function parse(parse) local x = [[<x xmlns:a="b"> <y xmlns:a="c"> <!-- this overwrites 'a' --> <a:z/> </y> <a:z/> <!-- prefix 'a' is nil here, but should be 'b' --> </x> ]] local stanza = parse(x); assert_equal(stanza.tags[2].attr.xmlns, "b"); end