Exported classes don't have any indication where they come from

[floitschG]

When a class is exported, then it should be visible where that class comes from.
For example, the Rectangle class in dart:html is just a reexport from dart:math:
export 'dart:math' show Rectangle, Point;
Currently it is not visible that this relationship exists (which means that it is, for example, not possible to know that html.Point is assignable to math.Point).

https://api.dartlang.org/1.12.1/dart-html/Rectangle-class.html

[sethladd]

Thanks for the feedback!

[jcollins-g]

The canonicalization system in dartdoc now makes these relationships much more clear by deduping the various instances and correctly rendering inheritance; please reopen if this still isn't clear.