Re: [GHC] #13803: Panic while forcing the thunk for TyThing IsFile (regression)

8 Jun 2017

      #13803: Panic while forcing the thunk for TyThing IsFile (regression)
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        Reporter:  inaki             |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.2.1-rc2
      Resolution:                    |             Keywords:  hs-boot
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:                    |
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Comment (by RyanGlScott):

 Now with even fewer //internal// dependencies:

 {{{#!hs
 {-# LANGUAGE TypeFamilies #-}
 module D (D) where

 type family D a
 type instance D Int = Int
 }}}

 {{{#!hs
 module GIGioInterfacesFile where

 import D ()
 import {-# SOURCE #-} qualified GIGioObjectsFileEnumerator as
 Gio.FileEnumerator
 import {-# SOURCE #-} qualified GIGioObjectsMountOperation as
 Gio.MountOperation

 class IsFile o
 }}}

 It looks like type family instances are the culprit.

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Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13803#comment:8
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