impl<T> [T] {
    pub const fn as_array<const N: usize>(&self) -> Option<&[T; N]>;

    pub const fn as_mut_array<const N: usize>(&mut self) -> Option<&mut [T; N]>;
}

impl<T> *const [T] {
    pub const fn as_array<const N: usize>(self) -> Option<*const [T; N]>;
}

impl<T> *mut [T] {
    pub const fn as_mut_array<const N: usize>(self) -> Option<*mut [T; N]>;
}

// alloc::boxed

impl<T> Box<[T]> {
    pub fn into_array<const N: usize>(self) -> Option<Box<[T; N]>>;
}

// alloc::rc

impl<T> Rc<[T]> {
    pub fn into_array<const N: usize>(self) -> Option<Rc<[T; N]>>;
}

// alloc::sync

impl<T> Arc<[T]> {
    pub fn into_array<const N: usize>(self) -> Option<Arc<[T; N]>>;
}