function-lookup: lookup of function in another module

[ChristianGruen]

The following code should return true:

(: x.xq :)
import module namespace a = "A" at "a.xqm";
import module namespace b = "B" at "b.xqm";

exists(a:lookup())

(: a.xqm :)
module namespace a = "A";

declare function a:lookup() {
  function-lookup(QName('B', 'test'), 0)
};

(: b.xqm :)
module namespace b = "B";

declare function b:test() {};

Caused by 4090444