PHP Changing Method Visibility


Example

trait HelloWorld {
    public function sayHello() {
        echo 'Hello World!';
    }
}

// Change visibility of sayHello
class MyClass1 {
    use HelloWorld { sayHello as protected; }
}

// Alias method with changed visibility
// sayHello visibility not changed
class MyClass2 {
    use HelloWorld { sayHello as private myPrivateHello; }
}

Running this example:

(new MyClass1())->sayHello();
// Fatal error: Uncaught Error: Call to protected method MyClass1::sayHello()

(new MyClass2())->myPrivateHello();
// Fatal error: Uncaught Error: Call to private method MyClass2::myPrivateHello()

(new MyClass2())->sayHello();
// Hello World!

So be aware that in the last example in MyClass2 the original un-aliased method from trait HelloWorld stays accessible as-is.