PHP OOP接口输入继承

Question

A code like that :

interface entite
{

}

class Foo implements entite
{

}


$foo = new foo;
if( $foo instanceof entite ) echo "he is";

Displays "he is". Foo inherit type "entite" from the interface But when try that :

class FooDeleter implements deleter
{
public function __construct(Foo $Foo)
{

}
}

interface deleter
{
public function __construct(entite $entite);
}

Gives me :

Fatal error: Declaration of FooDeleter::__construct() must be compatible with deleter::__construct(entite $entite)

Why ? How to ? =(

Edit : The unique way is actually define the typed deleter like that :

class FooDeleter implements deleter
{
public function __construct(entite $Foo)
{
    if( $Foo instanceof Foo ) { ... }       
}
}

Answer 1

By declaring your FooDeleter constructor with a type hint that is more strict than the interface, you are violating the interface.

If you changed your constructor to

public function __construct(entite $Foo)

...then you could still pass in a Foo object, and the interface would be implemented correctly.