[commit: ghc] ghc-8.2: Fix #13333 by fixing the covar's type in ctEvCoercion (51d80c3)

[git at git.haskell.org]

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

On branch  : ghc-8.2
Link       : http://ghc.haskell.org/trac/ghc/changeset/51d80c3b2c4c7d8f1f5dbcee39864c2de49143c7/ghc

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

commit 51d80c3b2c4c7d8f1f5dbcee39864c2de49143c7
Author: Richard Eisenberg <rae at cs.brynmawr.edu>
Date:   Sun Apr 23 10:24:30 2017 -0400

    Fix #13333 by fixing the covar's type in ctEvCoercion
    
    The change is noted in Note [Given in ctEvCoercion]. This patch
    also adds a bit more commentary to TcFlatten, documenting some
    key invariants of the flattening algorithm. While in the area,
    I also removed some stale commentary from TcCanonical.
    
    (cherry picked from commit 09bf135ace55ce2572bf4168124d631e386c64bb)


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

51d80c3b2c4c7d8f1f5dbcee39864c2de49143c7
 compiler/typecheck/TcCanonical.hs                  | 98 ++++------------------
 compiler/typecheck/TcFlatten.hs                    | 88 +++++++++++++++++--
 compiler/typecheck/TcRnTypes.hs                    | 21 +++--
 compiler/typecheck/TcSMonad.hs                     |  1 +
 testsuite/tests/typecheck/should_compile/T13333.hs | 28 +++++++
 testsuite/tests/typecheck/should_compile/all.T     |  1 +
 6 files changed, 143 insertions(+), 94 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 51d80c3b2c4c7d8f1f5dbcee39864c2de49143c7