[commit: ghc] master: Improve trimming of auto-rules (49370ce)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/49370cedccc9d51395a6cc3e182b55ce5a50b560/ghc

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commit 49370cedccc9d51395a6cc3e182b55ce5a50b560
Author: Simon Peyton Jones <simonpj at microsoft.com>
Date:   Fri Aug 29 08:06:36 2014 +0100

    Improve trimming of auto-rules
    
    I hadn't got the new function trimAutoRules quite right, so we had
    a left-over rule which mentioned a local variable whose binding had
    been discarded.  (Result: crash when compiling Haddock.)
    
    This patch merges trimAutoRules into an expanded version of
    findExternalRules, gets it right, and adds lots of comments.
    
    See Note [Finding external rules].
    
    And indeed in one regression test we get to trim off more rules
    (and hence code) than before.


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49370cedccc9d51395a6cc3e182b55ce5a50b560
 compiler/main/TidyPgm.lhs                         | 256 +++++++++++++---------
 testsuite/tests/simplCore/should_run/T2486.stderr |  16 --
 2 files changed, 151 insertions(+), 121 deletions(-)

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

    git diff-tree --root --patch-with-stat --no-color --find-copies-harder --ignore-space-at-eol --cc 49370cedccc9d51395a6cc3e182b55ce5a50b560