[commit: ghc] master: Fix #14167 by using isGadtSyntaxTyCon in more places (8e4229a)

[git at git.haskell.org]

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

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/8e4229ab3dc3e1717ad557ef00f3518da6b5c523/ghc

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commit 8e4229ab3dc3e1717ad557ef00f3518da6b5c523
Author: Ryan Scott <ryan.gl.scott at gmail.com>
Date:   Sat Sep 2 15:33:25 2017 -0400

    Fix #14167 by using isGadtSyntaxTyCon in more places
    
    Summary:
    Two places in GHC effectively attempt to //guess// whether a data type
    was declared using GADT syntax:
    
    1. When reifying a data type in Template Haskell
    2. When pretty-printing a data type (e.g., via `:info` in GHCi)
    
    But there's no need for heuristics here, since we have a 100% accurate way to
    determine whether a data type was declared using GADT syntax: the
    `isGadtSyntaxTyCon` function! By simply using that as the metric, we obtain
    far more accurate TH reification and pretty-printing results.
    
    This is technically a breaking change, since Template Haskell reification will
    now reify some data type constructors as `(Rec)GadtC` that it didn't before,
    and some data type constructors that were previously reified as `(Rec)GadtC`
    will no longer be reified as such. But it's a very understandable breaking
    change, since the previous behavior was simply incorrect.
    
    Test Plan: ./validate
    
    Reviewers: simonpj, goldfire, austin, bgamari
    
    Reviewed By: simonpj
    
    Subscribers: rwbarton, thomie
    
    GHC Trac Issues: #14167
    
    Differential Revision: https://phabricator.haskell.org/D3901


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8e4229ab3dc3e1717ad557ef00f3518da6b5c523
 compiler/iface/IfaceSyn.hs                         | 49 ++++++++++------------
 compiler/iface/IfaceType.hs                        |  9 +++-
 compiler/typecheck/TcSplice.hs                     | 34 ++-------------
 docs/users_guide/8.4.1-notes.rst                   |  6 +++
 testsuite/tests/ghci/scripts/T7730.stdout          |  3 +-
 testsuite/tests/ghci/scripts/T7873.stdout          |  4 +-
 testsuite/tests/ghci/scripts/T9181.stdout          | 30 +++++++------
 testsuite/tests/ghci/scripts/ghci030.stdout        |  8 +---
 .../tests/rename/should_fail/rnfail055.stderr      |  6 +--
 testsuite/tests/th/T4188.stderr                    | 11 ++---
 testsuite/tests/typecheck/should_fail/T3468.stderr |  3 +-
 11 files changed, 70 insertions(+), 93 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 8e4229ab3dc3e1717ad557ef00f3518da6b5c523