The current implementation does not yet completely implement the
Mercury language.  The main limitations of the current implementation
are the following:

* We do not allow definite aliasing in the mode system.
  Without this, partially instantiated modes are unusable, 
  and so are nested unique modes :-(

* The compiler does not yet use structure reuse or compile-time
  garbage collection to exploit unique modes :-(

* Type inference and mode inference are a bit imperfect.

We are working on eliminating all of these problems. 

In addition, design decisions in this implementation have imposed the
following fixed limits:

* Predicates and functions can have at most about 1000 arguments.

* Higher order terms are limited to arity of about 500.

These limits can be lifted (with some effort), but would possibly incur
performance penalties. Contact the Mercury team (mercury@cs.mu.oz.au) if
you find these limits are affecting your application.