#13018: TH-spliced pattern synonym declaration fails to typecheck -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler (Type | Version: 8.0.1 checker) | Keywords: Resolution: | PatternSynonyms 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 RyanGlScott): Well, there's certainly a technical issue in that quoting //any// function (not just pattern synonyms) will always add explicit quantification if it isn't present to begin with. For example: {{{ λ> putStrLn $([d| id :: a -> a; id x = x |] >>= stringE . pprint) id_0 :: forall a_1 . a_1 -> a_1 id_0 x_2 = x_2 λ> putStrLn $([d| id :: a -> a; id x = x |] >>= stringE . show) [SigD id_6989586621679026833 (ForallT [PlainTV a_6989586621679026832] [] (AppT (AppT ArrowT (VarT a_6989586621679026832)) (VarT a_6989586621679026832))),FunD id_6989586621679026833 [Clause [VarP x_6989586621679026834] (NormalB (VarE x_6989586621679026834)) []]] }}} Note how the `ForallT [PlainTV a_6989586621679026832] ...` gets added. So we'd need to be able to somehow preserve the fact that `id` was originally quoted without explicit quantification. We'd need to do this for functions and pattern synonyms for sure (and maybe other declarations that I'm not thinking of right now?). -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13018#comment:13 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler