Handle $ref as a parameter

[dickermoshe]

Example Schema

swagger: '2.0'
info:
  description: "This spec is for testing rust-server-specific things"
  version: 2.3.4
  title: rust-server-test
schemes:
  - http
paths:
  /dummy:
    get:
      summary: A dummy endpoint to make the spec valid.
      operationId: dummyGet
      responses:
        '200':
          description: Success
    put:
      operationId: dummyPut
      parameters:
        - $ref: '#/parameters/nested_response'
      responses:
        '200':
          description: Success
  /html:
    post:
      summary: Test HTML handling
      consumes: [text/html]
      produces: [text/html]
      operationId: htmlPost
      parameters:
      - in: body
        name: body
        required: true
        schema:
          type: string
      responses:
        200:
          description: Success
          schema:
            type: string
  /file_response:
    get:
      summary: Get a file
      operationId: file_responseGet
      produces:
        - application/json
      responses:
        200:
          description: Success
          schema:
            type: file
  /raw_json:
    get:
      summary: Get an arbitrary JSON blob.
      operationId: raw_jsonGet
      responses:
        200:
          description: Success
          schema:
            type: object
  /solo-object:
    post:
      summary: Send an arbitrary JSON blob
      operationId: solo_objectPost
      consumes:
        - application/json
      parameters:
        - name: value
          in: body
          required: true
          schema:
            type: object
      responses:
        '204':
          description: OK
  /post-yaml:
    post:
      description: Test sending an arbitrary unsupported format - e.g. YAML
      operationId: post_yaml
      consumes:
        - application/yaml
      parameters:
        - name: value
          description: The YAML body to test
          in: body
          required: true
          schema:
            type: string
      responses:
        '204':
          description: OK
  /get-structured-yaml:
    get:
      description: Test returning arbitrary structured YAML
      operationId: getStructuredYaml
      produces:
        - application/yaml
      responses:
        '200':
          description: OK
          schema:
            $ref: '#/definitions/get_yaml_response'
  /allOf:
    get:
      description: Test getting an object which uses allOf
      operationId: AllOf_Get
      responses:
        '200':
          description: OK
          schema:
            $ref: '#/definitions/allOfObject'

parameters:
  nested_response:
    name: nested_response
    in: body
    required: true
    schema:
      # Erroneously ends up as `Option<models::InlineObject>`
      properties:
        id:
          type: string
        password:
          type: string
      required:
        - id
definitions:
  additionalPropertiesObject:
    description: An additionalPropertiesObject
    type: object
    additionalProperties:
      type: string
    example: "foo"
  allOfObject:
    properties:
      sampleProperty:
        type: string
    allOf:
    - $ref: '#/definitions/baseAllOf'
  baseAllOf:
    type: object
    properties:
      sampleBaseProperty:
        type: string
  aNullableContainer:
    type: object
    properties:
      NullableThing:
        type: string
        x-nullable: true
      RequiredNullableThing:
        type: string
        x-nullable: true
    required:
      - RequiredNullableThing
  ObjectOfObjects:
    description: An object of objects
    type: object
    properties:
      inner:
        type: object
        required:
          - required_thing
        properties:
          required_thing:
            type: string
          optional_thing:
            type: integer
  get_yaml_response:
    description: structured response
    type: object
    properties:
      value:
        description: Inner string
        type: string
  # Currently broken - see https://github.com/OpenAPITools/openapi-generator/issues/8
  # ArrayOfObjects:
  #   description: An array of objects
  #   type: array
  #   items:
  #     properties:
  #       filename:
  #         description: A non-required property
  #         type: string
  #       contents:
  #         description: A required property
  #         type: string
  #     required:
  #     - contents
  #     type: object