[GHC] #14157: Flipping (give :: a -> (Given a => r) -> r) has type (r -> a -> r)
GHC
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Sat Aug 26 15:20:06 UTC 2017
#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: |
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Changes (by RyanGlScott):
* cc: RyanGlScott (added)
Comment:
This isn't limited to `flip`, since you can also trigger similar behavior
with a simple redefinition of `give`:
{{{
GHCi, version 8.2.1: http://www.haskell.org/ghc/ :? for help
Loaded GHCi configuration from /home/ryanglscott/.ghci
λ> :set -XRankNTypes
λ> class Given a
λ> let give :: a -> (Given a => r) -> r; give = undefined
λ> let f x y = give x y
λ> :type +v f
f :: a -> p -> p
λ> :type f
f :: a -> p -> p
}}}
--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14157#comment:2>
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