[commit: ghc] ghc-8.0: Use an Implication in 'deriving' error (6c956b6)

[git at git.haskell.org]

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

On branch  : ghc-8.0
Link       : http://ghc.haskell.org/trac/ghc/changeset/6c956b6d7e7b282a70a91019f017527892c7566d/ghc

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

commit 6c956b6d7e7b282a70a91019f017527892c7566d
Author: Simon Peyton Jones <simonpj at microsoft.com>
Date:   Wed Jan 6 17:22:02 2016 +0000

    Use an Implication in 'deriving' error
    
    Trac #11437 showed that erroneous constraints from a 'deriving'
    clause need to be wrapped in an Implication to properly scope
    their skolems.
    
    The main change is in TcDeriv.simplifyDeriv; the call to
    buildImplicationFor is new.
    
    (cherry picked from commit 02c1c5735aff0cce2b04a6b3e4732d62bb0a4f3c)


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

6c956b6d7e7b282a70a91019f017527892c7566d
 compiler/typecheck/TcDeriv.hs                      | 23 +++++++++++++++------
 compiler/typecheck/TcInstDcls.hs                   |  2 +-
 compiler/typecheck/TcPatSyn.hs                     |  2 +-
 compiler/typecheck/TcRnTypes.hs                    | 11 +++++++++-
 .../tests/deriving/should_compile/T10561.stderr    |  8 +++++---
 testsuite/tests/deriving/should_fail/T7148.stderr  | 24 +++++++++++++---------
 .../tests/typecheck/should_fail/T11347.stderr      | 13 ++++++++++--
 7 files changed, 59 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 6c956b6d7e7b282a70a91019f017527892c7566d