rust/tests/ui/iterators/into-iter-on-arrays-2018.rs

// check-pass
// edition:2018

use std::array::IntoIter;
use std::ops::Deref;
use std::rc::Rc;
use std::slice::Iter;

fn main() {
    let array = [0; 10];

    // Before 2021, the method dispatched to `IntoIterator for &[T; N]`,
    // which we continue to support for compatibility.
    let _: Iter<'_, i32> = array.into_iter();
    //~^ WARNING this method call resolves to `<&[T; N] as IntoIterator>::into_iter`
    //~| WARNING this changes meaning

    let _: Iter<'_, i32> = Box::new(array).into_iter();
    //~^ WARNING this method call resolves to `<&[T; N] as IntoIterator>::into_iter`
    //~| WARNING this changes meaning

    let _: Iter<'_, i32> = Rc::new(array).into_iter();
    //~^ WARNING this method call resolves to `<&[T; N] as IntoIterator>::into_iter`
    //~| WARNING this changes meaning
    let _: Iter<'_, i32> = Array(array).into_iter();
    //~^ WARNING this method call resolves to `<&[T; N] as IntoIterator>::into_iter`
    //~| WARNING this changes meaning

    // But you can always use the trait method explicitly as an array.
    let _: IntoIter<i32, 10> = IntoIterator::into_iter(array);

    for _ in [1, 2, 3].into_iter() {}
    //~^ WARNING this method call resolves to `<&[T; N] as IntoIterator>::into_iter`
    //~| WARNING this changes meaning
}

/// User type that dereferences to an array.
struct Array([i32; 10]);

impl Deref for Array {
    type Target = [i32; 10];

    fn deref(&self) -> &Self::Target {
        &self.0
    }
}