The other thing is that they have partially fixed the most "wat" bug in PHP: for some arrays that aren't even all that hard to come by when interacting with JS, the following code could change `count($arr)`:

    foreach ($arr as $key => $val) {
        $arr[$key] = f($key, $val);
    }

The issue is that `$key` could be a string describing an integer, but `$arr[$key]` will automatically see that you're using a string-int and convert it to an int-int, setting a different key than the internal one.

It's only a partial fix but it hits the most common case: you have a JSON payload that happens to have an index of objects which happens to have been given numeric keys:

    {
      "abcdef": {"prop1": "hello", "prop2": 123}, 
      "987132": {"prop1": "world", "prop2": 456}
    }

If your framework hands JSON to you as a StdClass object then you would typically convert this to an associative array since that's semantically what it is: as opposed to the internal entities, which in this case appear to be full-fledged objects. (The difference is that the keys of a full-fledged object should be known in advance at a data-schema level and have a control structure of getting/setting `->prop_name`; the keys of a dictionary should be user-settable and have a control structure of `foreach ($dict as $key => $val) {}`.)

So the bug still maybe exists in some fringe cases as the underlying cause is not treated, but it is now autofixed by the common idiom of casting `$dict = (array) $params->dict`.

I would typically write:

   foreach ($arr as $key => &$val)
        $val = f($key, $val);

This would avoid this issue, while bing simpler.