Why nexus can build zkp for a loop? I think it's a little strange ?

[HappyFox001]

why nexus can build a proof some code such as follow:
`#![cfg_attr(target_arch = "riscv32", no_std, no_main)]
use nexus_rt::print;
#[nexus_rt::main]

fn main() {
let mut a = 0;
while (true) {
a += 1;
}
}
`

[sjudson]

Can you explain what you see when you try to prove this program? In my testing, and as expected, the infinite loop causes the tracing/execution of the program to be killed by the OS after running for a length of time, with no proof generated.