Question/suggestion about exceptions

[Graham St Jack]

Is there a way to automatically keep track of what exceptions may be 
thrown by a function or method? Ideally, what I am looking for is 
something like Java's "throws" keyword, but I would be happy with almost 
anything.

It is way too hard to develop reliable code of any size that uses 
exceptions extensively, because as things change, you lose track of what 
exceptions are thrown from where. Some sort of compiler support would 
make this a lot easier.

What I had in mind was an optional compiler warning and a new "throws" 
keyword. The compiler would (optionally) issue a warning if a function 
or method can throw an exception that it hasn't declared that it 
"throws". With this assistance, it becomes is easy to keep track of what 
can be thrown from where. Making it a warning and optional stops it from 
breaking existing code, and makes quick code hacks easy to write still.

Thoughts?