Cast in front of conditional seems to be invalid in javac

[Roel Spilker]

By the way, ecj errors "The target type of this expression must be a
functional interface"



On Thu, May 8, 2014 at 12:28 AM, Roel Spilker <r.spilker at gmail.com> wrote:

> Hi all,
>
> Introducing a type cast just in front of a conditional (?:) seems not to
> be valid using javac 1.8.0_05
>
> The reason to add a cast might be to create a Runnable that is also
> Serializable:
>
> Runnable r = (Runnable & Serializable) ()->{};
>
> So I would expect adding a cast to any expression would be okay.
>
> Is this a bug? If so, how/where should I register it?
>
> Roel
>
> ==== file TestCastInFrontOfConditional.java ====
>
> public class TestCastInFrontOfConditional {
> {
>  Runnable works = (Boolean.TRUE ? () -> {} : () -> {});
> Runnable alsoWorks = Boolean.TRUE ? (Runnable) () -> {} : (Runnable) () ->
> {};
>  Runnable fails = (Runnable) (Boolean.TRUE ? () -> {} : () -> {});
> }
> }
>
> ==== output ====
>
> TestCastInFrontOfConditional.java:6: error: lambda expression not expected
> here
>                 Runnable fails = (Runnable) (Boolean.TRUE ? () -> {} : ()
> -> {});
>                                                             ^
> TestCastInFrontOfConditional.java:6: error: lambda expression not expected
> here
>                 Runnable fails = (Runnable) (Boolean.TRUE ? () -> {} : ()
> -> {});
>                                                                        ^
> 2 errors
>
> ==== end =====
>