Nested autowiring does not work

Nested autowire definitions do not seem to work.

The installed package versions can be found in the composer.lock file.

Usage

$ composer install
$ docker run --rm -it -v $PWD:/app -w /app php php run.php

Results

Error message: Entry "Father" cannot be resolved: Entry "" cannot be resolved: Parameter $toy of __construct() has no value defined or guessable

Don't know whether it's desired or not.