[commit: ghc] master: Normalise EmptyCase types using the constraint solver (e72d788)

[git at git.haskell.org]

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

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/e72d7880b940881d38b8c3db9a00d5d007b1458f/ghc

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commit e72d7880b940881d38b8c3db9a00d5d007b1458f
Author: Ryan Scott <ryan.gl.scott at gmail.com>
Date:   Fri Sep 28 14:22:48 2018 +0200

    Normalise EmptyCase types using the constraint solver
    
    Summary:
    Certain `EmptyCase` expressions were mistakently producing
    warnings since their types did not have as many type families reduced
    as they could have. The most direct way to fix this is to normalise
    these types initially using the constraint solver to solve for any
    local equalities that may be in scope.
    
    Test Plan: make test TEST=T14813
    
    Reviewers: simonpj, bgamari, goldfire
    
    Reviewed By: simonpj
    
    Subscribers: rwbarton, carter
    
    GHC Trac Issues: #14813
    
    Differential Revision: https://phabricator.haskell.org/D5094


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

e72d7880b940881d38b8c3db9a00d5d007b1458f
 compiler/deSugar/Check.hs                          | 89 +++++++++++++++-------
 compiler/typecheck/TcExpr.hs                       |  7 +-
 compiler/typecheck/TcMType.hs                      | 12 ++-
 compiler/typecheck/TcSimplify.hs                   | 53 ++++++++++++-
 compiler/utils/MonadUtils.hs                       |  7 ++
 testsuite/tests/pmcheck/should_compile/T14813.hs   | 28 +++++++
 testsuite/tests/pmcheck/should_compile/T15305.hs   |  5 --
 .../tests/pmcheck/should_compile/T15305.stderr     |  2 +-
 testsuite/tests/pmcheck/should_compile/all.T       |  2 +
 9 files changed, 162 insertions(+), 43 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 e72d7880b940881d38b8c3db9a00d5d007b1458f