Convert TickDuration to Duration?

[simendsjo]

On 09.06.2011 16:33, Steven Schveighoffer wrote:
> On Wed, 08 Jun 2011 18:02:40 -0400, Jonathan M Davis
> <jmdavisProg at gmx.com> wrote:
>
>> On 2011-06-08 14:30, David Nadlinger wrote:
>>> On 6/8/11 11:14 PM, Jonathan M Davis wrote:
>>> > On 2011-06-08 13:36, David Nadlinger wrote:
>>> >> Did I miss a way to convert a TickDuration to a Duration? If there
>>> >> really is none, is there a reason for this?
>>> >>
>>> >> Having to do an immediate conversion to a hnsecs long feels
>>> somehow odd:
>>> >>
>>> >> ---
>>> >> Duration maxFlushInterval;
>>> >> if (dur!"hnsecs"(flushTimer.peek.hnsecs)> maxFlushInterval) { … }
>>> >> ---
>>> >
>>> > Cast it. TickDuration overloaded opCast for Duration.
>>> >
>>> > - Jonathan M Davis
>>>
>>> Oh, of course, totally missed that.
>>
>> I probably should provide an example for it in the documentation
>> though, since
>> it's something that you're likely to want to do.
>
> Hm... this involves cast(Duration)x? That seems like a dangerous thing
> for a common operation, no?
>
> -Steve

Does this also mean code doing this cannot use @safe? Or is opCast 
excluded by that rule?