main.go

package main

import (
	"fmt"
	"log"

	"gopkg.in/yaml.v2"
)

const withAlias = `foo:
  <<: &integer
    type: integer
    format: int16
bar:
  <<: *integer
`

func main() {
	var ms yaml.MapSlice
	if err := yaml.Unmarshal([]byte(withAlias), &ms); err != nil {
		log.Fatal(err)
	}
	fmt.Println(pretty(ms))

	fmt.Println("----")

	var i interface{}
	if err := yaml.Unmarshal([]byte(withAlias), &i); err != nil {
		log.Fatal(err)
	}
	fmt.Println(pretty(i))
}

func pretty(i interface{}) string {
	bs, _ := yaml.Marshal(i)
	return string(bs)
}

output.txt

foo: {}
bar: {}

----
bar:
  format: int16
  type: integer
foo:
  format: int16
  type: integer