[commit: ghc] wip/rwbarton-D2992: Check local type family instances against all imported ones (28da0a9)

[git at git.haskell.org]

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

On branch  : wip/rwbarton-D2992
Link       : http://ghc.haskell.org/trac/ghc/changeset/28da0a94ea7640a94565500ee66093816f2cfe7f/ghc

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

commit 28da0a94ea7640a94565500ee66093816f2cfe7f
Author: Reid Barton <rwbarton at gmail.com>
Date:   Wed Feb 8 17:55:31 2017 -0500

    Check local type family instances against all imported ones
    
    Summary:
    We previously checked type family instance declarations
    in a module for consistency with all instances that we happened
    to have read into the EPS or HPT. It was possible to arrange that
    an imported type family instance (used by an imported function)
    was in a module whose interface file was never read during
    compilation; then we wouldn't check consistency of local instances
    with this imported instance and as a result type safety was lost.
    
    With this patch, we still check consistency of local type family
    instances with all type family instances that we have loaded; but
    we make sure to load the interface files of all our imports that
    define family instances first. More selective consistency checking
    is left to #13102.
    
    On the other hand, we can now safely assume when we import a module
    that it has been checked for consistency with its imports. So we
    can save checking in checkFamInstConsistency, and overall we should
    have less work to do now.
    
    This patch also adds a note describing the Plan for ensuring type
    family consistency.
    
    Test Plan: Two new tests added; harbormaster
    
    Reviewers: bgamari, austin, simonpj
    
    Reviewed By: simonpj
    
    Subscribers: thomie
    
    Differential Revision: https://phabricator.haskell.org/D2992


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

28da0a94ea7640a94565500ee66093816f2cfe7f
 compiler/basicTypes/Name.hs                        |  12 +-
 compiler/main/HscTypes.hs                          |   7 +-
 compiler/typecheck/FamInst.hs                      | 151 +++++++++++++++++++--
 compiler/typecheck/TcRnDriver.hs                   |  16 ++-
 testsuite/tests/ghci/scripts/T4175.stdout          |   2 +-
 .../indexed-types/should_compile/T13092b/Makefile  |  10 ++
 .../should_compile/T13092b/T13092b_1.hs            |   7 +
 .../should_compile/T13092b/T13092b_2.hs            |   8 ++
 .../indexed-types/should_compile/T13092b/all.T     |   5 +
 .../tests/indexed-types/should_fail/T13092/A.hs    |   3 +
 .../tests/indexed-types/should_fail/T13092/B.hs    |   5 +
 .../tests/indexed-types/should_fail/T13092/C.hs    |   6 +
 .../tests/indexed-types/should_fail/T13092/Main.hs |  18 +++
 .../indexed-types/should_fail/T13092/Makefile      |   9 ++
 .../indexed-types/should_fail/T13092/T13092.stderr |   5 +
 .../tests/indexed-types/should_fail/T13092/all.T   |   5 +
 .../indexed-types/should_fail/T13092c/Makefile     |  12 ++
 .../should_fail/T13092c/T13092c.stderr             |   5 +
 .../indexed-types/should_fail/T13092c/T13092c_1.hs |   6 +
 .../indexed-types/should_fail/T13092c/T13092c_2.hs |   8 ++
 .../indexed-types/should_fail/T13092c/T13092c_3.hs |   5 +
 .../indexed-types/should_fail/T13092c/T13092c_4.hs |   7 +
 .../tests/indexed-types/should_fail/T13092c/all.T  |   8 ++
 23 files changed, 301 insertions(+), 19 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 28da0a94ea7640a94565500ee66093816f2cfe7f