[commit: ghc] master: Improve the error messages for class instance errors (28ac9d3)

[git at git.haskell.org]

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

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/28ac9d31bcabeb44496c0e1750563f3091c62da9/ghc

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

commit 28ac9d31bcabeb44496c0e1750563f3091c62da9
Author: Simon Peyton Jones <simonpj at microsoft.com>
Date:   Wed Sep 2 14:05:36 2015 +0200

    Improve the error messages for class instance errors
    
    Summary: See Note [Displaying potential instances].
    
    Reviewers: austin
    
    Subscribers: KaneTW, thomie
    
    Differential Revision: https://phabricator.haskell.org/D1176


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

28ac9d31bcabeb44496c0e1750563f3091c62da9
 compiler/main/DynFlags.hs                          |   2 +
 compiler/typecheck/TcErrors.hs                     | 106 +++++++++++++++++----
 docs/users_guide/flags.xml                         |   6 ++
 docs/users_guide/using.xml                         |  10 ++
 .../tests/annotations/should_fail/annfail10.stderr |  10 +-
 .../tests/ghci.debugger/scripts/break006.stderr    |  10 +-
 .../tests/ghci.debugger/scripts/print019.stderr    |   5 +-
 testsuite/tests/ghci/scripts/Defer02.stderr        |  75 ++++++++-------
 .../tests/indexed-types/should_fail/T4485.stderr   |   6 +-
 .../should_fail/overloadedlistsfail01.stderr       |  14 +--
 testsuite/tests/quotes/TH_localname.stderr         |   3 +-
 testsuite/tests/rebindable/rebindable6.stderr      |   6 +-
 testsuite/tests/rename/should_fail/mc14.stderr     |   3 +-
 .../tests/typecheck/should_compile/holes2.stderr   |   3 +-
 testsuite/tests/typecheck/should_fail/T4921.stderr |   8 +-
 testsuite/tests/typecheck/should_fail/T5095.stderr |  78 +--------------
 testsuite/tests/typecheck/should_fail/T5858.stderr |   4 +-
 testsuite/tests/typecheck/should_fail/T7857.stderr |   4 +-
 .../tests/typecheck/should_fail/tcfail008.stderr   |   7 +-
 .../tests/typecheck/should_fail/tcfail040.stderr   |   4 +-
 .../tests/typecheck/should_fail/tcfail043.stderr   |   8 +-
 .../tests/typecheck/should_fail/tcfail072.stderr   |  12 ++-
 .../tests/typecheck/should_fail/tcfail128.stderr   |   4 +-
 .../tests/typecheck/should_fail/tcfail133.stderr   |   9 +-
 .../tests/typecheck/should_fail/tcfail181.stderr   |   5 +-
 25 files changed, 219 insertions(+), 183 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 28ac9d31bcabeb44496c0e1750563f3091c62da9