Stack traces

[Andrew Haley]

Nic Ferrier writes:
 > I've noticed a small but annoying problem with Throwable.
 > 
 > The fillinStackTrace gets the whole stack trace, not the stack trace
 > from  where the error occurred.
 > 
 > That means that Throwable is always in the stack trace.
 > 
 > That's not right is it? It's certainly annoying when you're trying to
 > debug stuff.

fillinStackTrace() doesn't know where it's been called from, so it
starts with the frame above itself.  Generally, that's Throwable().
However, if you call fillinStackTrace() directly from a method
foo.bar(), you _do_ want foo.bar() to appear in the stack trace.  

We could get around this by having a privateFillinStackTrace() that
Throwable() calls.  Is it worth it?  According to the ABI doc,
Throwable() calls fillInStackTrace(), so I don't even know if this
would be legal.

Andrew.