typeless reindex being called against indexes with `doc` mapping

mix_type_and_reindex

PUT _template/template_test
{
  "index_patterns": ["test*"],
  "settings": {
    "number_of_shards": 1
  },
  "mappings": {
    "doc": {
      "dynamic_templates": [
          {
            "strings": {
              "match_mapping_type": "string",
              "mapping": {
                "type": "keyword"
              }
            }
          }
        ],
        "properties": {
          "type": {
            "type": "keyword"
          }
        }
    }
  }
}

POST test1/doc
{
  "other": "bar"
}

POST test1/doc 
{
  "type": "foo"
}

POST _reindex
{
  "source": {
    "index": "test1"
  },
  "dest": {
    "index": "test2"
  }
}

> {
  "took": 215,
  "timed_out": false,
  "total": 2,
  "updated": 0,
  "created": 1,
  "deleted": 0,
  "batches": 1,
  "version_conflicts": 0,
  "noops": 0,
  "retries": {
    "bulk": 0,
    "search": 0
  },
  "throttled_millis": 0,
  "requests_per_second": -1,
  "throttled_until_millis": 0,
  "failures": [
    {
      "index": "test2",
      "type": "_doc",
      "id": "x79EEGgB0R88jZo7MC16",
      "cause": {
        "type": "mapper_parsing_exception",
        "reason": "Root mapping definition has unsupported parameters:  [doc : {properties={other={type=keyword}}}]"
      },
      "status": 400
    }
  ]
}