[RFC] Throwing an exception with null pointers

[Derek Fawcus]

On Thursday, 17 April 2025 at 05:09:41 UTC, Walter Bright wrote:
> ```C
> int foo(int * arg1, int * NULL_UNSPECIFIED arg2, int * NULLABLE 
> arg3) {
> ```
>
> https://www.youtube.com/watch?v=vEr0EAcSWcc

Yeah, but that is test code as I'm experimenting with the 
mechanism, and trying to figure out how it can be used, and what 
(if any) value I perceive it as adding.

I rather suspect the norm would to use the pragma such that most 
uses are implicitly non-null, and only the exceptional nullable 
pointer would have to be so marked.

On this particular point, my preferred form would be something 
similar to what Cyclone had, but not using its syntax forms.  
Possibly using the syntax from Zig.

So the common case would be a non-nuull pointer, using '*' alone 
in its declaration.  The nullable point would probably be 
declared as '?*' (or '*?' - not sure which).

Then for use, one could not assign from a nullable to a non-null 
unless DFA had already proved the value was not null.

Except those would be non backward compatible changes; so one 
would somehow have to opt in to them.