Open Radar

 
Summary:

A UIViewController contained within a UINavigationController has a topLayoutGuide property whose length correctly accounts for the height of the UINavigationBar and the status bar.

However, this value is not propagated correctly to child view controllers contained within the UIViewController.

Steps to Reproduce:

See attached file for source code. Explanation is:

Add a custom container controller as a child view controller of a UINavigationController, as such:
 
UINavigationController
    TSContainerController
        TSChildViewController
 
- The TSContainerController's topLayoutGuide is correct (64 points)
- The TSChildViewController's topLayoutGuide is incorrect (20 points)

Expected Results:

A child view controller should incorporate its parent view controller's topLayoutGuide length.

The docs for topLayoutGuide define the screen position as "If a navigation bar is visible onscreen, the bottom of the navigation bar," which is not true. A navigation bar is visible onscreen, but the the topLayoutGuide doesn't incorporate it.

Actual Results:

Child view controller only incorporates the height of the status bar.

Regression:

Notes:

I haven't tested if this is also true with bottomLayoutGuide.