--TEST-- Bug #53727 (Inconsistent behavior of is_subclass_of with interfaces) --FILE-- <?php interface MyInterface { const TEST_CONSTANT = true; } class ParentClass implements MyInterface { } class ChildClass extends ParentClass { } echo (is_subclass_of('ChildClass', 'MyInterface') ? 'true' : 'false') . "\n"; echo (defined('ChildClass::TEST_CONSTANT') ? 'true' : 'false') . "\n"; echo (is_subclass_of('ParentClass', 'MyInterface') ? 'true' : 'false') . "\n"; echo (defined('ParentClass::TEST_CONSTANT') ? 'true' : 'false') . "\n"; --EXPECT-- true true true true