[m-dev.] mmc bug

[Peter Schachte]

Hi,

It seems that Mark's concern about mmc handling any>>ground modes was
justified.  The attached test program gives this error:

    ground.m:049: In predicate `ground.eq/4':
    ground.m:049:   warning: declared impure but actually pure.
    ground.m:057: In clause for `label((any >> ground))':
    ground.m:057:  mode error: argument 1 did not get sufficiently
    instantiated.
    ground.m:057:  Final instantiatedness of `HeadVar__1' was
    `bound((list.[]) ;
    ground.m:057:   list.'[|]'(any, any))',
    ground.m:057:   expected final instantiatedness was `ground'.
    ground.m:023: In `label1((any >> ground))':
    ground.m:023:   warning: determinism declaration could be tighter.
    ground.m:023:   Declared `nondet', inferred `det'.

Ignore the warnings at the beginning and end.  The error in the middle
suggests to me that mmc doesn't think an any can ever become ground.

-- 
Peter Schachte              You should always go to other people's funerals;
schachte at cs.mu.OZ.AU        otherwise, they won't come to yours.
www.cs.mu.oz.au/~schachte/      -- Yogi Berra 
Phone: +61 3 8344 1338      
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%----------------------------------------------------------------------------%
% Copyright (C) 2006 Peter Schachte
% This file may only be copied under the terms of the GNU General
% Public License - see the file COPYING included in the distribution
%----------------------------------------------------------------------------%
% 
% RCS     : $Id$
% Authors : schachte (Peter Schachte)
% Purpose : test case
%

:- module ground.
:- interface.

:- import_module list.
:- import_module int.

:- solver type fdvar.
:- pred new_fdvar(fdvar::oa) is det.
:- pred eq(fdvar::ia, fdvar::ia) is semidet.

:- pred label(list(fdvar)::(any>>ground)) is nondet.
:- pred label1(fdvar::(any>>ground)) is nondet.
:- func value(fdvar) = int is det.


:- implementation.

:- import_module propagation.
:- import_module any_util.


:- solver type fdvar
	where	representation	is int,
		initialisation	is new_fdvar,
		equality	is eq.


new_fdvar(V) :-
	promise_pure
	(   impure V = 'representation to any fdvar/0'(0)
	).

eq(X, Y) :-
	promise_pure
	(   impure invoke(eq(X, Y))
	).

:- impure pred eq(fdvar::ia, fdvar::ia, pqueue::di, pqueue::uo) is semidet.

eq(X, X, !PQ).


label([]).
label([X | Xs]):-
        label1(X),
        label(Xs).

label1(X) :-
	promise_pure
	(   unsafe_cast_to_ground(X)
	).

value(_) = 42.