Likelihood of if statement and case

[IchorDev]

On Wednesday, 11 September 2024 at 09:26:16 UTC, Richard (Rikki) 
Andrew Cattermole wrote:
> ```d
> switch(e) {
>     /*@likely*/
>     case E.unlikely1:
>         break;
>     default:
>         break;
> }
>
> if (e.unlikely1) /*@likely*/ {
> } else {
> }
> ```
>
> ``@likely`` would be defined in core.attributes. It requires 
> minimal changes, but instead it requires us to explicitly 
> define this behavior of priorities and likelihood.

How would one emulate this?
```d
void x(int a, uint b){
   if(a < 0) @unlikely return;
   if(b == uint.max) @unlikely return;
   //do stuff
}
```
Not being able to mark an if-return as unlikely is one of the 
major problems with the current design, because the if-return 
pattern avoids issues with really deep nesting that would occur 
otherwise.