Compiler doesn't report an error about required classes from libraries ending up in VerifyErrors at runtime

Steps to reproduce:

1. Import project attached in FB-29740 into Flash Builder.
2. Run the application.

Actual Results:

The application launches and displays a VerifyError complaining that:

VerifyError: Error #1014: Class org.spicefactory.lib.errors::CompoundError could not be found.
atflash.display::MovieClip/nextFrame()
atmx.managers::SystemManager/deferredNextFrame()[E:\dev\hero_private\frameworks\projects\framework\src\mx\managers\SystemManager.as:284]
atmx.managers::SystemManager/preloader_preloaderDocFrameReadyHandler()[E:\dev\hero_private\frameworks\projects\framework\src\mx\managers\SystemManager.as:2572]
atflash.events::EventDispatcher/dispatchEventFunction()
atflash.events::EventDispatcher/dispatchEvent()
atmx.preloaders::Preloader/timerHandler()[E:\dev\hero_private\frameworks\projects\framework\src\mx\preloaders\Preloader.as:512]
atflash.utils::Timer/_timerDispatch()
atflash.utils::Timer/tick()

Expected Results:

The compiler reports an error saying that the classes are missing.

Workaround (if any):

None.

The same bug is reproducible via command line mxmlc as well. (For a simple AS project dependent on lib1 (merged into code) which is dependent on lib2 (external)

SDK version is: 19989.