Invalid trait insteadof list

[iluuu1994]

Description

The following code:

<?php

trait A {
    public function test() {
        return 'A';
    }
}

trait B {
    public function test() {
        return 'B';
    }
}

class C {
    use A, B {
        A::test insteadof B;
        B::test insteadof A;
    }
}

$c = new C();
var_dump($c->test());

Resulted in this output:

Fatal error: Uncaught Error: Call to undefined method C::test()

But I expected this output instead:

Some trait-resolution-time error

PHP Version

PHP-5.4+

Operating System

No response

[mvorisek]

Probably subissue of #17331.

[iluuu1994]

I don't think so. The problem here is that you may two trait methods may mutually suppress each other, resulting in neither method from being added. The problem in your issue is that use adaptations are not linked to the corresponding use block, which is not really a bug but just a very very weird design choice.

[mvorisek]

a repro with defined method in C class: https://3v4l.org/jeYMX

should fail probably too