[GHC] #4259: Relax restrictions on type family instance overlap

[GHC]

#4259: Relax restrictions on type family instance overlap
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        Reporter:  lilac                    |            Owner:
            Type:  feature request          |           Status:  new
        Priority:  normal                   |        Milestone:  7.8.1
       Component:  Compiler (Type checker)  |          Version:  6.12.1
      Resolution:                           |         Keywords:
Operating System:  Unknown/Multiple         |     Architecture:
 Type of failure:  None/Unknown             |  Unknown/Multiple
       Test Case:                           |       Difficulty:  Unknown
        Blocking:                           |       Blocked By:
                                            |  Related Tickets:  #8423
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Changes (by goldfire):

 * related:   => #8423


Comment:

 See also #8423 to see an example of this issue in action in the context of
 closed type families.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4259#comment:30>
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