Changes by: Aleksey Nogin (nogin at cs.caltech.edu)
Date: 2005-11-12 16:20:23 -0800 (Sat, 12 Nov 2005)
Revision: 8172
Log message:

      When a negative "sequent context" argument was too small (the absolute value
      too large), we were raising an "Invalid Argument: index out of bounds" instead
      of a proper RefineError.