Re: [GHC] #13526: -Wsimplifiable-class-constraints behaves differently with OVERLAPPING and OVERLAPPABLE

6 Apr 2017

      #13526: -Wsimplifiable-class-constraints behaves differently with OVERLAPPING and
OVERLAPPABLE
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        Reporter:  cocreature        |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.1
      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 Simon Peyton Jones ):

 In [changeset:"65b185d4886b4efa3efe3cc5ecc8dd6e07d89afe/ghc"
 65b185d4/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="65b185d4886b4efa3efe3cc5ecc8dd6e07d89afe"
 Be less aggressive about fragile-context warrnings

 In the implementation of WarnSimplifiableClassConstraints, be
 less aggressive about reporting a problem. We were complaining
 about a "fragile" case that in fact was not fragile.

 See Note [Simplifiable given constraints] in TcValidity.

 This fixes Trac #13526.
 }}}

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Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13526#comment:1
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