allOf dart-dio-next bug

json

{
  "openapi": "3.0.0",
  "info": {
    "title": "TestApi",
    "version": "1.0"
  },
  "paths": {
    "/users/{userId}": {
      "parameters": [
        {
          "schema": {
            "type": "integer"
          },
          "name": "userId",
          "in": "path",
          "required": true,
          "description": "Id of an existing user."
        }
      ],
      "get": {
        "summary": "Get User Info by User ID",
        "tags": [],
        "operationId": "get-users-userId",
        "description": "Retrieve the information of the user with the matching user ID.",
        "responses": {
          "200": {
            "description": "OK"
          }
        }
      }
    },
    "/user": {}
  },
  "components": {
    "schemas": {
      "User": {
        "type": "object",
        "properties": {
          "type": {
            "allOf": [
              {
                "$ref": "#/components/schemas/UserType"
              }
            ],
            "description": "type of user"
          }
        }
      },
      "UserType": {
        "type": "string",
        "title": "UserType",
        "enum": [
          "admin",
          "user"
        ]
      }
    }
  }
}