[GHC] #14822: -XQuantifiedConstraints: Turn term-level entailments (:-) into constraints (=>)
GHC
ghc-devs at haskell.org
Fri Feb 23 23:34:20 UTC 2018
#14822: -XQuantifiedConstraints: Turn term-level entailments (:-) into constraints
(=>)
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Reporter: Iceland_jack | Owner: (none)
Type: bug | Status: closed
Priority: normal | Milestone:
Component: Compiler | Version: 8.5
Resolution: invalid | Keywords:
| QuantifiedConstraints, wipT2893
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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Changes (by RyanGlScott):
* status: new => closed
* resolution: => invalid
Comment:
I fully agree with kcsongor's analysis. This is essentially asking for a
way to violate the open-world assumption, which isn't going to fly. If you
want to use `(SBoolI b, SBoolI b') => Funny b b'` as a quantified
constraint, then write an instance for it.
--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14822#comment:2>
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