Thanks everyone for the explanation, and the rather convoluted
discussion of the type system, which I don't really understand.

I'd just like to add that this error bit me in a real program, and it
would be nice if OCaml detected this common case and warned about it:

  if cond then (
    ...
    raise Exn
  )
  next_stmt       <-- catastrophic failure, because this statement
                      is silently ignored

Rich.

-- 
Richard Jones.  http://www.annexia.org/  http://www.j-london.com/
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