Consumers are contravariant in Scala, but producers are covariant. EDIT: Good reference: https://www.atlassian.com/blog/software-teams/covariance-and-contravar

Consumers are contravariant in Scala, but producers are covariant. EDIT: Good reference: https://www.atlassian.com/blog/software-teams/covariance-and-contravariance-in-scala https://www.atlassian.com/blog/software-teams/covariance-and...