Re: [GHC] #13710: panic with boot and -jX

18 May 2017

      #13710: panic with boot and -jX
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        Reporter:  pacak             |                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 ezyang):

 This is a record wild cards problem. Here is a further reduced test case:

 {{{
 -- A.hs
 {-# LANGUAGE RecordWildCards #-}
 module A where
 import B
 data E = MkE
 p (H{..}) = ()

 -- A.hs-boot
 module A ( E ) where
 data E

 -- B.hs
 module B where
 import {-# SOURCE #-} A
 data H = H { h :: E }
 }}}

 Probably what is happening is that record wildcards is forcing the thunk
 for E during renaming, which is far before it is ready. Workaround should
 be to replace the record wildcard with explicitly listed out fields.

--
Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13710#comment:9
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