anchor.diff:          |+> Instance [
                   "schemaTypeInfo" =@ TypeInfo
                   "tagName" =@ T<string>
  +
  +                // CSSOM
  +                "scrollTop" =? T<double>
  +                "scrollLeft" =? T<double>
  +                "scrollWidth" =? T<double>
  +                "scrollHeight" =? T<double>
  +                "clientTop" =? T<double>
  +                "clientLeft" =? T<double>
  +                "clientWidth" =? T<double>
  +                "clientHeight" =? T<double>
  +
  +                "getClientRects" => T<unit> ^-> Type.ArrayOf DOMRect
  +                "getBoundingClientRect" => T<unit> ^-> DOMRect
  +                // CSSOM
  +
                   "getAttribute" => T<string->string>
                   "setAttribute" => T<string> * T<string> ^-> T<unit>
                   "removeAttribute" => T<string->unit>
  
positive.code:                     T<string> ^-> DOMImplementation
                  "getDOMImplementationList" =>
                      T<string> ^-> DOMImplementationList
              ]
  
      let EventTarget =
  
negative.code:                 I.DOMImplementationList
                  I.DOMLocator
                  I.DOMStringList
                  I.DOMRect
                  I.Document
                  I.DocumentFragment
                  I.DocumentType
  