I think I can answer that even though I am not a glassfish implementer. The reason the container does not provide exceptions during processing the files if beans.xml is omitted is that the container does NO process the files at all if the beans.xml file is omitted (for performance reasons I guess).
But I guess you could submit a feature request to the Weld project guys that implement this to have a special "verify" mode which slows down the application but checks for cases like this?
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