Bring back foreach int indexes (or explicit index types in general)

[whitebyte]

Based on https://forum.dlang.org/thread/[email protected]
Currently working with foreach loops in D is ugly, because foreach(int i, el; myArray) is deprecated and foreach(i, el; myArray) is PITA because i is ulong now, and I rarely need ulong in my loops. Even worse, many 3rdp libs won't accept ulong, so I have to do tons of casts to int.

The discussion on the D forum went nowhere

[adamdruppe]

right now in opend, the deprecation is silenced if the size of the array is known at compile time

still there if it is only known at runtime

void main() {
        int[] a = [1, 2];
        foreach(int i, el; a[0..2]) {} // no error
}

but if it just foreach(int i, el; a) that is still an error. i want to fix it but idk how yet, i want it to put a bounds check before the loop in that case then carry on

[adamdruppe]

I think I got it figured out. It puts in an assert for the length before the foreach if you use a particular size like steven suggested in that thread:

void main() {
        int[] a;
        a.length = 257;
        foreach(ubyte idx, int item; a) {}
}

It automatically inserts this at the loop entry:

                assert(__r3.length < 256LU, "Array too large for index type");

So you run it and get, at runtime:

[email protected](4): Array too large for index type

So this lets it compile but still checks for the bound trouble.

that sound ok?

(of course also works with int and whatnot just ubyte length less likely to explode my ram lol)

[whitebyte]

That looks like a clear upgrade over the current situation