[GHC] #14450: GHCi spins forever

[GHC]

#14450: GHCi spins forever
-------------------------------------+-------------------------------------
        Reporter:  Iceland_jack      |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  high              |            Milestone:  8.4.1
       Component:  Compiler          |              Version:  8.2.1
      Resolution:                    |             Keywords:  TypeInType,
                                     |  PolyKinds
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  performance bug                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------
Changes (by RyanGlScott):

 * priority:  normal => high
 * failure:  None/Unknown => Compile-time performance bug
 * milestone:   => 8.4.1


Comment:

 This is a regression from GHC 8.0.2, which simply gives an error message:

 {{{
 $ /opt/ghc/8.0.2/bin/ghci Bug3.hs
 GHCi, version 8.0.2: http://www.haskell.org/ghc/  :? for help
 Loaded GHCi configuration from /home/rgscott/.ghci
 [1 of 1] Compiling Main             ( Bug3.hs, interpreted )

 Bug3.hs:31:12: error:
     • Expected kind ‘k ~> k’, but ‘IddSym0’ has kind ‘Type ~> Type’
     • In the first argument of ‘Dom’, namely
         ‘(IddSym0 :: Type ~> Type)’
       In the type instance declaration for ‘Dom’
       In the instance declaration for ‘Varpi (IddSym0 :: k ~> k)’
 }}}

 This bug first appeared in commit b207b536ded40156f9adb168565ca78e1eef2c74
 (`Generalize kind of the (->) tycon`).

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14450#comment:1>
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