What are the implications of removing the "&" symbol in PHP code, particularly in object instantiation and references?

When removing the "&" symbol in PHP code, particularly in object instantiation and references, it can affect how objects are passed by reference or by value. Without the "&" symbol, objects are passed by value, meaning changes made to the object within a function will not affect the original object outside of the function. To pass objects by reference and have changes reflected outside of the function, the "&" symbol should be used.

// Passing object by reference
class MyClass {
    public $value;
}

$obj = new MyClass();
$obj->value = 10;

function changeValue(&$obj) {
    $obj->value = 20;
}

changeValue($obj);

echo $obj->value; // Output will be 20