Foreign key reference a column in the same table causes error

What are you doing?

module.exports = (sequelize, DataTypes) => {
  class Test extends sequelize.Sequelize.Model { }

  Test.init({
    id: {
      field: 'id',
      allowNull: false,
      autoIncrement: true,
      primaryKey: true,
      type: DataTypes.BIGINT(11)
    },
    userId1: {
      field: 'user_id_1',
      allowNull: false,
      type: DataTypes.STRING(36),

    },
    userId2: {
      field: 'user_id_2',
      allowNull: false,
      type: DataTypes.STRING(64),
    },
  }, { indexes: [
      { unique: true, fields: [ 'user_id_1' ]},
      { fields: ['user_id_2' ]}
    ],
    underscored: true,
    sequelize, modelName: 'Test' });

  Test.associate = ({ Test }) => {
    Test.hasMany(Test, { sourceKey:'userId2', targetKey: 'userId1', foreignKey: 'user_id_2' });
  };

  return Test;
};

To Reproduce
Steps to reproduce the behavior:
Run Test.sync()

What do you expect to happen?

CREATE TABLE `tests` (
  `id` bigint(11) NOT NULL AUTO_INCREMENT,
  `user_id_1` varchar(36) NOT NULL,
  `user_id_2` varchar(64) NOT NULL,
  `created_at` datetime NOT NULL,
  `updated_at` datetime NOT NULL,
  PRIMARY KEY (`id`),
  UNIQUE KEY `tests_user_id_1` (`user_id_1`),
  KEY `tests_user_id_2` (`user_id_2`),
  CONSTRAINT `fk_userid1_userid2` FOREIGN KEY (`user_id_2`) REFERENCES `tests` (`user_id_1`)
    ON DELETE NO ACTION ON UPDATE NO ACTION
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

What is actually happening?

CREATE TABLE IF NOT EXISTS `tests` (
  `id` BIGINT(11) NOT NULL auto_increment ,
  `user_id_1` VARCHAR(36) NOT NULL, 
  `user_id_2` VARCHAR(36),
  `created_at` DATETIME NOT NULL, 
  `updated_at` DATETIME NOT NULL, 
  PRIMARY KEY (`id`),
  FOREIGN KEY (`user_id_2`) REFERENCES `tests` (`user_id_1`)
    ON DELETE SET NULL ON UPDATE CASCADE
) ENGINE=InnoDB;

Unhandled rejection SequelizeDatabaseError: Can't create table `test_bug`.`tests` (errno: 150 "Foreign key constraint is incorrectly formed")

Environment

Dialect:

• mysql
  Dialect library version: mysql2: "^1.6.5"
  Database version: '10.1.13-MariaDB'
  Sequelize version: 5.10.1
  Node Version: 8.9.1
  OS: windows

Start by running the provided Test.sync() reproduction against the stated MariaDB environment and compare the generated CREATE TABLE SQL with the expected SQL. Trace the foreign-key generation and same-table association handling until the column type and constraint options are preserved; done means the table is created successfully with the expected reference and actions.