const in functions

[Salih Dincer]

On Sunday, 12 March 2023 at 19:09:13 UTC, Ali Çehreli wrote:
> ---

In this case, using `ref` will increase performance while 
reducing the number of copies.  Would it be wise to use `const 
ref` to protect the routine from ourselves or someone else? For 
example:

```d
auto inConst(
   //const
   ref Int a, const ref Int b)
{
   a.x += 1;
   return Int(a.x + b.x);
}

struct Foo(T) {
   T x;
   alias x this;
   this(T n) { x = n; }
}
alias Int = Foo!int;
```

SDB at 79