Re: [GHC] #12837: Disallow users to write instances for KnownNat and KnownSymbol

#12837: Disallow users to write instances for KnownNat and KnownSymbol -------------------------------------+------------------------------------- Reporter: adamgundry | Owner: sean Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Resolution: | Keywords: newcomer Operating System: Unknown/Multiple | Architecture: Type of failure: GHC accepts | Unknown/Multiple invalid program | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D2898 Wiki Page: | -------------------------------------+------------------------------------- Comment (by Matthew Pickering ): In [changeset:"c5609577fab8a214c50561bea861c70d4bfd47c7/ghc" c5609577/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="c5609577fab8a214c50561bea861c70d4bfd47c7" Disallow users to write instances of KnownNat and KnownSym As noted in #12837, these classes are special and the user should not be able to define their own instances. Test Plan: Validate Reviewers: adamgundry, goldfire, mpickering, austin, bgamari Reviewed By: goldfire, mpickering Subscribers: goldfire, mpickering, thomie Differential Revision: https://phabricator.haskell.org/D2898 GHC Trac Issues: #12837 }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12837#comment:6 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler