Is it like?

<?php
['a'=>$a, 'b'=>$b] = [...json_decode('{"a":2}', 1), ...['b'=>'def val']];
var_dump($a, $b);

@kandy In that particular scenario of a top-level dimension with string keys, where no null values are present, yes.

But array unpacking won't help you with integer keys (because it will re-index them, consecutively), it doesn't allow for any nested destructuring, is not usable inline as a foreach target, and does not handle nulls for you.

I like it!

But what should happen if:

[ $a ?? '123', $b ] = [];
[ $a ?? '123', $b ] = [ 1 ];
[ $a ?? '123', $b ] = [ 1, 2 ];

It also supports ?: operator?

[ $a ?: '123' ] = []; // so $a = '123'
[ $a ?: '123' ] = [ false ]; // so $a = '123'
[ $a ?: '123' ] = [ 456 ]; // so $a = 456

I found this PR when looking for another. The RFC was declined, so I think this one can be closed.