#4009: can newtype be extended to permit GADT-like declarations -------------------------------------+------------------------------------- Reporter: nr | Owner: simonpj Type: feature request | Status: closed Priority: normal | Milestone: 7.0.1 Component: Compiler (Type | Version: 6.12.1 checker) | Resolution: invalid | Keywords: newtype GADT Operating System: Linux | Architecture: x86 Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by sighingnow): In ghc-8.2.1 and ghc-head, `newtype` definition in comment:2 is disallowed. But The following definition is accepted by GHC: {{{#!hs newtype T a where MkT :: a -> T a }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/4009#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler