The GNU Emacs interface takes advantage of this to provide a source-linked debugger. We've removed the support for using a Prolog debugger on Mercury programs. Now that we have a working Mercury debugger, there's no longer any need to use a Prolog debugger for debugging Mercury code. Normally we would warn at least one or two releases in advance, if any feature is to be removed. We've added support for user-guided type specialization.
Numerous bug fixes.