Perhaps we could use an Attribute to bind the operator to the method, which would also reduce the impact on tools that need to parse class definitions:
class Collection{ #[Operator('+')]
public function union(Collection$other, OperandPosition$operandPos) {}
}
An interesting extension would be to have an optional argument to the Attribute which binds separate methods for each direction of arguments, rather than exposing it as a parameter:
class Number{ #[Operator('/', OperandPosition::LeftSide)]
public function divideBy(Number $divisor) {}
#[Operator('/', OperandPosition::RightSide)]
publicfunction fractionOf(Number $dividend) {}
}