Assertion failed with collection delete

[Federico Cavalieri]

Trying to delete a collection twice during the same snapshot causes an assertion to fail.

import module namespace ddl = "http://www.zorba-xquery.com/modules/store/dynamic/collections/ddl";
import module namespace dml = "http://www.zorba-xquery.com/modules/store/dynamic/collections/dml";

ddl:create(xs:QName("ddl:coll"),(<a/>,<b/>));
(
ddl:delete(xs:QName("ddl:coll")),
ddl:delete(xs:QName("ddl:coll"))
);