions for classes and instances, type families, forall-types, etc. The first three modifiers can be used instead of the scary-sounding UndecidableInstances extension. The last three modifiers are supposed to be used instead of the  overlap*-pragmas for instances we already have. Note that this proposal doesn't suggest deprecating those extensions and pragmas.

I think that this proposal goes in the right direction and recommend accepting it.

As far as I understand, all the committee members, including those with terms about to expire, have the right to either support this proposal or to raise a voice against it either here or at https://github.com/ghc-proposals/ghc-proposals/pull/390.

Regards,

Vitaly