Editing Foreach loop (section)

=== Rust ===
{{Main|Rust (programming language)}}
The <code>for</code> loop has the structure <syntaxhighlight lang="rust" inline>for <pattern> in <expression> { /* optional statements */ }</syntaxhighlight>. It implicitly calls the [https://doc.rust-lang.org/std/iter/trait.IntoIterator.html <code>IntoIterator::into_iter</code>] method on the expression, and uses the resulting value, which must implement the [https://doc.rust-lang.org/std/iter/trait.Iterator.html <code>Iterator</code>] trait. If the expression is itself an iterator, it is used directly by the <code>for</code> loop through an [https://doc.rust-lang.org/std/iter/trait.IntoIterator.html#impl-IntoIterator-25 implementation of <code>IntoIterator</code> for all <code>Iterator</code>s] that returns the iterator unchanged. The loop calls the <code>Iterator::next</code> method on the iterator before executing the loop body. If <code>Iterator::next</code> returns <code>[[option type|Some(_)]]</code>, the value inside is assigned to the [[pattern matching|pattern]] and the loop body is executed; if it returns <code>None</code>, the loop is terminated.

<syntaxhighlight lang="Rust">
let mut numbers = vec![1, 2, 3];

// Immutable reference:
for number in &numbers { // calls IntoIterator::into_iter(&numbers)
    println!("{}", number);
}

for square in numbers.iter().map(|x| x * x) { // numbers.iter().map(|x| x * x) implements Iterator
    println!("{}", square);
}

// Mutable reference:
for number in &mut numbers { // calls IntoIterator::into_iter(&mut numbers)
    *number *= 2;
}

// prints "[2, 4, 6]":
println!("{:?}", numbers);

// Consumes the Vec and creates an Iterator:
for number in numbers { // calls IntoIterator::into_iter(numbers)
    // ...
}

// Errors with "borrow of moved value":
// println!("{:?}", numbers);
</syntaxhighlight>