class JSON::GeneratorError

This exception is raised if a generator or unparser error occurs.

def detailed_message(...) 

def detailed_message(...)
  # Exception#detailed_message doesn't exist until Ruby 3.2
  super_message = defined?(super) ? super : message
  if @invalid_object.nil?
    super_message
  else
    "#{super_message}\nInvalid object: #{@invalid_object.inspect}"
  end
end

def initialize(message, invalid_object = nil) 

def initialize(message, invalid_object = nil)
  super(message)
  @invalid_object = invalid_object
end