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

[GHC]

#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):

 So... apparently this patch fixes the problem, but I haven't quite figured
 out why.

 {{{
 diff --git a/compiler/iface/TcIface.hs b/compiler/iface/TcIface.hs
 index 3a6a4070d2..50fafcdadf 100644
 --- a/compiler/iface/TcIface.hs
 +++ b/compiler/iface/TcIface.hs
 @@ -908,7 +908,8 @@ tcIfaceDataCons tycon_name tycon tc_tybinders if_cons
          ; ~(eq_spec, theta, arg_tys, stricts) <- forkM (mk_doc dc_name) $
               do { eq_spec <- tcIfaceEqSpec spec
                  ; theta   <- tcIfaceCtxt ctxt
 -                ; arg_tys <- mapM tcIfaceType args
 +                ; arg_tys <- forkM (mk_doc dc_name <+> text "arg_tys")
 +                           $ mapM tcIfaceType args
                  ; stricts <- mapM tc_strict if_stricts
                          -- The IfBang field can mention
                          -- the type itself; hence inside forkM

 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13710#comment:12>
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