Merging upstream version 1.75.0+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

18 files changed, 410 insertions, 1301 deletions

diff --git a/vendor/icu_provider_adapters/.cargo-checksum.json b/vendor/icu_provider_adapters/.cargo-checksum.json
index 7b2a6906a..833d0f9e7 100644
--- a/vendor/icu_provider_adapters/.cargo-checksum.json
+++ b/vendor/icu_provider_adapters/.cargo-checksum.json
@@ -1 +1 @@
-{"files":{"Cargo.toml":"bc35c9045058859105d040996e5f8f204a2337b832f1a23cf6f1d10fb1eb45ee","LICENSE":"4ad7541d66a407234e2c84902124cef325c29f3e966353efdb800bedb8b8da21","README.md":"e6a08c2bc307b66c93de20c2c366da896f7fd3f5e5eb402edd2eeba79476b600","src/any_payload.rs":"165d41d018a611a7ef25dab621bbd408e6ba22dde58365817944898de138be3e","src/either.rs":"02e646af7aa6d8af1a03e448bedb2498b026d418de8340a5be52b1d366ad9b6c","src/empty.rs":"1503b2f73b2a727a9e502ab7081da3261df470bc86b762ab5748c31fad8cfbc6","src/fallback/adapter.rs":"55188c9acb6ddc852b9218b14c97304e0378f9e40eedb0f0af41b5036a78e54f","src/fallback/algorithms.rs":"9409ad6f6f617d4433b9f6b303d131782877a0a10470533e3864b97355b9a3f1","src/fallback/mod.rs":"9a1ba8dcba21dbcb5acc4a019d640fffcfd2efd043bfa42a5690a9de593479d1","src/fallback/provider.rs":"ef8a835e3ed2b7871b6f6e78ae2e73575b26adc9e8e0b5a7170c8513e7fe3269","src/filter/impls.rs":"588918fdcadda3572844352bf22419910ee6430f3e5a6e7c5e012120ad2eb932","src/filter/mod.rs":"33a622b9684c5e445b2af8aec9cd3ba5dfe3b51d917dd2776b267657e6a5b72d","src/fork/by_error.rs":"450a24bfaa17e32899e4ba4286623b2b3b36af81fb5abd9b1e28a2af18c3b9dc","src/fork/macros.rs":"5aebb0134923fa9fa0fe7c16d2d85a1a29cf4ea49505187db56bf0bc8e984ad0","src/fork/mod.rs":"7378895128bf1ccc9de7f5675668ef922d3df7b84b04f68af4d5b49efe60341e","src/fork/predicates.rs":"314bf33144c6827cd3df05877d7c20fb64c9b18f6230e229340b8f04f4ccf4d3","src/helpers.rs":"0e5c8424c9e51956cd065d4ecf4f478bbc3978888b4bbb012ad3f5d6a7062fb1","src/lib.rs":"243ec29c6e5fbe59004f5774f1b252166b06a264e218a7209fe6ed83c25dd03a","tests/data/langtest/de/core/helloworld@1/de.json":"5a45b1d80567de8c4ff754f7dbe20c22477c1e00a9400b38397eb034f295b8f8","tests/data/langtest/de/manifest.json":"fa2f848cff051fd12a909389fbbc44b93ae1feb92cce466cc4381f9548443ea9","tests/data/langtest/ro/core/helloworld@1/ro.json":"b6b68292746dd6bb2d92d9c08e2753db556ec9c954a3b593b0b8999df550f298","tests/data/langtest/ro/manifest.json":"fa2f848cff051fd12a909389fbbc44b93ae1feb92cce466cc4381f9548443ea9"},"package":"f4ae1e2bd0c41728b77e7c46e9afdec5e2127d1eedacc684724667d50c126bd3"}
\ No newline at end of file
+{"files":{"Cargo.toml":"cc4c433c73faa394a0bd721e086c1dfcd238e4efd6540886632e4be4b62183df","LICENSE":"853f87c96f3d249f200fec6db1114427bc8bdf4afddc93c576956d78152ce978","README.md":"d91500cb944c05c04ed9e6920d139199a9d1892346de50dccbdce5cbef3b9174","src/any_payload.rs":"165d41d018a611a7ef25dab621bbd408e6ba22dde58365817944898de138be3e","src/either.rs":"02e646af7aa6d8af1a03e448bedb2498b026d418de8340a5be52b1d366ad9b6c","src/empty.rs":"1503b2f73b2a727a9e502ab7081da3261df470bc86b762ab5748c31fad8cfbc6","src/fallback/mod.rs":"7f0cfc915cb95d1681befc52ef51ecaec0c900043a15d3feba3e5a8cc23c39ff","src/filter/impls.rs":"17b6ba2c7c72b72a72fbc57f31eec0cbe52d631a87012f6604fb1bf2e9f9137d","src/filter/mod.rs":"896de77291b093886a210dcbb30498aef2c9afe4ce984bd2ac517323e96917b4","src/fork/by_error.rs":"d7fee843306ab8b6e5de2abea8efb4409d01e2faf15fcb2ab4f6ba3cb0f47a09","src/fork/macros.rs":"9e8c071d7c21b93b4d07672542ec994d2fde2c19f14dd30f5c969215c73ebda7","src/fork/mod.rs":"64502e4d8a667e1ec5aa8339e07c1f2e5b0021e6ee4ca06722f6a1793f0e2b0d","src/fork/predicates.rs":"1191f9ff1ae2196255effb50e245a3f80c2a4429ea3e46499f0284835a51c1c9","src/helpers.rs":"0e5c8424c9e51956cd065d4ecf4f478bbc3978888b4bbb012ad3f5d6a7062fb1","src/lib.rs":"243ec29c6e5fbe59004f5774f1b252166b06a264e218a7209fe6ed83c25dd03a","tests/data/blob.postcard":"ae4478ddd635aa0f816d2abae9057dc9df0d9963e6b78b1b8e8722b318a513c5","tests/data/config.json":"0ec2a3ec6338767cee5e9bd1c27dceafcc10c28b5e0380059b7faf2f0cf707b7","tests/data/langtest/de.json":"6016405e1d9c63c2df940953fc3ae064b1fc4c0e3676ed78fafe4ec84596dfa3","tests/data/langtest/de/core/helloworld@1/de.json":"5a45b1d80567de8c4ff754f7dbe20c22477c1e00a9400b38397eb034f295b8f8","tests/data/langtest/de/manifest.json":"fa2f848cff051fd12a909389fbbc44b93ae1feb92cce466cc4381f9548443ea9","tests/data/langtest/ro.json":"c6ba5912f3ef51357c2d92596cd13b78080aee257132395d900ba4c76450c9ca","tests/data/langtest/ro/core/helloworld@1/ro.json":"b6b68292746dd6bb2d92d9c08e2753db556ec9c954a3b593b0b8999df550f298","tests/data/langtest/ro/manifest.json":"fa2f848cff051fd12a909389fbbc44b93ae1feb92cce466cc4381f9548443ea9"},"package":"36b380ef2d3d93b015cd0563d7e0d005cc07f82a5503716dbc191798d0079e1d"}
\ No newline at end of file
diff --git a/vendor/icu_provider_adapters/Cargo.toml b/vendor/icu_provider_adapters/Cargo.toml
index 291a17ffc..72f4592a7 100644
--- a/vendor/icu_provider_adapters/Cargo.toml
+++ b/vendor/icu_provider_adapters/Cargo.toml
@@ -11,10 +11,12 @@
 
 [package]
 edition = "2021"
+rust-version = "1.66"
 name = "icu_provider_adapters"
-version = "1.2.0"
+version = "1.3.2"
 authors = ["The ICU4X Project Developers"]
 include = [
+    "data/**/*",
     "src/**/*",
     "examples/**/*",
     "benches/**/*",
@@ -24,23 +26,31 @@ include = [
     "README.md",
 ]
 description = "Adapters for composing and manipulating data providers."
+homepage = "https://icu4x.unicode.org"
 readme = "README.md"
 categories = ["internationalization"]
-license = "Unicode-DFS-2016"
+license-file = "LICENSE"
 repository = "https://github.com/unicode-org/icu4x"
 
 [dependencies.databake]
-version = "0.1.3"
+version = "0.1.6"
 features = ["derive"]
 optional = true
+default-features = false
 
 [dependencies.icu_locid]
-version = "1.2.0"
+version = "~1.3.2"
 features = ["zerovec"]
+default-features = false
+
+[dependencies.icu_locid_transform]
+version = "~1.3.2"
+default-features = false
 
 [dependencies.icu_provider]
-version = "1.2.0"
+version = "~1.3.2"
 features = ["macros"]
+default-features = false
 
 [dependencies.serde]
 version = "1.0"
@@ -52,15 +62,14 @@ optional = true
 default-features = false
 
 [dependencies.tinystr]
-version = "0.7.1"
+version = "0.7.3"
 features = ["zerovec"]
-
-[dependencies.yoke]
-version = "0.7.1"
+default-features = false
 
 [dependencies.zerovec]
-version = "0.9.4"
+version = "0.10.0"
 features = ["yoke"]
+default-features = false
 
 [dev-dependencies]
 
@@ -68,15 +77,13 @@ features = ["yoke"]
 datagen = [
     "std",
     "serde",
-    "dep:databake",
     "icu_provider/datagen",
-    "icu_locid/databake",
-    "zerovec/databake",
 ]
 serde = [
     "dep:serde",
     "zerovec/serde",
     "icu_locid/serde",
+    "icu_locid_transform/serde",
     "icu_provider/serde",
 ]
 std = [
diff --git a/vendor/icu_provider_adapters/LICENSE b/vendor/icu_provider_adapters/LICENSE
index 9858d01ab..9845aa5f4 100644
--- a/vendor/icu_provider_adapters/LICENSE
+++ b/vendor/icu_provider_adapters/LICENSE
@@ -1,49 +1,42 @@
-UNICODE, INC. LICENSE AGREEMENT - DATA FILES AND SOFTWARE
-
-See Terms of Use <https://www.unicode.org/copyright.html>
-for definitions of Unicode Inc.’s Data Files and Software.
-
-NOTICE TO USER: Carefully read the following legal agreement.
-BY DOWNLOADING, INSTALLING, COPYING OR OTHERWISE USING UNICODE INC.'S
-DATA FILES ("DATA FILES"), AND/OR SOFTWARE ("SOFTWARE"),
-YOU UNEQUIVOCALLY ACCEPT, AND AGREE TO BE BOUND BY, ALL OF THE
-TERMS AND CONDITIONS OF THIS AGREEMENT.
-IF YOU DO NOT AGREE, DO NOT DOWNLOAD, INSTALL, COPY, DISTRIBUTE OR USE
-THE DATA FILES OR SOFTWARE.
+UNICODE LICENSE V3
 
 COPYRIGHT AND PERMISSION NOTICE
 
-Copyright © 1991-2022 Unicode, Inc. All rights reserved.
-Distributed under the Terms of Use in https://www.unicode.org/copyright.html.
-
-Permission is hereby granted, free of charge, to any person obtaining
-a copy of the Unicode data files and any associated documentation
-(the "Data Files") or Unicode software and any associated documentation
-(the "Software") to deal in the Data Files or Software
-without restriction, including without limitation the rights to use,
-copy, modify, merge, publish, distribute, and/or sell copies of
-the Data Files or Software, and to permit persons to whom the Data Files
-or Software are furnished to do so, provided that either
-(a) this copyright and permission notice appear with all copies
-of the Data Files or Software, or
-(b) this copyright and permission notice appear in associated
-Documentation.
-
-THE DATA FILES AND SOFTWARE ARE PROVIDED "AS IS", WITHOUT WARRANTY OF
-ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
-WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
-NONINFRINGEMENT OF THIRD PARTY RIGHTS.
-IN NO EVENT SHALL THE COPYRIGHT HOLDER OR HOLDERS INCLUDED IN THIS
-NOTICE BE LIABLE FOR ANY CLAIM, OR ANY SPECIAL INDIRECT OR CONSEQUENTIAL
-DAMAGES, OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
-DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
-TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
-PERFORMANCE OF THE DATA FILES OR SOFTWARE.
-
-Except as contained in this notice, the name of a copyright holder
-shall not be used in advertising or otherwise to promote the sale,
-use or other dealings in these Data Files or Software without prior
-written authorization of the copyright holder.
+Copyright © 2020-2023 Unicode, Inc.
+
+NOTICE TO USER: Carefully read the following legal agreement. BY
+DOWNLOADING, INSTALLING, COPYING OR OTHERWISE USING DATA FILES, AND/OR
+SOFTWARE, YOU UNEQUIVOCALLY ACCEPT, AND AGREE TO BE BOUND BY, ALL OF THE
+TERMS AND CONDITIONS OF THIS AGREEMENT. IF YOU DO NOT AGREE, DO NOT
+DOWNLOAD, INSTALL, COPY, DISTRIBUTE OR USE THE DATA FILES OR SOFTWARE.
+
+Permission is hereby granted, free of charge, to any person obtaining a
+copy of data files and any associated documentation (the "Data Files") or
+software and any associated documentation (the "Software") to deal in the
+Data Files or Software without restriction, including without limitation
+the rights to use, copy, modify, merge, publish, distribute, and/or sell
+copies of the Data Files or Software, and to permit persons to whom the
+Data Files or Software are furnished to do so, provided that either (a)
+this copyright and permission notice appear with all copies of the Data
+Files or Software, or (b) this copyright and permission notice appear in
+associated Documentation.
+
+THE DATA FILES AND SOFTWARE ARE PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
+KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF
+THIRD PARTY RIGHTS.
+
+IN NO EVENT SHALL THE COPYRIGHT HOLDER OR HOLDERS INCLUDED IN THIS NOTICE
+BE LIABLE FOR ANY CLAIM, OR ANY SPECIAL INDIRECT OR CONSEQUENTIAL DAMAGES,
+OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
+WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
+ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THE DATA
+FILES OR SOFTWARE.
+
+Except as contained in this notice, the name of a copyright holder shall
+not be used in advertising or otherwise to promote the sale, use or other
+dealings in these Data Files or Software without prior written
+authorization of the copyright holder.
 
 —
 
diff --git a/vendor/icu_provider_adapters/README.md b/vendor/icu_provider_adapters/README.md
index 28a29e6bc..fcbdce2c3 100644
--- a/vendor/icu_provider_adapters/README.md
+++ b/vendor/icu_provider_adapters/README.md
@@ -1,5 +1,7 @@
 # icu_provider_adapters [![crates.io](https://img.shields.io/crates/v/icu_provider_adapters)](https://crates.io/crates/icu_provider_adapters)
 
+<!-- cargo-rdme start -->
+
 Adapters for composing and manipulating data providers.
 
 - Use the [`fork`] module to marshall data requests between multiple possible providers.
@@ -7,6 +9,8 @@ Adapters for composing and manipulating data providers.
 - Use the [`filter`] module to programmatically reject certain data requests.
 - Use the [`fallback`] module to automatically resolve arbitrary locales for data loading.
 
+<!-- cargo-rdme end -->
+
 ## More Information
 
 For more information on development, authorship, contributing etc. please visit [`ICU4X home page`](https://github.com/unicode-org/icu4x).
diff --git a/vendor/icu_provider_adapters/src/fallback/adapter.rs b/vendor/icu_provider_adapters/src/fallback/adapter.rs
deleted file mode 100644
index 8d9d79f2d..000000000
--- a/vendor/icu_provider_adapters/src/fallback/adapter.rs
+++ /dev/null
@@ -1,284 +0,0 @@
-// 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 ).
-
-use super::*;
-use crate::helpers::result_is_err_missing_locale;
-
-/// A data provider wrapper that performs locale fallback. This enables arbitrary locales to be
-/// handled at runtime.
-///
-/// # Examples
-///
-/// ```
-/// use icu_locid::locale;
-/// use icu_provider::prelude::*;
-/// use icu_provider::hello_world::*;
-/// use icu_provider_adapters::fallback::LocaleFallbackProvider;
-///
-/// let provider = icu_testdata::unstable_no_fallback();
-///
-/// let req = DataRequest {
-///     locale: &locale!("ja-JP").into(),
-///     metadata: Default::default(),
-/// };
-///
-/// // The provider does not have data for "ja-JP":
-/// DataProvider::<HelloWorldV1Marker>::load(&provider, req).expect_err("No fallback");
-///
-/// // But if we wrap the provider in a fallback provider...
-/// let provider = LocaleFallbackProvider::try_new_unstable(provider)
-///     .expect("Fallback data present");
-///
-/// // ...then we can load "ja-JP" based on "ja" data
-/// let response =
-///   DataProvider::<HelloWorldV1Marker>::load(&provider, req).expect("successful with vertical fallback");
-///
-/// assert_eq!(
-///     response.metadata.locale.unwrap(),
-///     locale!("ja").into(),
-/// );
-/// assert_eq!(
-///     response.payload.unwrap().get().message,
-///     "こんにちは世界",
-/// );
-/// ```
-#[derive(Clone, Debug)]
-pub struct LocaleFallbackProvider<P> {
-    inner: P,
-    fallbacker: LocaleFallbacker,
-}
-
-impl<P> LocaleFallbackProvider<P>
-where
-    P: DataProvider<LocaleFallbackLikelySubtagsV1Marker>
-        + DataProvider<LocaleFallbackParentsV1Marker>
-        + DataProvider<CollationFallbackSupplementV1Marker>,
-{
-    /// Create a [`LocaleFallbackProvider`] by wrapping another data provider and then loading
-    /// fallback data from it.
-    ///
-    /// If the data provider being wrapped does not contain fallback data, use
-    /// [`LocaleFallbackProvider::new_with_fallbacker`].
-    pub fn try_new_unstable(provider: P) -> Result<Self, DataError> {
-        let fallbacker = LocaleFallbacker::try_new_unstable(&provider)?;
-        Ok(Self {
-            inner: provider,
-            fallbacker,
-        })
-    }
-}
-
-impl<P> LocaleFallbackProvider<P>
-where
-    P: AnyProvider,
-{
-    /// Create a [`LocaleFallbackProvider`] by wrapping another data provider and then loading
-    /// fallback data from it.
-    ///
-    /// If the data provider being wrapped does not contain fallback data, use
-    /// [`LocaleFallbackProvider::new_with_fallbacker`].
-    pub fn try_new_with_any_provider(provider: P) -> Result<Self, DataError> {
-        let fallbacker = LocaleFallbacker::try_new_with_any_provider(&provider)?;
-        Ok(Self {
-            inner: provider,
-            fallbacker,
-        })
-    }
-}
-
-#[cfg(feature = "serde")]
-impl<P> LocaleFallbackProvider<P>
-where
-    P: BufferProvider,
-{
-    /// Create a [`LocaleFallbackProvider`] by wrapping another data provider and then loading
-    /// fallback data from it.
-    ///
-    /// If the data provider being wrapped does not contain fallback data, use
-    /// [`LocaleFallbackProvider::new_with_fallbacker`].
-    pub fn try_new_with_buffer_provider(provider: P) -> Result<Self, DataError> {
-        let fallbacker = LocaleFallbacker::try_new_with_buffer_provider(&provider)?;
-        Ok(Self {
-            inner: provider,
-            fallbacker,
-        })
-    }
-}
-
-impl<P> LocaleFallbackProvider<P> {
-    /// Wrap a provider with an arbitrary fallback engine.
-    ///
-    /// This relaxes the requirement that the wrapped provider contains its own fallback data.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// use icu_locid::locale;
-    /// use icu_provider::hello_world::*;
-    /// use icu_provider::prelude::*;
-    /// use icu_provider_adapters::fallback::{
-    ///     LocaleFallbackProvider, LocaleFallbacker,
-    /// };
-    ///
-    /// let provider = HelloWorldProvider;
-    ///
-    /// let req = DataRequest {
-    ///     locale: &locale!("de-CH").into(),
-    ///     metadata: Default::default(),
-    /// };
-    ///
-    /// // There is no "de-CH" data in the `HelloWorldProvider`
-    /// DataProvider::<HelloWorldV1Marker>::load(&provider, req)
-    ///     .expect_err("No data for de-CH");
-    ///
-    /// // `HelloWorldProvider` does not contain fallback data,
-    /// // but we can fetch it from `icu_testdata`, and then
-    /// // use it to create the fallbacking data provider.
-    /// let fallbacker =
-    ///     LocaleFallbacker::try_new_unstable(&icu_testdata::unstable())
-    ///         .expect("Fallback data present");
-    /// let provider =
-    ///     LocaleFallbackProvider::new_with_fallbacker(provider, fallbacker);
-    ///
-    /// // Now we can load the "de-CH" data via fallback to "de".
-    /// let german_hello_world: DataPayload<HelloWorldV1Marker> = provider
-    ///     .load(req)
-    ///     .expect("Loading should succeed")
-    ///     .take_payload()
-    ///     .expect("Data should be present");
-    ///
-    /// assert_eq!("Hallo Welt", german_hello_world.get().message);
-    /// ```
-    pub fn new_with_fallbacker(provider: P, fallbacker: LocaleFallbacker) -> Self {
-        Self {
-            inner: provider,
-            fallbacker,
-        }
-    }
-
-    /// Returns a reference to the inner provider, bypassing fallback.
-    pub fn inner(&self) -> &P {
-        &self.inner
-    }
-
-    /// Returns a mutable reference to the inner provider.
-    pub fn inner_mut(&mut self) -> &mut P {
-        &mut self.inner
-    }
-
-    /// Returns ownership of the inner provider to the caller.
-    pub fn into_inner(self) -> P {
-        self.inner
-    }
-
-    /// Run the fallback algorithm with the data request using the inner data provider.
-    /// Internal function; external clients should use one of the trait impls below.
-    ///
-    /// Function arguments:
-    ///
-    /// - F1 should perform a data load for a single DataRequest and return the result of it
-    /// - F2 should map from the provider-specific response type to DataResponseMetadata
-    fn run_fallback<F1, F2, R>(
-        &self,
-        key: DataKey,
-        mut base_req: DataRequest,
-        mut f1: F1,
-        mut f2: F2,
-    ) -> Result<R, DataError>
-    where
-        F1: FnMut(DataRequest) -> Result<R, DataError>,
-        F2: FnMut(&mut R) -> &mut DataResponseMetadata,
-    {
-        let key_fallbacker = self.fallbacker.for_key(key);
-        let mut fallback_iterator = key_fallbacker.fallback_for(base_req.locale.clone());
-        let base_silent = core::mem::replace(&mut base_req.metadata.silent, true);
-        loop {
-            let result = f1(DataRequest {
-                locale: fallback_iterator.get(),
-                metadata: base_req.metadata,
-            });
-            if !result_is_err_missing_locale(&result) {
-                return result
-                    .map(|mut res| {
-                        f2(&mut res).locale = Some(fallback_iterator.take());
-                        res
-                    })
-                    // Log the original request rather than the fallback request
-                    .map_err(|e| {
-                        base_req.metadata.silent = base_silent;
-                        e.with_req(key, base_req)
-                    });
-            }
-            // If we just checked und, break out of the loop.
-            if fallback_iterator.get().is_empty() {
-                break;
-            }
-            fallback_iterator.step();
-        }
-        base_req.metadata.silent = base_silent;
-        Err(DataErrorKind::MissingLocale.with_req(key, base_req))
-    }
-}
-
-impl<P> AnyProvider for LocaleFallbackProvider<P>
-where
-    P: AnyProvider,
-{
-    fn load_any(&self, key: DataKey, base_req: DataRequest) -> Result<AnyResponse, DataError> {
-        self.run_fallback(
-            key,
-            base_req,
-            |req| self.inner.load_any(key, req),
-            |res| &mut res.metadata,
-        )
-    }
-}
-
-impl<P> BufferProvider for LocaleFallbackProvider<P>
-where
-    P: BufferProvider,
-{
-    fn load_buffer(
-        &self,
-        key: DataKey,
-        base_req: DataRequest,
-    ) -> Result<DataResponse<BufferMarker>, DataError> {
-        self.run_fallback(
-            key,
-            base_req,
-            |req| self.inner.load_buffer(key, req),
-            |res| &mut res.metadata,
-        )
-    }
-}
-
-impl<P, M> DynamicDataProvider<M> for LocaleFallbackProvider<P>
-where
-    P: DynamicDataProvider<M>,
-    M: DataMarker,
-{
-    fn load_data(&self, key: DataKey, base_req: DataRequest) -> Result<DataResponse<M>, DataError> {
-        self.run_fallback(
-            key,
-            base_req,
-            |req| self.inner.load_data(key, req),
-            |res| &mut res.metadata,
-        )
-    }
-}
-
-impl<P, M> DataProvider<M> for LocaleFallbackProvider<P>
-where
-    P: DataProvider<M>,
-    M: KeyedDataMarker,
-{
-    fn load(&self, base_req: DataRequest) -> Result<DataResponse<M>, DataError> {
-        self.run_fallback(
-            M::KEY,
-            base_req,
-            |req| self.inner.load(req),
-            |res| &mut res.metadata,
-        )
-    }
-}
diff --git a/vendor/icu_provider_adapters/src/fallback/algorithms.rs b/vendor/icu_provider_adapters/src/fallback/algorithms.rs
deleted file mode 100644
index 0edc59304..000000000
--- a/vendor/icu_provider_adapters/src/fallback/algorithms.rs
+++ /dev/null
@@ -1,439 +0,0 @@
-// 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 ).
-
-use icu_locid::extensions::unicode::Key;
-use icu_locid::extensions_unicode_key as key;
-use icu_locid::subtags::Language;
-use icu_locid::LanguageIdentifier;
-use icu_provider::FallbackPriority;
-
-use super::*;
-
-const SUBDIVISION_KEY: Key = key!("sd");
-
-impl<'a> LocaleFallbackerWithConfig<'a> {
-    pub(crate) fn normalize(&self, locale: &mut DataLocale) {
-        let language = locale.language();
-        // 1. Populate the region (required for region fallback only)
-        if self.config.priority == FallbackPriority::Region && locale.region().is_none() {
-            // 1a. First look for region based on language+script
-            if let Some(script) = locale.script() {
-                locale.set_region(
-                    self.likely_subtags
-                        .ls2r
-                        .get_2d(&language.into(), &script.into())
-                        .copied(),
-                );
-            }
-            // 1b. If that fails, try language only
-            if locale.region().is_none() {
-                locale.set_region(self.likely_subtags.l2r.get(&language.into()).copied());
-            }
-        }
-        // 2. Remove the script if it is implied by the other subtags
-        if let Some(script) = locale.script() {
-            let default_script = self
-                .likely_subtags
-                .l2s
-                .get_copied(&language.into())
-                .unwrap_or(DEFAULT_SCRIPT);
-            if let Some(region) = locale.region() {
-                if script
-                    == self
-                        .likely_subtags
-                        .lr2s
-                        .get_copied_2d(&language.into(), &region.into())
-                        .unwrap_or(default_script)
-                {
-                    locale.set_script(None);
-                }
-            } else if script == default_script {
-                locale.set_script(None);
-            }
-        }
-        // 3. Remove irrelevant extension subtags
-        locale.retain_unicode_ext(|key| {
-            match *key {
-                // Always retain -u-sd
-                SUBDIVISION_KEY => true,
-                // Retain the query-specific keyword
-                _ if Some(*key) == self.config.extension_key => true,
-                // Drop all others
-                _ => false,
-            }
-        });
-        // 4. If there is an invalid "sd" subtag, drop it
-        // For now, ignore it, and let fallback do it for us
-    }
-}
-
-impl<'a, 'b> LocaleFallbackIteratorInner<'a, 'b> {
-    pub fn step(&mut self, locale: &mut DataLocale) {
-        match self.config.priority {
-            FallbackPriority::Language => self.step_language(locale),
-            FallbackPriority::Region => self.step_region(locale),
-            // TODO(#1964): Change the collation fallback rules to be different
-            // from the language fallback fules.
-            FallbackPriority::Collation => self.step_language(locale),
-            // This case should not normally happen, but `FallbackPriority` is non_exhaustive.
-            // Make it go directly to `und`.
-            _ => {
-                debug_assert!(
-                    false,
-                    "Unknown FallbackPriority: {:?}",
-                    self.config.priority
-                );
-                *locale = Default::default()
-            }
-        }
-    }
-
-    fn step_language(&mut self, locale: &mut DataLocale) {
-        // 1. Remove the extension fallback keyword
-        if let Some(extension_key) = self.config.extension_key {
-            if let Some(value) = locale.remove_unicode_ext(&extension_key) {
-                self.backup_extension = Some(value);
-                return;
-            }
-        }
-        // 2. Remove the subdivision keyword
-        if let Some(value) = locale.remove_unicode_ext(&SUBDIVISION_KEY) {
-            self.backup_subdivision = Some(value);
-            return;
-        }
-        // 3. Assert that the locale is a language identifier
-        debug_assert!(!locale.has_unicode_ext());
-        // 4. Remove variants
-        if locale.has_variants() {
-            self.backup_variants = Some(locale.clear_variants());
-            return;
-        }
-        // 5. Check for parent override
-        if let Some(parent) = self.get_explicit_parent(locale) {
-            locale.set_langid(parent);
-            self.restore_extensions_variants(locale);
-            return;
-        }
-        // 6. Add the script subtag if necessary
-        if locale.script().is_none() {
-            if let Some(region) = locale.region() {
-                let language = locale.language();
-                if let Some(script) = self
-                    .likely_subtags
-                    .lr2s
-                    .get_copied_2d(&language.into(), &region.into())
-                {
-                    locale.set_script(Some(script));
-                    self.restore_extensions_variants(locale);
-                    return;
-                }
-            }
-        }
-        // 7. Remove region
-        if locale.region().is_some() {
-            locale.set_region(None);
-            return;
-        }
-        // 8. Remove language+script
-        debug_assert!(!locale.language().is_empty()); // don't call .step() on und
-        locale.set_script(None);
-        locale.set_language(Language::UND);
-    }
-
-    fn step_region(&mut self, locale: &mut DataLocale) {
-        // 1. Remove the extension fallback keyword
-        if let Some(extension_key) = self.config.extension_key {
-            if let Some(value) = locale.remove_unicode_ext(&extension_key) {
-                self.backup_extension = Some(value);
-                return;
-            }
-        }
-        // 2. Remove the subdivision keyword
-        if let Some(value) = locale.remove_unicode_ext(&SUBDIVISION_KEY) {
-            self.backup_subdivision = Some(value);
-            return;
-        }
-        // 3. Assert that the locale is a language identifier
-        debug_assert!(!locale.has_unicode_ext());
-        // 4. Remove variants
-        if locale.has_variants() {
-            self.backup_variants = Some(locale.clear_variants());
-            return;
-        }
-        // 5. Remove language+script
-        if !locale.language().is_empty() || locale.script().is_some() {
-            locale.set_script(None);
-            locale.set_language(Language::UND);
-            self.restore_extensions_variants(locale);
-            return;
-        }
-        // 6. Remove region
-        debug_assert!(locale.region().is_some()); // don't call .step() on und
-        locale.set_region(None);
-    }
-
-    fn restore_extensions_variants(&mut self, locale: &mut DataLocale) {
-        if let Some(value) = self.backup_extension.take() {
-            #[allow(clippy::unwrap_used)] // not reachable unless extension_key is present
-            locale.set_unicode_ext(self.config.extension_key.unwrap(), value);
-        }
-        if let Some(value) = self.backup_subdivision.take() {
-            locale.set_unicode_ext(SUBDIVISION_KEY, value);
-        }
-        if let Some(variants) = self.backup_variants.take() {
-            locale.set_variants(variants);
-        }
-    }
-
-    fn get_explicit_parent(&self, locale: &DataLocale) -> Option<LanguageIdentifier> {
-        self.supplement
-            .and_then(|supplement| {
-                supplement
-                    .parents
-                    .get_copied_by(|uvstr| locale.strict_cmp(uvstr).reverse())
-            })
-            .or_else(|| {
-                self.parents
-                    .parents
-                    .get_copied_by(|uvstr| locale.strict_cmp(uvstr).reverse())
-            })
-            .map(LanguageIdentifier::from)
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use icu_locid::Locale;
-    use std::str::FromStr;
-    use writeable::Writeable;
-
-    struct TestCase {
-        input: &'static str,
-        requires_data: bool,
-        extension_key: Option<Key>,
-        fallback_supplement: Option<FallbackSupplement>,
-        // Note: The first entry in the chain is the normalized locale
-        expected_language_chain: &'static [&'static str],
-        expected_region_chain: &'static [&'static str],
-    }
-
-    // TODO: Consider loading these from a JSON file
-    const TEST_CASES: &[TestCase] = &[
-        TestCase {
-            input: "en-u-hc-h12-sd-usca",
-            requires_data: false,
-            extension_key: None,
-            fallback_supplement: None,
-            expected_language_chain: &["en-u-sd-usca", "en"],
-            expected_region_chain: &["en-u-sd-usca", "en", "und-u-sd-usca"],
-        },
-        TestCase {
-            input: "en-US-u-hc-h12-sd-usca",
-            requires_data: false,
-            extension_key: None,
-            fallback_supplement: None,
-            expected_language_chain: &["en-US-u-sd-usca", "en-US", "en"],
-            expected_region_chain: &["en-US-u-sd-usca", "en-US", "und-US-u-sd-usca", "und-US"],
-        },
-        TestCase {
-            input: "en-US-fonipa-u-hc-h12-sd-usca",
-            requires_data: false,
-            extension_key: Some(key!("hc")),
-            fallback_supplement: None,
-            expected_language_chain: &[
-                "en-US-fonipa-u-hc-h12-sd-usca",
-                "en-US-fonipa-u-sd-usca",
-                "en-US-fonipa",
-                "en-US",
-                "en",
-            ],
-            expected_region_chain: &[
-                "en-US-fonipa-u-hc-h12-sd-usca",
-                "en-US-fonipa-u-sd-usca",
-                "en-US-fonipa",
-                "en-US",
-                "und-US-fonipa-u-hc-h12-sd-usca",
-                "und-US-fonipa-u-sd-usca",
-                "und-US-fonipa",
-                "und-US",
-            ],
-        },
-        TestCase {
-            input: "en-u-hc-h12-sd-usca",
-            requires_data: true,
-            extension_key: None,
-            fallback_supplement: None,
-            expected_language_chain: &["en-u-sd-usca", "en"],
-            expected_region_chain: &["en-US-u-sd-usca", "en-US", "und-US-u-sd-usca", "und-US"],
-        },
-        TestCase {
-            input: "en-Latn-u-sd-usca",
-            requires_data: true,
-            extension_key: None,
-            fallback_supplement: None,
-            expected_language_chain: &["en-u-sd-usca", "en"],
-            expected_region_chain: &["en-US-u-sd-usca", "en-US", "und-US-u-sd-usca", "und-US"],
-        },
-        TestCase {
-            input: "en-Latn-US-u-sd-usca",
-            requires_data: true,
-            extension_key: None,
-            fallback_supplement: None,
-            expected_language_chain: &["en-US-u-sd-usca", "en-US", "en"],
-            expected_region_chain: &["en-US-u-sd-usca", "en-US", "und-US-u-sd-usca", "und-US"],
-        },
-        TestCase {
-            // NOTE: -u-rg is not yet supported; when it is, this test should be updated
-            input: "en-u-rg-gbxxxx",
-            requires_data: false,
-            extension_key: None,
-            fallback_supplement: None,
-            expected_language_chain: &["en"],
-            expected_region_chain: &["en"],
-        },
-        TestCase {
-            input: "sr-ME",
-            requires_data: true,
-            extension_key: None,
-            fallback_supplement: None,
-            expected_language_chain: &["sr-ME", "sr-Latn-ME", "sr-Latn"],
-            expected_region_chain: &["sr-ME", "und-ME"],
-        },
-        TestCase {
-            input: "sr-ME-fonipa",
-            requires_data: true,
-            extension_key: None,
-            fallback_supplement: None,
-            expected_language_chain: &[
-                "sr-ME-fonipa",
-                "sr-ME",
-                "sr-Latn-ME-fonipa",
-                "sr-Latn-ME",
-                "sr-Latn",
-            ],
-            expected_region_chain: &["sr-ME-fonipa", "sr-ME", "und-ME-fonipa", "und-ME"],
-        },
-        TestCase {
-            input: "de-Latn-LI",
-            requires_data: true,
-            extension_key: None,
-            fallback_supplement: None,
-            expected_language_chain: &["de-LI", "de"],
-            expected_region_chain: &["de-LI", "und-LI"],
-        },
-        TestCase {
-            input: "ca-ES-valencia",
-            requires_data: true,
-            extension_key: None,
-            fallback_supplement: None,
-            expected_language_chain: &["ca-ES-valencia", "ca-ES", "ca"],
-            expected_region_chain: &["ca-ES-valencia", "ca-ES", "und-ES-valencia", "und-ES"],
-        },
-        TestCase {
-            input: "es-AR",
-            requires_data: true,
-            extension_key: None,
-            fallback_supplement: None,
-            expected_language_chain: &["es-AR", "es-419", "es"],
-            expected_region_chain: &["es-AR", "und-AR"],
-        },
-        TestCase {
-            input: "hi-IN",
-            requires_data: true,
-            extension_key: None,
-            fallback_supplement: None,
-            expected_language_chain: &["hi-IN", "hi"],
-            expected_region_chain: &["hi-IN", "und-IN"],
-        },
-        TestCase {
-            input: "hi-Latn-IN",
-            requires_data: true,
-            extension_key: None,
-            fallback_supplement: None,
-            expected_language_chain: &["hi-Latn-IN", "hi-Latn", "en-IN", "en-001", "en"],
-            expected_region_chain: &["hi-Latn-IN", "und-IN"],
-        },
-        TestCase {
-            input: "zh-CN",
-            requires_data: true,
-            extension_key: None,
-            fallback_supplement: None,
-            // Note: "zh-Hans" is not reachable because it is the default script for "zh".
-            // The fallback algorithm does not visit the language-script bundle when the
-            // script is the default for the language
-            expected_language_chain: &["zh-CN", "zh"],
-            expected_region_chain: &["zh-CN", "und-CN"],
-        },
-        TestCase {
-            input: "zh-TW",
-            requires_data: true,
-            extension_key: None,
-            fallback_supplement: None,
-            expected_language_chain: &["zh-TW", "zh-Hant-TW", "zh-Hant"],
-            expected_region_chain: &["zh-TW", "und-TW"],
-        },
-        TestCase {
-            input: "yue-HK",
-            requires_data: true,
-            extension_key: None,
-            fallback_supplement: None,
-            expected_language_chain: &["yue-HK", "yue"],
-            expected_region_chain: &["yue-HK", "und-HK"],
-        },
-        TestCase {
-            input: "yue-HK",
-            requires_data: true,
-            extension_key: None,
-            fallback_supplement: Some(FallbackSupplement::Collation),
-            // TODO(#1964): add "zh" as a target.
-            expected_language_chain: &["yue-HK", "yue", "zh-Hant"],
-            expected_region_chain: &["yue-HK", "und-HK"],
-        },
-    ];
-
-    #[test]
-    #[cfg(feature = "serde")]
-    fn test_fallback() {
-        let fallbacker_no_data = LocaleFallbacker::new_without_data();
-        let fallbacker_with_data =
-            LocaleFallbacker::try_new_with_buffer_provider(&icu_testdata::buffer()).unwrap();
-        for cas in TEST_CASES {
-            for (priority, expected_chain) in [
-                (FallbackPriority::Language, cas.expected_language_chain),
-                (FallbackPriority::Region, cas.expected_region_chain),
-            ] {
-                let config = LocaleFallbackConfig {
-                    priority,
-                    extension_key: cas.extension_key,
-                    fallback_supplement: cas.fallback_supplement,
-                };
-                let key_fallbacker = if cas.requires_data {
-                    fallbacker_with_data.for_config(config)
-                } else {
-                    fallbacker_no_data.for_config(config)
-                };
-                let locale = DataLocale::from(Locale::from_str(cas.input).unwrap());
-                let mut it = key_fallbacker.fallback_for(locale);
-                for &expected in expected_chain {
-                    assert_eq!(
-                        expected,
-                        &*it.get().write_to_string(),
-                        "{:?} ({:?})",
-                        cas.input,
-                        priority
-                    );
-                    it.step();
-                }
-                assert_eq!(
-                    "und",
-                    &*it.get().write_to_string(),
-                    "{:?} ({:?})",
-                    cas.input,
-                    priority
-                );
-            }
-        }
-    }
-}
diff --git a/vendor/icu_provider_adapters/src/fallback/mod.rs b/vendor/icu_provider_adapters/src/fallback/mod.rs
index a28620b25..c0a05d14e 100644
--- a/vendor/icu_provider_adapters/src/fallback/mod.rs
+++ b/vendor/icu_provider_adapters/src/fallback/mod.rs
@@ -2,421 +2,297 @@
 // called LICENSE at the top level of the ICU4X source tree
 // (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).
 
-//! Tools for locale fallback, enabling arbitrary input locales to be mapped into the nearest
-//! locale with data.
-//!
-//! The algorithm implemented in this module is called [Flexible Vertical Fallback](
-//! https://docs.google.com/document/d/1Mp7EUyl-sFh_HZYgyeVwj88vJGpCBIWxzlCwGgLCDwM/edit).
-//! Watch [#2243](https://github.com/unicode-org/icu4x/issues/2243) to track improvements to
-//! this algorithm and steps to enshrine the algorithm in CLDR.
-//!
-//! # Examples
-//!
-//! Run the locale fallback algorithm:
-//!
-//! ```
-//! use icu_locid::locale;
-//! use icu_provider_adapters::fallback::LocaleFallbacker;
-//! use icu_provider::prelude::*;
-//!
-//! // Set up a LocaleFallbacker with data.
-//! let fallbacker = LocaleFallbacker::try_new_unstable(&icu_testdata::unstable()).expect("data");
-//!
-//! // Create a LocaleFallbackerWithConfig with a configuration for a specific key.
-//! // By default, uses language priority with no additional extension keywords.
-//! let key_fallbacker = fallbacker.for_config(Default::default());
-//!
-//! // Set up the fallback iterator.
-//! let mut fallback_iterator = key_fallbacker.fallback_for(DataLocale::from(locale!("hi-Latn-IN")));
-//!
-//! // Run the algorithm and check the results.
-//! assert_eq!(fallback_iterator.get(), &DataLocale::from(locale!("hi-Latn-IN")));
-//! fallback_iterator.step();
-//! assert_eq!(fallback_iterator.get(), &DataLocale::from(locale!("hi-Latn")));
-//! fallback_iterator.step();
-//! assert_eq!(fallback_iterator.get(), &DataLocale::from(locale!("en-IN")));
-//! fallback_iterator.step();
-//! assert_eq!(fallback_iterator.get(), &DataLocale::from(locale!("en-001")));
-//! fallback_iterator.step();
-//! assert_eq!(fallback_iterator.get(), &DataLocale::from(locale!("en")));
-//! fallback_iterator.step();
-//! assert_eq!(fallback_iterator.get(), &DataLocale::from(locale!("und")));
-//! ```
+//! A data provider wrapper that performs locale fallback.
 
-use icu_locid::extensions::unicode::{Key, Value};
-use icu_locid::subtags::Variants;
+use crate::helpers::result_is_err_missing_locale;
+use icu_locid_transform::provider::*;
 use icu_provider::prelude::*;
-use icu_provider::FallbackPriority;
-use icu_provider::FallbackSupplement;
 
-mod adapter;
-mod algorithms;
-pub mod provider;
+#[doc(hidden)] // moved
+pub use icu_locid_transform::fallback::{
+    LocaleFallbackIterator, LocaleFallbacker, LocaleFallbackerWithConfig,
+};
+#[doc(hidden)] // moved
+pub use icu_provider::fallback::LocaleFallbackConfig;
 
-pub use adapter::LocaleFallbackProvider;
-
-use provider::*;
+/// A data provider wrapper that performs locale fallback. This enables arbitrary locales to be
+/// handled at runtime.
+///
+/// # Examples
+///
+/// ```
+/// use icu_locid::locale;
+/// use icu_provider::prelude::*;
+/// use icu_provider::hello_world::*;
+/// use icu_provider_adapters::fallback::LocaleFallbackProvider;
+///
+/// # let provider = icu_provider_blob::BlobDataProvider::try_new_from_static_blob(include_bytes!("../../tests/data/blob.postcard")).unwrap();
+/// # let provider = provider.as_deserializing();
+///
+/// let req = DataRequest {
+///     locale: &locale!("ja-JP").into(),
+///     metadata: Default::default(),
+/// };
+///
+/// // The provider does not have data for "ja-JP":
+/// DataProvider::<HelloWorldV1Marker>::load(&provider, req).expect_err("No fallback");
+///
+/// // But if we wrap the provider in a fallback provider...
+/// let provider = LocaleFallbackProvider::try_new_unstable(provider)
+///     .expect("Fallback data present");
+///
+/// // ...then we can load "ja-JP" based on "ja" data
+/// let response =
+///   DataProvider::<HelloWorldV1Marker>::load(&provider, req).expect("successful with vertical fallback");
+///
+/// assert_eq!(
+///     response.metadata.locale.unwrap(),
+///     locale!("ja").into(),
+/// );
+/// assert_eq!(
+///     response.payload.unwrap().get().message,
+///     "こんにちは世界",
+/// );
+/// ```
+#[derive(Clone, Debug)]
+pub struct LocaleFallbackProvider<P> {
+    inner: P,
+    fallbacker: LocaleFallbacker,
+}
 
-/// Configuration settings for a particular fallback operation.
-#[derive(Debug, Clone, PartialEq, Eq, Default)]
-#[non_exhaustive]
-pub struct LocaleFallbackConfig {
-    /// Strategy for choosing which subtags to drop during locale fallback.
-    ///
-    /// # Examples
+impl<P> LocaleFallbackProvider<P>
+where
+    P: DataProvider<LocaleFallbackLikelySubtagsV1Marker>
+        + DataProvider<LocaleFallbackParentsV1Marker>
+        + DataProvider<CollationFallbackSupplementV1Marker>,
+{
+    /// Create a [`LocaleFallbackProvider`] by wrapping another data provider and then loading
+    /// fallback data from it.
     ///
-    /// Retain the language and script subtags until the final step:
-    ///
-    /// ```
-    /// use icu_locid::locale;
-    /// use icu_provider::prelude::*;
-    /// use icu_provider::FallbackPriority;
-    /// use icu_provider_adapters::fallback::LocaleFallbackConfig;
-    /// use icu_provider_adapters::fallback::LocaleFallbacker;
-    ///
-    /// // Set up the fallback iterator.
-    /// let fallbacker =
-    ///     LocaleFallbacker::try_new_unstable(&icu_testdata::unstable())
-    ///         .expect("data");
-    /// let mut config = LocaleFallbackConfig::default();
-    /// config.priority = FallbackPriority::Language;
-    /// let key_fallbacker = fallbacker.for_config(config);
-    /// let mut fallback_iterator = key_fallbacker
-    ///     .fallback_for(DataLocale::from(locale!("ca-ES-valencia")));
-    ///
-    /// // Run the algorithm and check the results.
-    /// assert_eq!(
-    ///     fallback_iterator.get(),
-    ///     &DataLocale::from(locale!("ca-ES-valencia"))
-    /// );
-    /// fallback_iterator.step();
-    /// assert_eq!(fallback_iterator.get(), &DataLocale::from(locale!("ca-ES")));
-    /// fallback_iterator.step();
-    /// assert_eq!(fallback_iterator.get(), &DataLocale::from(locale!("ca")));
-    /// fallback_iterator.step();
-    /// assert_eq!(fallback_iterator.get(), &DataLocale::from(locale!("und")));
-    /// ```
-    ///
-    /// Retain the region subtag until the final step:
+    /// If the data provider being wrapped does not contain fallback data, use
+    /// [`LocaleFallbackProvider::new_with_fallbacker`].
+    pub fn try_new_unstable(provider: P) -> Result<Self, DataError> {
+        let fallbacker = LocaleFallbacker::try_new_unstable(&provider)?;
+        Ok(Self {
+            inner: provider,
+            fallbacker,
+        })
+    }
+}
+
+impl<P> LocaleFallbackProvider<P>
+where
+    P: AnyProvider,
+{
+    /// Create a [`LocaleFallbackProvider`] by wrapping another data provider and then loading
+    /// fallback data from it.
     ///
-    /// ```
-    /// use icu_locid::locale;
-    /// use icu_provider::prelude::*;
-    /// use icu_provider::FallbackPriority;
-    /// use icu_provider_adapters::fallback::LocaleFallbackConfig;
-    /// use icu_provider_adapters::fallback::LocaleFallbacker;
+    /// If the data provider being wrapped does not contain fallback data, use
+    /// [`LocaleFallbackProvider::new_with_fallbacker`].
+    pub fn try_new_with_any_provider(provider: P) -> Result<Self, DataError> {
+        let fallbacker = LocaleFallbacker::try_new_with_any_provider(&provider)?;
+        Ok(Self {
+            inner: provider,
+            fallbacker,
+        })
+    }
+}
+
+#[cfg(feature = "serde")]
+impl<P> LocaleFallbackProvider<P>
+where
+    P: BufferProvider,
+{
+    /// Create a [`LocaleFallbackProvider`] by wrapping another data provider and then loading
+    /// fallback data from it.
     ///
-    /// // Set up the fallback iterator.
-    /// let fallbacker =
-    ///     LocaleFallbacker::try_new_unstable(&icu_testdata::unstable())
-    ///         .expect("data");
-    /// let mut config = LocaleFallbackConfig::default();
-    /// config.priority = FallbackPriority::Region;
-    /// let key_fallbacker = fallbacker.for_config(config);
-    /// let mut fallback_iterator = key_fallbacker
-    ///     .fallback_for(DataLocale::from(locale!("ca-ES-valencia")));
+    /// If the data provider being wrapped does not contain fallback data, use
+    /// [`LocaleFallbackProvider::new_with_fallbacker`].
+    pub fn try_new_with_buffer_provider(provider: P) -> Result<Self, DataError> {
+        let fallbacker = LocaleFallbacker::try_new_with_buffer_provider(&provider)?;
+        Ok(Self {
+            inner: provider,
+            fallbacker,
+        })
+    }
+}
+
+impl<P> LocaleFallbackProvider<P> {
+    /// Wrap a provider with an arbitrary fallback engine.
     ///
-    /// // Run the algorithm and check the results.
-    /// assert_eq!(
-    ///     fallback_iterator.get(),
-    ///     &DataLocale::from(locale!("ca-ES-valencia"))
-    /// );
-    /// fallback_iterator.step();
-    /// assert_eq!(fallback_iterator.get(), &DataLocale::from(locale!("ca-ES")));
-    /// fallback_iterator.step();
-    /// assert_eq!(
-    ///     fallback_iterator.get(),
-    ///     &DataLocale::from(locale!("und-ES-valencia"))
-    /// );
-    /// fallback_iterator.step();
-    /// assert_eq!(
-    ///     fallback_iterator.get(),
-    ///     &DataLocale::from(locale!("und-ES"))
-    /// );
-    /// fallback_iterator.step();
-    /// assert_eq!(fallback_iterator.get(), &DataLocale::from(locale!("und")));
-    /// ```
-    pub priority: FallbackPriority,
-    /// An extension keyword to retain during locale fallback.
+    /// This relaxes the requirement that the wrapped provider contains its own fallback data.
     ///
     /// # Examples
     ///
     /// ```
     /// use icu_locid::locale;
+    /// use icu_locid_transform::LocaleFallbacker;
+    /// use icu_provider::hello_world::*;
     /// use icu_provider::prelude::*;
-    /// use icu_provider_adapters::fallback::LocaleFallbackConfig;
-    /// use icu_provider_adapters::fallback::LocaleFallbacker;
-    ///
-    /// // Set up the fallback iterator.
-    /// let fallbacker =
-    ///     LocaleFallbacker::try_new_unstable(&icu_testdata::unstable())
-    ///         .expect("data");
-    /// let mut config = LocaleFallbackConfig::default();
-    /// config.extension_key = Some(icu_locid::extensions_unicode_key!("nu"));
-    /// let key_fallbacker = fallbacker.for_config(config);
-    /// let mut fallback_iterator = key_fallbacker
-    ///     .fallback_for(DataLocale::from(locale!("ar-EG-u-nu-latn")));
-    ///
-    /// // Run the algorithm and check the results.
-    /// assert_eq!(
-    ///     fallback_iterator.get(),
-    ///     &DataLocale::from(locale!("ar-EG-u-nu-latn"))
-    /// );
-    /// fallback_iterator.step();
-    /// assert_eq!(fallback_iterator.get(), &DataLocale::from(locale!("ar-EG")));
-    /// fallback_iterator.step();
-    /// assert_eq!(fallback_iterator.get(), &DataLocale::from(locale!("ar")));
-    /// fallback_iterator.step();
-    /// assert_eq!(fallback_iterator.get(), &DataLocale::from(locale!("und")));
-    /// ```
-    pub extension_key: Option<Key>,
-    /// Fallback supplement data key to customize fallback rules.
+    /// use icu_provider_adapters::fallback::LocaleFallbackProvider;
     ///
-    /// For example, most data keys for collation add additional parent locales, such as
-    /// "yue" to "zh-Hant", and data used for the `"-u-co"` extension keyword fallback.
+    /// let provider = HelloWorldProvider;
     ///
-    /// Currently the only supported fallback supplement is `FallbackSupplement::Collation`, but more may be
-    /// added in the future.
+    /// let req = DataRequest {
+    ///     locale: &locale!("de-CH").into(),
+    ///     metadata: Default::default(),
+    /// };
     ///
-    /// # Examples
+    /// // There is no "de-CH" data in the `HelloWorldProvider`
+    /// DataProvider::<HelloWorldV1Marker>::load(&provider, req)
+    ///     .expect_err("No data for de-CH");
     ///
-    /// ```
-    /// use icu_locid::locale;
-    /// use icu_provider::prelude::*;
-    /// use icu_provider::FallbackPriority;
-    /// use icu_provider::FallbackSupplement;
-    /// use icu_provider_adapters::fallback::LocaleFallbackConfig;
-    /// use icu_provider_adapters::fallback::LocaleFallbacker;
-    /// use tinystr::tinystr;
+    /// // `HelloWorldProvider` does not contain fallback data,
+    /// // but we can construct a fallbacker with `icu_locid_transform`'s
+    /// // compiled data.
+    /// let provider = LocaleFallbackProvider::new_with_fallbacker(
+    ///     provider,
+    ///     LocaleFallbacker::new().static_to_owned(),
+    /// );
     ///
-    /// // Set up the fallback iterator.
-    /// let fallbacker =
-    ///     LocaleFallbacker::try_new_unstable(&icu_testdata::unstable())
-    ///         .expect("data");
-    /// let mut config = LocaleFallbackConfig::default();
-    /// config.priority = FallbackPriority::Collation;
-    /// config.fallback_supplement = Some(FallbackSupplement::Collation);
-    /// let key_fallbacker = fallbacker.for_config(config);
-    /// let mut fallback_iterator =
-    ///     key_fallbacker.fallback_for(DataLocale::from(locale!("yue-HK")));
+    /// // Now we can load the "de-CH" data via fallback to "de".
+    /// let german_hello_world: DataPayload<HelloWorldV1Marker> = provider
+    ///     .load(req)
+    ///     .expect("Loading should succeed")
+    ///     .take_payload()
+    ///     .expect("Data should be present");
     ///
-    /// // Run the algorithm and check the results.
-    /// // TODO(#1964): add "zh" as a target.
-    /// assert_eq!(
-    ///     fallback_iterator.get(),
-    ///     &DataLocale::from(locale!("yue-HK"))
-    /// );
-    /// fallback_iterator.step();
-    /// assert_eq!(fallback_iterator.get(), &DataLocale::from(locale!("yue")));
-    /// fallback_iterator.step();
-    /// assert_eq!(
-    ///     fallback_iterator.get(),
-    ///     &DataLocale::from(locale!("zh-Hant"))
-    /// );
-    /// fallback_iterator.step();
-    /// assert_eq!(fallback_iterator.get(), &DataLocale::from(locale!("und")));
+    /// assert_eq!("Hallo Welt", german_hello_world.get().message);
     /// ```
-    pub fallback_supplement: Option<FallbackSupplement>,
-}
-
-/// Entry type for locale fallbacking.
-///
-/// See the module-level documentation for an example.
-#[derive(Debug, Clone, PartialEq)]
-pub struct LocaleFallbacker {
-    likely_subtags: DataPayload<LocaleFallbackLikelySubtagsV1Marker>,
-    parents: DataPayload<LocaleFallbackParentsV1Marker>,
-    collation_supplement: Option<DataPayload<CollationFallbackSupplementV1Marker>>,
-}
+    pub fn new_with_fallbacker(provider: P, fallbacker: LocaleFallbacker) -> Self {
+        Self {
+            inner: provider,
+            fallbacker,
+        }
+    }
 
-/// Intermediate type for spawning locale fallback iterators based on a specific configuration.
-///
-/// See the module-level documentation for an example.
-#[derive(Debug, Clone, PartialEq)]
-pub struct LocaleFallbackerWithConfig<'a> {
-    likely_subtags: &'a LocaleFallbackLikelySubtagsV1<'a>,
-    parents: &'a LocaleFallbackParentsV1<'a>,
-    supplement: Option<&'a LocaleFallbackSupplementV1<'a>>,
-    config: LocaleFallbackConfig,
-}
+    /// Returns a reference to the inner provider, bypassing fallback.
+    pub fn inner(&self) -> &P {
+        &self.inner
+    }
 
-/// Inner iteration type. Does not own the item under fallback.
-#[derive(Debug)]
-struct LocaleFallbackIteratorInner<'a, 'b> {
-    likely_subtags: &'a LocaleFallbackLikelySubtagsV1<'a>,
-    parents: &'a LocaleFallbackParentsV1<'a>,
-    supplement: Option<&'a LocaleFallbackSupplementV1<'a>>,
-    config: &'b LocaleFallbackConfig,
-    backup_extension: Option<Value>,
-    backup_subdivision: Option<Value>,
-    backup_variants: Option<Variants>,
-}
+    /// Returns a mutable reference to the inner provider.
+    pub fn inner_mut(&mut self) -> &mut P {
+        &mut self.inner
+    }
 
-/// Iteration type for locale fallback operations.
-///
-/// Because the `Iterator` trait does not allow items to borrow from the iterator, this class does
-/// not implement that trait. Instead, use `.step()` and `.get()`.
-#[derive(Debug)]
-pub struct LocaleFallbackIterator<'a, 'b> {
-    current: DataLocale,
-    inner: LocaleFallbackIteratorInner<'a, 'b>,
-}
+    /// Returns ownership of the inner provider to the caller.
+    pub fn into_inner(self) -> P {
+        self.inner
+    }
 
-impl LocaleFallbacker {
-    /// Creates a [`LocaleFallbacker`] with fallback data (likely subtags and parent locales).
+    /// Run the fallback algorithm with the data request using the inner data provider.
+    /// Internal function; external clients should use one of the trait impls below.
     ///
-    /// [📚 Help choosing a constructor](icu_provider::constructors)
-    /// <div class="stab unstable">
-    /// ⚠️ The bounds on this function may change over time, including in SemVer minor releases.
-    /// </div>
-    pub fn try_new_unstable<P>(provider: &P) -> Result<Self, DataError>
+    /// Function arguments:
+    ///
+    /// - F1 should perform a data load for a single DataRequest and return the result of it
+    /// - F2 should map from the provider-specific response type to DataResponseMetadata
+    fn run_fallback<F1, F2, R>(
+        &self,
+        key: DataKey,
+        mut base_req: DataRequest,
+        mut f1: F1,
+        mut f2: F2,
+    ) -> Result<R, DataError>
     where
-        P: DataProvider<LocaleFallbackLikelySubtagsV1Marker>
-            + DataProvider<LocaleFallbackParentsV1Marker>
-            + DataProvider<CollationFallbackSupplementV1Marker>
-            + ?Sized,
+        F1: FnMut(DataRequest) -> Result<R, DataError>,
+        F2: FnMut(&mut R) -> &mut DataResponseMetadata,
     {
-        let likely_subtags = provider.load(Default::default())?.take_payload()?;
-        let parents = provider.load(Default::default())?.take_payload()?;
-        let collation_supplement = match DataProvider::<CollationFallbackSupplementV1Marker>::load(
-            provider,
-            Default::default(),
-        ) {
-            Ok(response) => Some(response.take_payload()?),
-            // It is expected that not all keys are present
-            Err(DataError {
-                kind: DataErrorKind::MissingDataKey,
-                ..
-            }) => None,
-            Err(e) => return Err(e),
-        };
-        Ok(LocaleFallbacker {
-            likely_subtags,
-            parents,
-            collation_supplement,
-        })
-    }
-
-    icu_provider::gen_any_buffer_constructors!(locale: skip, options: skip, error: DataError);
-
-    /// Creates a [`LocaleFallbacker`] without fallback data. Using this constructor may result in
-    /// surprising behavior, especially in multi-script languages.
-    pub fn new_without_data() -> Self {
-        LocaleFallbacker {
-            likely_subtags: DataPayload::from_owned(Default::default()),
-            parents: DataPayload::from_owned(Default::default()),
-            collation_supplement: None,
+        if key.metadata().singleton {
+            return f1(base_req);
         }
-    }
-
-    /// Creates the intermediate [`LocaleFallbackerWithConfig`] with configuration options.
-    pub fn for_config(&self, config: LocaleFallbackConfig) -> LocaleFallbackerWithConfig {
-        let supplement = match config.fallback_supplement {
-            Some(FallbackSupplement::Collation) => {
-                self.collation_supplement.as_ref().map(|p| p.get())
+        let mut fallback_iterator = self
+            .fallbacker
+            .for_config(key.fallback_config())
+            .fallback_for(base_req.locale.clone());
+        let base_silent = core::mem::replace(&mut base_req.metadata.silent, true);
+        loop {
+            let result = f1(DataRequest {
+                locale: fallback_iterator.get(),
+                metadata: base_req.metadata,
+            });
+            if !result_is_err_missing_locale(&result) {
+                return result
+                    .map(|mut res| {
+                        f2(&mut res).locale = Some(fallback_iterator.take());
+                        res
+                    })
+                    // Log the original request rather than the fallback request
+                    .map_err(|e| {
+                        base_req.metadata.silent = base_silent;
+                        e.with_req(key, base_req)
+                    });
+            }
+            // If we just checked und, break out of the loop.
+            if fallback_iterator.get().is_und() {
+                break;
             }
-            _ => None,
-        };
-        LocaleFallbackerWithConfig {
-            likely_subtags: self.likely_subtags.get(),
-            parents: self.parents.get(),
-            supplement,
-            config,
+            fallback_iterator.step();
         }
-    }
-
-    /// Creates the intermediate [`LocaleFallbackerWithConfig`] based on a
-    /// [`DataKey`] and a [`DataRequestMetadata`].
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// use icu_locid::locale;
-    /// use icu_provider::prelude::*;
-    /// use icu_provider_adapters::fallback::LocaleFallbacker;
-    /// use std::borrow::Cow;
-    ///
-    /// // Define the data struct with key.
-    /// #[icu_provider::data_struct(marker(
-    ///     FooV1Marker,
-    ///     "demo/foo@1",
-    ///     fallback_by = "region"
-    /// ))]
-    /// pub struct FooV1<'data> {
-    ///     message: Cow<'data, str>,
-    /// };
-    ///
-    /// // Set up the fallback iterator.
-    /// let fallbacker =
-    ///     LocaleFallbacker::try_new_unstable(&icu_testdata::unstable())
-    ///         .expect("data");
-    /// let key_fallbacker = fallbacker.for_key(FooV1Marker::KEY);
-    /// let mut fallback_iterator =
-    ///     key_fallbacker.fallback_for(DataLocale::from(locale!("en-GB")));
-    ///
-    /// // Run the algorithm and check the results.
-    /// assert_eq!(fallback_iterator.get(), &DataLocale::from(locale!("en-GB")));
-    /// fallback_iterator.step();
-    /// assert_eq!(
-    ///     fallback_iterator.get(),
-    ///     &DataLocale::from(locale!("und-GB"))
-    /// );
-    /// fallback_iterator.step();
-    /// assert_eq!(fallback_iterator.get(), &DataLocale::from(locale!("und")));
-    /// ```
-    ///
-    /// [`DataRequestMetadata`]: icu_provider::DataRequestMetadata
-    pub fn for_key(&self, data_key: DataKey) -> LocaleFallbackerWithConfig {
-        let priority = data_key.metadata().fallback_priority;
-        let extension_key = data_key.metadata().extension_key;
-        let fallback_supplement = data_key.metadata().fallback_supplement;
-        self.for_config(LocaleFallbackConfig {
-            priority,
-            extension_key,
-            fallback_supplement,
-        })
+        base_req.metadata.silent = base_silent;
+        Err(DataErrorKind::MissingLocale.with_req(key, base_req))
     }
 }
 
-impl<'a> LocaleFallbackerWithConfig<'a> {
-    /// Creates an iterator based on a [`DataLocale`] (which can be created from [`Locale`]).
-    ///
-    /// When first initialized, the locale is normalized according to the fallback algorithm.
-    ///
-    /// [`Locale`]: icu_locid::Locale
-    pub fn fallback_for<'b>(&'b self, mut locale: DataLocale) -> LocaleFallbackIterator<'a, 'b> {
-        self.normalize(&mut locale);
-        LocaleFallbackIterator {
-            current: locale,
-            inner: LocaleFallbackIteratorInner {
-                likely_subtags: self.likely_subtags,
-                parents: self.parents,
-                supplement: self.supplement,
-                config: &self.config,
-                backup_extension: None,
-                backup_subdivision: None,
-                backup_variants: None,
-            },
-        }
+impl<P> AnyProvider for LocaleFallbackProvider<P>
+where
+    P: AnyProvider,
+{
+    fn load_any(&self, key: DataKey, base_req: DataRequest) -> Result<AnyResponse, DataError> {
+        self.run_fallback(
+            key,
+            base_req,
+            |req| self.inner.load_any(key, req),
+            |res| &mut res.metadata,
+        )
     }
 }
 
-impl LocaleFallbackIterator<'_, '_> {
-    /// Borrows the current [`DataLocale`] under fallback.
-    pub fn get(&self) -> &DataLocale {
-        &self.current
+impl<P> BufferProvider for LocaleFallbackProvider<P>
+where
+    P: BufferProvider,
+{
+    fn load_buffer(
+        &self,
+        key: DataKey,
+        base_req: DataRequest,
+    ) -> Result<DataResponse<BufferMarker>, DataError> {
+        self.run_fallback(
+            key,
+            base_req,
+            |req| self.inner.load_buffer(key, req),
+            |res| &mut res.metadata,
+        )
     }
+}
 
-    /// Takes the current [`DataLocale`] under fallback.
-    pub fn take(self) -> DataLocale {
-        self.current
+impl<P, M> DynamicDataProvider<M> for LocaleFallbackProvider<P>
+where
+    P: DynamicDataProvider<M>,
+    M: DataMarker,
+{
+    fn load_data(&self, key: DataKey, base_req: DataRequest) -> Result<DataResponse<M>, DataError> {
+        self.run_fallback(
+            key,
+            base_req,
+            |req| self.inner.load_data(key, req),
+            |res| &mut res.metadata,
+        )
     }
+}
 
-    /// Performs one step of the locale fallback algorithm.
-    ///
-    /// The fallback is completed once the inner [`DataLocale`] becomes `und`.
-    pub fn step(&mut self) -> &mut Self {
-        self.inner.step(&mut self.current);
-        self
+impl<P, M> DataProvider<M> for LocaleFallbackProvider<P>
+where
+    P: DataProvider<M>,
+    M: KeyedDataMarker,
+{
+    fn load(&self, base_req: DataRequest) -> Result<DataResponse<M>, DataError> {
+        self.run_fallback(
+            M::KEY,
+            base_req,
+            |req| self.inner.load(req),
+            |res| &mut res.metadata,
+        )
     }
 }
diff --git a/vendor/icu_provider_adapters/src/fallback/provider.rs b/vendor/icu_provider_adapters/src/fallback/provider.rs
deleted file mode 100644
index edfa01f58..000000000
--- a/vendor/icu_provider_adapters/src/fallback/provider.rs
+++ /dev/null
@@ -1,111 +0,0 @@
-// 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 ).
-
-//! Data provider struct definitions for vertical fallback.
-//!
-//! Read more about data providers: [`icu_provider`]
-
-// Provider structs must be stable
-#![allow(clippy::exhaustive_structs)]
-
-use icu_locid::extensions::unicode::Key;
-use icu_locid::subtags::{Language, Region, Script};
-use icu_locid::{subtags_region as region, subtags_script as script};
-use tinystr::TinyAsciiStr;
-
-use icu_provider::prelude::*;
-
-use zerovec::ule::UnvalidatedStr;
-use zerovec::ZeroMap;
-use zerovec::ZeroMap2d;
-
-// We use raw TinyAsciiStrs for map keys, as we then don't have to
-// validate them as subtags on deserialization. Map lookup can be
-// done even if they are not valid tags (an invalid key will just
-// become inaccessible).
-type UnvalidatedLanguage = TinyAsciiStr<3>;
-type UnvalidatedScript = TinyAsciiStr<4>;
-type UnvalidatedRegion = TinyAsciiStr<3>;
-
-/// Locale fallback rules derived from likely subtags data.
-#[icu_provider::data_struct(LocaleFallbackLikelySubtagsV1Marker = "fallback/likelysubtags@1")]
-#[derive(Default, Clone, PartialEq, Debug)]
-#[cfg_attr(
-    feature = "datagen",
-    derive(serde::Serialize, databake::Bake),
-    databake(path = icu_provider_adapters::fallback::provider),
-)]
-#[cfg_attr(feature = "serde", derive(serde::Deserialize))]
-#[yoke(prove_covariance_manually)]
-pub struct LocaleFallbackLikelySubtagsV1<'data> {
-    /// Map from language to the default script in that language. Languages whose default script
-    /// is `Latn` are not included in the map for data size savings.
-    ///
-    /// Example: "zh" defaults to "Hans", which is in this map.
-    #[cfg_attr(feature = "serde", serde(borrow))]
-    pub l2s: ZeroMap<'data, UnvalidatedLanguage, Script>,
-    /// Map from language-region pairs to a script. Only populated if the script is different
-    /// from the one in `l2s` for that language.
-    ///
-    /// Example: "zh-TW" defaults to "Hant", which is in this map.
-    #[cfg_attr(feature = "serde", serde(borrow))]
-    pub lr2s: ZeroMap2d<'data, UnvalidatedLanguage, UnvalidatedRegion, Script>,
-    /// Map from language to the default region in that language. Languages whose default region
-    /// is `ZZ` are not included in the map for data size savings.
-    ///
-    /// Example: "zh" defaults to "CN".
-    #[cfg_attr(feature = "serde", serde(borrow))]
-    pub l2r: ZeroMap<'data, UnvalidatedLanguage, Region>,
-    /// Map from language-script pairs to a region. Only populated if the region is different
-    /// from the one in `l2r` for that language.
-    ///
-    /// Example: "zh-Hant" defaults to "TW".
-    #[cfg_attr(feature = "serde", serde(borrow))]
-    pub ls2r: ZeroMap2d<'data, UnvalidatedLanguage, UnvalidatedScript, Region>,
-}
-
-/// `Latn` is the most common script, so it is defaulted for data size savings.
-pub const DEFAULT_SCRIPT: Script = script!("Latn");
-
-/// `ZZ` is the most common region, so it is defaulted for data size savings.
-pub const DEFAULT_REGION: Region = region!("ZZ");
-
-/// Locale fallback rules derived from CLDR parent locales data.
-#[icu_provider::data_struct(LocaleFallbackParentsV1Marker = "fallback/parents@1")]
-#[derive(Default, Clone, PartialEq, Debug)]
-#[cfg_attr(
-    feature = "datagen",
-    derive(serde::Serialize, databake::Bake),
-    databake(path = icu_provider_adapters::fallback::provider),
-)]
-#[cfg_attr(feature = "serde", derive(serde::Deserialize))]
-#[yoke(prove_covariance_manually)]
-pub struct LocaleFallbackParentsV1<'data> {
-    /// Map from language identifier to language identifier, indicating that the language on the
-    /// left should inherit from the language on the right.
-    #[cfg_attr(feature = "serde", serde(borrow))]
-    pub parents: ZeroMap<'data, UnvalidatedStr, (Language, Option<Script>, Option<Region>)>,
-}
-
-/// Key-specific supplemental fallback data.
-#[icu_provider::data_struct(marker(
-    CollationFallbackSupplementV1Marker,
-    "fallback/supplement/co@1"
-))]
-#[derive(Default, Clone, PartialEq, Debug)]
-#[cfg_attr(
-    feature = "datagen",
-    derive(serde::Serialize, databake::Bake),
-    databake(path = icu_provider_adapters::fallback::provider),
-)]
-#[cfg_attr(feature = "serde", derive(serde::Deserialize))]
-#[yoke(prove_covariance_manually)]
-pub struct LocaleFallbackSupplementV1<'data> {
-    /// Additional parent locales to supplement the common ones.
-    #[cfg_attr(feature = "serde", serde(borrow))]
-    pub parents: ZeroMap<'data, UnvalidatedStr, (Language, Option<Script>, Option<Region>)>,
-    /// Default values for Unicode extension keywords.
-    #[cfg_attr(feature = "serde", serde(borrow))]
-    pub unicode_extension_defaults: ZeroMap2d<'data, Key, UnvalidatedStr, UnvalidatedStr>,
-}
diff --git a/vendor/icu_provider_adapters/src/filter/impls.rs b/vendor/icu_provider_adapters/src/filter/impls.rs
index df18cf72c..f24248eff 100644
--- a/vendor/icu_provider_adapters/src/filter/impls.rs
+++ b/vendor/icu_provider_adapters/src/filter/impls.rs
@@ -25,7 +25,7 @@ where
     ///
     /// ```
     /// use icu_locid::LanguageIdentifier;
-    /// use icu_locid::{langid, locale, subtags_language as language};
+    /// use icu_locid::{langid, locale, subtags::language};
     /// use icu_provider::datagen::*;
     /// use icu_provider::hello_world::*;
     /// use icu_provider::prelude::*;
@@ -106,7 +106,7 @@ where
     /// use icu_provider::prelude::*;
     /// use icu_provider_adapters::filter::Filterable;
     ///
-    /// let allowlist = vec![langid!("de"), langid!("zh")];
+    /// let allowlist = [langid!("de"), langid!("zh")];
     /// let provider = HelloWorldProvider
     ///     .filterable("Demo German+Chinese filter")
     ///     .filter_by_langid_allowlist_strict(&allowlist);
diff --git a/vendor/icu_provider_adapters/src/filter/mod.rs b/vendor/icu_provider_adapters/src/filter/mod.rs
index 83be9f779..19b6bf233 100644
--- a/vendor/icu_provider_adapters/src/filter/mod.rs
+++ b/vendor/icu_provider_adapters/src/filter/mod.rs
@@ -21,7 +21,7 @@
 //! # Examples
 //!
 //! ```
-//! use icu_locid::subtags_language as language;
+//! use icu_locid::subtags::language;
 //! use icu_provider::hello_world::*;
 //! use icu_provider::prelude::*;
 //! use icu_provider_adapters::filter::Filterable;
diff --git a/vendor/icu_provider_adapters/src/fork/by_error.rs b/vendor/icu_provider_adapters/src/fork/by_error.rs
index aae996761..5d25ce207 100644
--- a/vendor/icu_provider_adapters/src/fork/by_error.rs
+++ b/vendor/icu_provider_adapters/src/fork/by_error.rs
@@ -174,7 +174,7 @@ where
         key: DataKey,
         req: DataRequest,
     ) -> Result<DataResponse<BufferMarker>, DataError> {
-        let mut last_error = DataErrorKind::MissingDataKey.with_key(key);
+        let mut last_error = F::UNIT_ERROR.with_key(key);
         for provider in self.providers.iter() {
             let result = provider.load_buffer(key, req);
             match result {
@@ -193,7 +193,7 @@ where
     F: ForkByErrorPredicate,
 {
     fn load_any(&self, key: DataKey, req: DataRequest) -> Result<AnyResponse, DataError> {
-        let mut last_error = DataErrorKind::MissingDataKey.with_key(key);
+        let mut last_error = F::UNIT_ERROR.with_key(key);
         for provider in self.providers.iter() {
             let result = provider.load_any(key, req);
             match result {
@@ -213,7 +213,7 @@ where
     F: ForkByErrorPredicate,
 {
     fn load_data(&self, key: DataKey, req: DataRequest) -> Result<DataResponse<M>, DataError> {
-        let mut last_error = DataErrorKind::MissingDataKey.with_key(key);
+        let mut last_error = F::UNIT_ERROR.with_key(key);
         for provider in self.providers.iter() {
             let result = provider.load_data(key, req);
             match result {
@@ -234,7 +234,7 @@ where
     F: ForkByErrorPredicate,
 {
     fn supported_locales_for_key(&self, key: DataKey) -> Result<Vec<DataLocale>, DataError> {
-        let mut last_error = DataErrorKind::MissingDataKey.with_key(key);
+        let mut last_error = F::UNIT_ERROR.with_key(key);
         for provider in self.providers.iter() {
             let result = provider.supported_locales_for_key(key);
             match result {
@@ -260,7 +260,7 @@ where
         key: DataKey,
         mut from: DataPayload<MFrom>,
     ) -> Result<DataPayload<MTo>, (DataPayload<MFrom>, DataError)> {
-        let mut last_error = DataErrorKind::MissingDataKey.with_key(key);
+        let mut last_error = F::UNIT_ERROR.with_key(key);
         for provider in self.providers.iter() {
             let result = provider.convert(key, from);
             match result {
diff --git a/vendor/icu_provider_adapters/src/fork/macros.rs b/vendor/icu_provider_adapters/src/fork/macros.rs
index 7c18a9ba3..eb98ec693 100644
--- a/vendor/icu_provider_adapters/src/fork/macros.rs
+++ b/vendor/icu_provider_adapters/src/fork/macros.rs
@@ -11,27 +11,23 @@
 /// use icu_provider_adapters::fork::ForkByKeyProvider;
 ///
 /// // Some empty example providers:
-/// #[derive(Default, PartialEq, Debug)]
+/// #[derive(PartialEq, Debug)]
 /// struct Provider1;
-/// #[derive(Default, PartialEq, Debug)]
+/// #[derive(PartialEq, Debug)]
 /// struct Provider2;
-/// #[derive(Default, PartialEq, Debug)]
+/// #[derive(PartialEq, Debug)]
 /// struct Provider3;
 ///
 /// // Combine them into one:
 /// let forking1 = icu_provider_adapters::make_forking_provider!(
 ///     ForkByKeyProvider::new,
-///     [
-///         Provider1::default(),
-///         Provider2::default(),
-///         Provider3::default(),
-///     ]
+///     [Provider1, Provider2, Provider3,]
 /// );
 ///
 /// // This is equivalent to:
 /// let forking2 = ForkByKeyProvider::new(
-///     Provider1::default(),
-///     ForkByKeyProvider::new(Provider2::default(), Provider3::default()),
+///     Provider1,
+///     ForkByKeyProvider::new(Provider2, Provider3),
 /// );
 ///
 /// assert_eq!(forking1, forking2);
@@ -50,22 +46,15 @@ macro_rules! make_forking_provider {
 
 #[cfg(test)]
 mod test {
-    #[derive(Default)]
     struct Provider1;
-    #[derive(Default)]
     struct Provider2;
-    #[derive(Default)]
     struct Provider3;
 
     #[test]
     fn test_make_forking_provider() {
         make_forking_provider!(
             crate::fork::ForkByKeyProvider::new,
-            [
-                Provider1::default(),
-                Provider2::default(),
-                Provider3::default(),
-            ]
+            [Provider1, Provider2, Provider3,]
         );
     }
 }
diff --git a/vendor/icu_provider_adapters/src/fork/mod.rs b/vendor/icu_provider_adapters/src/fork/mod.rs
index 05ba5fd19..a15c742c6 100644
--- a/vendor/icu_provider_adapters/src/fork/mod.rs
+++ b/vendor/icu_provider_adapters/src/fork/mod.rs
@@ -80,9 +80,9 @@ use predicates::MissingDataKeyPredicate;
 ///     HelloWorldProvider.into_json_provider(),
 /// );
 ///
-/// let data_provider = forking_provider.as_deserializing();
+/// let provider = forking_provider.as_deserializing();
 ///
-/// let german_hello_world: DataPayload<HelloWorldV1Marker> = data_provider
+/// let german_hello_world: DataPayload<HelloWorldV1Marker> = provider
 ///     .load(DataRequest {
 ///         locale: &locale!("de").into(),
 ///         metadata: Default::default(),
@@ -97,7 +97,7 @@ use predicates::MissingDataKeyPredicate;
 /// Stops at the first provider supporting a key, even if the locale is not supported:
 ///
 /// ```
-/// use icu_locid::{subtags_language as language, locale};
+/// use icu_locid::{subtags::language, locale};
 /// use icu_provider::hello_world::*;
 /// use icu_provider::prelude::*;
 /// use icu_provider_adapters::filter::Filterable;
@@ -114,11 +114,11 @@ use predicates::MissingDataKeyPredicate;
 ///         .filter_by_langid(|langid| langid.language == language!("de")),
 /// );
 ///
-/// let data_provider: &dyn DataProvider<HelloWorldV1Marker> =
+/// let provider: &dyn DataProvider<HelloWorldV1Marker> =
 ///     &forking_provider.as_deserializing();
 ///
 /// // Chinese is the first provider, so this succeeds
-/// let chinese_hello_world = data_provider
+/// let chinese_hello_world = provider
 ///     .load(DataRequest {
 ///         locale: &locale!("zh").into(),
 ///         metadata: Default::default(),
@@ -130,7 +130,7 @@ use predicates::MissingDataKeyPredicate;
 /// assert_eq!("你好世界", chinese_hello_world.get().message);
 ///
 /// // German is shadowed by Chinese, so this fails
-/// data_provider
+/// provider
 ///     .load(DataRequest {
 ///         locale: &locale!("de").into(),
 ///         metadata: Default::default(),
@@ -166,7 +166,7 @@ impl<P0, P1> ForkByKeyProvider<P0, P1> {
 /// # Examples
 ///
 /// ```
-/// use icu_locid::{subtags_language as language, locale};
+/// use icu_locid::{subtags::language, locale};
 /// use icu_provider::hello_world::*;
 /// use icu_provider::prelude::*;
 /// use icu_provider_adapters::filter::Filterable;
@@ -185,11 +185,11 @@ impl<P0, P1> ForkByKeyProvider<P0, P1> {
 ///     ],
 /// );
 ///
-/// let data_provider: &dyn DataProvider<HelloWorldV1Marker> =
+/// let provider: &dyn DataProvider<HelloWorldV1Marker> =
 ///     &forking_provider.as_deserializing();
 ///
 /// // Chinese is the first provider, so this succeeds
-/// let chinese_hello_world = data_provider
+/// let chinese_hello_world = provider
 ///     .load(DataRequest {
 ///         locale: &locale!("zh").into(),
 ///         metadata: Default::default(),
@@ -201,7 +201,7 @@ impl<P0, P1> ForkByKeyProvider<P0, P1> {
 /// assert_eq!("你好世界", chinese_hello_world.get().message);
 ///
 /// // German is shadowed by Chinese, so this fails
-/// data_provider
+/// provider
 ///     .load(DataRequest {
 ///         locale: &locale!("de").into(),
 ///         metadata: Default::default(),
diff --git a/vendor/icu_provider_adapters/src/fork/predicates.rs b/vendor/icu_provider_adapters/src/fork/predicates.rs
index 0fefe5704..58ffa7416 100644
--- a/vendor/icu_provider_adapters/src/fork/predicates.rs
+++ b/vendor/icu_provider_adapters/src/fork/predicates.rs
@@ -10,6 +10,9 @@ use icu_provider::prelude::*;
 ///
 /// [`ForkByErrorProvider`]: super::ForkByErrorProvider
 pub trait ForkByErrorPredicate {
+    /// The error to return if there are zero providers.
+    const UNIT_ERROR: DataErrorKind = DataErrorKind::MissingDataKey;
+
     /// This function is called when a data request fails and there are additional providers
     /// that could possibly fulfill the request.
     ///
@@ -43,6 +46,8 @@ pub trait ForkByErrorPredicate {
 pub struct MissingDataKeyPredicate;
 
 impl ForkByErrorPredicate for MissingDataKeyPredicate {
+    const UNIT_ERROR: DataErrorKind = DataErrorKind::MissingDataKey;
+
     #[inline]
     fn test(&self, _: DataKey, _: Option<DataRequest>, err: DataError) -> bool {
         matches!(
@@ -125,6 +130,8 @@ impl ForkByErrorPredicate for MissingDataKeyPredicate {
 pub struct MissingLocalePredicate;
 
 impl ForkByErrorPredicate for MissingLocalePredicate {
+    const UNIT_ERROR: DataErrorKind = DataErrorKind::MissingLocale;
+
     #[inline]
     fn test(&self, _: DataKey, _: Option<DataRequest>, err: DataError) -> bool {
         matches!(
diff --git a/vendor/icu_provider_adapters/tests/data/blob.postcard b/vendor/icu_provider_adapters/tests/data/blob.postcard
new file mode 100644
index 000000000..c958c7bfd
--- /dev/null
+++ b/vendor/icu_provider_adapters/tests/data/blob.postcard
diff --git a/vendor/icu_provider_adapters/tests/data/config.json b/vendor/icu_provider_adapters/tests/data/config.json
new file mode 100644
index 000000000..db3a07ac1
--- /dev/null
+++ b/vendor/icu_provider_adapters/tests/data/config.json
@@ -0,0 +1,21 @@
+{
+  "keys": {
+    "explicit": [
+      "core/helloworld@1",
+      "fallback/likelysubtags@1",
+      "fallback/parents@1",
+      "fallback/supplement/co@1"
+    ]
+  },
+  "fallback": "runtimeManual",
+  "locales": "all",
+  "cldr": "latest",
+  "icuExport": "none",
+  "segmenterLstm": "none",
+  "export": {
+    "blob": {
+      "path": "blob.postcard"
+    }
+  },
+  "overwrite": true
+}
\ No newline at end of file
diff --git a/vendor/icu_provider_adapters/tests/data/langtest/de.json b/vendor/icu_provider_adapters/tests/data/langtest/de.json
new file mode 100644
index 000000000..8c69fa425
--- /dev/null
+++ b/vendor/icu_provider_adapters/tests/data/langtest/de.json
@@ -0,0 +1,23 @@
+{
+  "keys": {
+    "explicit": [
+      "core/helloworld@1"
+    ]
+  },
+  "fallback": "preresolved",
+  "locales": {
+    "explicit": [
+      "de"
+    ]
+  },
+  "cldr": "none",
+  "icuExport": "none",
+  "segmenterLstm": "none",
+  "export": {
+    "fileSystem": {
+      "path": "de",
+      "syntax": "json"
+    }
+  },
+  "overwrite": true
+}
\ No newline at end of file
diff --git a/vendor/icu_provider_adapters/tests/data/langtest/ro.json b/vendor/icu_provider_adapters/tests/data/langtest/ro.json
new file mode 100644
index 000000000..afae9e85a
--- /dev/null
+++ b/vendor/icu_provider_adapters/tests/data/langtest/ro.json
@@ -0,0 +1,23 @@
+{
+  "keys": {
+    "explicit": [
+      "core/helloworld@1"
+    ]
+  },
+  "fallback": "preresolved",
+  "locales": {
+    "explicit": [
+      "ro"
+    ]
+  },
+  "cldr": "none",
+  "icuExport": "none",
+  "segmenterLstm": "none",
+  "export": {
+    "fileSystem": {
+      "path": "ro",
+      "syntax": "json"
+    }
+  },
+  "overwrite": true
+}
\ No newline at end of file