Extremely stupid PHP question about inheritance

[rugged sonnet]

I have created a form request called FortifyLoginRequest which extends Laravel\Fortify\Http\Requests\LoginRequest

When I try to use it with Fortify's authenticateUsing() method, I get this error:

App\Providers\FortifyServiceProvider::App\Providers\{closure}(): Argument #1 ($request) must be of type App\Http\Requests\FortifyLoginRequest, Laravel\Fortify\Http\Requests\LoginRequest given

Am I going crazy? Shouldn't extending Fortify's base class make it an instance that would pass that level of scrutiny?

My entire form request for posterity:

<?php

namespace App\Http\Requests;

use Laravel\Fortify\Fortify;
use Laravel\Fortify\Http\Requests\LoginRequest;
use Rahul900day\Captcha\Facades\Captcha;

class FortifyLoginRequest extends LoginRequest
{
    public function authorize(): bool
    {
        return true;
    }

    public function rules(): array
    {
        return [
            Fortify::username() => ['required', 'string'],
            'password' => ['required', 'string'],
            Captcha::getResponseName() => ['required', 'captcha'],
        ];
    }
}

Also for posterity, here is how I'm attempting to use it:

Fortify::authenticateUsing(function (FortifyLoginRequest $request) {
    $user = User::where('email', $request->email)->first();

    if ($user && Hash::check($request->password, $user->password)) {
        return $user;
    }
});

[steep mulch]

Fortify is passing the parent LoginRequest to your function as it has no knowledge or context of your FortifyLoginRequest class.

In your FortifyServiceProvider you should bind your class via the container:

$this->app->bind(LoginRequest::class, FortifyLoginRequest::class);