[commit: ghc] master: Attempt to make lazy ST thread safe (2f5cb3d)

[git at git.haskell.org]

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

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/2f5cb3d44d05e581b75a47fec222577dfa7a533e/ghc

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

commit 2f5cb3d44d05e581b75a47fec222577dfa7a533e
Author: David Feuer <david.feuer at gmail.com>
Date:   Fri Feb 3 17:24:17 2017 -0500

    Attempt to make lazy ST thread safe
    
    Use `noDuplicate#` to prevent lazy `ST` thunks from
    being evaluated in multiple GHC threads.
    
    Some lazy `ST` functions added laziness that did not seem to be useful
    (e.g.,
    creating lazy pairs that will never be matched unless one of their
    components
    is demanded). Stripped that out.
    
    Reviewers: ekmett, simonpj, bgamari, simonmar, austin, hvr
    
    Subscribers: rwbarton, thomie
    
    Differential Revision: https://phabricator.haskell.org/D3038
    
    GHC Trac Issues: #11760


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

2f5cb3d44d05e581b75a47fec222577dfa7a533e
 libraries/base/Control/Monad/ST/Lazy/Imp.hs        | 142 +++++++++++++++++----
 libraries/base/tests/T11760.hs                     |  51 ++++++++
 .../tests/{IO/IOError002.stdout => T11760.stdout}  |   0
 libraries/base/tests/all.T                         |   2 +
 libraries/base/tests/fixUsingLazyST.stdout         |   2 +
 libraries/base/tests/lazySTexamples.hs             | 110 ++++++++++++++++
 libraries/base/tests/lazySTexamples.stderr         |  16 +++
 libraries/base/tests/lazySTexamples.stdout         |   6 +
 8 files changed, 305 insertions(+), 24 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 2f5cb3d44d05e581b75a47fec222577dfa7a533e