class Sass::Script::Value::String

def check_deprecated_interp
  return unless @deprecated_interp_equivalent
  @@interpolation_deprecation.warn(source_range.file, source_range.start_pos.line, <<WARNING)
 interpolation near operators will be simplified in a future version of Sass.
reserve the current behavior, use quotes:
@deprecated_interp_equivalent}
ING
end