There is a heated debate on PHP internals list -- this in itself is not news, the list should be called "php heated debate list" btw. -- about short array syntax. What I will write here is probably know to the Drupal readers -- less known to the PHP internals list, I guess. So, I am the form API maintainer of Drupal, which probably is the most complex array based API in existence. I support the
$b = ['foo' => 'orange', 'bar' => 'apple', 'baz' => 'lemon']; wholeheartedly.