[GHC] #11509: Incorrect error message in StandaloneDeriving: "The data constructors of <typeclass> are not all in scope"

[GHC]

#11509: Incorrect error message in StandaloneDeriving: "The data constructors of
<typeclass> are not all in scope"
-------------------------------------+-------------------------------------
        Reporter:  edsko             |                Owner:  RyanGlScott
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.0.1-rc1
      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:                    |
-------------------------------------+-------------------------------------
Changes (by RyanGlScott):

 * owner:   => RyanGlScott


Comment:

 After #10598, GHC has been refactored to propagate information about which
 deriving mechanism was chosen further into the compiler, so fixing this
 issue properly (i.e., erroring on stock or newtype deriving, but not on
 anyclass deriving) is much easier now. I'll take this one.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11509#comment:7>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler