} else if id.equalTags(t) {
		return t, nil
	}
	id.RemakeString()
	return id, nil
}

// specializeRegion attempts to specialize a group region.
func specializeRegion(t *Tag) bool {
	if i := regionInclusion[t.RegionID]; i < nRegionGroups {
		x := likelyRegionGroup[i]
		if Language(x.lang) == t.LangID && Script(x.script) == t.ScriptID {
			t.RegionID = Region(x.region)
		}
		return true
	}
	return false
}

func (r Region) IsGroup() bool {
	if r == 0 {
		return false
	}
	return int(regionInclusion[r]) < len(regionContainment)
}

// Contains returns whether Region c is contained by Region r. It returns true
// if c == r.
func (r Region) Contains(c Region) bool {
	if r == c {
		return true
	}
	g := regionInclusion[r]
	if g >= nRegionGroups {
		return false
	}
	m := regionContainment[g]

	// Entry 20 - 3F
	0x0000000100000000,
}

// regionInclusion maps region identifiers to sets of regions in regionInclusionBits,
// where each set holds all groupings that are directly connected in a region
// containment graph.
// Size: 359 bytes, 359 elements
var regionInclusion = [359]uint8{
	// Entry 0 - 3F
	0x00, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06,