Misleading error message on has_parent query

[fkelbert]

Elasticsearch version 6.4.2

The has_parent query returns misleading error messages, referring to field type rather than field parent_type:

    "type": "illegal_argument_exception",
    "reason": "[has_parent] requires 'type' field"

and

    "type": "parsing_exception",
    "reason": "[has_parent] query does not support [type]",

To reproduce:

POST _search
{
  "query": {
    "has_parent": {
    }
  }
}

and

POST _search
{
  "query": {
    "has_parent": {
      "type": "test"
    }
  }
}

[elasticmachine]

Pinging @elastic/es-search-aggs

[jimczi]

The issue was fixed on master but never backported to 6x. It is backported now so I am closing this issue. Thanks for reporting @fkelbert .