Implementation status

The following table gives an overview of the current implementation status. The goal is to have check marks everywhere!

Feature	PHP 7.4	PHP 8.0	PHP 8.1	PHP 8.2	PHP 8.3	PHP 8.4	PHP 8.5
Future PHP?
• Nullable casting	✔	✔	✔	✔	✔	✔	✔
• Match without expression	✔	✔	✔	✔	✔	✔	✔
• fn with block	✔	✔	✔	✔	✔	✔	✔
Hack
• Using statement / Disposables	✔	✔	✔	✔	✔	✔	✔
• Function types	✔(1)	✔(1)	✔(1)	✔(1)	✔(1)	✔(1)	✔(1)
• Array and map types	✔(1)	✔(1)	✔(1)	✔(1)	✔(1)	✔(1)	✔(1)
PHP 8.5
• Support Closures in constant expressions	✔	✔	✔	✔	✔	✔	✔
PHP 8.4
• Asymmetric visibility	✔(6)	✔(6)	✔(6)	✔(6)	✔(6)	native	native
• new ... without parentheses	✔	✔	✔	✔	✔	✔	✔
• Property hooks	✔(6)	✔(6)	✔(6)	✔(6)	✔(6)	native	native
PHP 8.3
• Typed class constants	✔(1)	✔(1)	✔(1)	✔(1)	native	native	native
• Marking overridden methods	✔	✔	✔	✔	native	native	native
• Dynamic class constant fetch	✔	✔	✔	✔	native	native	native
• Arbitrary static variable initializers	✔	✔	✔	native	native	native
PHP 8.2
• True type	✔(5)	✔(5)	✔(5)	native	native	native	native
• False type	✔(5)	✔(5)	✔(5)	native	native	native	native
• Null type	✔(1)	✔(1)	✔(1)	native	native	native	native
• Readonly classes	✔	✔	✔	native	native	native	native
PHP 8.1
• Array unpacking with string keys	✔	✔	native	native	native	native	native
• Readonly properties	✔	✔	native	native	native	native	native
• Pure intersection types	✔(1)	✔(1)	native	native	native	native	native
• First-class callable syntax	✔	✔	native	native	native	native	native
• Never return type	✔(4)	✔(4)	native	native	native	native	native
• New in initializers	✔(3)	✔(3)	✔(3)	✔(3)	✔(3)	✔(3)	✔(3)
• Enumerations	✔	✔	native	native	native	native	native
• Octal integer literal notation	✔	✔	native	native	native	native	native
PHP 8.0
• Static return type		native	native	native	native	native	native
• Match expression	✔	native	native	native	native	native	native
• Named Arguments	✔(2)	native	native	native	native	native	native
• Mixed type	✔(1)	native	native	native	native	native	native
• Attributes / Annotations	✔	✔	✔	✔	✔	✔	✔
• Null-safe instance operator	✔	native	native	native	native	native	native
• Constructor argument promotion	✔	native	native	native	native	native	native
• Throw expressions	✔	native	native	native	native	native	native
• ::class on objects	✔	native	native	native	native	native	native
• Union types	✔(1)	native	native	native	native	native	native
• Arbitrary expression support for new	✔	native	native	native	native	native	native
PHP 7.4
• Spread Operator in Array Expression	native	native	native	native	native	native	native
• Numeric Literal Separator	native	native	native	native	native	native	native
• Arrow functions	native	native	native	native	native	native	native
• Property types	native	native	native	native	native	native	native

Notes:

1. Currently unchecked.
2. Only in the correct order.
3. Except for class constants.
4. Emitted as void.
5. True and false types emitted as bool.
6. Limited in inheritance due to being emulated, see xp-framework/compiler#166