[commit: ghc] ghc-8.0: Fix #11407. (d23e9ef)

[git at git.haskell.org]

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

On branch  : ghc-8.0
Link       : http://ghc.haskell.org/trac/ghc/changeset/d23e9effcd23c9522e97eedc839c4ab819f4c1fb/ghc

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

commit d23e9effcd23c9522e97eedc839c4ab819f4c1fb
Author: Richard Eisenberg <eir at cis.upenn.edu>
Date:   Mon Feb 22 12:54:56 2016 -0500

    Fix #11407.
    
    This removes the `defer_me` check that was in checkTauTvUpdate
    and uses only a type family check instead. The old defer_me check
    repeated work done by fast_check in occurCheckExpand.
    
    There is also some error message improvement, necessitated by
    the terrible error message that the test case produced, even when
    it didn't consume all of memory.
    
    test case: dependent/should_fail/T11407
    
    [skip ci]
    
    (cherry picked from commit e9bf7bb5cc9fb3f87dd05111aa23da76b86a8967)


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

d23e9effcd23c9522e97eedc839c4ab819f4c1fb
 compiler/typecheck/TcErrors.hs                     | 15 +++++++-
 compiler/typecheck/TcUnify.hs                      | 45 +++++-----------------
 compiler/types/TyCoRep.hs                          | 25 ++++++------
 compiler/types/Type.hs                             |  9 ++++-
 compiler/types/Type.hs-boot                        |  5 +++
 testsuite/tests/dependent/should_fail/T11407.hs    | 10 +++++
 .../tests/dependent/should_fail/T11407.stderr      |  8 ++++
 testsuite/tests/dependent/should_fail/all.T        |  1 +
 8 files changed, 70 insertions(+), 48 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 d23e9effcd23c9522e97eedc839c4ab819f4c1fb