[GHC] #14490: TTG Snags

[GHC]

#14490: TTG Snags
-------------------------------------+-------------------------------------
        Reporter:  alanz             |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.3
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #14482            |  Differential Rev(s):
       Wiki Page:                    |
  ImplementingTreesThatGrow          |
-------------------------------------+-------------------------------------

Comment (by alanz):

 I am getting

 {{{#!hs
 instance Data (XOverLit (GhcPass p)) where
 ----
 compiler/hsSyn/HsLit.hs:143:10: error:
     • Illegal type synonym family application in instance:
         XOverLit (GhcPass p)
     • In the instance declaration for ‘Data (XOverLit (GhcPass p))’
     |
 143 | instance Data (XOverLit (GhcPass p)) where
     |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^
 }}}

 Am I missing something?

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14490#comment:11>
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