One of the most sought-after features for PHP is Generics: The ability to have a type that takes another type as a parameter. It’s a feature found in most compiled languages by now, but implementing generics in an interpreted language like PHP, where all the type checking would have to be done at runtime, has always proven Really Really Hard(tm), Really Really Slow(tm), or both.
PHP
New in PHP 8.6: Faster array_map with first-class callables
In this video, Tideways shows how PHP 8.6 speeds up array_map when you use first-class callables.