#11715: Constraint vs * -------------------------------------+------------------------------------- Reporter: bgamari | Owner: Type: bug | Status: new Priority: high | Milestone: 8.2.1 Component: Compiler (Type | Version: 8.0.1-rc1 checker) | Resolution: | Keywords: Typeable Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by Iceland_jack): Replying to [comment:26 int-index]:
Currently, all of those types are equivalent:
* `(a, b) => t` * `(b, a) => t` * `a => b => t` * `b => a => t`
Edwardk [https://gist.github.com/Icelandjack/5afdaa32f41adf3204ef9025d9da2a70 #reddit-you-can-write-show-a--read-a--a---a-instead-of-show-a-read-a--a--- a notes] that `a => b => t` is slightly weaker than `(a, b) => t` since it can “only reference backwards up the chain”. I can't produce an example of this though, there may be differences between `a => b => t` and `b => a => t` as well. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11715#comment:28 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler