[commit: ghc] master: Decompose wanted repr. eqs. when no matchable givens. (ff82387)

[git at git.haskell.org]

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

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/ff82387d6fe61762fe4f507e8f9799f5bdc3c43a/ghc

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

commit ff82387d6fe61762fe4f507e8f9799f5bdc3c43a
Author: Richard Eisenberg <eir at cis.upenn.edu>
Date:   Mon Jun 8 22:32:40 2015 -0400

    Decompose wanted repr. eqs. when no matchable givens.
    
    This is pursuant to a conversion with SPJ, where we agreed that
    the logic behind Note [Instance and Given overlap] in TcInteract
    applied to newtype decomposition for representational equality.
    
    There is no bug report or test case, as tickling this kind of thing
    is quite hard to do!


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ff82387d6fe61762fe4f507e8f9799f5bdc3c43a
 compiler/typecheck/TcCanonical.hs | 37 ++++++++++++++++-----------
 compiler/typecheck/TcInteract.hs  | 37 +++------------------------
 compiler/typecheck/TcSMonad.hs    | 53 ++++++++++++++++++++++++++++++++++++++-
 3 files changed, 79 insertions(+), 48 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 ff82387d6fe61762fe4f507e8f9799f5bdc3c43a