This mode supports most of D's syntax, including nested /+ +/
  comments and backquote `string literals`.

  This mode has been dubbed "2.0" because it is a complete rewrite
  from scratch.  The previous d-mode was based on cc-mode 5.28 or
  so.  This version is based on the cc-mode 5.30 derived mode
  example by Martin Stjernholm, 2002.