[GHC] #11518: Test TcCoercibleFail hangs with substitution sanity checks enabled

[GHC]

#11518: Test TcCoercibleFail hangs with substitution sanity checks enabled
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        Reporter:  niteria           |                Owner:  niteria
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler (Type    |              Version:  8.1
  checker)                           |
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  performance bug                    |            Test Case:
      Blocked By:                    |             Blocking:  11371
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Changes (by niteria):

 * owner:   => niteria


Comment:

 I'm going to dig more, but I expect I might not know how to best fix this.
 In general how does the typechecker deal with types that can get
 exponential?

 The part of the code that generates such types is:

 {{{
 newtype VoidBad a = VoidBad (VoidBad (a,a))
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11518#comment:3>
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