[GHC] #16127: Panic: piResultTys1 in compiler/types/Type.hs:1022:5

[GHC]

#16127: Panic: piResultTys1 in compiler/types/Type.hs:1022:5
-------------------------------------+-------------------------------------
        Reporter:  _deepfire         |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler (Type    |              Version:  8.6.1
  checker)                           |
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  crash or panic                     |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by simonpj):

 I know what is happening.  In `A.hs-boot` (which has `-XPolyKinds`) we
 have
 {{{
 T :: forall k. k  -> Type
 }}}
 Then in `B.hs-boot` we have
 {{{
 method :: forall i x. C i => T @Type i -> x
 }}}
 When compiling `A.hs` (no `-XPolyKinds`) we get
 {{{
 T :: Type -> Type
 }}}
 Now, when we deserialise that imported singature for `method` we construct
 the ill-kinded type `T @Type i`.  Result, disaster.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/16127#comment:8>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler