patch applied (ghc): Introducing a datatype for WorkLists that properly prioritizes equalities.

[Simon Peyton Jones]

Thu Mar 31 03:26:34 PDT 2011  dimitris at microsoft.com
  * Introducing a datatype for WorkLists that properly prioritizes equalities.
  
  We were not prioritizing the interaction of equalities in the worklist, because
  pre-canonicalization solved the constraints one by one, in their arrival order.
  This patch fixes this, so it's a generally useful improvement, mainly for
  efficiency. It makes #4981 go away, although it's not a definite answer to the
  cause of the problem. See discussion on Trac.
  

    M ./compiler/typecheck/TcCanonical.lhs -34 +47
    M ./compiler/typecheck/TcInteract.lhs -46 +36
    M ./compiler/typecheck/TcSMonad.lhs +54

View patch online:
http://darcs.haskell.org/cgi-bin/darcsweb.cgi?r=ghc;a=darcs_commitdiff;h=20110331102634-da291-e72477ac46afcca8d278b66c90680d0ced85899a.gz