Unmarshall deep nested array in golang

I am trying to iterate over the "Inner" elements in "List", but only the last "Inner - type" is recovered, ie, "c1":

jsonData := []byte(`{
"List": [{
	"Inner":{"type":"a1"},   	
	"Inner":{"type":"b1"},
    "Inner":{"type":"c1"}
}]}`)

type Test struct {
  List []struct {
    Inner struct {
      Type string `json:"type"` 
    } `json:"Inner"`
  } `json:"List"`
}

var test Test
json.Unmarshal(jsonData, &test)

fmt.Println(test.List[0].Inner.Type)

So, Is there any way to print all elements in "List" ?

you might need to decide on a type for the objects coming inside the []List object, and implement the JSONUnmarshaller interface with a custom logic as follows to achieve this.

package main

import (
	"encoding/json"
	"fmt"
	"regexp"
	"strings"
)

type Inner struct{
	Type string `json:"type"`
}

type List []Inner

type Test struct {
	List [] List `json:"List"`
}

func main() {
	jsonData := []byte(`{
"List": [{
    "Inner":{"type":"a1"},      
    "Inner":{"type":"b1"},
    "Inner":{"type":"c1"}
}]}`)

	var test Test
	err := json.Unmarshal(jsonData, &test)
	if err != nil{
		fmt.Println(err)
		return
	}

	for _,v := range test.List[0]{
		fmt.Println(v.Type)
	}
}

func (l *List) UnmarshalJSON(bytes []byte) error {
	out := make(List,0)
	re := regexp.MustCompile(`"Inner":{.*}`)
	objects := re.FindAll(bytes,-1)
	for _,v := range objects{
		inner := Inner{}
		s := strings.TrimLeft(string(v),`"Inner":`)
		err := json.Unmarshal([]byte(s),&inner)
		if err != nil{
			return err
		}
		out = append(out,inner)
	}
	*l = out
	return nil
}

output:

a1
b1
c1

You can't have multiple identical keys on the same object in JSON:

<!-- begin snippet: js hide: false console: true babel: false -->

<!-- language: lang-js -->

console.log(JSON.parse(`{
    "Inner":{"type":"a1"},      
    "Inner":{"type":"b1"},
    "Inner":{"type":"c1"}
}`))

<!-- end snippet -->

so without writing a custom unmarshaller, no.