fn maybe_uninit_code(use_feature: bool) -> String {
    let feature = if use_feature {
        "#![feature(untagged_unions)]"
    } else {
        ""
    };

    let code = "
    #![allow(warnings)]
    use std::mem::ManuallyDrop;

    #[derive(Copy)]
    pub union MaybeUninit<T> {
        empty: (),
        value: ManuallyDrop<T>,
    }

    impl<T> Clone for MaybeUninit<T> where T: Copy
    {
        fn clone(&self) -> Self { *self }
    }

    fn main() {
        let value1 = MaybeUninit::<[i32; 3]> { empty: () };
        let value2 = MaybeUninit { value: ManuallyDrop::new([1, 2, 3]) };
    }
    ";

    [feature, code].concat()
}
// To guard against changes in this currently unstable feature, use
// a detection tests instead of a Rustc version and/or date test.
To guard against changes in this currently unstable feature, use
a detection tests instead of a Rustc version and/or date test.
To guard against changes in this currently unstable feature use a detection tests instead of a Rustc version and / or date test .
fn maybe_uninit_code(use_feature: bool) -> String {
    let feature = if use_feature {
        "#![feature(untagged_unions)]"
    } else {
        ""
    };
    let code = "
    #![allow(warnings)]
    use std::mem::ManuallyDrop;
    #[derive(Copy)]
    pub union MaybeUninit<T> {
        empty: (),
        value: ManuallyDrop<T>,
    }
    impl<T> Clone for MaybeUninit<T> where T: Copy
    {
        fn clone(&self) -> Self { *self }
    }
    fn main() {
        let value1 = MaybeUninit::<[i32; 3]> { empty: () };
        let value2 = MaybeUninit { value: ManuallyDrop::new([1, 2, 3]) };
    }
    ";
    [feature, code].concat()
}
fn maybe_uninit_code ( use_feature : bool ) -> String { let feature = if use_feature { " " } else { " " } ; let code = " " ; [ feature , code ] . concat ( ) }
To guard against changes in this currently unstable feature, use
a detection tests instead of a Rustc version and/or date test.
To guard against changes in this currently unstable feature use a detection tests instead of a Rustc version and / or date test .
use_feature
bool