HList in go2go. https://go2goplay.golang.org/p/7txHLqANAiu

hlist.go

package main

import (
	"fmt"
	"net/http"
)

type HList interface {
	hlist()
}

func (n Nil) hlist()  {}
func (c Cons[H, T]) hlist() {}

type Nil struct{}

type Cons[H any, T HList] struct {
	Head H
	Tail T
}

func Create[H any](h H) Cons[H, Nil] {
	return Cons[H, Nil]{
		Head: h,
		Tail: Nil{},
	}
}

func Prepend[H, T any, L HList](l Cons[T, L], h H) Cons[H, Cons[T, L]] {
	return Cons[H, Cons[T, L]]{
		Head: h,
		Tail: l,
	}
}

func PopFront[H, T any, L HList](l Cons[H, Cons[T, L]]) (H, Cons[T, L]) {
	return l.Head, l.Tail
}

func main() {
	a := Create(1)
	b := Prepend(a, "abc")
	c := Prepend(b, true)
	d := Prepend(c, new(http.Client))
	fmt.Println(d)
}