[project @ 2002-02-13 14:14:09 by simonpj]

[project @ 2002-02-13 14:14:09 by simonpj]
------------------------------
	Fix the "occurs check" so that
	it handles unifying a type variable
	with a type scheme
	------------------------------

It's illegal to unify a type variable with a type scheme:

	a  :=:  (forall b. b->b) -> Int

But I wasn't detecting that properly.  Now, the same code
that does the occurs check also looks for foralls.