use NonZeroU8

components/datetime/src/provider/time_zones.rs

@@ -7,7 +7,7 @@
 use alloc::borrow::Cow;
 use icu_pattern::{DoublePlaceholderPattern, SinglePlaceholderPattern};
 use icu_provider::prelude::*;
-use zerovec::{ZeroMap, ZeroMap2d};
+use zerovec::{ule::NichedOption, ZeroMap, ZeroMap2d};
 
 use icu_timezone::{provider::IsoMinutesSinceEpoch, TimeZoneBcp47Id, ZoneVariant};
 
@@ -202,7 +202,7 @@ pub struct MetazoneSpecificNamesV1<'data> {
 /// including in SemVer minor releases. While the serde representation of data structs is guaranteed
 /// to be stable, their Rust representation might not be. Use with caution.
 /// </div>
-pub type MetazoneId = u8;
+pub type MetazoneId = core::num::NonZeroU8;
 
 /// An ICU4X mapping to the metazones at a given period.
 /// See CLDR-JSON metaZones.json for more context.
@@ -226,5 +226,5 @@ pub struct MetazonePeriodV1<'data>(
     /// The default mapping between period and metazone id. The second level key is a wall-clock time represented as
     /// the number of minutes since the local [`EPOCH`](icu_timezone::provider::EPOCH). It represents when the metazone started to be used.
     #[cfg_attr(feature = "serde", serde(borrow))]
-    pub ZeroMap2d<'data, TimeZoneBcp47Id, IsoMinutesSinceEpoch, Option<MetazoneId>>,
+    pub ZeroMap2d<'data, TimeZoneBcp47Id, IsoMinutesSinceEpoch, NichedOption<MetazoneId, 1>>,
 );