#12179: Incorrect parsing of a pattern synonym type -------------------------------------+------------------------------------- Reporter: mpickering | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Keywords: | Operating System: Unknown/Multiple PatternSynonyms | Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: #12108 Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- The following definition is accepted by GHC. {{{ pattern Q :: a -> forall. (Bool -> a) pattern Q v <- (($ True) -> v) }}} What does this type signature mean? Who knows. It should be rejected for being an invalid form. Maybe see #12108 -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12179 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler