Re: [GHC] #14228: PatternSynonyms Non-exhaustive with UnboxedSums

#14228: PatternSynonyms Non-exhaustive with UnboxedSums -------------------------------------+------------------------------------- Reporter: guibou | Owner: (none) Type: bug | Status: patch Priority: normal | Milestone: 8.2.2 Component: Compiler | Version: 8.2.1 Resolution: | Keywords: UnboxedSums, | PatternSynonyms Operating System: Unknown/Multiple | Architecture: Type of failure: Incorrect result | Unknown/Multiple at runtime | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D3951 Wiki Page: | -------------------------------------+------------------------------------- Comment (by Ben Gamari ): In [changeset:"f4d50a0ec0d23dbcd61a014c8a773030c8fe310d/ghc" f4d50a0e/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="f4d50a0ec0d23dbcd61a014c8a773030c8fe310d" Fix #14228 by marking SumPats as non-irrefutable `isIrrefutableHsPat` should always return `False` for unboxed sum patterns (`SumPat`s), since they always have at least one other corresponding pattern of the same arity (since the minimum arity for a `SumPat` is 2). Failure to do so causes incorrect code to be generated for pattern synonyms that use unboxed sums, as shown in #14228. Test Plan: make test TEST=T14228 Reviewers: austin, bgamari, simonpj Reviewed By: simonpj Subscribers: simonpj, rwbarton, thomie GHC Trac Issues: #14228 Differential Revision: https://phabricator.haskell.org/D3951 }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14228#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler