[GHC] #8806: Invalid constraints should fail to type check

[GHC]

#8806: Invalid constraints should fail to type check
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        Reporter:  erikd                    |            Owner:  erikd
            Type:  bug                      |           Status:  new
        Priority:  normal                   |        Milestone:
       Component:  Compiler (Type checker)  |          Version:  7.6.3
      Resolution:                           |         Keywords:
Operating System:  Unknown/Multiple         |     Architecture:
 Type of failure:  None/Unknown             |  Unknown/Multiple
       Test Case:                           |       Difficulty:  Unknown
        Blocking:                           |       Blocked By:
                                            |  Related Tickets:
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Comment (by Erik de Castro Lopo <erikd@…>):

 In [changeset:"55cc01a95328667e5e26f1e3062a45059cc3cbec/ghc"]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="55cc01a95328667e5e26f1e3062a45059cc3cbec"
 Add test case for #8806.

 GHC 7.6.3 and earlier should fail to type check this but don't.
 This was fixed some time between the 7.6.3 and the 7.8rc1 release, so
 we're just adding a test to prevent future regressions.
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8806#comment:1>
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