[GHC] #12682: ASSERT failures in testsuite

[GHC]

#12682: ASSERT failures in testsuite
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        Reporter:  simonpj           |                Owner:
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.0.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by Simon Peyton Jones <simonpj@…>):

 In [changeset:"76a5477b86c66c52854d8d4fbabbd15ce128fa83/ghc"
 76a5477b/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="76a5477b86c66c52854d8d4fbabbd15ce128fa83"
 Move zonking out of tcFamTyPats

 In tcFamTyPats we were zonking from the TcType world to the
 Type world, ready to build the results into a CoAxiom (which
 should have no TcType stuff.  But the 'thing_inside' for
 tcFamTyPats also must be zonked, and that zonking must have
 the ZonkEnv from the binders zonked tcFamTyPats.

 Ugh.  This caused an assertion failure (with DEBUG on) in
 RaeBlobPost and TypeLevelVec, both in tests/dependent, as
 shown in Trac #12682.  Why it hasn't shown up before now
 is obscure to me.

 So I moved the zonking stuff out of tcFamTyPats to its
 three call sites, where we can do it all together. Very
 slightly longer, but much more robust.
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12682#comment:1>
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