reference to comparing is ambiguous & inference loop

[Henry Jen]

On Jun 12, 2013, at 12:20 PM, Boaz Nahum <boaznahum at gmail.com> wrote:

> 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 ?
> 

Compiler is looking to improve this, add a cast for now.

(ToDoubleFunction<TestResult>) TestResult::getRank.

Cheers,
Henry