Interface constants, Late Static Bindings

interface PasswordBrokerContract
{
    const PASSWORD_RESET = 'passwords.reset';

    public function reset(array $credentials, Closure $callback);
}

class PasswordBroker implements PasswordBrokerContract
{
    public function reset(array $credentials, Closure $callback)
    {
        // implementation

        return static::PASSWORD_RESET;
    }

}

Does it matter if you use self or static considering that interface constants can't be overridden by a class/interface that inherits them?

It could matter, because even if you can't override interface constants in classes implementing an interface, you can override these constants in classes extending the class that originally implemented the interface:

E.g. the following:

<?php

interface Contract
{
    const PASSWORD_RESET = 'passwords.reset';
    public function reset(): void;
}


class A implements Contract
{
    public function reset(): void
    {
        echo static::PASSWORD_RESET, "\n";
    }
}

class B extends A {
    const PASSWORD_RESET = 'foobar';
}

Now this:

(new A())->reset();

would output passwords.reset.

But this:

(new B())->reset();

would output foobar.

But if you didn't use late static binding, and used self, you'd get passwords.reset every time.

See it working here.