Generate spec: Unable to find responses defined in other package using swagger:operation

[aasikraja]

Swagger operation is unable to find definitions for models defined in another package when generating spec. I am getting "$refs must reference a valid location in the document " error when opening the generated yaml using swagger editor.

How to annotate and generate spec in this case?

File model/user.go:
package model

type User struct {
        ID        string   `json:"id"`
}
// User response payload
// swagger:response User
type swaggUserInfo struct {
        // in:body
        Body model.User
}

File docs/docs.go:
package docs
import "xxx/model"

// swagger:operation GET /user queryUser
// ---
// responses:
//   '200':
//     schema:
//       "$ref": "#/definitions/User"

Environment

swagger version: v0.21.0
go version: go1.12.12
OS: RHEL