pragma(explicit_gc)

[Timon Gehr]

On 5/2/24 03:52, Richard (Rikki) Andrew Cattermole wrote:
> On 02/05/2024 1:45 PM, Timon Gehr wrote:
>> Proposal: Add `pragma(explicit_gc)`. Functions marked with this pragma 
>> will non-transitively error out on implicit GC allocations. This is a 
>> useful tool to check expectations about escape analysis precision.
> 
> I have been proposing this for years under the name ``@localnogc``.
> ...

I see. I do think that making it a `pragma` may be more fruitful, 
because a function attribute would typically be part of the type of a 
function. However, the interface of the function is not actually 
affected by such checks.

> Although I would disallow new'ing an exception with it annotated.
> ...

I guess this check could be bypassed using a nested function if needed, 
but I think explicit allocations are simply not an issue as they do not 
defy expectations.

> At some point I want to do an attribute cleanup DIP.
> 
> Make all attributes positive, include negation form, introduce the 
> throws set and of course ``@localnogc`` and ``@notls``.

Sounds good.