Open Radar

 
Summary:
When setting a custom subclass for a UI component in Interface Builder, the IB interface allows the selection of classes that are not reachable by the storyboard’s/xib’s main target. Further, in the case of a Swift-based project, it sets the Module setting to the target containing the class whether that’s sensible or not. For example, adding a custom button subclass that exists in the main app to a Today Widget’s view will set the Module value to the main app if the subclass has not been added to the Widget’s target.

Steps to Reproduce:
1. Start with a basic project that includes an app and a Today Widget.
2. Add a button subclass to the app.
3. Add a button to the Today Widget’s storyboard.
4. Set the button’s class to the subclass created in #2.
5. The button will appear correctly in Interface Builder but will fail loading at runtime.

Expected Results:
Xcode should warn that the button subclass is not reachable, possibly prompting to add it to the target.

Actual Results:
The custom button will appear correctly in Interface Builder but will fail loading at runtime.