[commit: ghc] ghc-8.2: Handle type-lets better (c7d8099)

[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/c7d809928d87a7a54bcea6badea3e7ee5f7181db/ghc

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

commit c7d809928d87a7a54bcea6badea3e7ee5f7181db
Author: Simon Peyton Jones <simonpj at microsoft.com>
Date:   Wed May 17 09:44:46 2017 +0100

    Handle type-lets better
    
    Core allows non-recursive type-lets, thus
    
       let a = TYPE ty in ...
    
    They are substituted away very quickly, but it's convenient for
    some passes to produce them (rather than to have to substitute
    immediately).
    
    Trac #13708 tried the effect of not running the simplifer at all
    (a rather bizarre thing to do, but still).  That showed that some
    passes crashed because they always treated a let-bounder binder
    as an Id.  This patch adds some easy fixes.
    
    (cherry picked from commit d6461f9684f6f758320a5e5afbf0634fcc2996a5)


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

c7d809928d87a7a54bcea6badea3e7ee5f7181db
 compiler/basicTypes/Id.hs                          |  6 +++--
 compiler/basicTypes/Var.hs                         |  4 ++--
 compiler/coreSyn/CoreFVs.hs                        | 27 ++++++++--------------
 compiler/simplCore/CSE.hs                          | 14 +++++++----
 compiler/simplCore/FloatIn.hs                      |  4 ++--
 testsuite/tests/simplCore/should_compile/T13708.hs | 11 +++++++++
 testsuite/tests/simplCore/should_compile/all.T     |  1 +
 7 files changed, 39 insertions(+), 28 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 c7d809928d87a7a54bcea6badea3e7ee5f7181db