HelpPage generates samples based on the return type of the actions. If IHttpActionResult is the declarated return type of the action, then HelPage will not be able to generate samples. This behavior is not something new and users today already would see this experience if someone returns the type HttpResponseMessage.
There is a workaround for this in HelpPage, where users can explicitly set samples for specific actions which return HttpResponseMessage and this workaround could be used for actions returning IHttpActionResult too.
But this workaround would be too cumbersome on users as going forward users might tend to return IHttpActionResult from all their actions due to their easy testability.
David & Yao already have some ideas regarding this and this issue is to keep track of it.
There is a workaround for this in HelpPage, where users can explicitly set samples for specific actions which return HttpResponseMessage and this workaround could be used for actions returning IHttpActionResult too.
But this workaround would be too cumbersome on users as going forward users might tend to return IHttpActionResult from all their actions due to their easy testability.
David & Yao already have some ideas regarding this and this issue is to keep track of it.