Bug in deep copy

[Thomas Charles CONWAY]

The following program, if built in GRADE=asm_fast, aborts in deep_copy.
(Note that at 11am today, I still haven't committed the stuff necessary
to build this test case, but I will do so shortly.)

-- 
Thomas Conway               				      conway at cs.mu.oz.au
AD DEUM ET VINUM	  "Thomas Tallis is dead, and muic dies." - William Byrd

:- module x.

:- interface.

:- import_module io.

:- pred main(io__state::di, io__state::uo) is det.

:- implementation.

:- import_module int, std_util, list, term, varset.

main -->
	{ Lambda = lambda([X::out] is nondet,
	(
		varset__init(Varset0),
		varset__new_vars(Varset0, 10, Vars, _),
		list__member(X, Vars)
	)) },
	{ solutions(Lambda, List) },
	io__write(List),
	io__write_string("\n").