let arr = [String::from("a"), String::from("b")];
// *** before: ***
// a loop over an array gave references; values came from ArrayVec
// or from std::array::IntoIter::new
for s in std::array::IntoIter::new(arr) {
println!("{}", s);
}
// *** in version 1.53: ***
// an array is an IntoIterator by value itself now
for s in arr {
let owned: String = s;
println!("{}", owned);
}