#14157: Flipping (give :: a -> (Given a => r) -> r) has type (r -> a -> r) -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Description changed by Iceland_jack: Old description:
[https://hackage.haskell.org/package/reflection-2.1.2/docs/Data- Reflection.html#v:give give] from the ''reflection'' library has the following type
{{{#!hs give :: forall a r. a -> (Given a => r) -> r }}}
but `flip give :: r -> a -> r`!
This works with our own `Given`, `give`
{{{ $ ghci -ignore-dot-ghci -XRankNTypes GHCi, version 8.3.20170605: http://www.haskell.org/ghc/ :? for help Prelude> class Given a Prelude> give :: a -> (Given a => r) -> r; give = undefined Prelude> :t flip give flip give :: c -> a -> c Prelude> }}}
New description: [https://hackage.haskell.org/package/reflection-2.1.2/docs/Data- Reflection.html#v:give give] from the ''reflection'' library has the following type {{{#!hs give :: forall a r. a -> (Given a => r) -> r }}} but `flip give :: r -> a -> r`! Same happens with our own `Given`, `give` {{{ $ ghci -ignore-dot-ghci -XRankNTypes GHCi, version 8.3.20170605: http://www.haskell.org/ghc/ :? for help Prelude> class Given a Prelude> give :: a -> (Given a => r) -> r; give = undefined Prelude> :t flip give flip give :: c -> a -> c Prelude> }}} -- -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14157#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler