UnusedPrivateClass has false positive behavior for deserialized items

[imanushin]

Code:

   fun readId() = 
       jacksonObjectMapper().readValue<Response>(content).id

  private class Response(
      val id: Int
  )

Expected Behavior

Response class is used, so rule "UnusedPrivateClass" skips it.

Observed Behavior

Rule "UnusedPrivateClass" warns, that Response class is private and is not used.

Context

Private classes for deserialization are very useful to hide interops inside deserialization wrappers.

Your Environment

• Version of detekt used: 1.2.1
• Version of Gradle used (if applicable): 6.0.1
• Operating System and version: Windows 7 x64
• Link to your project (if it's a public repository): NDA

[schalkms]

Thanks for reporting this bug.