belongsToMany Association on the same model with a different foreign key and alias fails

What you are doing?

I have defined my association on the User model as follows

    User.belongsToMany(User, {
      through: models.Following,
      as: 'Follower',
      foreignKey: 'following_id',
    });

    User.belongsToMany(User, {
      through: models.Following,
      as: 'Following',
      foreignKey: 'follower_id',
    });

What do you expect to happen?

I did this so that I could then call user.GetFollower() and user.GetFollowing() functions. This worked fine with sequelize v3

What is actually happening?

With sequelize v4, I now get the error
SequelizeAssociationError: You have used the alias Following in two separate associations. Aliased associations must have unique aliases.

If I remove the second User.belongsToMany, it solves the problem but I am no longer able to use user.getFollowing() which returns as undefined.

Dialect: mysql
Database version: 5.7
Sequelize version: 4.8

P.S. I did check https://github.com/sequelize/sequelize/issues/7775. But it is not applicable to my case. I do not have the Model.associate(models) being called multiple times. I have it called only once - in the index.js file that sequelize-cli generated.

Start with the two User.belongsToMany(User) definitions and the sequelize-cli-generated index.js association setup. Reproduce the alias error with Sequelize 4.8 and MySQL 5.7, then inspect how the associations are registered. Done means both associations can coexist with distinct aliases and the corresponding getter methods are available.