[commit: ghc] master: Fix #14369 by making injectivity warnings finer-grained (8846a7f)

[git at git.haskell.org]

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

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/8846a7fdcf2060dd37e66b4d1f89bd8fdfad4620/ghc

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

commit 8846a7fdcf2060dd37e66b4d1f89bd8fdfad4620
Author: Ryan Scott <ryan.gl.scott at gmail.com>
Date:   Thu Oct 19 10:21:28 2017 -0400

    Fix #14369 by making injectivity warnings finer-grained
    
    Summary:
    Previously, GHC would always raise the possibility that a
    type family might not be injective in certain error messages, even if
    that type family actually //was// injective. Fix this by actually
    checking for a type family's lack of injectivity before emitting
    such an error message.
    
    Test Plan: ./validate
    
    Reviewers: goldfire, austin, bgamari, simonpj
    
    Reviewed By: simonpj
    
    Subscribers: simonpj, rwbarton, thomie
    
    GHC Trac Issues: #14369
    
    Differential Revision: https://phabricator.haskell.org/D4106


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

8846a7fdcf2060dd37e66b4d1f89bd8fdfad4620
 compiler/typecheck/TcErrors.hs                     |  3 ++-
 .../indexed-types/should_fail/NoMatchErr.stderr    |  5 ++--
 .../tests/indexed-types/should_fail/T14369.hs      | 27 ++++++++++++++++++++++
 .../tests/indexed-types/should_fail/T14369.stderr  |  9 ++++++++
 .../tests/indexed-types/should_fail/T1897b.stderr  |  2 +-
 .../tests/indexed-types/should_fail/T1900.stderr   |  2 +-
 .../tests/indexed-types/should_fail/T2544.stderr   |  4 ++--
 .../tests/indexed-types/should_fail/T2664.stderr   |  2 +-
 .../tests/indexed-types/should_fail/T4099.stderr   |  2 +-
 .../tests/indexed-types/should_fail/T4179.stderr   |  2 +-
 .../tests/indexed-types/should_fail/T9036.stderr   |  2 +-
 .../tests/indexed-types/should_fail/T9171.stderr   |  2 +-
 testsuite/tests/indexed-types/should_fail/all.T    |  1 +
 testsuite/tests/typecheck/should_fail/T5853.stderr | 16 ++++---------
 testsuite/tests/typecheck/should_fail/T8030.stderr |  4 ++--
 testsuite/tests/typecheck/should_fail/T8034.stderr |  2 +-
 16 files changed, 58 insertions(+), 27 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 8846a7fdcf2060dd37e66b4d1f89bd8fdfad4620