class ActionController::UnpermittedParameters

# => ActionController::UnpermittedParameters: found unpermitted parameters: a, b
params.permit(:c)
params = ActionController::Parameters.new(a: “123”, b: “456”)
is set to :raise.
ActionController::Parameters.action_on_unpermitted_parameters
Raised when a supplied parameter is not expected and

def initialize(params) # :nodoc:

:nodoc: 
def initialize(params) # :nodoc:
  @params = params
  super("found unpermitted parameter#{'s' if params.size > 1 }: #{params.join(", ")}")
end