reference to comparing is ambiguous & inference loop

[Boaz Nahum]

I built lambda/lambda today



class TestResult {
        public double getRank() { ... }
}

List<TestResult> results = ..
results.sort(Comparator.comparing(TestResult::getRank));

Got this error:
java: reference to comparing is ambiguous
  both method <T>comparing(java.util.function.ToLongFunction<? super T>) in
java.util.Comparator and method
<T>comparing(java.util.function.ToDoubleFunction<? super T>) in
java.util.Comparator match

java: incompatible types: Cannot instantiate inference variables T because
of an inference loop


Any way to get around this ?

Thanks
Boaz