Array destructuring: already existed, list() pseudo-function
Array spreading: already existed, array_merge
Variadic functions: are probably better implemented as a function accepting an array, especially now that there's a proper array syntax instead of a pseudo-function. Also already existed, func_get_args.
Argument unpacking: already existed, call_user_func_array
Arrow functions: are not any shorter, and are less clear, than anonymous functions.
Literally the only item on your list that was any good for the language is the null coalescing operator. The rest are just re-implementing something that PHP already had, in yet another incompatible (and often unclear) way.
Hell, good luck coming across '??' and trying to find any documentation on what it does. Searching Google for 'php ??' returns results for 'php', searching php.net for '??' returns seemingly random functions, going to php.net/?? gives you the homepage.
Array spreading: already existed, array_merge
Variadic functions: are probably better implemented as a function accepting an array, especially now that there's a proper array syntax instead of a pseudo-function. Also already existed, func_get_args.
Argument unpacking: already existed, call_user_func_array
Arrow functions: are not any shorter, and are less clear, than anonymous functions.
Literally the only item on your list that was any good for the language is the null coalescing operator. The rest are just re-implementing something that PHP already had, in yet another incompatible (and often unclear) way.
Hell, good luck coming across '??' and trying to find any documentation on what it does. Searching Google for 'php ??' returns results for 'php', searching php.net for '??' returns seemingly random functions, going to php.net/?? gives you the homepage.