I tried this code: Also godbolt link https://rust.godbolt.org/z/9qs4cTP4v

pub struct MB {
    addr: u8,
}

pub fn new(addr: u8) -> Option<MB> {
    if !(1..=247).contains(&addr) {
        return None;
    }
    Some(MB { addr })
}

I expected to see this happen:

I was trying this code to see what kind of assemble the compilers makes.
I tried different optimize levels.
I see with optimize levels s and 1, that the RangeInclusive bits are still there but not used in the function.
function is self takes about 5 instructions and the RangeInclusive code about 40 instruction, which is dead code.

Instead, this happened:
RangeInclusive bits removed in all the optimize levels.
I was using a similar code on a embedded device.

FYI: It also happens with Range . Remove the = before 247.

Meta

I see this happen on stable and nightly both for x86_64 and thumbv6/v7.