[commit: ghc] master: Fix instantiation of pattern synonyms (6b77914)

[git at git.haskell.org]

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

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/6b77914cd37b697354611bcd87897885c1e5b4a6/ghc

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commit 6b77914cd37b697354611bcd87897885c1e5b4a6
Author: Simon Peyton Jones <simonpj at microsoft.com>
Date:   Thu Jul 27 14:45:54 2017 +0100

    Fix instantiation of pattern synonyms
    
    In Check.hs (pattern match ovelap checking) we to figure out the
    instantiation of a pattern synonym from the type of the pattern. We
    were doing this utterly wrongly.  Trac #13768 demonstrated this
    bogosity.
    
    The fix is easy; and is described in PatSyn.hs
      Note [Pattern synonym result type]


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6b77914cd37b697354611bcd87897885c1e5b4a6
 compiler/basicTypes/PatSyn.hs                   | 54 +++++++++++++++++++++----
 compiler/deSugar/Check.hs                       | 17 ++++----
 testsuite/tests/patsyn/should_compile/T13768.hs | 33 +++++++++++++++
 testsuite/tests/patsyn/should_compile/all.T     |  1 +
 4 files changed, 89 insertions(+), 16 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 6b77914cd37b697354611bcd87897885c1e5b4a6