[commit: ghc] ghc-8.2: Fix unused-given-constraint bug (776a660)

[git at git.haskell.org]

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

On branch  : ghc-8.2
Link       : http://ghc.haskell.org/trac/ghc/changeset/776a660a66404408a36b92cb84397815d283b6a5/ghc

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

commit 776a660a66404408a36b92cb84397815d283b6a5
Author: Simon Peyton Jones <simonpj at microsoft.com>
Date:   Tue Sep 19 12:37:13 2017 +0100

    Fix unused-given-constraint bug
    
    This bug was shown up by Trac #14237.  It turned out
    to be an outright error in TcSimplify.neededEvVars,
    easily fixed.
    
    I improved the comments.
    
    (cherry picked from commit 1db0f4a48e9db5e85782e32f074cc83bbc145cb7)


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

776a660a66404408a36b92cb84397815d283b6a5
 compiler/typecheck/TcEvidence.hs                   |    2 +
 compiler/typecheck/TcSimplify.hs                   |   15 +-
 .../tests/indexed-types/should_compile/T14237.hs   |    7 +
 testsuite/tests/indexed-types/should_compile/all.T |    1 +
 .../partial-sigs/should_compile/SuperCls.stderr    |    2 +-
 .../partial-sigs/should_compile/T11016.stderr      |    2 +-
 .../partial-sigs/should_compile/T12845.stderr      |    2 +-
 .../partial-sigs/should_compile/T14217.stderr      | 4869 +++++++++++++++++++-
 .../tests/partial-sigs/should_fail/T12634.stderr   |    2 +-
 9 files changed, 4814 insertions(+), 88 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 776a660a66404408a36b92cb84397815d283b6a5