Prevent improper composition

[muglug]

With Config::$use_property_default_for_type = true this emits an issue

<?php

class C1 {
    public $p = 42;
}

trait T1 {
    public $p = 'string';
}

class C2 extends C1 {
    use T1;
}

(borrowed from phan/phan#300)

InvalidPropertyAssignment - file.php:8 - $this->p with declared type 'int' cannot be assigned type 'string'

but should emit a stronger issue InvalidPropertyComposition

[muglug]

Closing as something PHPCS could find