Description:
------------
hello

i think that non-type-hinted arguments (mixed values):

class a
{
     function test([mixed] $argument){}
}

should allow type hinting in child classes

class b extends a
{
     function test(ImageFile $argument){}
}

Reproduce code:
---------------
"mixed" is a general type... means "everything"
but if i want to build an ArrayObject object with one-only type

i cannot do this

[internal]
class ArrayObject implements ArrayAccess
{
      function offsetSet($o, [mixed] $value)
      {}
}

class ImageList extends ArrayObject
{
      function offsetSet($o, Image $imageObject) // fatal error!
      {}
}

Actual result:
--------------
Fatal error: Declaration of ImageList::offsetSet() must be compatible with that of ArrayAccess::offsetSet() in xx on line 8

thank you