[m-dev.] equivalence type expansion

[Fergus Henderson]

On 23-Oct-2003, Simon Taylor <stayl at cs.mu.OZ.AU> wrote:
> equiv_type__replace_in_type currently modifies the tvarset
> of the item being expanded.  I'm not sure why.  Shouldn't
> all type variables occurring in the body of the equivalence
> type be substituted away?

Currently I think that is the case, yes.

But in future we might want to allow the cases which don't satisfy that,
e.g. for first-class polymorphism:

	:- type foo == (all [X] pred(X, int)).

-- 
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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