[commit: ghc] wip/ghc-8.8-merges: Fix #16188 (52a5400)

[git at git.haskell.org]

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

On branch  : wip/ghc-8.8-merges
Link       : http://ghc.haskell.org/trac/ghc/changeset/52a5400baefb6425438356e3c74856352324f01b/ghc

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

commit 52a5400baefb6425438356e3c74856352324f01b
Author: Richard Eisenberg <rae at cs.brynmawr.edu>
Date:   Thu Jan 17 17:17:02 2019 -0700

    Fix #16188
    
    There was an awful lot of zipping going on in
    canDecomposableTyConAppOK, and one of the lists being zipped
    was too short, causing the result to be too short. Easily
    fixed.
    
    Also fixes #16204 and #16225
    
    test case: typecheck/should_compile/T16188
               typecheck/should_compile/T16204[ab]
               typecheck/should_fail/T16204c
               typecheck/should_compile/T16225
    
    (cherry picked from commit 4a4ae70f09009c5d32696445a06eacb273f364b5)


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

52a5400baefb6425438356e3c74856352324f01b
 compiler/typecheck/TcCanonical.hs                  | 40 +++++++++------
 compiler/types/Coercion.hs                         |  3 ++
 .../tests/indexed-types/should_fail/T2544.stderr   | 12 -----
 testsuite/tests/polykinds/T14172.stderr            | 15 ------
 testsuite/tests/typecheck/should_compile/T16188.hs | 48 ++++++++++++++++++
 .../tests/typecheck/should_compile/T16204a.hs      | 58 ++++++++++++++++++++++
 .../tests/typecheck/should_compile/T16204b.hs      | 58 ++++++++++++++++++++++
 testsuite/tests/typecheck/should_compile/T16225.hs | 25 ++++++++++
 testsuite/tests/typecheck/should_compile/all.T     |  4 ++
 testsuite/tests/typecheck/should_fail/T16204c.hs   | 16 ++++++
 .../tests/typecheck/should_fail/T16204c.stderr     | 12 +++++
 testsuite/tests/typecheck/should_fail/all.T        |  1 +
 12 files changed, 251 insertions(+), 41 deletions(-)

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