func (o Option[T]) Unwrap() T
> Generic types can have methods. The receiver type of a method must declare the same number of type parameters as are declared in the receiver type's definition. They are declared without any constraint.
// Push adds a value to the end of a vector.
func (v *Vector[T]) Push(x T) { *v = append(*v, x) }
That methods can't be parametric is still annoying though because it means utility methods can't have generic parameters unrelated to the subject e.g. can't define a map or fold method, because there's nowhere to put the output type, it has to be a free function instead.
But it's not like adding the generic spec thing between the subject and the method name would be a big issue so that can always be added later after the MVP has been exercised a bit.
A related "missing bit" which I'd guess they want more feedback before adding would be "conditional methods" aka methods which are only present if the generic types of the subject have a specific property (e.g. in Rust it's common for the generic container to be unbounded but for functions to be bounded on specific traits).
It's very unfortunate thay didn't do this from the start. The original paper that introduced Go generics had this and used to to solve the Expression Problem.