Correction: Strange Error in Mozart 1.2.5 Upon Usage of '!' Operator

[Benjamin L. Russell]

For some reason, I get an error message every time
when I try to run one of the code snippets in the
online Tutorial of Oz (see Section 5.5: Anonymous
Procedures and Variable Initialization at
http://www.mozart-oz.org/documentation/tutorial/node5.html#chapter.control
).

Although this tutorial is designed for Mozart 1.3.1,
the corresponding code for the downloadable tutorial
for Mozart 1.2.5 is identical.

Specifically, here is the code snippet:

----- code begins immediately after this line -----
local
   Y = 1
in
   local
      M = f(M Y)
      [X1 !Y] = L
      L = [1 2]
   in
      {Browse [M L]}
   end
end
----- code ends immediately before this line -----

Here is the corresponding error message:

----- error begins immediately after this line -----
%********************** static analysis error
*******************
%**
%** equality constraint failed
%**
%** First value:             1
%** Second value:            2
%** Original assertion:      [X1<optimized> 1] = [1 2]
%** Offending expression in: file "Oz", line 85,
column 85
%** in file "Oz", line 90, column 10
%** ------------------ rejected (1 error)
----- error ends immediately before this line -----

Any ideas?

-- Benjamin L. Russell