• Ryan Scott's avatar
    Fix #14369 by making injectivity warnings finer-grained · 8846a7fd
    Ryan Scott authored
    Summary:
    Previously, GHC would always raise the possibility that a
    type family might not be injective in certain error messages, even if
    that type family actually //was// injective. Fix this by actually
    checking for a type family's lack of injectivity before emitting
    such an error message.
    
    Test Plan: ./validate
    
    Reviewers: goldfire, austin, bgamari, simonpj
    
    Reviewed By: simonpj
    
    Subscribers: simonpj, rwbarton, thomie
    
    GHC Trac Issues: #14369
    
    Differential Revision: https://phabricator.haskell.org/D4106
    8846a7fd
TcErrors.hs 126 KB