> (Imagine two LazyExceptions in different threads getting
> raised simultaneously for the same parent exception -- how
> will the backtraces accumulate, exactly? There may not be a
> problem, but I think it bears investigation...)

There can't be two LazyExceptions with the same "original"
exception. The LazyException is created and stored in
Lazy@excpetion in the Mutex#synchronize block, along with
Lazy@result.

It can be thrown multiple times, concurrently, though. But
since both Exception@backtrace and LazyException@backtrace are
built when they are created (they are, aren't they?), I don't
see a problem.

gegroet,
Erik V. - http://www.erikveen.dds.nl/