[GHC] #16362: Deriving a class via an instance that has a TypeError constraint using standalone deriving fails during compilation.

[GHC]

#16362: Deriving a class via an instance that has a TypeError constraint using
standalone deriving fails during compilation.
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        Reporter:  j9794             |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.6.3
      Resolution:                    |             Keywords:  TypeErrors
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:                    |
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Comment (by RyanGlScott):

 I don't think I'm qualified to say. I've never been clear on what exactly
 the semantics of `TypeError` actually //intended// to be, so it's anyone's
 guess as to whether this is a bug or a feature.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/16362#comment:4>
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