<?php
                                         class Foo {
                                                 var $type;
                                                 Function Foo() {
                                                         $this->type = 'Foo';
                                                 }
                                         }

                                         class Bar {
                                                 var $type;
                                                 Function Bar() {
                                                         $this->type = 'Bar';
				return new Foo();
                                                 }
                                         }

                                         // This will work
                                         $foo = new Foo();
                                         echo( 'I am foo : ' . $foo->type );

                                         // This will not
                                         $bar = new Bar();
                                         echo( 'I should be foo also : ' . $bar->type );

                                         ?>

This is not a bug. You are misusing constructors. What the new operator does is similar to C++. It first allocates memory for the object and then calls the objects constructor. The constructor does not have a return value and returning something from it is pointless. When you're calling new Bar(); you're telling PHP you want a new object of type Bar and not foo. Maybe what you want is inheritence?