[GHC] #11762: GHC 8 superclass chain constraint regression
GHC
ghc-devs at haskell.org
Tue Mar 29 10:21:11 UTC 2016
#11762: GHC 8 superclass chain constraint regression
-------------------------------------+-------------------------------------
Reporter: _deepfire | Owner:
Type: bug | Status: new
Priority: highest | Milestone: 8.0.1
Component: Compiler (Type | Version: 8.0.1-rc2
checker) |
Resolution: | Keywords:
Operating System: Unknown/Multiple | Architecture:
Type of failure: GHC rejects | Unknown/Multiple
valid program | Test Case:
Blocked By: | Blocking:
Related Tickets: #11427 | Differential Rev(s):
Wiki Page: |
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Comment (by simonpj):
Yes, it's the same as #11427.
It doesn't bite often, and it's also easy to fix, thus
{{{
instance (Super a, Left a) ⇒ Right a
}}}
What I most dislike about it is that it's hard to explain and justify. I
would like a better way to do this, but I don't know one. Better ideas
welcome!
Simon
--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11762#comment:5>
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