patch applied (ghc): Lint should check for duplicate top-level bindings with same qualified name

[Ian Lynagh]

On Mon, Oct 25, 2010 at 07:24:00AM +0000, Simon Peyton-Jones wrote:
> Now that *is* strange. The change only affects Lint, ant it affects Lint only by gathering the top-level names (done already) and checking that "M.x" doesn't occur twice (for any M, x). I would not have expected that to double space usage!
> 
> Might you investigate a bit more with your profiled compiler?

Aha, top of the profile:

findDupsEq                     ListSetOps            14.1   35.6
lintCoreBindings               CoreLint               7.3    0.1

I imagine the quadratic behaviour of findDupsEq is the problem, with
most of the lintCoreBindings time being spent in eq_ext. So I guess we
want a findDupsOrd, which sorts first?


Thanks
Ian