`alias x = v.x;` not working in struct bodies?

[evilrat]

On Saturday, 20 January 2024 at 10:00:15 UTC, Danilo wrote:
> All of this advanced stuff in D seems to be implemented for 
> very specific and very limited use cases only.
> It could be much more better if it would be implemented for 
> general and broader use cases.

In your vec3 example, while it is tempting to automate this using 
cool smart features, you will end up regretting using it.

And in this example you can use union to join vec2 and add extra 
synonyms members.
I see there is a lot of libraries that using similar smart 
metaprogramming for basic types in D, but when I tried to do 
"smart" things using alias this in the end I often got bitten by 
it and regretting using templates and stuff.

Alias this has annoying property to mess up with your RAII 
wrappers.
The fancy metaprogramming engineering results in poor IDE 
experience and slower compilation(neglectible in this case) times 
along with even more horrible debugging.

```d
struct Vec3 {

     union {
         struct {
             float x = 0;
             float y = 0;
             float z = 0;
         }
         struct {
             Vec2 _xy;
             float _z;
         }
         float[3] values;
     }

     // ...
}
```