[commit: ghc] master: Fix Trac #7585. (a6ab0a4)

[Richard Eisenberg]

Repository : ssh://darcs.haskell.org//srv/darcs/ghc

On branch  : master

http://hackage.haskell.org/trac/ghc/changeset/a6ab0a40ac750914640613c77148e948fabf35d5

>---------------------------------------------------------------

commit a6ab0a40ac750914640613c77148e948fabf35d5
Author: Richard Eisenberg <eir at cis.upenn.edu>
Date:   Tue Jan 15 17:19:37 2013 -0500

    Fix Trac #7585.
    
    The coercion optimizer was optimizing coercions inside of branched
    axiom applications, sometimes invalidating the branch choice within
    the axiom application. Now, we check to make sure we are not
    invalidating this invariant before proceeding with the optimization.

 compiler/coreSyn/CoreLint.lhs  |   41 +------------------
 compiler/types/OptCoercion.lhs |   88 +++++++++++++++++++++++++++++++++++-----
 2 files changed, 79 insertions(+), 50 deletions(-)


Diff suppressed because of size. To see it, use:

    git show a6ab0a40ac750914640613c77148e948fabf35d5