"Doctrine\ORM\Mapping\Embeddable" has already been autoconfigured and merge  
() does not support merging autoconfiguration for the same attribute.        

p$ composer show doctrine/*
doctrine/collections                2.3.0  PHP Doctrine Collections library that adds additional functionality on top of PHP arrays.
doctrine/data-fixtures              2.0.2  Data Fixtures for all Doctrine Object Managers
doctrine/dbal                       4.2.3  Powerful PHP database abstraction layer (DBAL) with many features for database schema introspection and management.
doctrine/deprecations               1.1.5  A small layer on top of trigger_error(E_USER_DEPRECATED) or PSR-3 logging with options to disable all deprecations or selectively for pa...
doctrine/doctrine-bundle            2.15.0 Symfony DoctrineBundle
doctrine/doctrine-migrations-bundle 3.4.2  Symfony DoctrineMigrationsBundle
doctrine/event-manager              2.0.1  The Doctrine Event Manager is a simple PHP event system that was built to be used with the various Doctrine projects.
doctrine/inflector                  2.0.10 PHP Doctrine Inflector is a small library that can perform string manipulations with regard to upper/lowercase and singular/plural forms...
doctrine/instantiator               2.0.0  A small, lightweight utility to instantiate objects in PHP without invoking their constructors
doctrine/lexer                      3.0.1  PHP Doctrine Lexer parser library that can be used in Top-Down, Recursive Descent Parsers.
doctrine/migrations                 3.9.0  PHP Doctrine Migrations project offer additional functionality on top of the database abstraction layer (DBAL) for versioning your datab...
doctrine/orm                        3.3.4  Object-Relational-Mapper for PHP
doctrine/persistence                4.0.0  The Doctrine Persistence project is a set of shared interfaces and functionality that the different Doctrine object mappers share.
doctrine/sql-formatter              1.5.2  a PHP SQL highlighting library