[GHC] #12616: type synonyms confuse generalized newtype deriving role checking

[GHC]

#12616: type synonyms confuse generalized newtype deriving role checking
-------------------------------------+-------------------------------------
        Reporter:  daviddarais       |                Owner:  goldfire
            Type:  bug               |               Status:  new
        Priority:  low               |            Milestone:
       Component:  Compiler          |              Version:  8.0.1
      Resolution:                    |             Keywords:  generalized
                                     |  newtype deriving roles rankntypes
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  GHC rejects       |  Unknown/Multiple
  valid program                      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------
Changes (by goldfire):

 * owner:   => goldfire


Comment:

 I think this issue is just an infelicity in the code generator for GND.
 Should be easy to fix.

 NB: There are no higher-rank types in the example. Just a fancy type
 synonym.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12616#comment:1>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler