MapCSS: make class selectors work for parent/child selectors

[simon04]

Make the snipped from ticket:10120#comment:1 work. The difficulty is to determine the class water_area for the second primitive. Currently the matching process is as follows:

Consider as an example a dataset containing landuse=reservoir X=1 and landuse=reservoir Y=1 which overlap. When performing the matching process …

1. MapCSS Environment is set empty.
2. landuse=reservoir X=1 matches first rule rule. water_area is set in environment.
3. All possible crossing primitives are tested with an empty Environment (since the Environment associated to landuse=reservoir X=1 cannot be used)
4. landuse=reservoir Y=1 doesn't match the selector area:closed:areaStyle.water_area since water_area isn't set in the environment

[simon04]

In 7280/josm:

fix #10120 see #10215 - Validator: do not warn "Overlapping Water Areas" for overlaps of water areas with normal areas

[simon04]

Ticket #11523 has been marked as a duplicate of this ticket.

The example from ticket:11523#comment:description

way[highway] > node { set .is_in_highway; }

node.is_in_highway < area[!highway] {
        throwWarning: tr("you should not attach the area to the highway");
}

[anonymous]

Is it possible to target crossing ways with mapCSS?