map_ = walkExpr(map_, init)
	key = walkExpr(key, init)

	t := map_.Type()
	fast := mapfast(t)
	key = mapKeyArg(fast, n, key, false)
	return mkcall1(mapfndel(mapdelete[fast], t), nil, init, reflectdata.DeleteMapRType(base.Pos, n), map_, key)
}

// walkLenCap walks an OLEN or OCAP node.
func walkLenCap(n *ir.UnaryExpr, init *ir.Nodes) ir.Node {
	if isRuneCount(n) {