[GHC] #14661: Cannot derive (newtype I a b = I (F a -> F b) deriving newtype Category) for type family F
GHC
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Thu Jan 11 21:13:42 UTC 2018
#14661: Cannot derive (newtype I a b = I (F a -> F b) deriving newtype Category)
for type family F
-------------------------------------+-------------------------------------
Reporter: Iceland_jack | Owner: (none)
Type: feature request | Status: new
Priority: normal | Milestone:
Component: Compiler | Version: 8.4.1-alpha1
Resolution: | Keywords:
| DerivingStrategies, deriving,
| TypeFamilies
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):
My belief is that `DerivingVia` is exactly what you're looking for
(instead of attempting to encode this into GHC somehow in an //ad hoc//
fashion).
--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14661#comment:6>
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