water area inside water area

[Geimas5]

Attached is a case that would be nice if was caught by the validation rules.

[Don-vip]

It's not an overlap but an identical shape. If we change the tags to building=yes we don't get "overlapping buildings" but "Building inside building" warning:

/* Building inside building (spatial test) */
*[building][building!~/no|entrance/][any(tag("layer"),"0") = any(parent_tag("layer"),"0")] ∈
area[building][building!~/no|entrance/] {
  throwWarning: tr("Building inside building");
}

/* Building overlapping building (spatial test) */
area[building][building!~/no|entrance/] ⧉ area[building][building!~/no|entrance/] {
  throwWarning: tr("Overlapping buildings");
}

We have an overlap water area check, it works:

/* Overlapping areas (spatial test) */
area[natural =~ /^(water|wetland|coastline)$/], area[landuse=reservoir] {
  set water_area;
}

/* area:closed:areaStyle.water_area ⧉ area:closed:areaStyle.water_area -- does not work for now -- see ticket#10215 */
area:closed:areaStyle[natural =~ /^(water|wetland|coastline)$/] ⧉ area:closed:areaStyle.water_area,
area:closed:areaStyle[landuse=reservoir]                        ⧉ area:closed:areaStyle.water_area {
  throwWarning: tr("Overlapping Water Areas");
}

So what's missing is a "water area inside water area" check.

[Don-vip]

In 16145/josm:

fix #18937 - add "water area inside water area" check