Which RFCs were approved in PHP 8 and how did they affect its functionality?

In PHP 8, several important RFCs were approved, which significantly expanded and improved the language's functionality:

• Union Types — now you can specify multiple types for parameters and return values, for example function foo(int|string $param): int|string {}.
• Named Arguments — allows passing function arguments by name, enhancing readability and flexibility.
• Attributes (Annotations) — native support for attributes for metadata in code was introduced.
• Constructor Property Promotion — reduces the boilerplate for property declaration and initialization in constructors.
• Match Expression — a more powerful and safe alternative to switch, returning a value.
• JIT (Just In Time) Compiler — improves performance by compiling bytecode into machine code at runtime.

Example of Union Types and Named Arguments:

function example(int|string $value): void {
    echo $value;
}

example(value: "text");

These changes make PHP 8 a more modern, convenient, and efficient language.