#14135: PatternSynonyms regression in GHC HEAD (expectJust mkOneConFull) -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: dfeuer Type: bug | Status: new Priority: highest | Milestone: 8.4.1 Component: Compiler | Version: 8.3 Resolution: | Keywords: | PatternSynonyms Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple crash or panic | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D3981 Wiki Page: | -------------------------------------+------------------------------------- Comment (by Ben Gamari <ben@…>): In [changeset:"16c7d9dc9ea7505256e0792c958cab8ae7c8a5c4/ghc" 16c7d9dc/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="16c7d9dc9ea7505256e0792c958cab8ae7c8a5c4" Fix #14135 by validity checking matches We filter the complete patterns given in a COMPLETE set to only those that subsume the type we are matching. Otherwise we end up introducing an ill- typed equation into the overlap checking, provoking a crash. This was the cause of Trac #14135. Reviewers: austin, bgamari, mpickering, gkaracha, simonpj, RyanGlScott, carlostome Reviewed By: bgamari Subscribers: carter, dfeuer, RyanGlScott, goldfire, rwbarton, thomie GHC Trac Issues: #14135 Differential Revision: https://phabricator.haskell.org/D3981 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14135#comment:21> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler