compilation error with shared ReadWriteMutex

[jj75607 via Digitalmars-d-learn]

On Thursday, 30 June 2016 at 12:25:54 UTC, Steven Schveighoffer 
wrote:
> On 6/30/16 8:18 AM, jj75607 wrote:
>>       [...]
>
> You don't need to mark this shared, because the entire class is 
> shared, all members are implicitly marked shared.
>
> [...]

Thanks! Is this a compilation only 'cast' with no runtime works?