`return const` parameters make `inout` obsolete

[Idan Arye via Digitalmars-d]

On Monday, 16 March 2015 at 14:17:58 UTC, Zach the Mystic wrote:
> char* fun(return const char* x);
>
> Compiler has enough information to adjust the return type of 
> `fun()` to that of input `x`. This assumes return parameters 
> have been generalized to all reference types. Destroy.

Is the `return` in the argument list a new feature? It doesn't 
compile in 2.066, and I don't see it in 2.067's changelog...