[m-rev.] for review: Define behaviour of string.to_char_list (and rev) on ill-formed sequences.

[Peter Wang]

On Mon, 21 Oct 2019 14:06:40 +1100, Peter Wang <novalazy at gmail.com> wrote:
>                                      Since `pragma obsolete' cannot warn
> about uses of a particular mode of a predicate only, I suggest we mark
> the predicates obsolete

Having tried it, tainting the forward modes with `pragma obsolete'
creates a lot of busy work to convert predicate calls to function calls,
essentially for no gain. The reverse modes are hardly ever used in the
Mercury system, and probably the same is true in other projects.

I think simply deleting the reverse modes (with a suitable deprecation
period) will annoy fewer people.

Peter