[GHC] #15505: Assertion failure in test T7224

[GHC]

#15505: Assertion failure in test T7224
-------------------------------------+-------------------------------------
           Reporter:  osa1           |             Owner:  (none)
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:  8.6.1
          Component:  Compiler       |           Version:  8.5
  (Type checker)                     |
           Keywords:                 |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  None/Unknown
  Unknown/Multiple                   |
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
-------------------------------------+-------------------------------------
 To reproduce, build GHC HEAD with slow validate settings, then run test
 `T7224`. Output:

 {{{
 =====> T7224(normal) 9 of 15 [0, 2, 0]
 cd "polykinds/T7224.run" &&  "/home/omer/haskell/ghc/inplace/test   spaces
 /ghc-stage2" -c T7224.hs -dcore-lint -dcmm-lint -no-user-package-db
 -rtsopts -fno-warn-missed-specialisations -fshow-warning-groups
 -fdiagnostics-color=never -fno-diagnostics-show-caret -dno-debug-output
 Actual stderr output differs from expected:
 diff -uw "polykinds/T7224.run/T7224.stderr.normalised"
 "polykinds/T7224.run/T7224.comp.stderr.normalised"
 --- polykinds/T7224.run/T7224.stderr.normalised 2018-08-11
 13:33:16.874459507 +0300
 +++ polykinds/T7224.run/T7224.comp.stderr.normalised    2018-08-11
 13:33:16.874459507 +0300
 @@ -1,13 +1,11 @@
 +ghc: panic! (the 'impossible' happened)
 +  (GHC version 8.7.20180809 for x86_64-unknown-linux):
 +       ASSERT failed!
 +  Type-correct unfilled coercion hole {co_asw}
 +  Call stack:
 +      CallStack (from HasCallStack):
 +        callStackDoc, called at
 compiler/utils/Outputable.hs:<line>:<column> in <package-id>:Outputable
 +        pprPanic, called at compiler/utils/Outputable.hs:<line>:<column>
 in <package-id>:Outputable
 +        assertPprPanic, called at
 compiler/typecheck/TcHsSyn.hs:<line>:<column> in <package-id>:TcHsSyn

 -T7224.hs:6:19:
 -     Expected kind ‘i’, but ‘i’ has kind ‘*’
 -     In the first argument of ‘m’, namely ‘i’
 -      In the type signature: ret' :: a -> m i i a
 -      In the class declaration for ‘PMonad'’
 -
 -T7224.hs:7:14:
 -     Expected kind ‘i’, but ‘i’ has kind ‘*’
 -     In the first argument of ‘m’, namely ‘i’
 -      In the type signature:
 -        bind' :: m i j a -> (a -> m j k b) -> m i k b
 -      In the class declaration for ‘PMonad'’
 +Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug
 *** unexpected failure for T7224(normal)
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15505>
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