class Sass::Tree::PropNode

def check!
  if @options[:property_syntax] && @options[:property_syntax] != @prop_syntax
    raise Sass::SyntaxError.new(
      "Illegal property syntax: can't use #{@prop_syntax} syntax when :property_syntax => #{@options[:property_syntax].inspect} is set.")
  elsif resolved_value.empty?
    raise Sass::SyntaxError.new("Invalid property: #{declaration.dump} (no value)." +
      pseudo_class_selector_message)
  end
end