[commit: ghc] type-nats: Add the improvement step, for more direct evaluation. (9efd621)

Repository : ssh://darcs.haskell.org//srv/darcs/ghc

On branch  : type-nats

http://hackage.haskell.org/trac/ghc/changeset/9efd6210c653bcc990476e31530865702b0728d0

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

commit 9efd6210c653bcc990476e31530865702b0728d0
Author: Iavor S. Diatchki <[email protected]>
Date:   Fri Dec 28 11:41:03 2012 -0800

    Add the improvement step, for more direct evaluation.
    
    Previously we relied on derived constraints to achieve the same, but
    this is (i) more direct, (ii) using derived constraints delayed evaluation
    too much, so we ended up interacting constraints that can be solved with
    existing assumptions, which may lead to non-termination because it
    generates infinitely many useless constraints.

 compiler/typecheck/TcTypeNats.hs |  142 ++++++++++++++++++++++++++++++++++----
 1 files changed, 129 insertions(+), 13 deletions(-)


Diff suppressed because of size. To see it, use:

    git show 9efd6210c653bcc990476e31530865702b0728d0