How long does the context of a delegate exist?

[cc]

On Thursday, 27 May 2021 at 20:46:22 UTC, Adam D. Ruppe wrote:
> On Thursday, 27 May 2021 at 20:44:21 UTC, frame wrote:
>> Did you mean to add the delegate as GC root or the data?
>
> The delegate.ptr property.

Is there any way to enforce at compile time that we're not 
accidentally allocating when creating a delegate, other than 
being carefully aware of what variables are referenced inside the 
body?  Something like:
```d
auto dg = delegate {...}
assert(dg.ptr is null, "Oops, we unintentionally allocated on GC 
here, check delegate body!"); // can't static assert
```