patch applied (ghc): Gather constraints in program order

[Simon Peyton Jones]

Fri Nov 24 00:40:11 PST 2006  simonpj at microsoft.com
  * Gather constraints in program order
  
  Provoked by a suggestion of Simon's, this patch makes a half-hearted attempt
  to gather constraints in program order, so that we tend to report an error
  at its first occurrence, rather than its last.  Examples:
  	mdofail001, tcfail015
  
  It's "half-hearted" because generally-speaking the typechecker does not
  guaranteed to keep constraints in order; it treats them as a set.  Nevertheless
  this very small change seems to improve matters, so it seems a good one.
  

    M ./compiler/typecheck/TcRnTypes.lhs -1 +11
    M ./compiler/typecheck/TcSimplify.lhs -3