public void visit_getfield(final Instruction inst) {
		final MemberRef field = (MemberRef) inst.operand();
		final Type type = field.nameAndType().type();
		final Expr obj = stack.pop(Type.OBJECT);
		final Expr check = new ZeroCheckExpr(obj, obj.type());
		final Expr top = new FieldExpr(check, field, type);
		stack.push(top);
	}