[GHC] #11381: Put injective type families in a separate language extension

[GHC]

#11381: Put injective type families in a separate language extension
-------------------------------------+-------------------------------------
           Reporter:  jstolarek      |             Owner:  jstolarek
               Type:  task           |            Status:  new
           Priority:  normal         |         Milestone:  8.0.1
          Component:  Compiler       |           Version:  8.0.1-rc1
           Keywords:  TypeFamilies,  |  Operating System:  Unknown/Multiple
  Injective                          |
       Architecture:                 |   Type of failure:  None/Unknown
  Unknown/Multiple                   |
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:  #6018
Differential Rev(s):                 |         Wiki Page:
-------------------------------------+-------------------------------------
 Injective type families should only be enabled when language extension
 `InjectiveTypeFamilies` is specified. This extension should imply
 `TypeFamilies`.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11381>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler