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diff --git a/third_party/rust/zerofrom-derive/examples/zf_derive.rs b/third_party/rust/zerofrom-derive/examples/zf_derive.rs
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index 0000000000..a1bde83733
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+++ b/third_party/rust/zerofrom-derive/examples/zf_derive.rs
@@ -0,0 +1,113 @@
+// This file is part of ICU4X. For terms of use, please see the file
+// called LICENSE at the top level of the ICU4X source tree
+// (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).
+
+#![allow(unused)]
+
+use std::borrow::Cow;
+use zerofrom::ZeroFrom;
+use zerovec::{maps::ZeroMapKV, ule::AsULE, VarZeroVec, ZeroMap, ZeroVec};
+
+#[derive(ZeroFrom, Copy, Clone)]
+pub struct IntExample {
+    x: u32,
+}
+
+#[derive(ZeroFrom, Copy, Clone)]
+pub struct GenericsExample<T> {
+    x: u32,
+    y: T,
+}
+
+#[derive(ZeroFrom, Copy, Clone)]
+pub struct GenericsExampleWithDefault<T, U = usize> {
+    x: T,
+    y: U,
+}
+
+#[derive(ZeroFrom)]
+pub struct CowExample<'a> {
+    x: u8,
+    y: &'a str,
+    z: Cow<'a, str>,
+    w: Cow<'a, [u8]>,
+}
+
+#[derive(ZeroFrom)]
+pub struct ZeroVecExample<'a> {
+    var: VarZeroVec<'a, str>,
+    vec: ZeroVec<'a, u16>,
+}
+
+#[derive(ZeroFrom)]
+pub struct ZeroVecExampleWithGenerics<'a, T: AsULE> {
+    gen: ZeroVec<'a, T>,
+    vec: ZeroVec<'a, u16>,
+    bare: T,
+}
+
+#[derive(ZeroFrom)]
+pub struct HasTuples<'data> {
+    pub bar: (&'data str, &'data str),
+}
+
+pub fn assert_zf_tuples<'b>(x: &'b HasTuples) -> HasTuples<'b> {
+    HasTuples::zero_from(x)
+}
+pub fn assert_zf_generics<'a, 'b>(
+    x: &'b ZeroVecExampleWithGenerics<'a, u8>,
+) -> ZeroVecExampleWithGenerics<'b, u8> {
+    ZeroVecExampleWithGenerics::<'b, u8>::zero_from(x)
+}
+
+#[derive(ZeroFrom)]
+pub struct ZeroMapGenericExample<'a, T: for<'b> ZeroMapKV<'b> + ?Sized> {
+    map: ZeroMap<'a, str, T>,
+}
+
+pub fn assert_zf_map<'b>(x: &'b ZeroMapGenericExample<str>) -> ZeroMapGenericExample<'b, str> {
+    ZeroMapGenericExample::zero_from(x)
+}
+
+#[derive(Clone, ZeroFrom)]
+pub struct CloningZF1 {
+    #[zerofrom(clone)] // Vec is not ZeroFrom, so it needs to be cloned
+    vec: Vec<u8>,
+}
+
+#[derive(Clone, ZeroFrom)]
+pub struct CloningZF2<'data> {
+    #[zerofrom(clone)] // Cow is ZeroFrom, but we force a clone
+    cow: Cow<'data, str>,
+}
+
+#[derive(ZeroFrom)]
+pub enum CloningZF3<'data> {
+    Cow(#[zerofrom(clone)] Cow<'data, str>),
+}
+
+#[derive(ZeroFrom)]
+#[zerofrom(may_borrow(T))] // instead of treating T as a copy type, we want to allow zerofromming T too
+pub struct GenericsThatAreAlsoZf<T> {
+    x: T,
+    y: Option<T>,
+}
+
+pub fn assert_zf_generics_may_borrow<'a, 'b>(
+    x: &'b GenericsThatAreAlsoZf<&'a str>,
+) -> GenericsThatAreAlsoZf<&'b str> {
+    GenericsThatAreAlsoZf::<&'b str>::zero_from(x)
+}
+
+#[derive(ZeroFrom)]
+pub struct UsesGenericsThatAreAlsoZf<'a> {
+    x: GenericsThatAreAlsoZf<&'a str>,
+}
+
+// Ensure it works with invariant types too
+#[derive(ZeroFrom)]
+pub struct UsesGenericsThatAreAlsoZfWithMap<'a> {
+    x: GenericsThatAreAlsoZf<ZeroMap<'a, str, str>>,
+}
+
+fn main() {}