Summary:
Litho uses an idiom as follows. `Component.Builder` has an abstract method `T getThis()` which is supposed to be implemented as `{return this;}`.
I believe the reason it's there is to have covariant return types in subclasses, though this doesn't really matter.
We don't do dynamic dispatch, so instead of summarising `getThis` as having a return ownership of `OwnedIf({ 0 })` we just return `Unowned`.
This is generating many false positives, which are really hard to debug.
Here I'm special-casing any abstract method whose return type is equal to that of it's only argument, to return conditional ownership.
Reviewed By: da319
Differential Revision: D8947992
fbshipit-source-id: 33c7e952d
Nikos Gorogiannis