Question: I've been working on code that's intended to be used with objects, without really caring what the kind of object is. I wanted to type hint that the method being written expected an object of any type, but ran into some difficulty. 

I tried `function myFunc (object $obj)` and `function myFunc (stdClass $obj)` but both of these generated errors when I tried to pass objects in: 

> 
> Catchable fatal error: Argument 1 passed to MyClass::MyFunc() must be an instance of object, instance of ObjectActualClass given
> 
> 
> 

The same happened with `stdClass` as well

What am I missing? I thought that all classes that didn't explicitly inherit from another class inherited from `stdClass`, meaning that the base class of every class in PHP would be `stdClass`. Is this not the case?

Answer: 
There is no base class that all objects extend from. You should just remove the typehint and document the expected type in the `@param` annotation.
There is no built-in mechanism to do this without requiring all users of your interface to extend a specified class. But why would you want to do this anyway? What do all object types have in common that's enough to make them suitable input for your API?

In all probability you wouldn't gain anything even if able to type hint like this. On the other hand, type hinting a parameter to implement an interface (such as `Traversable`) would be much more meaningful.

If you still want something akin to type hinting, the best you can do is substitute a runtime check with `is_object` on the parameter.