http://wiki.dlang.org/DIP53 Redesign currently implemented qualified constructor concept.
http://wiki.dlang.org/DIP49 Improved points from version 1: - Swap meanings of 'this(this) inout' and 'this(this) const' - Inout postblit now covers all cheap (== not rebind indirections) copies between same qualifiers Kenji Hara
