const/immutable on delegates

[Tofu Ninja via Digitalmars-d]

On Friday, 3 July 2015 at 02:13:39 UTC, Timon Gehr wrote:
> On 07/03/2015 02:26 AM, Tofu Ninja wrote:
>> So this idea spawned from a thread I posted over in learn[1]. 
>> Similar to
>> how you can mark a member function as const or immutable, 
>> there should
>> be a way to mark a delegate as const or immutable.
>>...
>>
>> Thoughts?
>>
>
> https://issues.dlang.org/show_bug.cgi?id=14745

-_-

Is that documented anywhere? I can't find anything in the docs 
that says nested functions can have immutable, const, shared, 
inout attached to them. This seems to be a wholly unknown and 
undocumented feature, and the fact that it doesn't work on 
anonymous delegates seems like it's not even fully implemented, 
like someone started to implement it and stopped half way though.