[GHC] #13775: Type family expansion is too lazy, allows accepting of ill-typed terms

[GHC]

#13775: Type family expansion is too lazy, allows accepting of ill-typed terms
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        Reporter:  fizruk            |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler (Type    |              Version:  8.0.2
  checker)                           |             Keywords:
      Resolution:                    |  CustomTypeErrors
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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Changes (by RyanGlScott):

 * keywords:   => CustomTypeErrors
 * os:  MacOS X => Unknown/Multiple
 * architecture:  x86_64 (amd64) => Unknown/Multiple


Comment:

 Also reproducible in GHC 8.2 and HEAD.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13775#comment:1>
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