• Ryan Scott's avatar
    Fix newtype instance GADTs · eb680f2c
    Ryan Scott authored
    Summary: This was taken from Richard's branch, which in turn was
    submitted to Phab by Matthew, which in turn was commandeered by Ryan.
    This fixes an issue with newtype instances in which too many
    coercions were being applied in the worker. This fixes the issue by
    removing the data family instance axiom from the worker and moving
    to the wrapper. Moreover, we now require all newtype instances
    to have wrappers, for symmetry with data instances.
    Reviewers: goldfire, bgamari, simonpj, mpickering
    Reviewed By: mpickering
    Subscribers: simonpj, rwbarton, thomie, carter
    GHC Trac Issues: #15318
    Differential Revision: https://phabricator.haskell.org/D4902
    (cherry picked from commit 92751866)
MkId.hs 59.9 KB