Before WikiPage can be made compatible with PageRecord, we first have to make sure WikiPage alwas represents a page that can exist on the wiki. A WikiPage should never be a SpecialPage, a section link, and interwiki link, etc.
- deprecate construction of WikiPage with a Title that does not represent a proper page
Once we are sure that the deprecation warning isn't triggered by anything that WMF uses:
- make WikiPage implement PageIdentity, make some methods throw when called on an instance that does not represent a proper page.
- make WikiPage implement ProperPageIdentity, make the constructor throw when given a PageIdentity that isn't proper.
We may even wait until 1.36 is branched.