Under what circumstances is exception throwing currently `@nogc` if the dmd flag `-dip1008` is used?

For instance in code such as:

void main() @nogc
{
    throw new Exception("I'm @nogc now");
}

Are all exceptions forced to be statically allocated when -dip1008 is used or can exception throwing be `@nogc` only when certain conditions hold?

I can't find any docs on DIP-1008. The link

https://github.com/dlang/DIPs/blob/master/DIPs/DIP1008.md

given in the release notes here

Ref: https://dlang.org/changelog/2.079.0.html#dip1008

is broken.

On Monday, 22 June 2020 at 13:59:22 UTC, Per Nordlöw wrote:
> I can't find any docs on DIP-1008. The link
>
> https://github.com/dlang/DIPs/blob/master/DIPs/DIP1008.md
>
> is broken.

Found the postponed spec here:

https://github.com/dlang/DIPs/blob/master/DIPs/other/DIP1008.md

On Monday, 22 June 2020 at 13:59:22 UTC, Per Nordlöw wrote:

> I can't find any docs on DIP-1008. The link
>
> https://github.com/dlang/DIPs/blob/master/DIPs/DIP1008.md
>
> given in the release notes here
>
> Ref: https://dlang.org/changelog/2.079.0.html#dip1008
>
> is broken.

https://github.com/dlang/DIPs/blob/master/DIPs/other/DIP1008.md

On Monday, 22 June 2020 at 14:10:15 UTC, Mike Parker wrote:
> https://github.com/dlang/DIPs/blob/master/DIPs/other/DIP1008.md

The spec says:

"
The only place a refcounted Throwable is ever created is when the following statement is in the user code:

throw new E(string);
"

What other typical throw cases will _not_ be allocated on the GC?

On 6/22/20 10:36 AM, Per Nordlöw wrote:
> On Monday, 22 June 2020 at 14:10:15 UTC, Mike Parker wrote:
>> https://github.com/dlang/DIPs/blob/master/DIPs/other/DIP1008.md
> 
> The spec says:
> 
> "
> The only place a refcounted Throwable is ever created is when the following statement is in the user code:
> 
> throw new E(string);
> "
> 
> What other typical throw cases will _not_ be allocated on the GC?

My understanding is none.

So for example:

auto ex = new Exception(string); // heap allocated
throw ex;

It entirely depends on you immediately throwing the exception because otherwise, you may have stored a pointer elsewhere. Because classes (exceptions) cannot be truly refcounted on copy, you need a very controlled environment to ensure the ref-counting works.

-Steve