Generated compile error: discriminator field is set but not declared

This is the type definition in the json specification file:

{
   "swagger": "2.0",
   ...,
   "definitions":{
      ...,
      "Message":{
         "type":"object",
         "discriminator":"msg_type",
         "title":"Message"
      },

      ...
   }
}

This is the java class that gets generated:

public class Message {
  public Message() {
    this.msgType = this.getClass().getSimpleName();
  }

  ...

The correct generated code would be:

public class Message {
  String msgType;

  public Message() {
    this.msgType = this.getClass().getSimpleName();
  }

  ...

Feels like it would be a simple fix, I'd do it myself but I don't know how. If anyone wants to point me in the right direction I can try and put in a PR.

Inspect the Java generator template responsible for discriminator fields and compare it with the generated Message class shown in the issue. Confirm that the discriminator assignment has a corresponding field declaration, then verify that the generated class compiles without the reported error.