[GHC] #11648: assertPprPanic, called at compiler/types/TyCoRep.hs:1932

[GHC]

#11648: assertPprPanic, called at compiler/types/TyCoRep.hs:1932
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        Reporter:  thomie            |                Owner:  goldfire
            Type:  bug               |               Status:  new
        Priority:  highest           |            Milestone:  8.0.1
       Component:  Compiler          |              Version:  8.1
      Resolution:                    |             Keywords:  TypeInType
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by simonpj):

 Well maybe it does, but the ASSERT fails because in `getInitialKinds`
 because there is a CUSK we compute an initial kind for `MComp` that
 contains a unification variable.

 Now, if the ASSERT isn't there nothing actually breaks.  But it's plainly
 wrong for `MComp` to have a kind (even temporarily) that has a free levity
 variable.

 I don't want to fix this by adding this bogus unification variable to the
 in-scope set; nor by disabling the ASSERT.

 But you could argue that since nothing is actually broken this doesn't
 matter, and the dragon is sleeping.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11648#comment:13>
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