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| -rw-r--r-- | library/std/src/primitive_docs.rs | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/library/std/src/primitive_docs.rs b/library/std/src/primitive_docs.rs index ef0ab05a58d..a5292c8b878 100644 --- a/library/std/src/primitive_docs.rs +++ b/library/std/src/primitive_docs.rs @@ -603,6 +603,48 @@ mod prim_pointer {} /// } /// ``` /// +/// Future language versions might start treating the `array.into_iter()` +/// syntax on editions 2015 and 2018 the same as on edition 2021. So code using +/// those older editions should still be written with this change in mind, to +/// prevent breakage in the future. The safest way to accomplish this is to +/// avoid the `into_iter` syntax on those editions. If an edition update is not +/// viable/desired, there are multiple alternatives: +/// * use `iter`, equivalent to the old behavior, creating references +/// * use [`array::IntoIter`], equivalent to the post-2021 behavior (Rust 1.51+) +/// * replace `for ... in array.into_iter() {` with `for ... in array {`, +/// equivalent to the post-2021 behavior (Rust 1.53+) +/// +/// ```rust,edition2018 +/// use std::array::IntoIter; +/// +/// let array: [i32; 3] = [0; 3]; +/// +/// // This iterates by reference: +/// for item in array.iter() { +/// let x: &i32 = item; +/// println!("{}", x); +/// } +/// +/// // This iterates by value: +/// for item in IntoIter::new(array) { +/// let x: i32 = item; +/// println!("{}", x); +/// } +/// +/// // This iterates by value: +/// for item in array { +/// let x: i32 = item; +/// println!("{}", x); +/// } +/// +/// // IntoIter can also start a chain. +/// // This iterates by value: +/// for item in IntoIter::new(array).enumerate() { +/// let (i, x): (usize, i32) = item; +/// println!("array[{}] = {}", i, x); +/// } +/// ``` +/// /// [slice]: prim@slice /// [`Debug`]: fmt::Debug /// [`Hash`]: hash::Hash |