Re: [GHC] #16300: Make TH always reify data types with explicit return kinds

11 Feb 2019

      #16300: Make TH always reify data types with explicit return kinds
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        Reporter:  RyanGlScott       |                Owner:  (none)
            Type:  feature request   |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Template Haskell  |              Version:  8.6.3
      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:                    |
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Comment (by RyanGlScott):

 As further evidence for how //ad hoc// the restriction in comment:1 is, if
 I change the program to use `NewtypeD` instead:

 {{{#!hs
 {-# LANGUAGE KindSignatures #-}
 {-# LANGUAGE TemplateHaskell #-}
 module Bug where

 import Language.Haskell.TH

 $(pure [NewtypeD [] (mkName "D") [] (Just StarT)
                  (NormalC (mkName "MkD")
                           [(Bang NoSourceUnpackedness NoSourceStrictness,
 ConT ''Int)])
                  []])
 }}}

 Then GHC accepts it without issue!

-- 
Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/16300#comment:2
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