[GHC] #6018: Injective type families

[GHC]

#6018: Injective type families
-------------------------------------+-------------------------------------
              Reporter:  lunaris     |            Owner:  jstolarek
                  Type:  feature     |           Status:  new
  request                            |        Milestone:  7.10.1
              Priority:  normal      |          Version:  7.4.1
             Component:  Compiler    |         Keywords:  TypeFamilies,
            Resolution:              |  Injective
      Operating System:              |     Architecture:  Unknown/Multiple
  Unknown/Multiple                   |       Difficulty:  Unknown
       Type of failure:              |       Blocked By:
  None/Unknown                       |  Related Tickets:  #4259
             Test Case:              |
              Blocking:              |
Differential Revisions:  Phab:D202   |
-------------------------------------+-------------------------------------

Comment (by jstolarek):

 Replying to [comment:69 rwbarton]:
 > That reads very oddly to me, but how about...?
 > {{{
 > type family Id a = result | result -> a where
 > }}}
 You mean that the `:: result` syntax reads oddly? It is already supported
 by GHC and the nice thing about this proposal is that we can piggyback on
 the syntax we already have.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/6018#comment:70>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler