#14253: Pattern match checker mistakenly concludes pattern match on pattern synonym is unreachable -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: bug | Status: new Priority: high | Milestone: 8.4.1 Component: Compiler | Version: 8.2.1 Resolution: | Keywords: | PatternSynonyms, | PatternMatchWarnings Operating System: Unknown/Multiple | Architecture: Type of failure: GHC rejects | Unknown/Multiple valid program | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by simonpj): OK, but then lies might give rise to error messages or warnings that lie, mightn't they. As here. We need a specification of the expected behaviour of lying COMPLETE pragmas before we can discuss what programs like these "should" do. Or we could say "if the pragma lies, the compiler can do what it likes". -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14253#comment:5 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler