[m-rev.] for review: constrained polymorphic insts

[Fergus Henderson]

On 07-Mar-2002, David Overton <dmo at cs.mu.OZ.AU> wrote:
> On Thu, Feb 21, 2002 at 06:40:38PM +1100, Fergus Henderson wrote:
> > The line `Inst = Inst0' throws away information; the compiler knows that
> > Inst is at least as ground as InstVar, and is a subtype of InstVar,
> > but these facts are not recorded in the inst returned.
> > Is this going to cause trouble?
> > Maybe there should be an XXX comment there.
> 
> I don't think this is likely to be a problem in practice because
> 
> 	a) I don't think it's likely to occur very often with the
> 	   sorts of things I'm expecting this feature to be used for; and
> 	b) Even if the information is retained somehow, I can't see what
> 	   sort of situations it would actually be useful for.

OK.  But there should still be an XXX comment, IMHO.

> 	   Can you think of an example?

Not off-hand.

-- 
Fergus Henderson <fjh at cs.mu.oz.au>  |  "I have always known that the pursuit
The University of Melbourne         |  of excellence is a lethal habit"
WWW: <http://www.cs.mu.oz.au/~fjh>  |     -- the last words of T. S. Garp.
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