[GHC] #15398: GADT deriving Ord generates inaccessible code in a pattern with constructor.

[GHC]

#15398: GADT deriving Ord generates inaccessible code in a pattern with
constructor.
---------------------------------+--------------------------------------
        Reporter:  philderbeast  |                Owner:  (none)
            Type:  bug           |               Status:  new
        Priority:  normal        |            Milestone:  8.6.1
       Component:  Compiler      |              Version:  8.2.2
      Resolution:                |             Keywords:
Operating System:  MacOS X       |         Architecture:  x86_64 (amd64)
 Type of failure:  None/Unknown  |            Test Case:
      Blocked By:                |             Blocking:
 Related Tickets:                |  Differential Rev(s):
       Wiki Page:                |
---------------------------------+--------------------------------------

Comment (by RyanGlScott):

 I'm not sure what exactly the bug is here. The generated code genuinely
 has inaccessible cases, and since GHC 8.6+, this is a warning instead of
 an error, so you can now actually use this code.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15398#comment:1>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler