			     -*- Text -*-

Bugs tested: 1822

1. Create a listener and either type the following into it or create a
   file contain the following and "use" it :-

     Shell.Options.set (Shell.Options.Mode.debugging, true);

     fun foldl f z [] = z
       | foldl f z (x::xs) = foldl f (f (z, x)) xs;

     fun sum xs = foldl op+ 0 xs;

     Shell.Trace.breakpoint "sum";

     sum [1,2,3];

2. This should pop up a GUI stack browser.

3. Look at the local variables section in the stack browser.

4. If it is empty or contains "<empty>" then the test has passed and
   you can stop.  

5. If it contains one or more anomalous values, then submit a bug
   report.  An anomalous value should look like "<<invalid integer>:_>",
   "<<invalid list>:_>", ... etc., but due to 2911, you are
   unlikely to see such a value and instead are likely to see a "_"
   instead.

6. Press the <step> button at the top of the stack browser and goto 3.
