#8779: Exhaustiveness checks for pattern synonyms -------------------------------------+------------------------------------- Reporter: nomeata | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler (Type | Version: 7.8.1 checker) | Keywords: Resolution: | PatternSynonyms Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by mgsloan): * cc: mgsloan (added) Comment: +1 for resolving this (though I realize it's tricky)! Stack's build on 8.0 has this issue with ErrorCall's pattern synonym. Due to `-fwarn- incomplete-uni-patterns`, `catch f (\(ErrorCall x) -> g x)` causes a non- exhaustive case warning. See https://github.com/commercialhaskell/stack/pull/2145#issuecomment-219472907 -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8779#comment:21 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler