const

const.rs

#![crate_type = "lib"]
#![feature(const_fn)]

const fn foo() -> usize {
    10
}

// Ends up as simply return 25 in the mir output.
pub fn test1<T>() -> usize {
    if true {
        25
    } else {
        99
    }
}


// This does not.
pub fn test2<T>() -> usize {
    if foo() < 32 {
        25
    } else {
        99
    }
}


// Neither does this.
pub fn test3<T>() -> usize {
    if 10 < 32 {
        25
    } else {
        99
    }
}