Open Radar

 
Summary:
In iOS 10 and below, the text of the back button would hide when the navigation item's title was too long.

in iOS 11 with large titles enabled, the behaviour is kept when running at narrow size classes (iPhone portrait, or iPad in split screen) even though there can be no overlap between the title and the back button (the back button sits atop the title). This leads to the back button's text being shown incosnsitently

Steps to Reproduce:
(Xcode project attached for demo)

- Create a Navigation Controller in Interface Builder, add a root view controller
- Turn on “Prefers Large Titles” on the navigation controller
- Add a second controller pushed (“show” segue) form the first one
- Add a navigation item to the child controller and set a long title
- Run on a narrow size class (device or simulator)

Expected Results:
The back button always shows the title of the previous view controller in the navigation stack

Actual Results:
The back button’s text is hidden if the title is long enough that it would overlap without `prefersLargeTitles`

Version:
iOS 11.0 beta 4 (15A5327g)

Notes:
The back button behaves properly on wide size classes (iPad full size)