[commit: ghc] ghc-7.10: Add an ambient Id substitution to Subst (1171d42)

[git at git.haskell.org]

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

On branch  : ghc-7.10
Link       : http://ghc.haskell.org/trac/ghc/changeset/1171d420715eb7fbe8ac35d82e5dbc1476149c3c/ghc

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

commit 1171d420715eb7fbe8ac35d82e5dbc1476149c3c
Author: Simon Peyton Jones <simonpj at microsoft.com>
Date:   Wed Jul 8 17:39:21 2015 +0100

    Add an ambient Id substitution to Subst
    
    After a struggle, I fixed Trac #5113 (again) on the 7.10 branch,
    by adding an ambient substitution to Subst; see CoreSubst,
    esp Note [IdSubstEnv].
    
    This allowed me to do the impedence-matching in SimplEnv.substExpr
    efficiently (fixing #10370) as well correctly (fixing the latest
    problem with #5113).
    
    This cost me more time than I like to say.  Sigh.


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1171d420715eb7fbe8ac35d82e5dbc1476149c3c
 compiler/coreSyn/CoreSubst.hs  | 137 +++++++++++++++++++++++++++++++++--------
 compiler/simplCore/SimplEnv.hs | 118 ++++++++++++-----------------------
 compiler/simplCore/Simplify.hs |   2 +-
 compiler/specialise/Rules.hs   |   8 +--
 4 files changed, 156 insertions(+), 109 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 1171d420715eb7fbe8ac35d82e5dbc1476149c3c