copy_to field referring parent field in elasticsearch

Question

Here is my mapping of Product document type. I have "copy_to" : "product_all" in mapping.
I am expecting value of label in brand should be copied in 'product_all' in product. Is it correct way of referring the field in outer object from inner object i.e. (product_all in type product from brand), below mapping doesn't work as I don't get results back for a query made on product_all field for the value of label in brand. Am I missing something?

{
  "product": {
    "_timestamp": {
      "enabled": true,
      "store": true
    },
    "_all": {
      "enabled": false
    },
    "dynamic": "strict",
    "properties": {
      "brand": {
        "properties": {
          "id": {
            "type": "long"
          },
          "label": {
            "type": "multi_field",
            "fields": {
              "label": {
                "type": "string",
                "index_analyzer": "productAnalyzer",
                "search_analyzer": "productAnalyzer"
              },
              "raw": {
                "type": "string",
                "index": "not_analyzed"
              }
            },
            "copy_to": "product_all"
          }
        }
      },
      "product_all": {
        "type": "string",
        "index_analyzer": "productAnalyzer",
        "search_analyzer": "productAnalyzer"
      }
    }
  }
}

Answer 1

I moved "copy_to":"product_all" inside label.label of mutifield. Now it works

"label": {
            "type": "multi_field",
            "fields": {
              "label": {
                "type": "string",
                "copy_to": "product_all"
                "index_analyzer": "productAnalyzer",
                "search_analyzer": "productAnalyzer"
              },
              "raw": {
                "type": "string",
                "index": "not_analyzed"
              }
            }

          }