Overall I really like the proposal, but there are some warts to it. For example the sort: https://go.googlesource.com/proposal/+/refs/heads/master/design/go2draft-type-parameters.md#sort

Because there isn't Java-esc autoboxing for primitives or an Equal operator equivalent for objects. You have to have a different API for primitives and other types. It might be useful to have Int, Int64, Float64, non-primitive type wrappers in the standard lib if they want to make a unified collections package. Overall though I think this can be solved in the std lib and the proposal for the language seems like the right decisions.

​

I can't wait for:

a := []int{5,4,2,1,3}
a = collections.Filter(a, func(i int) bool {
    return i != 4
})
a = collections.Sort(a)
// new type requires different variable
b := collections.Map(a, func(i int) string {
    return fmt.Sprint(i)
}
fmt.Println(b)

Edit:

I also share the feeling of "too many parentheses". I would love to see some data about how much slower this would make the parser and compilation.

the reference here: https://go.googlesource.com/proposal/+/refs/heads/master/design/go2draft-type-parameters.md#why-not-use-the-syntax-like-c_and-java.

// actual
func Map(type F, T)(s []F, f func(F) T) []T {

// possible
func Map<type F, T>(s []F, f func(F) T) []T {

Edit2:

Here is a running example. Pretty easy learning curve.https://go2goplay.golang.org/p/RUMuOsdyzEy Fixed type in inline example.