[GHC] #10447: DeriveFoldable rejects instances with constraints in last argument of data type

GHC ghc-devs at haskell.org
Fri Jun 5 21:51:34 UTC 2015


#10447: DeriveFoldable rejects instances with constraints in last argument of data
type
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        Reporter:  RyanGlScott       |                   Owner:
            Type:  bug               |                  Status:  new
        Priority:  normal            |               Milestone:
       Component:  Compiler          |                 Version:  7.10.1
      Resolution:                    |                Keywords:
Operating System:  Unknown/Multiple  |            Architecture:
 Type of failure:  GHC rejects       |  Unknown/Multiple
  valid program                      |               Test Case:
      Blocked By:                    |                Blocking:
 Related Tickets:  #8678             |  Differential Revisions:
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Comment (by RyanGlScott):

 [https://ghc.haskell.org/trac/ghc/wiki/Commentary/Compiler/DeriveFunctor
 Here's a (rough draft of) a wiki article] about the {{{DeriveFunctor}}},
 {{{DeriveFoldable}}}, and {{{DeriveTraversable}}} trio, included the
 proposed change from this feature request. Feedback is very much
 appreciated.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10447#comment:21>
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