For clarity and less unexpected behavior between PHP5 and PHP7, break
mediawiki-extensions/Echo/includes/DataOutputFormatter.php's line
$formatter = new self::$formatters[$format]( $user, $lang );
into two explicit lines, due to
reference | old meaning | new meaning in PHP7 |
Foo::$bar['baz']() | Foo::{$bar['baz']}() | (Foo::$bar)['baz']() |