I just saw a case in which an abort due to:
[warn] creating stub symbol to defer error: bad symbolic reference. A signature in TraceMonitor.class refers to term actors
[warn] in package scala which is not available.
[warn] It may be completely missing from the current classpath, or the version on
[warn] the classpath might be incompatible with the version used when compiling TraceMonitor.class.
triggered a cyclic reference error in supplement error message, which is not caught by `case _: Exception`, and consequently obscured the original error.