[GHC] #13998: Default Signature messes up arity of type constructor
GHC
ghc-devs at haskell.org
Wed Jul 19 17:10:32 UTC 2017
#13998: Default Signature messes up arity of type constructor
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Reporter: andrewthad | Owner: (none)
Type: bug | Status: new
Priority: normal | Milestone:
Component: Compiler | Version: 8.0.1
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):
Replying to [comment:7 simonpj]:
> But the `classTyCon` has everything. The `classTyVars` are redundant,
just there for convenience.
Oops, I overlooked that.
Also, please ignore the noise in the latter part of comment:6 - the type
signature wasn't pretty-printing the way I expected because I neglected to
enable `-fprint-explicit-foralls`. If you do, you'll get:
{{{
λ> :set -fprint-explicit-foralls
λ> :type +v eqForallPoly
eqForallPoly
:: forall {k} (f :: k -> *).
EqForallPoly f =>
forall (a :: k) (b :: k). f a -> f b -> Bool
}}}
as expected. So that is working as expected.
--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13998#comment:8>
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