Files
mercury/tests/valid/use_import_only_for_instance.m
2019-07-26 01:29:53 +02:00

57 lines
1.8 KiB
Mathematica

%---------------------------------------------------------------------------%
% vim: ft=mercury ts=4 sw=4 et
%---------------------------------------------------------------------------%
%
% The bug that this test case tests for is that the compiler reports
% the import of the "int" module below as unused, even though without it,
% it generates an error saying
%
% In clause for predicate `build_zones_to_dup_vars'/4:
% unsatisfiable typeclass constraints: `enum.enum(int)', `enum.enum(int)'.
%
% This constraint is imposed by the use of sparse_bitset(int).
:- module use_import_only_for_instance.
:- interface.
:- import_module list.
:- import_module map.
:- import_module sparse_bitset.
:- type pvar == int.
:- type zone == int.
:- type vars_to_zones == map(pvar, sparse_bitset(zone)).
:- type zones_to_dup_vars == map(zone, list(pvar)).
:- pred build_zones_to_dup_vars(pvar::in, sparse_bitset(zone)::in,
zones_to_dup_vars::in, zones_to_dup_vars::out) is det.
%---------------------------------------------------------------------------%
%---------------------------------------------------------------------------%
:- implementation.
:- import_module int.
build_zones_to_dup_vars(Var, Zones, !ZonesToDupVars) :-
ZoneList = sparse_bitset.to_sorted_list(Zones),
( if
ZoneList = [FirstZone, _SecondZone | _],
FirstZone \= 0
then
list.foldl(add_var_to_zone(Var), ZoneList, !ZonesToDupVars)
else
true
).
:- pred add_var_to_zone(pvar::in, zone::in,
zones_to_dup_vars::in, zones_to_dup_vars::out) is det.
add_var_to_zone(Var, Zone, !ZonesToDupVars) :-
( if map.search(!.ZonesToDupVars, Zone, DupVars0) then
DupVars = [Var | DupVars0],
map.det_update(Zone, DupVars, !ZonesToDupVars)
else
map.det_insert(Zone, [Var], !ZonesToDupVars)
).