[GHC] #14449: Type variables allowed to unify in a partial type signature (PartialTypeSignatures)

[GHC]

#14449: Type variables allowed to unify in a partial type signature
(PartialTypeSignatures)
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        Reporter:  kcsongor          |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler (Type    |              Version:  8.2.1
  checker)                           |
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  GHC accepts       |  Unknown/Multiple
  invalid program                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by Simon Peyton Jones <simonpj@…>):

 In [changeset:"4efe5fed407067d4b27000e0cf4092cfb6f7502b/ghc"
 4efe5fed/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="4efe5fed407067d4b27000e0cf4092cfb6f7502b"
 Check quantification for partial type signatues

 Trac #14449 showed that we were failing to check that the
 quantified type variables of a partial type signature remained
 distinct.

 See Note [Quantified variables in partial type signatures]
 in TcBinds.

 A little refactoring along the way.
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14449#comment:2>
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