Common type of ubyte and const ubyte is int

[Walter Bright]

On 5/1/2024 7:42 AM, Steven Schveighoffer wrote:
> It seems rule 2 would apply instead of rule 6? but I don't like it.

```
#include <stdio.h>

void main()
{
     char u;
     const char v;
     printf("%ld %ld\n", sizeof(u), sizeof(1?u:v));
}
```

This prints "1 4". D follows the same integral promotion rules, and the reason 
is if one translates C code to D, one doesn't get an unpleasant hidden surprise.