`allOf` code generation does not work with types from other packages

[veger]

I have some standardized error struct which is used for all parts of my API, and put it into a separate package to make it easily reuasble

components:
  schemas:
    Error:
      type: object
      properties:
        message:
          type: string
        details:
          type: array
          items:
            $ref: "#/components/schemas/ErrorDetail"
    ErrorDetail:
      type: object
      properties:
        message:
          type: string
        target:
          type: string

This all works fine, but in some scenarios I'd like to have an example error message. So I use allOf to merge this struct with additional details:

allOf:
  - $ref: "#/components/schemas/Error" # I imported the errors.yaml in this components/schema to make errors.Error available.
  - type: object
    properties:
      message:
        example: "File non-existing.txt not found"

This results in the follow code:

type FileNotFound struct {
	// Optional list of additional error details.
	Details *[]ErrorDetail `json:"details,omitempty"`
	Message interface{}    `json:"message"`
}

The problem is that ErrorDetail is not defined (it is defined in another package containing the generated code of errors.yaml). Error itself is working as the code generator created this line

type Error = externalRef0.Error

Workaround

Import ErrorDetail in the yaml file as well:

    ErrorDetail:
      # This is needed for workaround a code generation bug
      $ref: "./errors.yaml#/components/schemas/ErrorDetail"

and it generates

type ErrorDetail = externalRef0.ErrorDetail

Unfortunately, linter detect that the ErrorDetail object is not used/referenced, so it issues a warning (in my IDE)

[veger]

Related to #648 ?