class Ransack::Search

def method_missing(method_id, *args)

params hash is built (#1472).
A scope wins over an attribute of the same name, as it does when the 
def method_missing(method_id, *args)
  method_name = method_id.to_s
  getter_name = method_name.sub(/=$/, ''.freeze)
  if @context.ransackable_scope?(getter_name, @context.object)
    if method_name =~ /=$/
      add_scope getter_name, args.size == 1 ? args.first : args
    else
      @scope_args[method_name]
    end
  elsif base.attribute_method?(getter_name)
    base.send(method_id, *args)
  else
    super
  end
end