php strict error by including -

it looks strict errors not occur if classes in 1 file this:

abstract class food{}  class meat extends food{}                      abstract class animal{               function feed(food $food){ } }  class cat extends animal{                function feed(meat $meat){         parent::feed($meat);     }    }     

but if put class definition in separate files , include them that:

abstract class food{}  class meat extends food{}                      require 'animal.php'; require 'cat.php'; 

strict standards error message thrown:

strict standards: declaration of cat::feed() should compatible animal::feed(food $food) in c:\path\to\cat.php on line...

if in 1 file ok:

class dog extends animal{              function feed($qty = 1){      for($i = 0; $i < $qty; $i++){         $meat = new meat();         parent::feed($meat);     }          }  } 

is intended behavior?

because meat food, there shouldn't complain in first place, right? solution plain , clear: put in 1 file , strict standards satisfied ;)

any hints appreciated

is intended behavior?

unfortunately, yes. intricacies come play class declarations make strict rules aren't applied when occur in same script; single class per file doesn't exhibit issue.

because meat food, there shouldn't complain in first place, right?

wrong 2 reasons:

1. meat smaller type food , therefore allowing smaller type in descendent class you're violating lsp; can't substitute cat animal.

2. in php, argument types invariant when overloading methods, i.e. accepted types must match of parent. while argued contravariant types make sense, due technical reasons can't done.

so solution plain , clear: put in 1 file , strict standards satisfied ;)

no, , should not rely on behaviour.