@nogc and exceptions

[Johannes Pfau via Digitalmars-d]

Am Fri, 12 Sep 2014 12:59:22 +0000
schrieb "Marc Schütz" <schuetzm at gmx.net>:

> On Friday, 12 September 2014 at 03:37:10 UTC, Jakob Ovrum wrote:
> >   1b) Exceptions constructed at compile-time which are then 
> > later referenced at runtime (as in the above snippet) must be 
> > immutable (the compiler enforces this), as this feature only 
> > supports allocation in global memory, not in TLS. This brings 
> > us to an unsolved bug in the exception mechanism - the ability 
> > to get a mutable reference to an immutable exception without 
> > using a cast:
> 
> Related: Last time I checked the runtime caches unwinding or 
> stack trace information in the exception. It does this even for 
> immutable exceptions...

Yes, in order to avoid allocating a stack trace helper you need to cast
the exception from its .init property, IIRC. There's some code in
druntime which does that (the out-of-memory error handling code).