Is synchronized(...){...} doomed to never be nothrow/@nogc?

[Jack Stouffer via Digitalmars-d]

On Tuesday, 10 May 2016 at 17:46:17 UTC, Vladimir Panteleev wrote:
> because we can't know that the Monitor implementation doesn't 
> throw / use the GC.

Why not? Surely this information is available at compile-time?