I think that if you begin with the idea that you have multiple conventions and you cannot avoid that, therefore you won't solve the problem with "+" operator. You have just one more convention. Type 1 defines: .add(x), Type 2 defines: .plus(x), Type 3 defines: operator+, ... If you assume that you can convince people to adopt a convention, you can use .add(x) and avoid the problem in the first place. Go for example tries to have always one obvious way to write things. The Go standard library it's the idiomatic Go bible.