Open Radar

 
Summary:
With voice over on, when scanning over a UITextView with an attributed string that has both a custom font, and a paragraph style, a crash will occur.  Interestingly, this appears to be specific to 64bit devices.  I’m unable to get it to crash on 32 bit devices.  And, if I disable the 64bit slice and deploy to a 64bit device, it no longer crashes.  Sample back traces of crash attached

Steps to Reproduce:
1) Launch included test project on a 64 bit device.  I’m using a iPhone 6+, and an iPad Air 2.
2) Enable voice over
3) Scan over the text with your finger, which prompts voice over to read the text line by line
4) The crash generally occurs when you reverse you scan direction from top to bottom to bottom to top.

Change the project’s Architectures setting from “Standard Architectures” to armv7.  Notice that the crash no longer occurs.

Expected Results:
Voice over should read the text line by line without crashing.

Actual Results:
Crash occurs on 64bit devices when complied for 64bit.

Regression:
Crash occurs on 64bit devices when compiles for 64bit.  Does not occur on 32 bit devices, or when compiling for 32bit only and running on a 64bit device.

Notes:
The only workaround I could find (other than disabling 64bit compilation) was to set the UITextView’s accessibilityTraits to UIAccessibilityTraitStaticText.  This prevents Voice over from reading the text line by line, and avoids the crash.