Why is this legal?

[abad via Digitalmars-d-learn]

On Wednesday, 29 March 2017 at 11:06:55 UTC, Petar Kirov 
[ZombineDev] wrote:
> On Wednesday, 29 March 2017 at 10:12:08 UTC, abad wrote:
>> On Wednesday, 29 March 2017 at 10:08:02 UTC, abad wrote:
>>> Related question, it seems that final methods are allowed in 
>>> interfaces. Obviously you can't implement them anywhere, so 
>>> is this also on purpose and on what rationale? :)
>>
>> So actually it's just a question of not catching this mistake 
>> early, because obviously compilation will fail when any class 
>> tries to implement the interface so the end result is ok.
>>
>> Maybe it _could_ just disallow final methods altogether to 
>> catch the errors earlier. But very minor detail overall.
>
> The idea between `final` functions in interfaces is to provide 
> a default non-overridable implementation. For example:
>

Yes, does make sense. I was looking this from Java 7 perspective 
where interfaces can't implement any methods.