please include function iteratorFromFunction_withEndMarker. static IterableIterator iteratorFromFunction_withEndMarker_f0(final F0 f) { class IFF2 extends IterableIterator { A a; bool have, done; public bool hasNext() { getNext(); ret !done; } public A next() { getNext(); if (done) fail(); A _a = a; a = null; have = false; ret _a; } void getNext() { if (done || have) ret; a = f.get(); set have; if (a == iteratorFromFunction_endMarker) done = true; } }; ret new IFF2; }