#13068: GHC should not allow modules to define instances of abstract type classes -------------------------------------+------------------------------------- Reporter: ezyang | Owner: (none) Type: bug | Status: patch Priority: low | Milestone: 8.2.1 Component: Compiler (Type | Version: 8.1 checker) | Resolution: | Keywords: backpack 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:D3254 Wiki Page: | -------------------------------------+------------------------------------- Comment (by Edward Z. Yang <ezyang@…>): In [changeset:"bba004f2a0642d3bb8c8876543aaa1a48a2f9a43/ghc" bba004f2/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="bba004f2a0642d3bb8c8876543aaa1a48a2f9a43" Prevent users from defining instances for abstract classes. Summary: Fixes #13068. Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu> Test Plan: validate Reviewers: simonpj, austin, bgamari Subscribers: thomie Differential Revision: https://phabricator.haskell.org/D3254 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13068#comment:3> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler