[GHC] #14075: GHC panic with parallel make

[GHC]

#14075: GHC panic with parallel make
-------------------------------------+-------------------------------------
        Reporter:  inaki             |                Owner:  (none)
            Type:  bug               |               Status:  patch
        Priority:  high              |            Milestone:  8.2.2
       Component:  Compiler          |              Version:  8.2.1
      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:  #13803, #13981    |  Differential Rev(s):  Phab:D3815
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by Ben Gamari <ben@…>):

 In [changeset:"4717ce8658f12f425aebd1fc7f7ad8fe04a81df5/ghc"
 4717ce86/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="4717ce8658f12f425aebd1fc7f7ad8fe04a81df5"
 Fix incorrect retypecheck loop in -j (#14075)

 The parallel codepath was incorrectly retypechecking the
 hs-boot ModIface prior to typechecking the hs file,
 which was inconsistent with the non-parallel case.  The
 non-parallel case gets it right: you don't want to retypecheck
 the hs-boot file itself (forwarding its declarations to hs)
 because you need it to be consistently knot-tied with itself
 when you compare the interfaces.

 Signed-off-by: Edward Z. Yang <ezyang at cs.stanford.edu>

 Test Plan: validate

 Reviewers: bgamari, simonpj, austin

 Reviewed By: bgamari

 Subscribers: duog, rwbarton, thomie

 GHC Trac Issues: #14075

 Differential Revision: https://phabricator.haskell.org/D3815
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14075#comment:6>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler