[commit: ghc] ghc-8.0: Fix #11254. (4c53ab2)

[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/4c53ab2a108a749ae45657c73cda233b528fb029/ghc

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commit 4c53ab2a108a749ae45657c73cda233b528fb029
Author: Richard Eisenberg <eir at cis.upenn.edu>
Date:   Mon Jan 11 14:47:49 2016 -0500

    Fix #11254.
    
    This moves the call to tcSubType into the context of the
    checkInstConstraints call, allowing the deferred type error
    somewhere to hang its hat.
    
    (cherry picked from commit 39ea4b4b19ea65d05f0d946084b316d5f5d2e675)


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4c53ab2a108a749ae45657c73cda233b528fb029
 compiler/typecheck/TcInstDcls.hs                   | 113 +++++++++++----------
 .../tests/typecheck/should_compile/T11254.stderr   |  25 +++++
 testsuite/tests/typecheck/should_compile/all.T     |   2 +-
 3 files changed, 88 insertions(+), 52 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 4c53ab2a108a749ae45657c73cda233b528fb029