• Ryan Scott's avatar
    Remove unused DerivInst constructor for DerivStuff · f4384ef5
    Ryan Scott authored
    Back when derived `Generic` instances used to generate auxiliary datatypes,
    they would also generate instances for those datatypes. Nowadays, GHC generics
    uses a `DataKinds`-based encoding that requires neither auxiliary datatypes
    (corresponding to the `DerivTyCon` constructor of `DerivStuff`) nor instances
    for them (the `DerivInst` constructor of `DerivStuff`). It appears that
    `DerivTyCon` constructor was removed at some point, but `DerivInst` never was.
    No `DerivInst` values are ever constructed, so we can safely remove it.
    Test Plan: It builds
    Reviewers: austin, hvr, bgamari
    Reviewed By: bgamari
    Subscribers: thomie
    Differential Revision: https://phabricator.haskell.org/D2481
TcDeriv.hs 103 KB