flagging unsigned subtraction assigned to bigger signed number?

[Araq]

On Wednesday, 21 May 2025 at 18:19:19 UTC, Walter Bright wrote:
> (trying to make a memory allocator with no unsigned types is 
> going to wind up pretty ugly).
>

Not really. You can just follow the instructions here to emulate 
unsigned in a principled way: 
https://www.nayuki.io/page/unsigned-int-considered-harmful-for-java

It's not much harder than your rules that effectively ban the 
minus operator for unsigned arithmetic.