<?php $instance1 = new class extends \Foo implements \HandleableInterface { }; $instance2 = new class extends \Foo implements \ArrayAccess, \Countable, \Serializable { }; $instance3 = new class { }; $instance4 = new class ($arg) { }; $instance5 = new class { }; $instance6 = new class { }; // Bad $instance1 = new class( $arg ) {}; $instance2 = new class ($one , $two ) {}; $instance3 = new class( $one , $two, $three, $four) {}; $instance4 = new class extends \Foo { }; $instance5 = new class($one , $two , $three) extends \Foo implements \HandleableInterface {}; $instance6 = new class extends \Foo implements \HandleableInterface { // Class content }; $instance7 = new class extends \Foo implements \One, \Two, \Three, \Four, \Five { // Class content }; if ($foo) { $instance8 = new class extends \Foo implements \One, \Five { // Class content }; } $instance9 = new class ( $one, $two ) extends \Foo implements \One { // Class content }; $instance10 = new class {}; $foo->bar( new class implements Bar { // ... }, ); foo(new class { });