[GHC] #11444: 8.0 rc1 panics in applyTypeToArgs

[GHC]

#11444: 8.0 rc1 panics in applyTypeToArgs
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        Reporter:  osa1              |                Owner:
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.0.1-rc1
      Resolution:                    |             Keywords:
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 RyanGlScott):

 Two things:

 1. osa1, I can't seem to reproduce the error you originally reported in
 this ticket on GHC 8.0.1, 8.0.2, or HEAD.
 2. On GHC HEAD, I noticed that the package fails to build with `-dcore-
 lint` on:

 {{{
 *** Core Lint errors : in result of Float out(FOS {Lam = Just 0,
                                                    Consts = True,
                                                    OverSatApps = False})
 ***
 <no location info>: warning:
     In the expression: I# (reallyUnsafePtrEquality# @ a x_a1B9 y_a1Ba)
     This argument does not satisfy the let/app invariant:
       reallyUnsafePtrEquality# @ a x_a1B9 y_a1Ba
 *** Offending Program ***
 ...
 ptrEq [InlPrag=NOINLINE] :: forall a. a -> a -> Bool
 [LclIdX, Arity=2]
 ptrEq =
   \ (@ a_a1Dh) (x_a1B9 :: a) (y_a1Ba :: a) ->
     case x_a1B9 of x_X1Bi { __DEFAULT ->
     case y_a1Ba of y_X1Bk { __DEFAULT ->
     eqInt (I# (reallyUnsafePtrEquality# @ a x_a1B9 y_a1Ba)) lvl_s1QL
     }
     }
 }}}

    Possibly related to #13027?

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11444#comment:8>
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