A simplification of the RvalueRef idiom

[TheGag96 via Digitalmars-d-learn]

On Tuesday, 22 November 2016 at 13:06:27 UTC, Nordlöw wrote:
> On Monday, 21 November 2016 at 20:04:51 UTC, Ali Çehreli wrote:
>> mixin template RvalueRef()    // <-- DOES NOT TAKE A PARAMETER 
>> ANY MORE
>> {
>>     alias T = typeof(this);
>>     static assert (is(T == struct));
>>
>>     @nogc @safe
>>     ref const(T) byRef() const pure nothrow return
>
> Why do you need to qualify `byRef` as pure nothrow when it's a 
> template?

The thing that gets me more is "return" as a function attribute. 
I see it under "MemberFunctionAttribute" in the grammar but I 
can't find an explanation for its use anywhere...