[m-dev.] for review: fix polymorphism bug

[Fergus Henderson]

On 07-Feb-2001, David Glen JEFFERY <dgj at cs.mu.OZ.AU> wrote:
> Fix a bug reported by petdr on October 30th last year.
> 
> compiler/polymorphism.m:
> 	When looking up the variable which contains a typeclass info for
> 	a particular constraint to be passed to a call, handle the case where 
> 	there is *no* variable for such a constraint. This occurs in the case
> 	where the producer of the variable occurs later on in the goal (but
> 	will get re-ordered by the mode checker). The solution is to just
> 	create a variable for the typeclass info, and whenever creating
> 	a `head' variable to hold a constraint being produced by a call,
> 	check first whether there is already a variable allocated for that
> 	constraint.

Could you please post a diff of that file with `-b'?

Also, I think the section on "Known Bugs" in the existential types
section of the language reference manual can be deleted now.

-- 
Fergus Henderson <fjh at cs.mu.oz.au>  |  "I have always known that the pursuit
                                    |  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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