Conditional `char` counter not recognized as never-overflowing

[Rudxain]

When conditionally incrementing a usize counter by 1, the optimizer doesn't detect that overflow is impossible, when using the Chars iterator. As an example, I wrote a lines-of-codecontent counter that iterates over chars: Playground

Can repro on 1.90.0-nightly (2025-07-14 a001497)

@rustbot label: +I-slow

[hkBst]

@Rudxain how are you determining your claim about the optimizer? Maybe you can provide a godbolt link?

[Rudxain]

I'm sorry, I forgot to include that. I set the profile to release and then built the assembly. The asm has panic code and a .ascii "internal error: entered unreachable code". However, if I replace the unwrap_or_else(|| unreachable!()) by unwrap_unchecked() (inside unsafe{}), all of the panic code is eliminated