#9953: Pattern synonyms don't work with GADTs -------------------------------------+------------------------------------- Reporter: simonpj | Owner: cactus Type: bug | Status: new Priority: normal | Milestone: 7.10.1 Component: Compiler (Type | Version: 7.10.1-rc1 checker) | Keywords: Resolution: | PatternSynonyms Operating System: Unknown/Multiple | Architecture: Type of failure: None/Unknown | Unknown/Multiple Blocked By: | Test Case: Related Tickets: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- Comment (by cactus): I almost have this working in the `wip/T9953` branch. However, there is one tricky question, very much related to #9954: what do we do with required constraints that mention some GADT indices? For example, if `pattern C` also happened to have a required constraint, e.g. `Eq a`, where would we put that, if `a` is no longer a universally- quantified type argument of `C`? What would be the type of `C`'s matcher? -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9953#comment:6 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler