[GHC] #8020: Closed type families break substitution

[GHC]

#8020: Closed type families break substitution
-------------------------------------+------------------------------------
        Reporter:  goldfire          |            Owner:  goldfire
            Type:  bug               |           Status:  new
        Priority:  normal            |        Milestone:
       Component:  Compiler          |          Version:  7.7
      Resolution:                    |         Keywords:
Operating System:  Unknown/Multiple  |     Architecture:  Unknown/Multiple
 Type of failure:  None/Unknown      |       Blocked By:
        Blocking:                    |  Related Tickets:
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Comment (by eir@…):

 commit bd0ab6c2b478aea308ec405a3c24d0068bb96569
 {{{
 Author: Richard Eisenberg <eir at cis.upenn.edu>
 Date:   Fri Aug 2 10:51:35 2013 +0100

     Fix Trac #8020.

     The solution is to use a different notion of apartness. See
     http://research.microsoft.com/en-us/um/people/simonpj/papers/ext-f
 /axioms-extended.pdf
     for the gory details. Some comments are also in Notes [Compatibility]
     and [Apartness] in FamInstEnv.

  compiler/coreSyn/TrieMap.lhs   |   11 +++-
  compiler/ghc.mk                |    2 +-
  compiler/types/FamInstEnv.lhs  |  136
 ++++++++++++++++++++++++++++++++++++--
  compiler/types/OptCoercion.lhs |   15 +++--
  compiler/types/Unify.lhs       |  143
 +++++++++++-----------------------------
  docs/core-spec/core-spec.mng   |   14 ++--
  docs/core-spec/core-spec.pdf   |  Bin 347921 -> 349150 bytes
  7 files changed, 197 insertions(+), 124 deletions(-)
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8020#comment:1>
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