[commit: ghc] ghc-8.0: Check generic-default method for ambiguity (8540c65)

[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/8540c65a61e92e9c4bedb934c241e8e3eaa67047/ghc

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

commit 8540c65a61e92e9c4bedb934c241e8e3eaa67047
Author: Simon Peyton Jones <simonpj at microsoft.com>
Date:   Fri Jul 1 22:33:33 2016 +0100

    Check generic-default method for ambiguity
    
    Fixes Trac #7497 and #12151.   In some earlier upheaval I introduced
    a bug in the ambiguity check for genreric-default method.
    
    This patch fixes it.  But in fixing it I realised that the
    sourc-location of any such error message was bogus, so I fixed
    that too, which involved a slightly wider change; see the
    comments with TcMethInfo.
    
    (cherry picked from commit 85aa6ef09346e841abf4e089b24c7f783286cd74)


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8540c65a61e92e9c4bedb934c241e8e3eaa67047
 compiler/iface/BuildTyCl.hs                        | 47 +++++++++++++++++-----
 compiler/iface/TcIface.hs                          |  4 +-
 compiler/typecheck/TcClassDcl.hs                   |  8 ++--
 compiler/typecheck/TcTyClsDecls.hs                 | 16 +++++---
 compiler/typecheck/TcTyDecls.hs                    | 19 ++++-----
 compiler/types/Class.hs                            | 10 +----
 compiler/vectorise/Vectorise/Type/TyConDecl.hs     |  9 +++++
 testsuite/tests/typecheck/should_fail/T12151.hs    | 10 +++++
 .../tests/typecheck/should_fail/T12151.stderr      | 12 ++++++
 testsuite/tests/typecheck/should_fail/T7437.hs     | 15 +++++++
 testsuite/tests/typecheck/should_fail/T7437.stderr | 12 ++++++
 testsuite/tests/typecheck/should_fail/all.T        |  2 +
 12 files changed, 125 insertions(+), 39 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 8540c65a61e92e9c4bedb934c241e8e3eaa67047