[m-users.] problem with unique modes

Mark Brown mark at mercurylang.org
Fri Jun 19 08:56:39 AEST 2015

On Tue, Jun 16, 2015 at 3:52 PM, Matthias G├╝demann
<matthias.guedemann at googlemail.com> wrote:
> also in this thread, Edsko de Vries managed to abuse insts to duplicate
> the IO state, this still works (rotd-06-04)
> http://www.mercurylang.org/list-archives/users/2008-July/004782.html

Please read Julien's remarks made at the time. The inst
`bound(mk_pair(unique, ground))' does not make sense, and ought to be
rejected before mode analysis starts.

Given that nested unique modes are not supported at all, it would
hardly be a high priority to check for unique insts wrongly occurring
inside bound insts. It isn't something that users will stumble upon
unsuspectingly, in my view.

> Is this topic still worked on?

You mean are people still abusing insts in an attempt to prove that
Mercury doesn't work? You tell me. ;-)


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