Import Upstream version 0.12.3

2023-04-03 09:07:04 +08:00 · 2023-04-03 09:07:04 +08:00 · 6323e923d8
commit 6323e923d8
51 changed files with 19397 additions and 0 deletions
--- a/.cargo_vcs_info.json
+++ b/.cargo_vcs_info.json
@ -0,0 +1,6 @@
+{
+  "git": {
+    "sha1": "1d2c1a81d1b53285decbd64410a21a90112613d7"
+  },
+  "path_in_vcs": ""
+}
--- a/.gitignore
+++ b/.gitignore
@ -0,0 +1,3 @@
+/target
+**/*.rs.bk
+Cargo.lock
--- a/.pc/.quilt_patches
+++ b/.pc/.quilt_patches
@ -0,0 +1 @@
+debian/patches
--- a/.pc/.quilt_series
+++ b/.pc/.quilt_series
@ -0,0 +1 @@
+series
--- a/.pc/.version
+++ b/.pc/.version
@ -0,0 +1 @@
+2
--- a/.pc/applied-patches
+++ b/.pc/applied-patches
@ -0,0 +1 @@
+disable-alloc.diff
--- a/.pc/disable-alloc.diff/Cargo.toml
+++ b/.pc/disable-alloc.diff/Cargo.toml
@ -0,0 +1,113 @@
+# THIS FILE IS AUTOMATICALLY GENERATED BY CARGO
+#
+# When uploading crates to the registry Cargo will automatically
+# "normalize" Cargo.toml files for maximal compatibility
+# with all versions of Cargo and also rewrite `path` dependencies
+# to registry (e.g., crates.io) dependencies.
+#
+# If you are reading this file be aware that the original Cargo.toml
+# will likely look very different (and much more reasonable).
+# See Cargo.toml.orig for the original contents.
+
+[package]
+edition = "2021"
+rust-version = "1.56.0"
+name = "hashbrown"
+version = "0.12.3"
+authors = ["Amanieu d'Antras <amanieu@gmail.com>"]
+exclude = [
+    ".github",
+    "/ci/*",
+]
+description = "A Rust port of Google's SwissTable hash map"
+readme = "README.md"
+keywords = [
+    "hash",
+    "no_std",
+    "hashmap",
+    "swisstable",
+]
+categories = [
+    "data-structures",
+    "no-std",
+]
+license = "MIT OR Apache-2.0"
+repository = "https://github.com/rust-lang/hashbrown"
+resolver = "2"
+
+[package.metadata.docs.rs]
+features = [
+    "nightly",
+    "rayon",
+    "serde",
+    "raw",
+]
+
+[dependencies.ahash]
+version = "0.7.0"
+optional = true
+default-features = false
+
+[dependencies.alloc]
+version = "1.0.0"
+optional = true
+package = "rustc-std-workspace-alloc"
+
+[dependencies.bumpalo]
+version = "3.5.0"
+optional = true
+
+[dependencies.compiler_builtins]
+version = "0.1.2"
+optional = true
+
+[dependencies.core]
+version = "1.0.0"
+optional = true
+package = "rustc-std-workspace-core"
+
+[dependencies.rayon]
+version = "1.0"
+optional = true
+
+[dependencies.serde]
+version = "1.0.25"
+optional = true
+default-features = false
+
+[dev-dependencies.doc-comment]
+version = "0.3.1"
+
+[dev-dependencies.fnv]
+version = "1.0.7"
+
+[dev-dependencies.lazy_static]
+version = "1.4"
+
+[dev-dependencies.rand]
+version = "0.8.3"
+features = ["small_rng"]
+
+[dev-dependencies.rayon]
+version = "1.0"
+
+[dev-dependencies.serde_test]
+version = "1.0"
+
+[features]
+ahash-compile-time-rng = ["ahash/compile-time-rng"]
+default = [
+    "ahash",
+    "inline-more",
+]
+inline-more = []
+nightly = []
+raw = []
+rustc-dep-of-std = [
+    "nightly",
+    "core",
+    "compiler_builtins",
+    "alloc",
+    "rustc-internal-api",
+]
+rustc-internal-api = []
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@ -0,0 +1,402 @@
+# Change Log
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/)
+and this project adheres to [Semantic Versioning](https://semver.org/).
+
+## [Unreleased]
+
+## [v0.12.3] - 2022-07-17
+
+## Fixed
+
+- Fixed double-drop in `RawTable::clone_from`. (#348)
+
+## [v0.12.2] - 2022-07-09
+
+## Added
+
+- Added `Entry` API for `HashSet`. (#342)
+- Added `Extend<&'a (K, V)> for HashMap<K, V, S, A>`. (#340)
+- Added length-based short-circuiting for hash table iteration. (#338)
+- Added a function to access the `RawTable` of a `HashMap`. (#335)
+
+## Changed
+
+- Edited `do_alloc` to reduce LLVM IR generated. (#341)
+
+## [v0.12.1] - 2022-05-02
+
+## Fixed
+
+- Fixed underflow in `RawIterRange::size_hint`. (#325)
+- Fixed the implementation of `Debug` for `ValuesMut` and `IntoValues`. (#325)
+
+## [v0.12.0] - 2022-01-17
+
+## Added
+
+- Added `From<[T; N]>` and `From<[(K, V); N]>` for `HashSet` and `HashMap` respectively. (#297)
+- Added an `allocator()` getter to HashMap and HashSet. (#257)
+- Added `insert_unique_unchecked` to `HashMap` and `HashSet`. (#293)
+- Added `into_keys` and `into_values` to HashMap. (#295)
+- Implement `From<array>` on `HashSet` and `HashMap`. (#298)
+- Added `entry_ref` API to `HashMap`. (#201)
+
+## Changed
+
+- Bumped minimum Rust version to 1.56.1 and edition to 2021.
+- Use u64 for the GroupWord on WebAssembly. (#271)
+- Optimized `find`. (#279)
+- Made rehashing and resizing less generic to reduce compilation time. (#282)
+- Inlined small functions. (#283)
+- Use `BuildHasher::hash_one` when `feature = "nightly"` is enabled. (#292)
+- Relaxed the bounds on `Debug` for `HashSet`. (#296)
+- Rename `get_each_mut` to `get_many_mut` and align API with the stdlib. (#291)
+- Don't hash the key when searching in an empty table. (#305)
+
+## Fixed
+
+- Guard against allocations exceeding isize::MAX. (#268)
+- Made `RawTable::insert_no_grow` unsafe. (#254)
+- Inline `static_empty`. (#280)
+- Fixed trait bounds on Send/Sync impls. (#303)
+
+## [v0.11.2] - 2021-03-25
+
+## Fixed
+
+- Added missing allocator type parameter to `HashMap`'s and `HashSet`'s `Clone` impls. (#252)
+
+## [v0.11.1] - 2021-03-20
+
+## Fixed
+
+- Added missing `pub` modifier to `BumpWrapper`. (#251)
+
+## [v0.11.0] - 2021-03-14
+
+## Added
+- Added safe `try_insert_no_grow` method to `RawTable`. (#229)
+- Added support for `bumpalo` as an allocator without the `nightly` feature. (#231)
+- Implemented `Default` for `RawTable`. (#237)
+- Added new safe methods `RawTable::get_each_mut`, `HashMap::get_each_mut`, and
+  `HashMap::get_each_key_value_mut`. (#239)
+- Added `From<HashMap<T, ()>>` for `HashSet<T>`. (#235)
+- Added `try_insert` method to `HashMap`. (#247)
+
+## Changed
+- The minimum Rust version has been bumped to 1.49.0. (#230)
+- Significantly improved compilation times by reducing the amount of generated IR. (#205)
+
+## Removed
+- We no longer re-export the unstable allocator items from the standard library, nor the stable shims approximating the same. (#227)
+- Removed hasher specialization support from `aHash`, which was resulting in inconsistent hashes being generated for a key. (#248)
+
+## Fixed
+- Fixed union length comparison. (#228)
+
+## ~~[v0.10.0] - 2021-01-16~~
+
+This release was _yanked_ due to inconsistent hashes being generated with the `nightly` feature. (#248)
+
+## Changed
+- Parametrized `RawTable`, `HashSet` and `HashMap` over an allocator. (#133)
+- Improved branch prediction hints on stable. (#209)
+- Optimized hashing of primitive types with AHash using specialization. (#207)
+- Only instantiate `RawTable`'s reserve functions once per key-value. (#204)
+
+## [v0.9.1] - 2020-09-28
+
+## Added
+- Added safe methods to `RawTable` (#202):
+  - `get`: `find` and `as_ref`
+  - `get_mut`: `find` and `as_mut`
+  - `insert_entry`: `insert` and `as_mut`
+  - `remove_entry`: `find` and `remove`
+  - `erase_entry`: `find` and `erase`
+
+## Changed
+- Removed `from_key_hashed_nocheck`'s `Q: Hash`. (#200)
+- Made `RawTable::drain` safe. (#201)
+
+## [v0.9.0] - 2020-09-03
+
+### Fixed
+- `drain_filter` now removes and yields items that do match the predicate,
+  rather than items that don't.  This is a **breaking change** to match the
+  behavior of the `drain_filter` methods in `std`. (#187)
+
+### Added
+- Added `replace_entry_with` to `OccupiedEntry`, and `and_replace_entry_with` to `Entry`. (#190)
+- Implemented `FusedIterator` and `size_hint` for `DrainFilter`. (#188)
+
+### Changed
+- The minimum Rust version has been bumped to 1.36 (due to `crossbeam` dependency). (#193)
+- Updated `ahash` dependency to 0.4. (#198)
+- `HashMap::with_hasher` and `HashSet::with_hasher` are now `const fn`. (#195)
+- Removed `T: Hash + Eq` and `S: BuildHasher` bounds on `HashSet::new`,
+  `with_capacity`, `with_hasher`, and `with_capacity_and_hasher`.  (#185)
+
+## [v0.8.2] - 2020-08-08
+
+### Changed
+- Avoid closures to improve compile times. (#183)
+- Do not iterate to drop if empty. (#182)
+
+## [v0.8.1] - 2020-07-16
+
+### Added
+- Added `erase` and `remove` to `RawTable`. (#171)
+- Added `try_with_capacity` to `RawTable`. (#174)
+- Added methods that allow re-using a `RawIter` for `RawDrain`,
+  `RawIntoIter`, and `RawParIter`. (#175)
+- Added `reflect_remove` and `reflect_insert` to `RawIter`. (#175)
+- Added a `drain_filter` function to `HashSet`. (#179)
+
+### Changed
+- Deprecated `RawTable::erase_no_drop` in favor of `erase` and `remove`. (#176)
+- `insert_no_grow` is now exposed under the `"raw"` feature. (#180)
+
+## [v0.8.0] - 2020-06-18
+
+### Fixed
+- Marked `RawTable::par_iter` as `unsafe`. (#157)
+
+### Changed
+- Reduced the size of `HashMap`. (#159)
+- No longer create tables with a capacity of 1 element. (#162)
+- Removed `K: Eq + Hash` bounds on `retain`. (#163)
+- Pulled in `HashMap` changes from rust-lang/rust (#164):
+  - `extend_one` support on nightly.
+  - `CollectionAllocErr` renamed to `TryReserveError`.
+  - Added `HashSet::get_or_insert_owned`.
+  - `Default` for `HashSet` no longer requires `T: Eq + Hash` and `S: BuildHasher`.
+
+## [v0.7.2] - 2020-04-27
+
+### Added
+- Added `or_insert_with_key` to `Entry`. (#152)
+
+### Fixed
+- Partially reverted `Clone` optimization which was unsound. (#154)
+
+### Changed
+- Disabled use of `const-random` by default, which prevented reproducible builds. (#155)
+- Optimized `repeat` function. (#150)
+- Use `NonNull` for buckets, which improves codegen for iterators. (#148)
+
+## [v0.7.1] - 2020-03-16
+
+### Added
+- Added `HashMap::get_key_value_mut`. (#145)
+
+### Changed
+- Optimized `Clone` implementation. (#146)
+
+## [v0.7.0] - 2020-01-31
+
+### Added
+- Added a `drain_filter` function to `HashMap`. (#135)
+
+### Changed
+- Updated `ahash` dependency to 0.3. (#141)
+- Optimized set union and intersection. (#130)
+- `raw_entry` can now be used without requiring `S: BuildHasher`. (#123)
+- `RawTable::bucket_index` can now be used under the `raw` feature. (#128)
+
+## [v0.6.3] - 2019-10-31
+
+### Added
+- Added an `ahash-compile-time-rng` feature (enabled by default) which allows disabling the
+  `compile-time-rng` feature in `ahash` to work around a Cargo bug. (#125)
+
+## [v0.6.2] - 2019-10-23
+
+### Added
+- Added an `inline-more` feature (enabled by default) which allows choosing a tradeoff between 
+  runtime performance and compilation time. (#119)
+
+## [v0.6.1] - 2019-10-04
+
+### Added
+- Added `Entry::insert` and `RawEntryMut::insert`. (#118)
+
+### Changed
+- `Group::static_empty` was changed from a `const` to a `static` (#116).
+
+## [v0.6.0] - 2019-08-13
+
+### Fixed
+- Fixed AHash accidentally depending on `std`. (#110)
+
+### Changed
+- The minimum Rust version has been bumped to 1.32 (due to `rand` dependency).
+
+## ~~[v0.5.1] - 2019-08-04~~
+
+This release was _yanked_ due to a breaking change for users of `no-default-features`.
+
+### Added
+- The experimental and unsafe `RawTable` API is available under the "raw" feature. (#108)
+- Added entry-like methods for `HashSet`. (#98)
+
+### Changed
+- Changed the default hasher from FxHash to AHash. (#97)
+- `hashbrown` is now fully `no_std` on recent Rust versions (1.36+). (#96)
+
+### Fixed
+- We now avoid growing the table during insertions when it wasn't necessary. (#106)
+- `RawOccupiedEntryMut` now properly implements `Send` and `Sync`. (#100)
+- Relaxed `lazy_static` version. (#92)
+
+## [v0.5.0] - 2019-06-12
+
+### Fixed
+- Resize with a more conservative amount of space after deletions. (#86)
+
+### Changed
+- Exposed the Layout of the failed allocation in CollectionAllocErr::AllocErr. (#89)
+
+## [v0.4.0] - 2019-05-30
+
+### Fixed
+- Fixed `Send` trait bounds on `IterMut` not matching the libstd one. (#82)
+
+## [v0.3.1] - 2019-05-30
+
+### Fixed
+- Fixed incorrect use of slice in unsafe code. (#80)
+
+## [v0.3.0] - 2019-04-23
+
+### Changed
+- Changed shrink_to to not panic if min_capacity < capacity. (#67)
+
+### Fixed
+- Worked around emscripten bug emscripten-core/emscripten-fastcomp#258. (#66)
+
+## [v0.2.2] - 2019-04-16
+
+### Fixed
+- Inlined non-nightly lowest_set_bit_nonzero. (#64)
+- Fixed build on latest nightly. (#65)
+
+## [v0.2.1] - 2019-04-14
+
+### Changed
+- Use for_each in map Extend and FromIterator. (#58)
+- Improved worst-case performance of HashSet.is_subset. (#61)
+
+### Fixed
+- Removed incorrect debug_assert. (#60)
+
+## [v0.2.0] - 2019-03-31
+
+### Changed
+- The code has been updated to Rust 2018 edition. This means that the minimum
+  Rust version has been bumped to 1.31 (2018 edition).
+
+### Added
+- Added `insert_with_hasher` to the raw_entry API to allow `K: !(Hash + Eq)`. (#54)
+- Added support for using hashbrown as the hash table implementation in libstd. (#46)
+
+### Fixed
+- Fixed cargo build with minimal-versions. (#45)
+- Fixed `#[may_dangle]` attributes to match the libstd `HashMap`. (#46)
+- ZST keys and values are now handled properly. (#46)
+
+## [v0.1.8] - 2019-01-14
+
+### Added
+- Rayon parallel iterator support (#37)
+- `raw_entry` support (#31)
+- `#[may_dangle]` on nightly (#31)
+- `try_reserve` support (#31)
+
+### Fixed
+- Fixed variance on `IterMut`. (#31)
+
+## [v0.1.7] - 2018-12-05
+
+### Fixed
+- Fixed non-SSE version of convert_special_to_empty_and_full_to_deleted. (#32)
+- Fixed overflow in rehash_in_place. (#33)
+
+## [v0.1.6] - 2018-11-17
+
+### Fixed
+- Fixed compile error on nightly. (#29)
+
+## [v0.1.5] - 2018-11-08
+
+### Fixed
+- Fixed subtraction overflow in generic::Group::match_byte. (#28)
+
+## [v0.1.4] - 2018-11-04
+
+### Fixed
+- Fixed a bug in the `erase_no_drop` implementation. (#26)
+
+## [v0.1.3] - 2018-11-01
+
+### Added
+- Serde support. (#14)
+
+### Fixed
+- Make the compiler inline functions more aggressively. (#20)
+
+## [v0.1.2] - 2018-10-31
+
+### Fixed
+- `clear` segfaults when called on an empty table. (#13)
+
+## [v0.1.1] - 2018-10-30
+
+### Fixed
+- `erase_no_drop` optimization not triggering in the SSE2 implementation. (#3)
+- Missing `Send` and `Sync` for hash map and iterator types. (#7)
+- Bug when inserting into a table smaller than the group width. (#5)
+
+## v0.1.0 - 2018-10-29
+
+- Initial release
+
+[Unreleased]: https://github.com/rust-lang/hashbrown/compare/v0.12.3...HEAD
+[v0.12.3]: https://github.com/rust-lang/hashbrown/compare/v0.12.2...v0.12.3
+[v0.12.2]: https://github.com/rust-lang/hashbrown/compare/v0.12.1...v0.12.2
+[v0.12.1]: https://github.com/rust-lang/hashbrown/compare/v0.12.0...v0.12.1
+[v0.12.0]: https://github.com/rust-lang/hashbrown/compare/v0.11.2...v0.12.0
+[v0.11.2]: https://github.com/rust-lang/hashbrown/compare/v0.11.1...v0.11.2
+[v0.11.1]: https://github.com/rust-lang/hashbrown/compare/v0.11.0...v0.11.1
+[v0.11.0]: https://github.com/rust-lang/hashbrown/compare/v0.10.0...v0.11.0
+[v0.10.0]: https://github.com/rust-lang/hashbrown/compare/v0.9.1...v0.10.0
+[v0.9.1]: https://github.com/rust-lang/hashbrown/compare/v0.9.0...v0.9.1
+[v0.9.0]: https://github.com/rust-lang/hashbrown/compare/v0.8.2...v0.9.0
+[v0.8.2]: https://github.com/rust-lang/hashbrown/compare/v0.8.1...v0.8.2
+[v0.8.1]: https://github.com/rust-lang/hashbrown/compare/v0.8.0...v0.8.1
+[v0.8.0]: https://github.com/rust-lang/hashbrown/compare/v0.7.2...v0.8.0
+[v0.7.2]: https://github.com/rust-lang/hashbrown/compare/v0.7.1...v0.7.2
+[v0.7.1]: https://github.com/rust-lang/hashbrown/compare/v0.7.0...v0.7.1
+[v0.7.0]: https://github.com/rust-lang/hashbrown/compare/v0.6.3...v0.7.0
+[v0.6.3]: https://github.com/rust-lang/hashbrown/compare/v0.6.2...v0.6.3
+[v0.6.2]: https://github.com/rust-lang/hashbrown/compare/v0.6.1...v0.6.2
+[v0.6.1]: https://github.com/rust-lang/hashbrown/compare/v0.6.0...v0.6.1
+[v0.6.0]: https://github.com/rust-lang/hashbrown/compare/v0.5.1...v0.6.0
+[v0.5.1]: https://github.com/rust-lang/hashbrown/compare/v0.5.0...v0.5.1
+[v0.5.0]: https://github.com/rust-lang/hashbrown/compare/v0.4.0...v0.5.0
+[v0.4.0]: https://github.com/rust-lang/hashbrown/compare/v0.3.1...v0.4.0
+[v0.3.1]: https://github.com/rust-lang/hashbrown/compare/v0.3.0...v0.3.1
+[v0.3.0]: https://github.com/rust-lang/hashbrown/compare/v0.2.2...v0.3.0
+[v0.2.2]: https://github.com/rust-lang/hashbrown/compare/v0.2.1...v0.2.2
+[v0.2.1]: https://github.com/rust-lang/hashbrown/compare/v0.2.0...v0.2.1
+[v0.2.0]: https://github.com/rust-lang/hashbrown/compare/v0.1.8...v0.2.0
+[v0.1.8]: https://github.com/rust-lang/hashbrown/compare/v0.1.7...v0.1.8
+[v0.1.7]: https://github.com/rust-lang/hashbrown/compare/v0.1.6...v0.1.7
+[v0.1.6]: https://github.com/rust-lang/hashbrown/compare/v0.1.5...v0.1.6
+[v0.1.5]: https://github.com/rust-lang/hashbrown/compare/v0.1.4...v0.1.5
+[v0.1.4]: https://github.com/rust-lang/hashbrown/compare/v0.1.3...v0.1.4
+[v0.1.3]: https://github.com/rust-lang/hashbrown/compare/v0.1.2...v0.1.3
+[v0.1.2]: https://github.com/rust-lang/hashbrown/compare/v0.1.1...v0.1.2
+[v0.1.1]: https://github.com/rust-lang/hashbrown/compare/v0.1.0...v0.1.1
--- a/Cargo.toml
+++ b/Cargo.toml
@ -0,0 +1,107 @@
+# THIS FILE IS AUTOMATICALLY GENERATED BY CARGO
+#
+# When uploading crates to the registry Cargo will automatically
+# "normalize" Cargo.toml files for maximal compatibility
+# with all versions of Cargo and also rewrite `path` dependencies
+# to registry (e.g., crates.io) dependencies.
+#
+# If you are reading this file be aware that the original Cargo.toml
+# will likely look very different (and much more reasonable).
+# See Cargo.toml.orig for the original contents.
+
+[package]
+edition = "2021"
+rust-version = "1.56.0"
+name = "hashbrown"
+version = "0.12.3"
+authors = ["Amanieu d'Antras <amanieu@gmail.com>"]
+exclude = [
+    ".github",
+    "/ci/*",
+]
+description = "A Rust port of Google's SwissTable hash map"
+readme = "README.md"
+keywords = [
+    "hash",
+    "no_std",
+    "hashmap",
+    "swisstable",
+]
+categories = [
+    "data-structures",
+    "no-std",
+]
+license = "MIT OR Apache-2.0"
+repository = "https://github.com/rust-lang/hashbrown"
+resolver = "2"
+
+[package.metadata.docs.rs]
+features = [
+    "nightly",
+    "rayon",
+    "serde",
+    "raw",
+]
+
+[dependencies.ahash]
+version = "0.7.0"
+optional = true
+default-features = false
+
+[dependencies.bumpalo]
+version = "3.5.0"
+optional = true
+
+[dependencies.compiler_builtins]
+version = "0.1.2"
+optional = true
+
+[dependencies.core]
+version = "1.0.0"
+optional = true
+package = "rustc-std-workspace-core"
+
+[dependencies.rayon]
+version = "1.0"
+optional = true
+
+[dependencies.serde]
+version = "1.0.25"
+optional = true
+default-features = false
+
+[dev-dependencies.doc-comment]
+version = "0.3.1"
+
+[dev-dependencies.fnv]
+version = "1.0.7"
+
+[dev-dependencies.lazy_static]
+version = "1.4"
+
+[dev-dependencies.rand]
+version = "0.8.3"
+features = ["small_rng"]
+
+[dev-dependencies.rayon]
+version = "1.0"
+
+[dev-dependencies.serde_test]
+version = "1.0"
+
+[features]
+ahash-compile-time-rng = ["ahash/compile-time-rng"]
+default = [
+    "ahash",
+    "inline-more",
+]
+inline-more = []
+nightly = []
+raw = []
+rustc-dep-of-std = [
+    "nightly",
+    "core",
+    "compiler_builtins",
+    "rustc-internal-api",
+]
+rustc-internal-api = []
--- a/Cargo.toml.orig
+++ b/Cargo.toml.orig
@ -0,0 +1,60 @@
+[package]
+name = "hashbrown"
+version = "0.12.3"
+authors = ["Amanieu d'Antras <amanieu@gmail.com>"]
+description = "A Rust port of Google's SwissTable hash map"
+license = "MIT OR Apache-2.0"
+repository = "https://github.com/rust-lang/hashbrown"
+readme = "README.md"
+keywords = ["hash", "no_std", "hashmap", "swisstable"]
+categories = ["data-structures", "no-std"]
+exclude = [".github", "/ci/*"]
+edition = "2021"
+rust-version = "1.56.0"
+
+[dependencies]
+# For the default hasher
+ahash = { version = "0.7.0", default-features = false, optional = true }
+
+# For external trait impls
+rayon = { version = "1.0", optional = true }
+serde = { version = "1.0.25", default-features = false, optional = true }
+
+# When built as part of libstd
+core = { version = "1.0.0", optional = true, package = "rustc-std-workspace-core" }
+compiler_builtins = { version = "0.1.2", optional = true }
+alloc = { version = "1.0.0", optional = true, package = "rustc-std-workspace-alloc" }
+
+# Optional support for bumpalo
+bumpalo = { version = "3.5.0", optional = true }
+
+[dev-dependencies]
+lazy_static = "1.4"
+rand = { version = "0.8.3", features = ["small_rng"] }
+rayon = "1.0"
+fnv = "1.0.7"
+serde_test = "1.0"
+doc-comment = "0.3.1"
+
+[features]
+default = ["ahash", "inline-more"]
+
+ahash-compile-time-rng = ["ahash/compile-time-rng"]
+nightly = []
+rustc-internal-api = []
+rustc-dep-of-std = [
+    "nightly",
+    "core",
+    "compiler_builtins",
+    "alloc",
+    "rustc-internal-api",
+]
+raw = []
+
+# Enables usage of `#[inline]` on far more functions than by default in this
+# crate. This may lead to a performance increase but often comes at a compile
+# time cost.
+inline-more = []
+
+[package.metadata.docs.rs]
+features = ["nightly", "rayon", "serde", "raw"]
--- a/201
+++ b/201
@ -0,0 +1,201 @@
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+END OF TERMS AND CONDITIONS
+
+APPENDIX: How to apply the Apache License to your work.
+
+   To apply the Apache License to your work, attach the following
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+Copyright [yyyy] [name of copyright owner]
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
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+
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+See the License for the specific language governing permissions and
+limitations under the License.
--- a/25
+++ b/25
@ -0,0 +1,25 @@
+Copyright (c) 2016 Amanieu d'Antras
+
+Permission is hereby granted, free of charge, to any
+person obtaining a copy of this software and associated
+documentation files (the "Software"), to deal in the
+Software without restriction, including without
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+conditions:
+
+The above copyright notice and this permission notice
+shall be included in all copies or substantial portions
+of the Software.
+
+THE SOFTWARE IS 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. IN NO EVENT
+SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
+IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.
--- a/README.md
+++ b/README.md
@ -0,0 +1,126 @@
+hashbrown
+=========
+
+[![Build Status](https://github.com/rust-lang/hashbrown/actions/workflows/rust.yml/badge.svg)](https://github.com/rust-lang/hashbrown/actions)
+[![Crates.io](https://img.shields.io/crates/v/hashbrown.svg)](https://crates.io/crates/hashbrown)
+[![Documentation](https://docs.rs/hashbrown/badge.svg)](https://docs.rs/hashbrown)
+[![Rust](https://img.shields.io/badge/rust-1.56.1%2B-blue.svg?maxAge=3600)](https://github.com/rust-lang/hashbrown)
+
+This crate is a Rust port of Google's high-performance [SwissTable] hash
+map, adapted to make it a drop-in replacement for Rust's standard `HashMap`
+and `HashSet` types.
+
+The original C++ version of SwissTable can be found [here], and this
+[CppCon talk] gives an overview of how the algorithm works.
+
+Since Rust 1.36, this is now the `HashMap` implementation for the Rust standard
+library. However you may still want to use this crate instead since it works
+in environments without `std`, such as embedded systems and kernels.
+
+[SwissTable]: https://abseil.io/blog/20180927-swisstables
+[here]: https://github.com/abseil/abseil-cpp/blob/master/absl/container/internal/raw_hash_set.h
+[CppCon talk]: https://www.youtube.com/watch?v=ncHmEUmJZf4
+
+## [Change log](CHANGELOG.md)
+
+## Features
+
+- Drop-in replacement for the standard library `HashMap` and `HashSet` types.
+- Uses [AHash](https://github.com/tkaitchuck/aHash) as the default hasher, which is much faster than SipHash.
+  However, AHash does *not provide the same level of HashDoS resistance* as SipHash, so if that is important to you, you might want to consider using a different hasher.
+- Around 2x faster than the previous standard library `HashMap`.
+- Lower memory usage: only 1 byte of overhead per entry instead of 8.
+- Compatible with `#[no_std]` (but requires a global allocator with the `alloc` crate).
+- Empty hash maps do not allocate any memory.
+- SIMD lookups to scan multiple hash entries in parallel.
+
+## Performance
+
+Compared to the previous implementation of `std::collections::HashMap` (Rust 1.35).
+
+With the hashbrown default AHash hasher:
+
+| name                    |  oldstdhash ns/iter | hashbrown ns/iter | diff ns/iter |  diff %  | speedup |
+|:------------------------|:-------------------:|------------------:|:------------:|---------:|---------|
+| insert_ahash_highbits       | 18,865      | 8,020         |               -10,845 | -57.49%  | x 2.35 |
+| insert_ahash_random         | 19,711      | 8,019         |               -11,692 | -59.32%  | x 2.46 |
+| insert_ahash_serial         | 19,365      | 6,463         |               -12,902 | -66.63%  | x 3.00 |
+| insert_erase_ahash_highbits | 51,136      | 17,916        |               -33,220 | -64.96%  | x 2.85 |
+| insert_erase_ahash_random   | 51,157      | 17,688        |               -33,469 | -65.42%  | x 2.89 |
+| insert_erase_ahash_serial   | 45,479      | 14,895        |               -30,584 | -67.25%  | x 3.05 |
+| iter_ahash_highbits         | 1,399       | 1,092         |                  -307 | -21.94%  | x 1.28 |
+| iter_ahash_random           | 1,586       | 1,059         |                  -527 | -33.23%  | x 1.50 |
+| iter_ahash_serial           | 3,168       | 1,079         |                -2,089 | -65.94%  | x 2.94 |
+| lookup_ahash_highbits       | 32,351      | 4,792         |               -27,559 | -85.19%  | x 6.75 |
+| lookup_ahash_random         | 17,419      | 4,817         |               -12,602 | -72.35%  | x 3.62 |
+| lookup_ahash_serial         | 15,254      | 3,606         |               -11,648 | -76.36%  | x 4.23 |
+| lookup_fail_ahash_highbits  | 21,187      | 4,369         |               -16,818 | -79.38%  | x 4.85 |
+| lookup_fail_ahash_random    | 21,550      | 4,395         |               -17,155 | -79.61%  | x 4.90 |
+| lookup_fail_ahash_serial    | 19,450      | 3,176         |               -16,274 | -83.67%  | x 6.12 |
+
+
+With the libstd default SipHash hasher:
+
+|name                     |  oldstdhash ns/iter | hashbrown ns/iter | diff ns/iter |  diff %  | speedup |
+|:------------------------|:-------------------:|------------------:|:------------:|---------:|---------|
+|insert_std_highbits       |19,216      |16,885           |            -2,331    |   -12.13%  | x 1.14 |
+|insert_std_random         |19,179      |17,034           |            -2,145    |   -11.18%  | x 1.13 |
+|insert_std_serial         |19,462      |17,493           |            -1,969    |   -10.12%  | x 1.11 |
+|insert_erase_std_highbits |50,825      |35,847           |            -14,978   |   -29.47%  | x 1.42 |
+|insert_erase_std_random   |51,448      |35,392           |            -16,056   |   -31.21%  | x 1.45 |
+|insert_erase_std_serial   |87,711      |38,091           |            -49,620   |   -56.57%  | x 2.30 |
+|iter_std_highbits         |1,378       |1,159            |            -219      |   -15.89%  | x 1.19 |
+|iter_std_random           |1,395       |1,132            |            -263      |   -18.85%  | x 1.23 |
+|iter_std_serial           |1,704       |1,105            |            -599      |   -35.15%  | x 1.54 |
+|lookup_std_highbits       |17,195      |13,642           |            -3,553    |   -20.66%  | x 1.26 |
+|lookup_std_random         |17,181      |13,773           |            -3,408    |   -19.84%  | x 1.25 |
+|lookup_std_serial         |15,483      |13,651           |            -1,832    |   -11.83%  | x 1.13 |
+|lookup_fail_std_highbits  |20,926      |13,474           |            -7,452    |   -35.61%  | x 1.55 |
+|lookup_fail_std_random    |21,766      |13,505           |            -8,261    |   -37.95%  | x 1.61 |
+|lookup_fail_std_serial    |19,336      |13,519           |            -5,817    |   -30.08%  | x 1.43 |
+
+## Usage
+
+Add this to your `Cargo.toml`:
+
+```toml
+[dependencies]
+hashbrown = "0.12"
+```
+
+Then:
+
+```rust
+use hashbrown::HashMap;
+
+let mut map = HashMap::new();
+map.insert(1, "one");
+```
+## Flags
+This crate has the following Cargo features:
+
+- `nightly`: Enables nightly-only features including: `#[may_dangle]`.
+- `serde`: Enables serde serialization support.
+- `rayon`: Enables rayon parallel iterator support.
+- `raw`: Enables access to the experimental and unsafe `RawTable` API.
+- `inline-more`: Adds inline hints to most functions, improving run-time performance at the cost
+  of compilation time. (enabled by default)
+- `bumpalo`: Provides a `BumpWrapper` type which allows `bumpalo` to be used for memory allocation.
+- `ahash`: Compiles with ahash as default hasher. (enabled by default)
+- `ahash-compile-time-rng`: Activates the `compile-time-rng` feature of ahash. For targets with no random number generator
+this pre-generates seeds at compile time and embeds them as constants. See [aHash's documentation](https://github.com/tkaitchuck/aHash#flags) (disabled by default)
+
+## License
+
+Licensed under either of:
+
+ * Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or https://www.apache.org/licenses/LICENSE-2.0)
+ * MIT license ([LICENSE-MIT](LICENSE-MIT) or https://opensource.org/licenses/MIT)
+
+at your option.
+
+### Contribution
+
+Unless you explicitly state otherwise, any contribution intentionally submitted
+for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any
+additional terms or conditions.
--- a/benches/bench.rs
+++ b/benches/bench.rs
@ -0,0 +1,331 @@
+// This benchmark suite contains some benchmarks along a set of dimensions:
+//   Hasher: std default (SipHash) and crate default (AHash).
+//   Int key distribution: low bit heavy, top bit heavy, and random.
+//   Task: basic functionality: insert, insert_erase, lookup, lookup_fail, iter
+#![feature(test)]
+
+extern crate test;
+
+use test::{black_box, Bencher};
+
+use hashbrown::hash_map::DefaultHashBuilder;
+use hashbrown::{HashMap, HashSet};
+use std::{
+    collections::hash_map::RandomState,
+    sync::atomic::{self, AtomicUsize},
+};
+
+const SIZE: usize = 1000;
+
+// The default hashmap when using this crate directly.
+type AHashMap<K, V> = HashMap<K, V, DefaultHashBuilder>;
+// This uses the hashmap from this crate with the default hasher of the stdlib.
+type StdHashMap<K, V> = HashMap<K, V, RandomState>;
+
+// A random key iterator.
+#[derive(Clone, Copy)]
+struct RandomKeys {
+    state: usize,
+}
+
+impl RandomKeys {
+    fn new() -> Self {
+        RandomKeys { state: 0 }
+    }
+}
+
+impl Iterator for RandomKeys {
+    type Item = usize;
+    fn next(&mut self) -> Option<usize> {
+        // Add 1 then multiply by some 32 bit prime.
+        self.state = self.state.wrapping_add(1).wrapping_mul(3_787_392_781);
+        Some(self.state)
+    }
+}
+
+// Just an arbitrary side effect to make the maps not shortcircuit to the non-dropping path
+// when dropping maps/entries (most real world usages likely have drop in the key or value)
+lazy_static::lazy_static! {
+    static ref SIDE_EFFECT: AtomicUsize = AtomicUsize::new(0);
+}
+
+#[derive(Clone)]
+struct DropType(usize);
+impl Drop for DropType {
+    fn drop(&mut self) {
+        SIDE_EFFECT.fetch_add(self.0, atomic::Ordering::SeqCst);
+    }
+}
+
+macro_rules! bench_suite {
+    ($bench_macro:ident, $bench_ahash_serial:ident, $bench_std_serial:ident,
+     $bench_ahash_highbits:ident, $bench_std_highbits:ident,
+     $bench_ahash_random:ident, $bench_std_random:ident) => {
+        $bench_macro!($bench_ahash_serial, AHashMap, 0..);
+        $bench_macro!($bench_std_serial, StdHashMap, 0..);
+        $bench_macro!(
+            $bench_ahash_highbits,
+            AHashMap,
+            (0..).map(usize::swap_bytes)
+        );
+        $bench_macro!(
+            $bench_std_highbits,
+            StdHashMap,
+            (0..).map(usize::swap_bytes)
+        );
+        $bench_macro!($bench_ahash_random, AHashMap, RandomKeys::new());
+        $bench_macro!($bench_std_random, StdHashMap, RandomKeys::new());
+    };
+}
+
+macro_rules! bench_insert {
+    ($name:ident, $maptype:ident, $keydist:expr) => {
+        #[bench]
+        fn $name(b: &mut Bencher) {
+            let mut m = $maptype::with_capacity_and_hasher(SIZE, Default::default());
+            b.iter(|| {
+                m.clear();
+                for i in ($keydist).take(SIZE) {
+                    m.insert(i, (DropType(i), [i; 20]));
+                }
+                black_box(&mut m);
+            });
+            eprintln!("{}", SIDE_EFFECT.load(atomic::Ordering::SeqCst));
+        }
+    };
+}
+
+bench_suite!(
+    bench_insert,
+    insert_ahash_serial,
+    insert_std_serial,
+    insert_ahash_highbits,
+    insert_std_highbits,
+    insert_ahash_random,
+    insert_std_random
+);
+
+macro_rules! bench_grow_insert {
+    ($name:ident, $maptype:ident, $keydist:expr) => {
+        #[bench]
+        fn $name(b: &mut Bencher) {
+            b.iter(|| {
+                let mut m = $maptype::default();
+                for i in ($keydist).take(SIZE) {
+                    m.insert(i, DropType(i));
+                }
+                black_box(&mut m);
+            })
+        }
+    };
+}
+
+bench_suite!(
+    bench_grow_insert,
+    grow_insert_ahash_serial,
+    grow_insert_std_serial,
+    grow_insert_ahash_highbits,
+    grow_insert_std_highbits,
+    grow_insert_ahash_random,
+    grow_insert_std_random
+);
+
+macro_rules! bench_insert_erase {
+    ($name:ident, $maptype:ident, $keydist:expr) => {
+        #[bench]
+        fn $name(b: &mut Bencher) {
+            let mut base = $maptype::default();
+            for i in ($keydist).take(SIZE) {
+                base.insert(i, DropType(i));
+            }
+            let skip = $keydist.skip(SIZE);
+            b.iter(|| {
+                let mut m = base.clone();
+                let mut add_iter = skip.clone();
+                let mut remove_iter = $keydist;
+                // While keeping the size constant,
+                // replace the first keydist with the second.
+                for (add, remove) in (&mut add_iter).zip(&mut remove_iter).take(SIZE) {
+                    m.insert(add, DropType(add));
+                    black_box(m.remove(&remove));
+                }
+                black_box(m);
+            });
+            eprintln!("{}", SIDE_EFFECT.load(atomic::Ordering::SeqCst));
+        }
+    };
+}
+
+bench_suite!(
+    bench_insert_erase,
+    insert_erase_ahash_serial,
+    insert_erase_std_serial,
+    insert_erase_ahash_highbits,
+    insert_erase_std_highbits,
+    insert_erase_ahash_random,
+    insert_erase_std_random
+);
+
+macro_rules! bench_lookup {
+    ($name:ident, $maptype:ident, $keydist:expr) => {
+        #[bench]
+        fn $name(b: &mut Bencher) {
+            let mut m = $maptype::default();
+            for i in $keydist.take(SIZE) {
+                m.insert(i, DropType(i));
+            }
+
+            b.iter(|| {
+                for i in $keydist.take(SIZE) {
+                    black_box(m.get(&i));
+                }
+            });
+            eprintln!("{}", SIDE_EFFECT.load(atomic::Ordering::SeqCst));
+        }
+    };
+}
+
+bench_suite!(
+    bench_lookup,
+    lookup_ahash_serial,
+    lookup_std_serial,
+    lookup_ahash_highbits,
+    lookup_std_highbits,
+    lookup_ahash_random,
+    lookup_std_random
+);
+
+macro_rules! bench_lookup_fail {
+    ($name:ident, $maptype:ident, $keydist:expr) => {
+        #[bench]
+        fn $name(b: &mut Bencher) {
+            let mut m = $maptype::default();
+            let mut iter = $keydist;
+            for i in (&mut iter).take(SIZE) {
+                m.insert(i, DropType(i));
+            }
+
+            b.iter(|| {
+                for i in (&mut iter).take(SIZE) {
+                    black_box(m.get(&i));
+                }
+            })
+        }
+    };
+}
+
+bench_suite!(
+    bench_lookup_fail,
+    lookup_fail_ahash_serial,
+    lookup_fail_std_serial,
+    lookup_fail_ahash_highbits,
+    lookup_fail_std_highbits,
+    lookup_fail_ahash_random,
+    lookup_fail_std_random
+);
+
+macro_rules! bench_iter {
+    ($name:ident, $maptype:ident, $keydist:expr) => {
+        #[bench]
+        fn $name(b: &mut Bencher) {
+            let mut m = $maptype::default();
+            for i in ($keydist).take(SIZE) {
+                m.insert(i, DropType(i));
+            }
+
+            b.iter(|| {
+                for i in &m {
+                    black_box(i);
+                }
+            })
+        }
+    };
+}
+
+bench_suite!(
+    bench_iter,
+    iter_ahash_serial,
+    iter_std_serial,
+    iter_ahash_highbits,
+    iter_std_highbits,
+    iter_ahash_random,
+    iter_std_random
+);
+
+#[bench]
+fn clone_small(b: &mut Bencher) {
+    let mut m = HashMap::new();
+    for i in 0..10 {
+        m.insert(i, DropType(i));
+    }
+
+    b.iter(|| {
+        black_box(m.clone());
+    })
+}
+
+#[bench]
+fn clone_from_small(b: &mut Bencher) {
+    let mut m = HashMap::new();
+    let mut m2 = HashMap::new();
+    for i in 0..10 {
+        m.insert(i, DropType(i));
+    }
+
+    b.iter(|| {
+        m2.clone_from(&m);
+        black_box(&mut m2);
+    })
+}
+
+#[bench]
+fn clone_large(b: &mut Bencher) {
+    let mut m = HashMap::new();
+    for i in 0..1000 {
+        m.insert(i, DropType(i));
+    }
+
+    b.iter(|| {
+        black_box(m.clone());
+    })
+}
+
+#[bench]
+fn clone_from_large(b: &mut Bencher) {
+    let mut m = HashMap::new();
+    let mut m2 = HashMap::new();
+    for i in 0..1000 {
+        m.insert(i, DropType(i));
+    }
+
+    b.iter(|| {
+        m2.clone_from(&m);
+        black_box(&mut m2);
+    })
+}
+
+#[bench]
+fn rehash_in_place(b: &mut Bencher) {
+    b.iter(|| {
+        let mut set = HashSet::new();
+
+        // Each loop triggers one rehash
+        for _ in 0..10 {
+            for i in 0..224 {
+                set.insert(i);
+            }
+
+            assert_eq!(
+                set.capacity(),
+                224,
+                "The set must be at or close to capacity to trigger a re hashing"
+            );
+
+            for i in 100..1400 {
+                set.remove(&(i - 100));
+                set.insert(i);
+            }
+            set.clear();
+        }
+    });
+}
--- a/benches/insert_unique_unchecked.rs
+++ b/benches/insert_unique_unchecked.rs
@ -0,0 +1,32 @@
+//! Compare `insert` and `insert_unique_unchecked` operations performance.
+
+#![feature(test)]
+
+extern crate test;
+
+use hashbrown::HashMap;
+use test::Bencher;
+
+#[bench]
+fn insert(b: &mut Bencher) {
+    let keys: Vec<String> = (0..1000).map(|i| format!("xxxx{}yyyy", i)).collect();
+    b.iter(|| {
+        let mut m = HashMap::with_capacity(1000);
+        for k in &keys {
+            m.insert(k, k);
+        }
+        m
+    });
+}
+
+#[bench]
+fn insert_unique_unchecked(b: &mut Bencher) {
+    let keys: Vec<String> = (0..1000).map(|i| format!("xxxx{}yyyy", i)).collect();
+    b.iter(|| {
+        let mut m = HashMap::with_capacity(1000);
+        for k in &keys {
+            m.insert_unique_unchecked(k, k);
+        }
+        m
+    });
+}
--- a/clippy.toml
+++ b/clippy.toml
@ -0,0 +1 @@
+doc-valid-idents = [ "CppCon", "SwissTable", "SipHash", "HashDoS" ]
--- a/debian-orig/cargo-checksum.json
+++ b/debian-orig/cargo-checksum.json
@ -0,0 +1 @@
+{"package":"Could not get crate checksum","files":{}}
--- a/debian-orig/changelog
+++ b/debian-orig/changelog
@ -0,0 +1,51 @@
+rust-hashbrown (0.12.3-1) unstable; urgency=medium
+
+  * Team upload.
+  * Package hashbrown 0.12.3 from crates.io using debcargo 2.5.0
+
+ -- Blair Noctis <n@sail.ng>  Thu, 13 Oct 2022 22:10:16 -0400
+
+rust-hashbrown (0.12.1-1) unstable; urgency=medium
+
+  * Team upload.
+  * Package hashbrown 0.12.1 from crates.io using debcargo 2.5.0
+  * drop patches already upstream.
+
+ -- Daniel Kahn Gillmor <dkg@fifthhorseman.net>  Mon, 27 Jun 2022 17:02:36 -0400
+
+rust-hashbrown (0.11.2-3) unstable; urgency=medium
+
+  * Team upload.
+  * Package hashbrown 0.11.2 from crates.io using debcargo 2.5.0
+  * Reinstate ahash feature (Closes: 987324)
+  * Add patch to make testsuite work with rand 0.8.
+  * Establish baseline for tests.
+
+ -- Peter Michael Green <plugwash@debian.org>  Sun, 29 May 2022 16:45:06 +0000
+
+rust-hashbrown (0.11.2-2) unstable; urgency=medium
+
+  * Team upload.
+  * Package hashbrown 0.11.2 from crates.io using debcargo 2.5.0
+
+ -- Sylvestre Ledru <sylvestre@debian.org>  Sat, 01 Jan 2022 21:21:30 +0100
+
+rust-hashbrown (0.11.2-1) unstable; urgency=medium
+
+  * Team upload.
+  * Package hashbrown 0.11.2 from crates.io using debcargo 2.5.0
+
+ -- Sylvestre Ledru <sylvestre@debian.org>  Sat, 01 Jan 2022 21:11:11 +0100
+
+rust-hashbrown (0.9.1-1) unstable; urgency=medium
+
+  * Team upload.
+  * Package hashbrown 0.9.1 from crates.io using debcargo 2.4.4-alpha.0
+
+ -- Sylvestre Ledru <sylvestre@debian.org>  Tue, 22 Dec 2020 16:57:52 +0100
+
+rust-hashbrown (0.1.8-1) unstable; urgency=medium
+
+  * Package hashbrown 0.1.8 from crates.io using debcargo 2.2.9
+
+ -- Ximin Luo <infinity0@debian.org>  Sat, 19 Jan 2019 12:49:57 -0800
--- a/debian-orig/compat
+++ b/debian-orig/compat
@ -0,0 +1 @@
+12
--- a/debian-orig/control
+++ b/debian-orig/control
@ -0,0 +1,88 @@
+Source: rust-hashbrown
+Section: rust
+Priority: optional
+Build-Depends: debhelper (>= 12),
+ dh-cargo (>= 25),
+ cargo:native <!nocheck>,
+ rustc:native <!nocheck>,
+ libstd-rust-dev <!nocheck>,
+ librust-ahash-0.7-dev <!nocheck>
+Maintainer: Debian Rust Maintainers <pkg-rust-maintainers@alioth-lists.debian.net>
+Uploaders:
+ Ximin Luo <infinity0@debian.org>
+Standards-Version: 4.5.1
+Vcs-Git: https://salsa.debian.org/rust-team/debcargo-conf.git [src/hashbrown]
+Vcs-Browser: https://salsa.debian.org/rust-team/debcargo-conf/tree/master/src/hashbrown
+Rules-Requires-Root: no
+
+Package: librust-hashbrown-dev
+Architecture: any
+Multi-Arch: same
+Depends:
+ ${misc:Depends},
+ librust-ahash-0.7+compile-time-rng-dev,
+ librust-ahash-0.7-dev,
+ librust-bumpalo-3+default-dev (>= 3.5.0-~~),
+ librust-compiler-builtins-0.1+default-dev (>= 0.1.2-~~),
+ librust-rayon-1+default-dev,
+ librust-rustc-std-workspace-core-1+default-dev,
+ librust-serde-1-dev (>= 1.0.25-~~)
+Provides:
+ librust-hashbrown+ahash-dev (= ${binary:Version}),
+ librust-hashbrown+ahash-compile-time-rng-dev (= ${binary:Version}),
+ librust-hashbrown+bumpalo-dev (= ${binary:Version}),
+ librust-hashbrown+compiler-builtins-dev (= ${binary:Version}),
+ librust-hashbrown+core-dev (= ${binary:Version}),
+ librust-hashbrown+default-dev (= ${binary:Version}),
+ librust-hashbrown+inline-more-dev (= ${binary:Version}),
+ librust-hashbrown+nightly-dev (= ${binary:Version}),
+ librust-hashbrown+raw-dev (= ${binary:Version}),
+ librust-hashbrown+rayon-dev (= ${binary:Version}),
+ librust-hashbrown+rustc-dep-of-std-dev (= ${binary:Version}),
+ librust-hashbrown+rustc-internal-api-dev (= ${binary:Version}),
+ librust-hashbrown+serde-dev (= ${binary:Version}),
+ librust-hashbrown-0-dev (= ${binary:Version}),
+ librust-hashbrown-0+ahash-dev (= ${binary:Version}),
+ librust-hashbrown-0+ahash-compile-time-rng-dev (= ${binary:Version}),
+ librust-hashbrown-0+bumpalo-dev (= ${binary:Version}),
+ librust-hashbrown-0+compiler-builtins-dev (= ${binary:Version}),
+ librust-hashbrown-0+core-dev (= ${binary:Version}),
+ librust-hashbrown-0+default-dev (= ${binary:Version}),
+ librust-hashbrown-0+inline-more-dev (= ${binary:Version}),
+ librust-hashbrown-0+nightly-dev (= ${binary:Version}),
+ librust-hashbrown-0+raw-dev (= ${binary:Version}),
+ librust-hashbrown-0+rayon-dev (= ${binary:Version}),
+ librust-hashbrown-0+rustc-dep-of-std-dev (= ${binary:Version}),
+ librust-hashbrown-0+rustc-internal-api-dev (= ${binary:Version}),
+ librust-hashbrown-0+serde-dev (= ${binary:Version}),
+ librust-hashbrown-0.12-dev (= ${binary:Version}),
+ librust-hashbrown-0.12+ahash-dev (= ${binary:Version}),
+ librust-hashbrown-0.12+ahash-compile-time-rng-dev (= ${binary:Version}),
+ librust-hashbrown-0.12+bumpalo-dev (= ${binary:Version}),
+ librust-hashbrown-0.12+compiler-builtins-dev (= ${binary:Version}),
+ librust-hashbrown-0.12+core-dev (= ${binary:Version}),
+ librust-hashbrown-0.12+default-dev (= ${binary:Version}),
+ librust-hashbrown-0.12+inline-more-dev (= ${binary:Version}),
+ librust-hashbrown-0.12+nightly-dev (= ${binary:Version}),
+ librust-hashbrown-0.12+raw-dev (= ${binary:Version}),
+ librust-hashbrown-0.12+rayon-dev (= ${binary:Version}),
+ librust-hashbrown-0.12+rustc-dep-of-std-dev (= ${binary:Version}),
+ librust-hashbrown-0.12+rustc-internal-api-dev (= ${binary:Version}),
+ librust-hashbrown-0.12+serde-dev (= ${binary:Version}),
+ librust-hashbrown-0.12.3-dev (= ${binary:Version}),
+ librust-hashbrown-0.12.3+ahash-dev (= ${binary:Version}),
+ librust-hashbrown-0.12.3+ahash-compile-time-rng-dev (= ${binary:Version}),
+ librust-hashbrown-0.12.3+bumpalo-dev (= ${binary:Version}),
+ librust-hashbrown-0.12.3+compiler-builtins-dev (= ${binary:Version}),
+ librust-hashbrown-0.12.3+core-dev (= ${binary:Version}),
+ librust-hashbrown-0.12.3+default-dev (= ${binary:Version}),
+ librust-hashbrown-0.12.3+inline-more-dev (= ${binary:Version}),
+ librust-hashbrown-0.12.3+nightly-dev (= ${binary:Version}),
+ librust-hashbrown-0.12.3+raw-dev (= ${binary:Version}),
+ librust-hashbrown-0.12.3+rayon-dev (= ${binary:Version}),
+ librust-hashbrown-0.12.3+rustc-dep-of-std-dev (= ${binary:Version}),
+ librust-hashbrown-0.12.3+rustc-internal-api-dev (= ${binary:Version}),
+ librust-hashbrown-0.12.3+serde-dev (= ${binary:Version})
+Description: Rust port of Google's SwissTable hash map - Rust source code
+ This package contains the source for the Rust hashbrown crate, packaged by
+ debcargo for use with cargo and dh-cargo.
--- a/debian-orig/copyright
+++ b/debian-orig/copyright
@ -0,0 +1,37 @@
+Format: https://www.debian.org/doc/packaging-manuals/copyright-format/1.0/
+Upstream-Name: hashbrown
+Upstream-Contact: Amanieu d'Antras <amanieu@gmail.com>
+Source: https://github.com/rust-lang/hashbrown
+
+Files: *
+Copyright: 2018-2019 Amanieu d'Antras <amanieu@gmail.com>
+License: MIT or Apache-2.0
+
+Files: debian/*
+Copyright:
+ 2019 Debian Rust Maintainers <pkg-rust-maintainers@alioth-lists.debian.net>
+ 2019 Ximin Luo <infinity0@debian.org>
+License: MIT or Apache-2.0
+
+License: Apache-2.0
+ Debian systems provide the Apache 2.0 license in
+ /usr/share/common-licenses/Apache-2.0
+
+License: MIT
+ Permission is hereby granted, free of charge, to any person obtaining a copy
+ of this software and associated documentation files (the "Software"), to deal
+ in the Software without restriction, including without limitation the rights
+ to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ copies of the Software, and to permit persons to whom the Software is
+ furnished to do so, subject to the following conditions:
+ .
+ The above copyright notice and this permission notice shall be included in all
+ copies or substantial portions of the Software.
+ .
+ THE SOFTWARE IS 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.  IN NO EVENT SHALL THE
+ AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ SOFTWARE.
--- a/debian-orig/copyright.debcargo.hint
+++ b/debian-orig/copyright.debcargo.hint
@ -0,0 +1,49 @@
+Format: https://www.debian.org/doc/packaging-manuals/copyright-format/1.0/
+Upstream-Name: hashbrown
+Upstream-Contact: Amanieu d'Antras <amanieu@gmail.com>
+Source: https://github.com/rust-lang/hashbrown
+
+Files: *
+Copyright: FIXME (overlay) UNKNOWN-YEARS Amanieu d'Antras <amanieu@gmail.com>
+License: MIT or Apache-2.0
+Comment:
+ FIXME (overlay): Since upstream copyright years are not available in
+ Cargo.toml, they were extracted from the upstream Git repository. This may not
+ be correct information so you should review and fix this before uploading to
+ the archive.
+
+Files: ./LICENSE-MIT
+Copyright: 2016 Amanieu d'Antras
+License: UNKNOWN-LICENSE; FIXME (overlay)
+Comment:
+ FIXME (overlay): These notices are extracted from files. Please review them
+ before uploading to the archive.
+
+Files: debian/*
+Copyright:
+ 2019-2022 Debian Rust Maintainers <pkg-rust-maintainers@alioth-lists.debian.net>
+ 2019-2022 Ximin Luo <infinity0@debian.org>
+License: MIT or Apache-2.0
+
+License: Apache-2.0
+ Debian systems provide the Apache 2.0 license in
+ /usr/share/common-licenses/Apache-2.0
+
+License: MIT
+ Permission is hereby granted, free of charge, to any person obtaining a copy
+ of this software and associated documentation files (the "Software"), to deal
+ in the Software without restriction, including without limitation the rights
+ to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ copies of the Software, and to permit persons to whom the Software is
+ furnished to do so, subject to the following conditions:
+ .
+ The above copyright notice and this permission notice shall be included in all
+ copies or substantial portions of the Software.
+ .
+ THE SOFTWARE IS 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.  IN NO EVENT SHALL THE
+ AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ SOFTWARE.
--- a/debian-orig/debcargo.toml
+++ b/debian-orig/debcargo.toml
@ -0,0 +1,20 @@
+overlay = "."
+uploaders = ["Ximin Luo <infinity0@debian.org>"]
+collapse_features = true
+
+# tests fail without default features.
+[packages.lib]
+test_is_broken = true
+
+# tests fail with "core" feature
+[packages."lib+core"]
+test_is_broken = true
+
+# tests pass with default features
+[packages."lib+default"]
+test_is_broken = false
+
+# tests pass with ahash feature.
+[packages."lib+ahash"]
+test_is_broken = false
+
--- a/debian-orig/patches/disable-alloc.diff
+++ b/debian-orig/patches/disable-alloc.diff
@ -0,0 +1,22 @@
+--- hashbrown/Cargo.toml
+++ hashbrown/Cargo.toml
+@@ -48,11 +48,6 @@
+ optional = true
+ default-features = false
+ 
+-[dependencies.alloc]
+-version = "1.0.0"
+-optional = true
+-package = "rustc-std-workspace-alloc"
+-
+ [dependencies.bumpalo]
+ version = "3.5.0"
+ optional = true
+@@ -107,7 +102,6 @@
+     "nightly",
+     "core",
+     "compiler_builtins",
+-    "alloc",
+     "rustc-internal-api",
+ ]
+ rustc-internal-api = []
--- a/debian-orig/patches/series
+++ b/debian-orig/patches/series
@ -0,0 +1 @@
+disable-alloc.diff
--- a/debian-orig/rules
+++ b/debian-orig/rules
@ -0,0 +1,3 @@
+#!/usr/bin/make -f
+%:
+	dh $@ --buildsystem cargo
--- a/debian-orig/source/format
+++ b/debian-orig/source/format
@ -0,0 +1 @@
+3.0 (quilt)
--- a/debian-orig/tests/control
+++ b/debian-orig/tests/control
@ -0,0 +1,74 @@
+Test-Command: /usr/share/cargo/bin/cargo-auto-test hashbrown 0.12.3 --all-targets --all-features
+Features: test-name=rust-hashbrown:@
+Depends: dh-cargo (>= 18), librust-doc-comment-0.3+default-dev (>= 0.3.1-~~), librust-fnv-1+default-dev (>= 1.0.7-~~), librust-lazy-static-1+default-dev (>= 1.4-~~), librust-rand-0.8+default-dev (>= 0.8.3-~~), librust-rand-0.8+small-rng-dev (>= 0.8.3-~~), librust-rayon-1+default-dev, librust-serde-test-1+default-dev, @
+Restrictions: allow-stderr, skip-not-installable, flaky
+
+Test-Command: /usr/share/cargo/bin/cargo-auto-test hashbrown 0.12.3 --all-targets --no-default-features --features ahash
+Features: test-name=librust-hashbrown-dev:ahash
+Depends: dh-cargo (>= 18), librust-doc-comment-0.3+default-dev (>= 0.3.1-~~), librust-fnv-1+default-dev (>= 1.0.7-~~), librust-lazy-static-1+default-dev (>= 1.4-~~), librust-rand-0.8+default-dev (>= 0.8.3-~~), librust-rand-0.8+small-rng-dev (>= 0.8.3-~~), librust-rayon-1+default-dev, librust-serde-test-1+default-dev, @
+Restrictions: allow-stderr, skip-not-installable
+
+Test-Command: /usr/share/cargo/bin/cargo-auto-test hashbrown 0.12.3 --all-targets --no-default-features --features ahash-compile-time-rng
+Features: test-name=librust-hashbrown-dev:ahash-compile-time-rng
+Depends: dh-cargo (>= 18), librust-doc-comment-0.3+default-dev (>= 0.3.1-~~), librust-fnv-1+default-dev (>= 1.0.7-~~), librust-lazy-static-1+default-dev (>= 1.4-~~), librust-rand-0.8+default-dev (>= 0.8.3-~~), librust-rand-0.8+small-rng-dev (>= 0.8.3-~~), librust-rayon-1+default-dev, librust-serde-test-1+default-dev, @
+Restrictions: allow-stderr, skip-not-installable, flaky
+
+Test-Command: /usr/share/cargo/bin/cargo-auto-test hashbrown 0.12.3 --all-targets --no-default-features --features bumpalo
+Features: test-name=librust-hashbrown-dev:bumpalo
+Depends: dh-cargo (>= 18), librust-doc-comment-0.3+default-dev (>= 0.3.1-~~), librust-fnv-1+default-dev (>= 1.0.7-~~), librust-lazy-static-1+default-dev (>= 1.4-~~), librust-rand-0.8+default-dev (>= 0.8.3-~~), librust-rand-0.8+small-rng-dev (>= 0.8.3-~~), librust-rayon-1+default-dev, librust-serde-test-1+default-dev, @
+Restrictions: allow-stderr, skip-not-installable, flaky
+
+Test-Command: /usr/share/cargo/bin/cargo-auto-test hashbrown 0.12.3 --all-targets --no-default-features --features compiler_builtins
+Features: test-name=librust-hashbrown-dev:compiler_builtins
+Depends: dh-cargo (>= 18), librust-doc-comment-0.3+default-dev (>= 0.3.1-~~), librust-fnv-1+default-dev (>= 1.0.7-~~), librust-lazy-static-1+default-dev (>= 1.4-~~), librust-rand-0.8+default-dev (>= 0.8.3-~~), librust-rand-0.8+small-rng-dev (>= 0.8.3-~~), librust-rayon-1+default-dev, librust-serde-test-1+default-dev, @
+Restrictions: allow-stderr, skip-not-installable, flaky
+
+Test-Command: /usr/share/cargo/bin/cargo-auto-test hashbrown 0.12.3 --all-targets --no-default-features --features core
+Features: test-name=librust-hashbrown-dev:core
+Depends: dh-cargo (>= 18), librust-doc-comment-0.3+default-dev (>= 0.3.1-~~), librust-fnv-1+default-dev (>= 1.0.7-~~), librust-lazy-static-1+default-dev (>= 1.4-~~), librust-rand-0.8+default-dev (>= 0.8.3-~~), librust-rand-0.8+small-rng-dev (>= 0.8.3-~~), librust-rayon-1+default-dev, librust-serde-test-1+default-dev, @
+Restrictions: allow-stderr, skip-not-installable, flaky
+
+Test-Command: /usr/share/cargo/bin/cargo-auto-test hashbrown 0.12.3 --all-targets 
+Features: test-name=librust-hashbrown-dev:default
+Depends: dh-cargo (>= 18), librust-doc-comment-0.3+default-dev (>= 0.3.1-~~), librust-fnv-1+default-dev (>= 1.0.7-~~), librust-lazy-static-1+default-dev (>= 1.4-~~), librust-rand-0.8+default-dev (>= 0.8.3-~~), librust-rand-0.8+small-rng-dev (>= 0.8.3-~~), librust-rayon-1+default-dev, librust-serde-test-1+default-dev, @
+Restrictions: allow-stderr, skip-not-installable
+
+Test-Command: /usr/share/cargo/bin/cargo-auto-test hashbrown 0.12.3 --all-targets --no-default-features --features inline-more
+Features: test-name=librust-hashbrown-dev:inline-more
+Depends: dh-cargo (>= 18), librust-doc-comment-0.3+default-dev (>= 0.3.1-~~), librust-fnv-1+default-dev (>= 1.0.7-~~), librust-lazy-static-1+default-dev (>= 1.4-~~), librust-rand-0.8+default-dev (>= 0.8.3-~~), librust-rand-0.8+small-rng-dev (>= 0.8.3-~~), librust-rayon-1+default-dev, librust-serde-test-1+default-dev, @
+Restrictions: allow-stderr, skip-not-installable, flaky
+
+Test-Command: /usr/share/cargo/bin/cargo-auto-test hashbrown 0.12.3 --all-targets --no-default-features --features nightly
+Features: test-name=librust-hashbrown-dev:nightly
+Depends: dh-cargo (>= 18), librust-doc-comment-0.3+default-dev (>= 0.3.1-~~), librust-fnv-1+default-dev (>= 1.0.7-~~), librust-lazy-static-1+default-dev (>= 1.4-~~), librust-rand-0.8+default-dev (>= 0.8.3-~~), librust-rand-0.8+small-rng-dev (>= 0.8.3-~~), librust-rayon-1+default-dev, librust-serde-test-1+default-dev, @
+Restrictions: allow-stderr, skip-not-installable, flaky
+
+Test-Command: /usr/share/cargo/bin/cargo-auto-test hashbrown 0.12.3 --all-targets --no-default-features --features raw
+Features: test-name=librust-hashbrown-dev:raw
+Depends: dh-cargo (>= 18), librust-doc-comment-0.3+default-dev (>= 0.3.1-~~), librust-fnv-1+default-dev (>= 1.0.7-~~), librust-lazy-static-1+default-dev (>= 1.4-~~), librust-rand-0.8+default-dev (>= 0.8.3-~~), librust-rand-0.8+small-rng-dev (>= 0.8.3-~~), librust-rayon-1+default-dev, librust-serde-test-1+default-dev, @
+Restrictions: allow-stderr, skip-not-installable, flaky
+
+Test-Command: /usr/share/cargo/bin/cargo-auto-test hashbrown 0.12.3 --all-targets --no-default-features --features rayon
+Features: test-name=librust-hashbrown-dev:rayon
+Depends: dh-cargo (>= 18), librust-doc-comment-0.3+default-dev (>= 0.3.1-~~), librust-fnv-1+default-dev (>= 1.0.7-~~), librust-lazy-static-1+default-dev (>= 1.4-~~), librust-rand-0.8+default-dev (>= 0.8.3-~~), librust-rand-0.8+small-rng-dev (>= 0.8.3-~~), librust-rayon-1+default-dev, librust-serde-test-1+default-dev, @
+Restrictions: allow-stderr, skip-not-installable, flaky
+
+Test-Command: /usr/share/cargo/bin/cargo-auto-test hashbrown 0.12.3 --all-targets --no-default-features --features rustc-dep-of-std
+Features: test-name=librust-hashbrown-dev:rustc-dep-of-std
+Depends: dh-cargo (>= 18), librust-doc-comment-0.3+default-dev (>= 0.3.1-~~), librust-fnv-1+default-dev (>= 1.0.7-~~), librust-lazy-static-1+default-dev (>= 1.4-~~), librust-rand-0.8+default-dev (>= 0.8.3-~~), librust-rand-0.8+small-rng-dev (>= 0.8.3-~~), librust-rayon-1+default-dev, librust-serde-test-1+default-dev, @
+Restrictions: allow-stderr, skip-not-installable, flaky
+
+Test-Command: /usr/share/cargo/bin/cargo-auto-test hashbrown 0.12.3 --all-targets --no-default-features --features rustc-internal-api
+Features: test-name=librust-hashbrown-dev:rustc-internal-api
+Depends: dh-cargo (>= 18), librust-doc-comment-0.3+default-dev (>= 0.3.1-~~), librust-fnv-1+default-dev (>= 1.0.7-~~), librust-lazy-static-1+default-dev (>= 1.4-~~), librust-rand-0.8+default-dev (>= 0.8.3-~~), librust-rand-0.8+small-rng-dev (>= 0.8.3-~~), librust-rayon-1+default-dev, librust-serde-test-1+default-dev, @
+Restrictions: allow-stderr, skip-not-installable, flaky
+
+Test-Command: /usr/share/cargo/bin/cargo-auto-test hashbrown 0.12.3 --all-targets --no-default-features --features serde
+Features: test-name=librust-hashbrown-dev:serde
+Depends: dh-cargo (>= 18), librust-doc-comment-0.3+default-dev (>= 0.3.1-~~), librust-fnv-1+default-dev (>= 1.0.7-~~), librust-lazy-static-1+default-dev (>= 1.4-~~), librust-rand-0.8+default-dev (>= 0.8.3-~~), librust-rand-0.8+small-rng-dev (>= 0.8.3-~~), librust-rayon-1+default-dev, librust-serde-test-1+default-dev, @
+Restrictions: allow-stderr, skip-not-installable, flaky
+
+Test-Command: /usr/share/cargo/bin/cargo-auto-test hashbrown 0.12.3 --all-targets --no-default-features
+Features: test-name=librust-hashbrown-dev:
+Depends: dh-cargo (>= 18), librust-doc-comment-0.3+default-dev (>= 0.3.1-~~), librust-fnv-1+default-dev (>= 1.0.7-~~), librust-lazy-static-1+default-dev (>= 1.4-~~), librust-rand-0.8+default-dev (>= 0.8.3-~~), librust-rand-0.8+small-rng-dev (>= 0.8.3-~~), librust-rayon-1+default-dev, librust-serde-test-1+default-dev, @
+Restrictions: allow-stderr, skip-not-installable, flaky
--- a/debian-orig/watch
+++ b/debian-orig/watch
@ -0,0 +1,4 @@
+version=4
+opts=filenamemangle=s/.*\/(.*)\/download/hashbrown-$1\.tar\.gz/g,\
+uversionmangle=s/(\d)[_\.\-\+]?((RC|rc|pre|dev|beta|alpha)\d*)$/$1~$2/ \
+https://qa.debian.org/cgi-bin/fakeupstream.cgi?upstream=crates.io/hashbrown .*/crates/hashbrown/@ANY_VERSION@/download
--- a/src/external_trait_impls/mod.rs
+++ b/src/external_trait_impls/mod.rs
@ -0,0 +1,4 @@
+#[cfg(feature = "rayon")]
+pub(crate) mod rayon;
+#[cfg(feature = "serde")]
+mod serde;
--- a/src/external_trait_impls/rayon/helpers.rs
+++ b/src/external_trait_impls/rayon/helpers.rs
@ -0,0 +1,27 @@
+use alloc::collections::LinkedList;
+use alloc::vec::Vec;
+
+use rayon::iter::{IntoParallelIterator, ParallelIterator};
+
+/// Helper for collecting parallel iterators to an intermediary
+#[allow(clippy::linkedlist)] // yes, we need linked list here for efficient appending!
+pub(super) fn collect<I: IntoParallelIterator>(iter: I) -> (LinkedList<Vec<I::Item>>, usize) {
+    let list = iter
+        .into_par_iter()
+        .fold(Vec::new, |mut vec, elem| {
+            vec.push(elem);
+            vec
+        })
+        .map(|vec| {
+            let mut list = LinkedList::new();
+            list.push_back(vec);
+            list
+        })
+        .reduce(LinkedList::new, |mut list1, mut list2| {
+            list1.append(&mut list2);
+            list1
+        });
+
+    let len = list.iter().map(Vec::len).sum();
+    (list, len)
+}
--- a/src/external_trait_impls/rayon/map.rs
+++ b/src/external_trait_impls/rayon/map.rs
@ -0,0 +1,734 @@
+//! Rayon extensions for `HashMap`.
+
+use super::raw::{RawIntoParIter, RawParDrain, RawParIter};
+use crate::hash_map::HashMap;
+use crate::raw::{Allocator, Global};
+use core::fmt;
+use core::hash::{BuildHasher, Hash};
+use core::marker::PhantomData;
+use rayon::iter::plumbing::UnindexedConsumer;
+use rayon::iter::{FromParallelIterator, IntoParallelIterator, ParallelExtend, ParallelIterator};
+
+/// Parallel iterator over shared references to entries in a map.
+///
+/// This iterator is created by the [`par_iter`] method on [`HashMap`]
+/// (provided by the [`IntoParallelRefIterator`] trait).
+/// See its documentation for more.
+///
+/// [`par_iter`]: /hashbrown/struct.HashMap.html#method.par_iter
+/// [`HashMap`]: /hashbrown/struct.HashMap.html
+/// [`IntoParallelRefIterator`]: https://docs.rs/rayon/1.0/rayon/iter/trait.IntoParallelRefIterator.html
+pub struct ParIter<'a, K, V> {
+    inner: RawParIter<(K, V)>,
+    marker: PhantomData<(&'a K, &'a V)>,
+}
+
+impl<'a, K: Sync, V: Sync> ParallelIterator for ParIter<'a, K, V> {
+    type Item = (&'a K, &'a V);
+
+    #[cfg_attr(feature = "inline-more", inline)]
+    fn drive_unindexed<C>(self, consumer: C) -> C::Result
+    where
+        C: UnindexedConsumer<Self::Item>,
+    {
+        self.inner
+            .map(|x| unsafe {
+                let r = x.as_ref();
+                (&r.0, &r.1)
+            })
+            .drive_unindexed(consumer)
+    }
+}
+
+impl<K, V> Clone for ParIter<'_, K, V> {
+    #[cfg_attr(feature = "inline-more", inline)]
+    fn clone(&self) -> Self {
+        Self {
+            inner: self.inner.clone(),
+            marker: PhantomData,
+        }
+    }
+}
+
+impl<K: fmt::Debug + Eq + Hash, V: fmt::Debug> fmt::Debug for ParIter<'_, K, V> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let iter = unsafe { self.inner.iter() }.map(|x| unsafe {
+            let r = x.as_ref();
+            (&r.0, &r.1)
+        });
+        f.debug_list().entries(iter).finish()
+    }
+}
+
+/// Parallel iterator over shared references to keys in a map.
+///
+/// This iterator is created by the [`par_keys`] method on [`HashMap`].
+/// See its documentation for more.
+///
+/// [`par_keys`]: /hashbrown/struct.HashMap.html#method.par_keys
+/// [`HashMap`]: /hashbrown/struct.HashMap.html
+pub struct ParKeys<'a, K, V> {
+    inner: RawParIter<(K, V)>,
+    marker: PhantomData<(&'a K, &'a V)>,
+}
+
+impl<'a, K: Sync, V: Sync> ParallelIterator for ParKeys<'a, K, V> {
+    type Item = &'a K;
+
+    #[cfg_attr(feature = "inline-more", inline)]
+    fn drive_unindexed<C>(self, consumer: C) -> C::Result
+    where
+        C: UnindexedConsumer<Self::Item>,
+    {
+        self.inner
+            .map(|x| unsafe { &x.as_ref().0 })
+            .drive_unindexed(consumer)
+    }
+}
+
+impl<K, V> Clone for ParKeys<'_, K, V> {
+    #[cfg_attr(feature = "inline-more", inline)]
+    fn clone(&self) -> Self {
+        Self {
+            inner: self.inner.clone(),
+            marker: PhantomData,
+        }
+    }
+}
+
+impl<K: fmt::Debug + Eq + Hash, V> fmt::Debug for ParKeys<'_, K, V> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let iter = unsafe { self.inner.iter() }.map(|x| unsafe { &x.as_ref().0 });
+        f.debug_list().entries(iter).finish()
+    }
+}
+
+/// Parallel iterator over shared references to values in a map.
+///
+/// This iterator is created by the [`par_values`] method on [`HashMap`].
+/// See its documentation for more.
+///
+/// [`par_values`]: /hashbrown/struct.HashMap.html#method.par_values
+/// [`HashMap`]: /hashbrown/struct.HashMap.html
+pub struct ParValues<'a, K, V> {
+    inner: RawParIter<(K, V)>,
+    marker: PhantomData<(&'a K, &'a V)>,
+}
+
+impl<'a, K: Sync, V: Sync> ParallelIterator for ParValues<'a, K, V> {
+    type Item = &'a V;
+
+    #[cfg_attr(feature = "inline-more", inline)]
+    fn drive_unindexed<C>(self, consumer: C) -> C::Result
+    where
+        C: UnindexedConsumer<Self::Item>,
+    {
+        self.inner
+            .map(|x| unsafe { &x.as_ref().1 })
+            .drive_unindexed(consumer)
+    }
+}
+
+impl<K, V> Clone for ParValues<'_, K, V> {
+    #[cfg_attr(feature = "inline-more", inline)]
+    fn clone(&self) -> Self {
+        Self {
+            inner: self.inner.clone(),
+            marker: PhantomData,
+        }
+    }
+}
+
+impl<K: Eq + Hash, V: fmt::Debug> fmt::Debug for ParValues<'_, K, V> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let iter = unsafe { self.inner.iter() }.map(|x| unsafe { &x.as_ref().1 });
+        f.debug_list().entries(iter).finish()
+    }
+}
+
+/// Parallel iterator over mutable references to entries in a map.
+///
+/// This iterator is created by the [`par_iter_mut`] method on [`HashMap`]
+/// (provided by the [`IntoParallelRefMutIterator`] trait).
+/// See its documentation for more.
+///
+/// [`par_iter_mut`]: /hashbrown/struct.HashMap.html#method.par_iter_mut
+/// [`HashMap`]: /hashbrown/struct.HashMap.html
+/// [`IntoParallelRefMutIterator`]: https://docs.rs/rayon/1.0/rayon/iter/trait.IntoParallelRefMutIterator.html
+pub struct ParIterMut<'a, K, V> {
+    inner: RawParIter<(K, V)>,
+    marker: PhantomData<(&'a K, &'a mut V)>,
+}
+
+impl<'a, K: Sync, V: Send> ParallelIterator for ParIterMut<'a, K, V> {
+    type Item = (&'a K, &'a mut V);
+
+    #[cfg_attr(feature = "inline-more", inline)]
+    fn drive_unindexed<C>(self, consumer: C) -> C::Result
+    where
+        C: UnindexedConsumer<Self::Item>,
+    {
+        self.inner
+            .map(|x| unsafe {
+                let r = x.as_mut();
+                (&r.0, &mut r.1)
+            })
+            .drive_unindexed(consumer)
+    }
+}
+
+impl<K: fmt::Debug + Eq + Hash, V: fmt::Debug> fmt::Debug for ParIterMut<'_, K, V> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        ParIter {
+            inner: self.inner.clone(),
+            marker: PhantomData,
+        }
+        .fmt(f)
+    }
+}
+
+/// Parallel iterator over mutable references to values in a map.
+///
+/// This iterator is created by the [`par_values_mut`] method on [`HashMap`].
+/// See its documentation for more.
+///
+/// [`par_values_mut`]: /hashbrown/struct.HashMap.html#method.par_values_mut
+/// [`HashMap`]: /hashbrown/struct.HashMap.html
+pub struct ParValuesMut<'a, K, V> {
+    inner: RawParIter<(K, V)>,
+    marker: PhantomData<(&'a K, &'a mut V)>,
+}
+
+impl<'a, K: Sync, V: Send> ParallelIterator for ParValuesMut<'a, K, V> {
+    type Item = &'a mut V;
+
+    #[cfg_attr(feature = "inline-more", inline)]
+    fn drive_unindexed<C>(self, consumer: C) -> C::Result
+    where
+        C: UnindexedConsumer<Self::Item>,
+    {
+        self.inner
+            .map(|x| unsafe { &mut x.as_mut().1 })
+            .drive_unindexed(consumer)
+    }
+}
+
+impl<K: Eq + Hash, V: fmt::Debug> fmt::Debug for ParValuesMut<'_, K, V> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        ParValues {
+            inner: self.inner.clone(),
+            marker: PhantomData,
+        }
+        .fmt(f)
+    }
+}
+
+/// Parallel iterator over entries of a consumed map.
+///
+/// This iterator is created by the [`into_par_iter`] method on [`HashMap`]
+/// (provided by the [`IntoParallelIterator`] trait).
+/// See its documentation for more.
+///
+/// [`into_par_iter`]: /hashbrown/struct.HashMap.html#method.into_par_iter
+/// [`HashMap`]: /hashbrown/struct.HashMap.html
+/// [`IntoParallelIterator`]: https://docs.rs/rayon/1.0/rayon/iter/trait.IntoParallelIterator.html
+pub struct IntoParIter<K, V, A: Allocator + Clone = Global> {
+    inner: RawIntoParIter<(K, V), A>,
+}
+
+impl<K: Send, V: Send, A: Allocator + Clone + Send> ParallelIterator for IntoParIter<K, V, A> {
+    type Item = (K, V);
+
+    #[cfg_attr(feature = "inline-more", inline)]
+    fn drive_unindexed<C>(self, consumer: C) -> C::Result
+    where
+        C: UnindexedConsumer<Self::Item>,
+    {
+        self.inner.drive_unindexed(consumer)
+    }
+}
+
+impl<K: fmt::Debug + Eq + Hash, V: fmt::Debug, A: Allocator + Clone> fmt::Debug
+    for IntoParIter<K, V, A>
+{
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        ParIter {
+            inner: unsafe { self.inner.par_iter() },
+            marker: PhantomData,
+        }
+        .fmt(f)
+    }
+}
+
+/// Parallel draining iterator over entries of a map.
+///
+/// This iterator is created by the [`par_drain`] method on [`HashMap`].
+/// See its documentation for more.
+///
+/// [`par_drain`]: /hashbrown/struct.HashMap.html#method.par_drain
+/// [`HashMap`]: /hashbrown/struct.HashMap.html
+pub struct ParDrain<'a, K, V, A: Allocator + Clone = Global> {
+    inner: RawParDrain<'a, (K, V), A>,
+}
+
+impl<K: Send, V: Send, A: Allocator + Clone + Sync> ParallelIterator for ParDrain<'_, K, V, A> {
+    type Item = (K, V);
+
+    #[cfg_attr(feature = "inline-more", inline)]
+    fn drive_unindexed<C>(self, consumer: C) -> C::Result
+    where
+        C: UnindexedConsumer<Self::Item>,
+    {
+        self.inner.drive_unindexed(consumer)
+    }
+}
+
+impl<K: fmt::Debug + Eq + Hash, V: fmt::Debug, A: Allocator + Clone> fmt::Debug
+    for ParDrain<'_, K, V, A>
+{
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        ParIter {
+            inner: unsafe { self.inner.par_iter() },
+            marker: PhantomData,
+        }
+        .fmt(f)
+    }
+}
+
+impl<K: Sync, V: Sync, S, A: Allocator + Clone> HashMap<K, V, S, A> {
+    /// Visits (potentially in parallel) immutably borrowed keys in an arbitrary order.
+    #[cfg_attr(feature = "inline-more", inline)]
+    pub fn par_keys(&self) -> ParKeys<'_, K, V> {
+        ParKeys {
+            inner: unsafe { self.table.par_iter() },
+            marker: PhantomData,
+        }
+    }
+
+    /// Visits (potentially in parallel) immutably borrowed values in an arbitrary order.
+    #[cfg_attr(feature = "inline-more", inline)]
+    pub fn par_values(&self) -> ParValues<'_, K, V> {
+        ParValues {
+            inner: unsafe { self.table.par_iter() },
+            marker: PhantomData,
+        }
+    }
+}
+
+impl<K: Send, V: Send, S, A: Allocator + Clone> HashMap<K, V, S, A> {
+    /// Visits (potentially in parallel) mutably borrowed values in an arbitrary order.
+    #[cfg_attr(feature = "inline-more", inline)]
+    pub fn par_values_mut(&mut self) -> ParValuesMut<'_, K, V> {
+        ParValuesMut {
+            inner: unsafe { self.table.par_iter() },
+            marker: PhantomData,
+        }
+    }
+
+    /// Consumes (potentially in parallel) all values in an arbitrary order,
+    /// while preserving the map's allocated memory for reuse.
+    #[cfg_attr(feature = "inline-more", inline)]
+    pub fn par_drain(&mut self) -> ParDrain<'_, K, V, A> {
+        ParDrain {
+            inner: self.table.par_drain(),
+        }
+    }
+}
+
+impl<K, V, S, A> HashMap<K, V, S, A>
+where
+    K: Eq + Hash + Sync,
+    V: PartialEq + Sync,
+    S: BuildHasher + Sync,
+    A: Allocator + Clone + Sync,
+{
+    /// Returns `true` if the map is equal to another,
+    /// i.e. both maps contain the same keys mapped to the same values.
+    ///
+    /// This method runs in a potentially parallel fashion.
+    pub fn par_eq(&self, other: &Self) -> bool {
+        self.len() == other.len()
+            && self
+                .into_par_iter()
+                .all(|(key, value)| other.get(key).map_or(false, |v| *value == *v))
+    }
+}
+
+impl<K: Send, V: Send, S, A: Allocator + Clone + Send> IntoParallelIterator
+    for HashMap<K, V, S, A>
+{
+    type Item = (K, V);
+    type Iter = IntoParIter<K, V, A>;
+
+    #[cfg_attr(feature = "inline-more", inline)]
+    fn into_par_iter(self) -> Self::Iter {
+        IntoParIter {
+            inner: self.table.into_par_iter(),
+        }
+    }
+}
+
+impl<'a, K: Sync, V: Sync, S, A: Allocator + Clone> IntoParallelIterator
+    for &'a HashMap<K, V, S, A>
+{
+    type Item = (&'a K, &'a V);
+    type Iter = ParIter<'a, K, V>;
+
+    #[cfg_attr(feature = "inline-more", inline)]
+    fn into_par_iter(self) -> Self::Iter {
+        ParIter {
+            inner: unsafe { self.table.par_iter() },
+            marker: PhantomData,
+        }
+    }
+}
+
+impl<'a, K: Sync, V: Send, S, A: Allocator + Clone> IntoParallelIterator
+    for &'a mut HashMap<K, V, S, A>
+{
+    type Item = (&'a K, &'a mut V);
+    type Iter = ParIterMut<'a, K, V>;
+
+    #[cfg_attr(feature = "inline-more", inline)]
+    fn into_par_iter(self) -> Self::Iter {
+        ParIterMut {
+            inner: unsafe { self.table.par_iter() },
+            marker: PhantomData,
+        }
+    }
+}
+
+/// Collect (key, value) pairs from a parallel iterator into a
+/// hashmap. If multiple pairs correspond to the same key, then the
+/// ones produced earlier in the parallel iterator will be
+/// overwritten, just as with a sequential iterator.
+impl<K, V, S> FromParallelIterator<(K, V)> for HashMap<K, V, S, Global>
+where
+    K: Eq + Hash + Send,
+    V: Send,
+    S: BuildHasher + Default,
+{
+    fn from_par_iter<P>(par_iter: P) -> Self
+    where
+        P: IntoParallelIterator<Item = (K, V)>,
+    {
+        let mut map = HashMap::default();
+        map.par_extend(par_iter);
+        map
+    }
+}
+
+/// Extend a hash map with items from a parallel iterator.
+impl<K, V, S, A> ParallelExtend<(K, V)> for HashMap<K, V, S, A>
+where
+    K: Eq + Hash + Send,
+    V: Send,
+    S: BuildHasher,
+    A: Allocator + Clone,
+{
+    fn par_extend<I>(&mut self, par_iter: I)
+    where
+        I: IntoParallelIterator<Item = (K, V)>,
+    {
+        extend(self, par_iter);
+    }
+}
+
+/// Extend a hash map with copied items from a parallel iterator.
+impl<'a, K, V, S, A> ParallelExtend<(&'a K, &'a V)> for HashMap<K, V, S, A>
+where
+    K: Copy + Eq + Hash + Sync,
+    V: Copy + Sync,
+    S: BuildHasher,
+    A: Allocator + Clone,
+{
+    fn par_extend<I>(&mut self, par_iter: I)
+    where
+        I: IntoParallelIterator<Item = (&'a K, &'a V)>,
+    {
+        extend(self, par_iter);
+    }
+}
+
+// This is equal to the normal `HashMap` -- no custom advantage.
+fn extend<K, V, S, A, I>(map: &mut HashMap<K, V, S, A>, par_iter: I)
+where
+    K: Eq + Hash,
+    S: BuildHasher,
+    I: IntoParallelIterator,
+    A: Allocator + Clone,
+    HashMap<K, V, S, A>: Extend<I::Item>,
+{
+    let (list, len) = super::helpers::collect(par_iter);
+
+    // Keys may be already present or show multiple times in the iterator.
+    // Reserve the entire length if the map is empty.
+    // Otherwise reserve half the length (rounded up), so the map
+    // will only resize twice in the worst case.
+    let reserve = if map.is_empty() { len } else { (len + 1) / 2 };
+    map.reserve(reserve);
+    for vec in list {
+        map.extend(vec);
+    }
+}
+
+#[cfg(test)]
+mod test_par_map {
+    use alloc::vec::Vec;
+    use core::hash::{Hash, Hasher};
+    use core::sync::atomic::{AtomicUsize, Ordering};
+
+    use rayon::prelude::*;
+
+    use crate::hash_map::HashMap;
+
+    struct Dropable<'a> {
+        k: usize,
+        counter: &'a AtomicUsize,
+    }
+
+    impl Dropable<'_> {
+        fn new(k: usize, counter: &AtomicUsize) -> Dropable<'_> {
+            counter.fetch_add(1, Ordering::Relaxed);
+
+            Dropable { k, counter }
+        }
+    }
+
+    impl Drop for Dropable<'_> {
+        fn drop(&mut self) {
+            self.counter.fetch_sub(1, Ordering::Relaxed);
+        }
+    }
+
+    impl Clone for Dropable<'_> {
+        fn clone(&self) -> Self {
+            Dropable::new(self.k, self.counter)
+        }
+    }
+
+    impl Hash for Dropable<'_> {
+        fn hash<H>(&self, state: &mut H)
+        where
+            H: Hasher,
+        {
+            self.k.hash(state);
+        }
+    }
+
+    impl PartialEq for Dropable<'_> {
+        fn eq(&self, other: &Self) -> bool {
+            self.k == other.k
+        }
+    }
+
+    impl Eq for Dropable<'_> {}
+
+    #[test]
+    fn test_into_iter_drops() {
+        let key = AtomicUsize::new(0);
+        let value = AtomicUsize::new(0);
+
+        let hm = {
+            let mut hm = HashMap::new();
+
+            assert_eq!(key.load(Ordering::Relaxed), 0);
+            assert_eq!(value.load(Ordering::Relaxed), 0);
+
+            for i in 0..100 {
+                let d1 = Dropable::new(i, &key);
+                let d2 = Dropable::new(i + 100, &value);
+                hm.insert(d1, d2);
+            }
+
+            assert_eq!(key.load(Ordering::Relaxed), 100);
+            assert_eq!(value.load(Ordering::Relaxed), 100);
+
+            hm
+        };
+
+        // By the way, ensure that cloning doesn't screw up the dropping.
+        drop(hm.clone());
+
+        assert_eq!(key.load(Ordering::Relaxed), 100);
+        assert_eq!(value.load(Ordering::Relaxed), 100);
+
+        // Ensure that dropping the iterator does not leak anything.
+        drop(hm.clone().into_par_iter());
+
+        {
+            assert_eq!(key.load(Ordering::Relaxed), 100);
+            assert_eq!(value.load(Ordering::Relaxed), 100);
+
+            // retain only half
+            let _v: Vec<_> = hm
+                .into_par_iter()
+                .filter(|&(ref key, _)| key.k < 50)
+                .collect();
+
+            assert_eq!(key.load(Ordering::Relaxed), 50);
+            assert_eq!(value.load(Ordering::Relaxed), 50);
+        };
+
+        assert_eq!(key.load(Ordering::Relaxed), 0);
+        assert_eq!(value.load(Ordering::Relaxed), 0);
+    }
+
+    #[test]
+    fn test_drain_drops() {
+        let key = AtomicUsize::new(0);
+        let value = AtomicUsize::new(0);
+
+        let mut hm = {
+            let mut hm = HashMap::new();
+
+            assert_eq!(key.load(Ordering::Relaxed), 0);
+            assert_eq!(value.load(Ordering::Relaxed), 0);
+
+            for i in 0..100 {
+                let d1 = Dropable::new(i, &key);
+                let d2 = Dropable::new(i + 100, &value);
+                hm.insert(d1, d2);
+            }
+
+            assert_eq!(key.load(Ordering::Relaxed), 100);
+            assert_eq!(value.load(Ordering::Relaxed), 100);
+
+            hm
+        };
+
+        // By the way, ensure that cloning doesn't screw up the dropping.
+        drop(hm.clone());
+
+        assert_eq!(key.load(Ordering::Relaxed), 100);
+        assert_eq!(value.load(Ordering::Relaxed), 100);
+
+        // Ensure that dropping the drain iterator does not leak anything.
+        drop(hm.clone().par_drain());
+
+        {
+            assert_eq!(key.load(Ordering::Relaxed), 100);
+            assert_eq!(value.load(Ordering::Relaxed), 100);
+
+            // retain only half
+            let _v: Vec<_> = hm.drain().filter(|&(ref key, _)| key.k < 50).collect();
+            assert!(hm.is_empty());
+
+            assert_eq!(key.load(Ordering::Relaxed), 50);
+            assert_eq!(value.load(Ordering::Relaxed), 50);
+        };
+
+        assert_eq!(key.load(Ordering::Relaxed), 0);
+        assert_eq!(value.load(Ordering::Relaxed), 0);
+    }
+
+    #[test]
+    fn test_empty_iter() {
+        let mut m: HashMap<isize, bool> = HashMap::new();
+        assert_eq!(m.par_drain().count(), 0);
+        assert_eq!(m.par_keys().count(), 0);
+        assert_eq!(m.par_values().count(), 0);
+        assert_eq!(m.par_values_mut().count(), 0);
+        assert_eq!(m.par_iter().count(), 0);
+        assert_eq!(m.par_iter_mut().count(), 0);
+        assert_eq!(m.len(), 0);
+        assert!(m.is_empty());
+        assert_eq!(m.into_par_iter().count(), 0);
+    }
+
+    #[test]
+    fn test_iterate() {
+        let mut m = HashMap::with_capacity(4);
+        for i in 0..32 {
+            assert!(m.insert(i, i * 2).is_none());
+        }
+        assert_eq!(m.len(), 32);
+
+        let observed = AtomicUsize::new(0);
+
+        m.par_iter().for_each(|(k, v)| {
+            assert_eq!(*v, *k * 2);
+            observed.fetch_or(1 << *k, Ordering::Relaxed);
+        });
+        assert_eq!(observed.into_inner(), 0xFFFF_FFFF);
+    }
+
+    #[test]
+    fn test_keys() {
+        let vec = vec![(1, 'a'), (2, 'b'), (3, 'c')];
+        let map: HashMap<_, _> = vec.into_par_iter().collect();
+        let keys: Vec<_> = map.par_keys().cloned().collect();
+        assert_eq!(keys.len(), 3);
+        assert!(keys.contains(&1));
+        assert!(keys.contains(&2));
+        assert!(keys.contains(&3));
+    }
+
+    #[test]
+    fn test_values() {
+        let vec = vec![(1, 'a'), (2, 'b'), (3, 'c')];
+        let map: HashMap<_, _> = vec.into_par_iter().collect();
+        let values: Vec<_> = map.par_values().cloned().collect();
+        assert_eq!(values.len(), 3);
+        assert!(values.contains(&'a'));
+        assert!(values.contains(&'b'));
+        assert!(values.contains(&'c'));
+    }
+
+    #[test]
+    fn test_values_mut() {
+        let vec = vec![(1, 1), (2, 2), (3, 3)];
+        let mut map: HashMap<_, _> = vec.into_par_iter().collect();
+        map.par_values_mut().for_each(|value| *value *= 2);
+        let values: Vec<_> = map.par_values().cloned().collect();
+        assert_eq!(values.len(), 3);
+        assert!(values.contains(&2));
+        assert!(values.contains(&4));
+        assert!(values.contains(&6));
+    }
+
+    #[test]
+    fn test_eq() {
+        let mut m1 = HashMap::new();
+        m1.insert(1, 2);
+        m1.insert(2, 3);
+        m1.insert(3, 4);
+
+        let mut m2 = HashMap::new();
+        m2.insert(1, 2);
+        m2.insert(2, 3);
+
+        assert!(!m1.par_eq(&m2));
+
+        m2.insert(3, 4);
+
+        assert!(m1.par_eq(&m2));
+    }
+
+    #[test]
+    fn test_from_iter() {
+        let xs = [(1, 1), (2, 2), (3, 3), (4, 4), (5, 5), (6, 6)];
+
+        let map: HashMap<_, _> = xs.par_iter().cloned().collect();
+
+        for &(k, v) in &xs {
+            assert_eq!(map.get(&k), Some(&v));
+        }
+    }
+
+    #[test]
+    fn test_extend_ref() {
+        let mut a = HashMap::new();
+        a.insert(1, "one");
+        let mut b = HashMap::new();
+        b.insert(2, "two");
+        b.insert(3, "three");
+
+        a.par_extend(&b);
+
+        assert_eq!(a.len(), 3);
+        assert_eq!(a[&1], "one");
+        assert_eq!(a[&2], "two");
+        assert_eq!(a[&3], "three");
+    }
+}
--- a/src/external_trait_impls/rayon/mod.rs
+++ b/src/external_trait_impls/rayon/mod.rs
@ -0,0 +1,4 @@
+mod helpers;
+pub(crate) mod map;
+pub(crate) mod raw;
+pub(crate) mod set;
--- a/src/external_trait_impls/rayon/raw.rs
+++ b/src/external_trait_impls/rayon/raw.rs
@ -0,0 +1,231 @@
+use crate::raw::Bucket;
+use crate::raw::{Allocator, Global, RawIter, RawIterRange, RawTable};
+use crate::scopeguard::guard;
+use alloc::alloc::dealloc;
+use core::marker::PhantomData;
+use core::mem;
+use core::ptr::NonNull;
+use rayon::iter::{
+    plumbing::{self, Folder, UnindexedConsumer, UnindexedProducer},
+    ParallelIterator,
+};
+
+/// Parallel iterator which returns a raw pointer to every full bucket in the table.
+pub struct RawParIter<T> {
+    iter: RawIterRange<T>,
+}
+
+impl<T> RawParIter<T> {
+    #[cfg_attr(feature = "inline-more", inline)]
+    pub(super) unsafe fn iter(&self) -> RawIterRange<T> {
+        self.iter.clone()
+    }
+}
+
+impl<T> Clone for RawParIter<T> {
+    #[cfg_attr(feature = "inline-more", inline)]
+    fn clone(&self) -> Self {
+        Self {
+            iter: self.iter.clone(),
+        }
+    }
+}
+
+impl<T> From<RawIter<T>> for RawParIter<T> {
+    fn from(it: RawIter<T>) -> Self {
+        RawParIter { iter: it.iter }
+    }
+}
+
+impl<T> ParallelIterator for RawParIter<T> {
+    type Item = Bucket<T>;
+
+    #[cfg_attr(feature = "inline-more", inline)]
+    fn drive_unindexed<C>(self, consumer: C) -> C::Result
+    where
+        C: UnindexedConsumer<Self::Item>,
+    {
+        let producer = ParIterProducer { iter: self.iter };
+        plumbing::bridge_unindexed(producer, consumer)
+    }
+}
+
+/// Producer which returns a `Bucket<T>` for every element.
+struct ParIterProducer<T> {
+    iter: RawIterRange<T>,
+}
+
+impl<T> UnindexedProducer for ParIterProducer<T> {
+    type Item = Bucket<T>;
+
+    #[cfg_attr(feature = "inline-more", inline)]
+    fn split(self) -> (Self, Option<Self>) {
+        let (left, right) = self.iter.split();
+        let left = ParIterProducer { iter: left };
+        let right = right.map(|right| ParIterProducer { iter: right });
+        (left, right)
+    }
+
+    #[cfg_attr(feature = "inline-more", inline)]
+    fn fold_with<F>(self, folder: F) -> F
+    where
+        F: Folder<Self::Item>,
+    {
+        folder.consume_iter(self.iter)
+    }
+}
+
+/// Parallel iterator which consumes a table and returns elements.
+pub struct RawIntoParIter<T, A: Allocator + Clone = Global> {
+    table: RawTable<T, A>,
+}
+
+impl<T, A: Allocator + Clone> RawIntoParIter<T, A> {
+    #[cfg_attr(feature = "inline-more", inline)]
+    pub(super) unsafe fn par_iter(&self) -> RawParIter<T> {
+        self.table.par_iter()
+    }
+}
+
+impl<T: Send, A: Allocator + Clone + Send> ParallelIterator for RawIntoParIter<T, A> {
+    type Item = T;
+
+    #[cfg_attr(feature = "inline-more", inline)]
+    fn drive_unindexed<C>(self, consumer: C) -> C::Result
+    where
+        C: UnindexedConsumer<Self::Item>,
+    {
+        let iter = unsafe { self.table.iter().iter };
+        let _guard = guard(self.table.into_allocation(), |alloc| {
+            if let Some((ptr, layout)) = *alloc {
+                unsafe {
+                    dealloc(ptr.as_ptr(), layout);
+                }
+            }
+        });
+        let producer = ParDrainProducer { iter };
+        plumbing::bridge_unindexed(producer, consumer)
+    }
+}
+
+/// Parallel iterator which consumes elements without freeing the table storage.
+pub struct RawParDrain<'a, T, A: Allocator + Clone = Global> {
+    // We don't use a &'a mut RawTable<T> because we want RawParDrain to be
+    // covariant over T.
+    table: NonNull<RawTable<T, A>>,
+    marker: PhantomData<&'a RawTable<T, A>>,
+}
+
+unsafe impl<T: Send, A: Allocator + Clone> Send for RawParDrain<'_, T, A> {}
+
+impl<T, A: Allocator + Clone> RawParDrain<'_, T, A> {
+    #[cfg_attr(feature = "inline-more", inline)]
+    pub(super) unsafe fn par_iter(&self) -> RawParIter<T> {
+        self.table.as_ref().par_iter()
+    }
+}
+
+impl<T: Send, A: Allocator + Clone> ParallelIterator for RawParDrain<'_, T, A> {
+    type Item = T;
+
+    #[cfg_attr(feature = "inline-more", inline)]
+    fn drive_unindexed<C>(self, consumer: C) -> C::Result
+    where
+        C: UnindexedConsumer<Self::Item>,
+    {
+        let _guard = guard(self.table, |table| unsafe {
+            table.as_mut().clear_no_drop();
+        });
+        let iter = unsafe { self.table.as_ref().iter().iter };
+        mem::forget(self);
+        let producer = ParDrainProducer { iter };
+        plumbing::bridge_unindexed(producer, consumer)
+    }
+}
+
+impl<T, A: Allocator + Clone> Drop for RawParDrain<'_, T, A> {
+    fn drop(&mut self) {
+        // If drive_unindexed is not called then simply clear the table.
+        unsafe {
+            self.table.as_mut().clear();
+        }
+    }
+}
+
+/// Producer which will consume all elements in the range, even if it is dropped
+/// halfway through.
+struct ParDrainProducer<T> {
+    iter: RawIterRange<T>,
+}
+
+impl<T: Send> UnindexedProducer for ParDrainProducer<T> {
+    type Item = T;
+
+    #[cfg_attr(feature = "inline-more", inline)]
+    fn split(self) -> (Self, Option<Self>) {
+        let (left, right) = self.iter.clone().split();
+        mem::forget(self);
+        let left = ParDrainProducer { iter: left };
+        let right = right.map(|right| ParDrainProducer { iter: right });
+        (left, right)
+    }
+
+    #[cfg_attr(feature = "inline-more", inline)]
+    fn fold_with<F>(mut self, mut folder: F) -> F
+    where
+        F: Folder<Self::Item>,
+    {
+        // Make sure to modify the iterator in-place so that any remaining
+        // elements are processed in our Drop impl.
+        for item in &mut self.iter {
+            folder = folder.consume(unsafe { item.read() });
+            if folder.full() {
+                return folder;
+            }
+        }
+
+        // If we processed all elements then we don't need to run the drop.
+        mem::forget(self);
+        folder
+    }
+}
+
+impl<T> Drop for ParDrainProducer<T> {
+    #[cfg_attr(feature = "inline-more", inline)]
+    fn drop(&mut self) {
+        // Drop all remaining elements
+        if mem::needs_drop::<T>() {
+            for item in &mut self.iter {
+                unsafe {
+                    item.drop();
+                }
+            }
+        }
+    }
+}
+
+impl<T, A: Allocator + Clone> RawTable<T, A> {
+    /// Returns a parallel iterator over the elements in a `RawTable`.
+    #[cfg_attr(feature = "inline-more", inline)]
+    pub unsafe fn par_iter(&self) -> RawParIter<T> {
+        RawParIter {
+            iter: self.iter().iter,
+        }
+    }
+
+    /// Returns a parallel iterator over the elements in a `RawTable`.
+    #[cfg_attr(feature = "inline-more", inline)]
+    pub fn into_par_iter(self) -> RawIntoParIter<T, A> {
+        RawIntoParIter { table: self }
+    }
+
+    /// Returns a parallel iterator which consumes all elements of a `RawTable`
+    /// without freeing its memory allocation.
+    #[cfg_attr(feature = "inline-more", inline)]
+    pub fn par_drain(&mut self) -> RawParDrain<'_, T, A> {
+        RawParDrain {
+            table: NonNull::from(self),
+            marker: PhantomData,
+        }
+    }
+}
--- a/src/external_trait_impls/rayon/set.rs
+++ b/src/external_trait_impls/rayon/set.rs
@ -0,0 +1,659 @@
+//! Rayon extensions for `HashSet`.
+
+use super::map;
+use crate::hash_set::HashSet;
+use crate::raw::{Allocator, Global};
+use core::hash::{BuildHasher, Hash};
+use rayon::iter::plumbing::UnindexedConsumer;
+use rayon::iter::{FromParallelIterator, IntoParallelIterator, ParallelExtend, ParallelIterator};
+
+/// Parallel iterator over elements of a consumed set.
+///
+/// This iterator is created by the [`into_par_iter`] method on [`HashSet`]
+/// (provided by the [`IntoParallelIterator`] trait).
+/// See its documentation for more.
+///
+/// [`into_par_iter`]: /hashbrown/struct.HashSet.html#method.into_par_iter
+/// [`HashSet`]: /hashbrown/struct.HashSet.html
+/// [`IntoParallelIterator`]: https://docs.rs/rayon/1.0/rayon/iter/trait.IntoParallelIterator.html
+pub struct IntoParIter<T, A: Allocator + Clone = Global> {
+    inner: map::IntoParIter<T, (), A>,
+}
+
+impl<T: Send, A: Allocator + Clone + Send> ParallelIterator for IntoParIter<T, A> {
+    type Item = T;
+
+    fn drive_unindexed<C>(self, consumer: C) -> C::Result
+    where
+        C: UnindexedConsumer<Self::Item>,
+    {
+        self.inner.map(|(k, _)| k).drive_unindexed(consumer)
+    }
+}
+
+/// Parallel draining iterator over entries of a set.
+///
+/// This iterator is created by the [`par_drain`] method on [`HashSet`].
+/// See its documentation for more.
+///
+/// [`par_drain`]: /hashbrown/struct.HashSet.html#method.par_drain
+/// [`HashSet`]: /hashbrown/struct.HashSet.html
+pub struct ParDrain<'a, T, A: Allocator + Clone = Global> {
+    inner: map::ParDrain<'a, T, (), A>,
+}
+
+impl<T: Send, A: Allocator + Clone + Send + Sync> ParallelIterator for ParDrain<'_, T, A> {
+    type Item = T;
+
+    fn drive_unindexed<C>(self, consumer: C) -> C::Result
+    where
+        C: UnindexedConsumer<Self::Item>,
+    {
+        self.inner.map(|(k, _)| k).drive_unindexed(consumer)
+    }
+}
+
+/// Parallel iterator over shared references to elements in a set.
+///
+/// This iterator is created by the [`par_iter`] method on [`HashSet`]
+/// (provided by the [`IntoParallelRefIterator`] trait).
+/// See its documentation for more.
+///
+/// [`par_iter`]: /hashbrown/struct.HashSet.html#method.par_iter
+/// [`HashSet`]: /hashbrown/struct.HashSet.html
+/// [`IntoParallelRefIterator`]: https://docs.rs/rayon/1.0/rayon/iter/trait.IntoParallelRefIterator.html
+pub struct ParIter<'a, T> {
+    inner: map::ParKeys<'a, T, ()>,
+}
+
+impl<'a, T: Sync> ParallelIterator for ParIter<'a, T> {
+    type Item = &'a T;
+
+    fn drive_unindexed<C>(self, consumer: C) -> C::Result
+    where
+        C: UnindexedConsumer<Self::Item>,
+    {
+        self.inner.drive_unindexed(consumer)
+    }
+}
+
+/// Parallel iterator over shared references to elements in the difference of
+/// sets.
+///
+/// This iterator is created by the [`par_difference`] method on [`HashSet`].
+/// See its documentation for more.
+///
+/// [`par_difference`]: /hashbrown/struct.HashSet.html#method.par_difference
+/// [`HashSet`]: /hashbrown/struct.HashSet.html
+pub struct ParDifference<'a, T, S, A: Allocator + Clone = Global> {
+    a: &'a HashSet<T, S, A>,
+    b: &'a HashSet<T, S, A>,
+}
+
+impl<'a, T, S, A> ParallelIterator for ParDifference<'a, T, S, A>
+where
+    T: Eq + Hash + Sync,
+    S: BuildHasher + Sync,
+    A: Allocator + Clone + Sync,
+{
+    type Item = &'a T;
+
+    fn drive_unindexed<C>(self, consumer: C) -> C::Result
+    where
+        C: UnindexedConsumer<Self::Item>,
+    {
+        self.a
+            .into_par_iter()
+            .filter(|&x| !self.b.contains(x))
+            .drive_unindexed(consumer)
+    }
+}
+
+/// Parallel iterator over shared references to elements in the symmetric
+/// difference of sets.
+///
+/// This iterator is created by the [`par_symmetric_difference`] method on
+/// [`HashSet`].
+/// See its documentation for more.
+///
+/// [`par_symmetric_difference`]: /hashbrown/struct.HashSet.html#method.par_symmetric_difference
+/// [`HashSet`]: /hashbrown/struct.HashSet.html
+pub struct ParSymmetricDifference<'a, T, S, A: Allocator + Clone = Global> {
+    a: &'a HashSet<T, S, A>,
+    b: &'a HashSet<T, S, A>,
+}
+
+impl<'a, T, S, A> ParallelIterator for ParSymmetricDifference<'a, T, S, A>
+where
+    T: Eq + Hash + Sync,
+    S: BuildHasher + Sync,
+    A: Allocator + Clone + Sync,
+{
+    type Item = &'a T;
+
+    fn drive_unindexed<C>(self, consumer: C) -> C::Result
+    where
+        C: UnindexedConsumer<Self::Item>,
+    {
+        self.a
+            .par_difference(self.b)
+            .chain(self.b.par_difference(self.a))
+            .drive_unindexed(consumer)
+    }
+}
+
+/// Parallel iterator over shared references to elements in the intersection of
+/// sets.
+///
+/// This iterator is created by the [`par_intersection`] method on [`HashSet`].
+/// See its documentation for more.
+///
+/// [`par_intersection`]: /hashbrown/struct.HashSet.html#method.par_intersection
+/// [`HashSet`]: /hashbrown/struct.HashSet.html
+pub struct ParIntersection<'a, T, S, A: Allocator + Clone = Global> {
+    a: &'a HashSet<T, S, A>,
+    b: &'a HashSet<T, S, A>,
+}
+
+impl<'a, T, S, A> ParallelIterator for ParIntersection<'a, T, S, A>
+where
+    T: Eq + Hash + Sync,
+    S: BuildHasher + Sync,
+    A: Allocator + Clone + Sync,
+{
+    type Item = &'a T;
+
+    fn drive_unindexed<C>(self, consumer: C) -> C::Result
+    where
+        C: UnindexedConsumer<Self::Item>,
+    {
+        self.a
+            .into_par_iter()
+            .filter(|&x| self.b.contains(x))
+            .drive_unindexed(consumer)
+    }
+}
+
+/// Parallel iterator over shared references to elements in the union of sets.
+///
+/// This iterator is created by the [`par_union`] method on [`HashSet`].
+/// See its documentation for more.
+///
+/// [`par_union`]: /hashbrown/struct.HashSet.html#method.par_union
+/// [`HashSet`]: /hashbrown/struct.HashSet.html
+pub struct ParUnion<'a, T, S, A: Allocator + Clone = Global> {
+    a: &'a HashSet<T, S, A>,
+    b: &'a HashSet<T, S, A>,
+}
+
+impl<'a, T, S, A> ParallelIterator for ParUnion<'a, T, S, A>
+where
+    T: Eq + Hash + Sync,
+    S: BuildHasher + Sync,
+    A: Allocator + Clone + Sync,
+{
+    type Item = &'a T;
+
+    fn drive_unindexed<C>(self, consumer: C) -> C::Result
+    where
+        C: UnindexedConsumer<Self::Item>,
+    {
+        // We'll iterate one set in full, and only the remaining difference from the other.
+        // Use the smaller set for the difference in order to reduce hash lookups.
+        let (smaller, larger) = if self.a.len() <= self.b.len() {
+            (self.a, self.b)
+        } else {
+            (self.b, self.a)
+        };
+        larger
+            .into_par_iter()
+            .chain(smaller.par_difference(larger))
+            .drive_unindexed(consumer)
+    }
+}
+
+impl<T, S, A> HashSet<T, S, A>
+where
+    T: Eq + Hash + Sync,
+    S: BuildHasher + Sync,
+    A: Allocator + Clone + Sync,
+{
+    /// Visits (potentially in parallel) the values representing the union,
+    /// i.e. all the values in `self` or `other`, without duplicates.
+    #[cfg_attr(feature = "inline-more", inline)]
+    pub fn par_union<'a>(&'a self, other: &'a Self) -> ParUnion<'a, T, S, A> {
+        ParUnion { a: self, b: other }
+    }
+
+    /// Visits (potentially in parallel) the values representing the difference,
+    /// i.e. the values that are in `self` but not in `other`.
+    #[cfg_attr(feature = "inline-more", inline)]
+    pub fn par_difference<'a>(&'a self, other: &'a Self) -> ParDifference<'a, T, S, A> {
+        ParDifference { a: self, b: other }
+    }
+
+    /// Visits (potentially in parallel) the values representing the symmetric
+    /// difference, i.e. the values that are in `self` or in `other` but not in both.
+    #[cfg_attr(feature = "inline-more", inline)]
+    pub fn par_symmetric_difference<'a>(
+        &'a self,
+        other: &'a Self,
+    ) -> ParSymmetricDifference<'a, T, S, A> {
+        ParSymmetricDifference { a: self, b: other }
+    }
+
+    /// Visits (potentially in parallel) the values representing the
+    /// intersection, i.e. the values that are both in `self` and `other`.
+    #[cfg_attr(feature = "inline-more", inline)]
+    pub fn par_intersection<'a>(&'a self, other: &'a Self) -> ParIntersection<'a, T, S, A> {
+        ParIntersection { a: self, b: other }
+    }
+
+    /// Returns `true` if `self` has no elements in common with `other`.
+    /// This is equivalent to checking for an empty intersection.
+    ///
+    /// This method runs in a potentially parallel fashion.
+    pub fn par_is_disjoint(&self, other: &Self) -> bool {
+        self.into_par_iter().all(|x| !other.contains(x))
+    }
+
+    /// Returns `true` if the set is a subset of another,
+    /// i.e. `other` contains at least all the values in `self`.
+    ///
+    /// This method runs in a potentially parallel fashion.
+    pub fn par_is_subset(&self, other: &Self) -> bool {
+        if self.len() <= other.len() {
+            self.into_par_iter().all(|x| other.contains(x))
+        } else {
+            false
+        }
+    }
+
+    /// Returns `true` if the set is a superset of another,
+    /// i.e. `self` contains at least all the values in `other`.
+    ///
+    /// This method runs in a potentially parallel fashion.
+    pub fn par_is_superset(&self, other: &Self) -> bool {
+        other.par_is_subset(self)
+    }
+
+    /// Returns `true` if the set is equal to another,
+    /// i.e. both sets contain the same values.
+    ///
+    /// This method runs in a potentially parallel fashion.
+    pub fn par_eq(&self, other: &Self) -> bool {
+        self.len() == other.len() && self.par_is_subset(other)
+    }
+}
+
+impl<T, S, A> HashSet<T, S, A>
+where
+    T: Eq + Hash + Send,
+    A: Allocator + Clone + Send,
+{
+    /// Consumes (potentially in parallel) all values in an arbitrary order,
+    /// while preserving the set's allocated memory for reuse.
+    #[cfg_attr(feature = "inline-more", inline)]
+    pub fn par_drain(&mut self) -> ParDrain<'_, T, A> {
+        ParDrain {
+            inner: self.map.par_drain(),
+        }
+    }
+}
+
+impl<T: Send, S, A: Allocator + Clone + Send> IntoParallelIterator for HashSet<T, S, A> {
+    type Item = T;
+    type Iter = IntoParIter<T, A>;
+
+    #[cfg_attr(feature = "inline-more", inline)]
+    fn into_par_iter(self) -> Self::Iter {
+        IntoParIter {
+            inner: self.map.into_par_iter(),
+        }
+    }
+}
+
+impl<'a, T: Sync, S, A: Allocator + Clone> IntoParallelIterator for &'a HashSet<T, S, A> {
+    type Item = &'a T;
+    type Iter = ParIter<'a, T>;
+
+    #[cfg_attr(feature = "inline-more", inline)]
+    fn into_par_iter(self) -> Self::Iter {
+        ParIter {
+            inner: self.map.par_keys(),
+        }
+    }
+}
+
+/// Collect values from a parallel iterator into a hashset.
+impl<T, S> FromParallelIterator<T> for HashSet<T, S, Global>
+where
+    T: Eq + Hash + Send,
+    S: BuildHasher + Default,
+{
+    fn from_par_iter<P>(par_iter: P) -> Self
+    where
+        P: IntoParallelIterator<Item = T>,
+    {
+        let mut set = HashSet::default();
+        set.par_extend(par_iter);
+        set
+    }
+}
+
+/// Extend a hash set with items from a parallel iterator.
+impl<T, S> ParallelExtend<T> for HashSet<T, S, Global>
+where
+    T: Eq + Hash + Send,
+    S: BuildHasher,
+{
+    fn par_extend<I>(&mut self, par_iter: I)
+    where
+        I: IntoParallelIterator<Item = T>,
+    {
+        extend(self, par_iter);
+    }
+}
+
+/// Extend a hash set with copied items from a parallel iterator.
+impl<'a, T, S> ParallelExtend<&'a T> for HashSet<T, S, Global>
+where
+    T: 'a + Copy + Eq + Hash + Sync,
+    S: BuildHasher,
+{
+    fn par_extend<I>(&mut self, par_iter: I)
+    where
+        I: IntoParallelIterator<Item = &'a T>,
+    {
+        extend(self, par_iter);
+    }
+}
+
+// This is equal to the normal `HashSet` -- no custom advantage.
+fn extend<T, S, I, A>(set: &mut HashSet<T, S, A>, par_iter: I)
+where
+    T: Eq + Hash,
+    S: BuildHasher,
+    A: Allocator + Clone,
+    I: IntoParallelIterator,
+    HashSet<T, S, A>: Extend<I::Item>,
+{
+    let (list, len) = super::helpers::collect(par_iter);
+
+    // Values may be already present or show multiple times in the iterator.
+    // Reserve the entire length if the set is empty.
+    // Otherwise reserve half the length (rounded up), so the set
+    // will only resize twice in the worst case.
+    let reserve = if set.is_empty() { len } else { (len + 1) / 2 };
+    set.reserve(reserve);
+    for vec in list {
+        set.extend(vec);
+    }
+}
+
+#[cfg(test)]
+mod test_par_set {
+    use alloc::vec::Vec;
+    use core::sync::atomic::{AtomicUsize, Ordering};
+
+    use rayon::prelude::*;
+
+    use crate::hash_set::HashSet;
+
+    #[test]
+    fn test_disjoint() {
+        let mut xs = HashSet::new();
+        let mut ys = HashSet::new();
+        assert!(xs.par_is_disjoint(&ys));
+        assert!(ys.par_is_disjoint(&xs));
+        assert!(xs.insert(5));
+        assert!(ys.insert(11));
+        assert!(xs.par_is_disjoint(&ys));
+        assert!(ys.par_is_disjoint(&xs));
+        assert!(xs.insert(7));
+        assert!(xs.insert(19));
+        assert!(xs.insert(4));
+        assert!(ys.insert(2));
+        assert!(ys.insert(-11));
+        assert!(xs.par_is_disjoint(&ys));
+        assert!(ys.par_is_disjoint(&xs));
+        assert!(ys.insert(7));
+        assert!(!xs.par_is_disjoint(&ys));
+        assert!(!ys.par_is_disjoint(&xs));
+    }
+
+    #[test]
+    fn test_subset_and_superset() {
+        let mut a = HashSet::new();
+        assert!(a.insert(0));
+        assert!(a.insert(5));
+        assert!(a.insert(11));
+        assert!(a.insert(7));
+
+        let mut b = HashSet::new();
+        assert!(b.insert(0));
+        assert!(b.insert(7));
+        assert!(b.insert(19));
+        assert!(b.insert(250));
+        assert!(b.insert(11));
+        assert!(b.insert(200));
+
+        assert!(!a.par_is_subset(&b));
+        assert!(!a.par_is_superset(&b));
+        assert!(!b.par_is_subset(&a));
+        assert!(!b.par_is_superset(&a));
+
+        assert!(b.insert(5));
+
+        assert!(a.par_is_subset(&b));
+        assert!(!a.par_is_superset(&b));
+        assert!(!b.par_is_subset(&a));
+        assert!(b.par_is_superset(&a));
+    }
+
+    #[test]
+    fn test_iterate() {
+        let mut a = HashSet::new();
+        for i in 0..32 {
+            assert!(a.insert(i));
+        }
+        let observed = AtomicUsize::new(0);
+        a.par_iter().for_each(|k| {
+            observed.fetch_or(1 << *k, Ordering::Relaxed);
+        });
+        assert_eq!(observed.into_inner(), 0xFFFF_FFFF);
+    }
+
+    #[test]
+    fn test_intersection() {
+        let mut a = HashSet::new();
+        let mut b = HashSet::new();
+
+        assert!(a.insert(11));
+        assert!(a.insert(1));
+        assert!(a.insert(3));
+        assert!(a.insert(77));
+        assert!(a.insert(103));
+        assert!(a.insert(5));
+        assert!(a.insert(-5));
+
+        assert!(b.insert(2));
+        assert!(b.insert(11));
+        assert!(b.insert(77));
+        assert!(b.insert(-9));
+        assert!(b.insert(-42));
+        assert!(b.insert(5));
+        assert!(b.insert(3));
+
+        let expected = [3, 5, 11, 77];
+        let i = a
+            .par_intersection(&b)
+            .map(|x| {
+                assert!(expected.contains(x));
+                1
+            })
+            .sum::<usize>();
+        assert_eq!(i, expected.len());
+    }
+
+    #[test]
+    fn test_difference() {
+        let mut a = HashSet::new();
+        let mut b = HashSet::new();
+
+        assert!(a.insert(1));
+        assert!(a.insert(3));
+        assert!(a.insert(5));
+        assert!(a.insert(9));
+        assert!(a.insert(11));
+
+        assert!(b.insert(3));
+        assert!(b.insert(9));
+
+        let expected = [1, 5, 11];
+        let i = a
+            .par_difference(&b)
+            .map(|x| {
+                assert!(expected.contains(x));
+                1
+            })
+            .sum::<usize>();
+        assert_eq!(i, expected.len());
+    }
+
+    #[test]
+    fn test_symmetric_difference() {
+        let mut a = HashSet::new();
+        let mut b = HashSet::new();
+
+        assert!(a.insert(1));
+        assert!(a.insert(3));
+        assert!(a.insert(5));
+        assert!(a.insert(9));
+        assert!(a.insert(11));
+
+        assert!(b.insert(-2));
+        assert!(b.insert(3));
+        assert!(b.insert(9));
+        assert!(b.insert(14));
+        assert!(b.insert(22));
+
+        let expected = [-2, 1, 5, 11, 14, 22];
+        let i = a
+            .par_symmetric_difference(&b)
+            .map(|x| {
+                assert!(expected.contains(x));
+                1
+            })
+            .sum::<usize>();
+        assert_eq!(i, expected.len());
+    }
+
+    #[test]
+    fn test_union() {
+        let mut a = HashSet::new();
+        let mut b = HashSet::new();
+
+        assert!(a.insert(1));
+        assert!(a.insert(3));
+        assert!(a.insert(5));
+        assert!(a.insert(9));
+        assert!(a.insert(11));
+        assert!(a.insert(16));
+        assert!(a.insert(19));
+        assert!(a.insert(24));
+
+        assert!(b.insert(-2));
+        assert!(b.insert(1));
+        assert!(b.insert(5));
+        assert!(b.insert(9));
+        assert!(b.insert(13));
+        assert!(b.insert(19));
+
+        let expected = [-2, 1, 3, 5, 9, 11, 13, 16, 19, 24];
+        let i = a
+            .par_union(&b)
+            .map(|x| {
+                assert!(expected.contains(x));
+                1
+            })
+            .sum::<usize>();
+        assert_eq!(i, expected.len());
+    }
+
+    #[test]
+    fn test_from_iter() {
+        let xs = [1, 2, 3, 4, 5, 6, 7, 8, 9];
+
+        let set: HashSet<_> = xs.par_iter().cloned().collect();
+
+        for x in &xs {
+            assert!(set.contains(x));
+        }
+    }
+
+    #[test]
+    fn test_move_iter() {
+        let hs = {
+            let mut hs = HashSet::new();
+
+            hs.insert('a');
+            hs.insert('b');
+
+            hs
+        };
+
+        let v = hs.into_par_iter().collect::<Vec<char>>();
+        assert!(v == ['a', 'b'] || v == ['b', 'a']);
+    }
+
+    #[test]
+    fn test_eq() {
+        // These constants once happened to expose a bug in insert().
+        // I'm keeping them around to prevent a regression.
+        let mut s1 = HashSet::new();
+
+        s1.insert(1);
+        s1.insert(2);
+        s1.insert(3);
+
+        let mut s2 = HashSet::new();
+
+        s2.insert(1);
+        s2.insert(2);
+
+        assert!(!s1.par_eq(&s2));
+
+        s2.insert(3);
+
+        assert!(s1.par_eq(&s2));
+    }
+
+    #[test]
+    fn test_extend_ref() {
+        let mut a = HashSet::new();
+        a.insert(1);
+
+        a.par_extend(&[2, 3, 4][..]);
+
+        assert_eq!(a.len(), 4);
+        assert!(a.contains(&1));
+        assert!(a.contains(&2));
+        assert!(a.contains(&3));
+        assert!(a.contains(&4));
+
+        let mut b = HashSet::new();
+        b.insert(5);
+        b.insert(6);
+
+        a.par_extend(&b);
+
+        assert_eq!(a.len(), 6);
+        assert!(a.contains(&1));
+        assert!(a.contains(&2));
+        assert!(a.contains(&3));
+        assert!(a.contains(&4));
+        assert!(a.contains(&5));
+        assert!(a.contains(&6));
+    }
+}
--- a/src/external_trait_impls/serde.rs
+++ b/src/external_trait_impls/serde.rs
@ -0,0 +1,201 @@
+mod size_hint {
+    use core::cmp;
+
+    /// This presumably exists to prevent denial of service attacks.
+    ///
+    /// Original discussion: https://github.com/serde-rs/serde/issues/1114.
+    #[cfg_attr(feature = "inline-more", inline)]
+    pub(super) fn cautious(hint: Option<usize>) -> usize {
+        cmp::min(hint.unwrap_or(0), 4096)
+    }
+}
+
+mod map {
+    use core::fmt;
+    use core::hash::{BuildHasher, Hash};
+    use core::marker::PhantomData;
+    use serde::de::{Deserialize, Deserializer, MapAccess, Visitor};
+    use serde::ser::{Serialize, Serializer};
+
+    use crate::hash_map::HashMap;
+
+    use super::size_hint;
+
+    impl<K, V, H> Serialize for HashMap<K, V, H>
+    where
+        K: Serialize + Eq + Hash,
+        V: Serialize,
+        H: BuildHasher,
+    {
+        #[cfg_attr(feature = "inline-more", inline)]
+        fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+        where
+            S: Serializer,
+        {
+            serializer.collect_map(self)
+        }
+    }
+
+    impl<'de, K, V, S> Deserialize<'de> for HashMap<K, V, S>
+    where
+        K: Deserialize<'de> + Eq + Hash,
+        V: Deserialize<'de>,
+        S: BuildHasher + Default,
+    {
+        fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+        where
+            D: Deserializer<'de>,
+        {
+            struct MapVisitor<K, V, S> {
+                marker: PhantomData<HashMap<K, V, S>>,
+            }
+
+            impl<'de, K, V, S> Visitor<'de> for MapVisitor<K, V, S>
+            where
+                K: Deserialize<'de> + Eq + Hash,
+                V: Deserialize<'de>,
+                S: BuildHasher + Default,
+            {
+                type Value = HashMap<K, V, S>;
+
+                fn expecting(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
+                    formatter.write_str("a map")
+                }
+
+                #[cfg_attr(feature = "inline-more", inline)]
+                fn visit_map<A>(self, mut map: A) -> Result<Self::Value, A::Error>
+                where
+                    A: MapAccess<'de>,
+                {
+                    let mut values = HashMap::with_capacity_and_hasher(
+                        size_hint::cautious(map.size_hint()),
+                        S::default(),
+                    );
+
+                    while let Some((key, value)) = map.next_entry()? {
+                        values.insert(key, value);
+                    }
+
+                    Ok(values)
+                }
+            }
+
+            let visitor = MapVisitor {
+                marker: PhantomData,
+            };
+            deserializer.deserialize_map(visitor)
+        }
+    }
+}
+
+mod set {
+    use core::fmt;
+    use core::hash::{BuildHasher, Hash};
+    use core::marker::PhantomData;
+    use serde::de::{Deserialize, Deserializer, SeqAccess, Visitor};
+    use serde::ser::{Serialize, Serializer};
+
+    use crate::hash_set::HashSet;
+
+    use super::size_hint;
+
+    impl<T, H> Serialize for HashSet<T, H>
+    where
+        T: Serialize + Eq + Hash,
+        H: BuildHasher,
+    {
+        #[cfg_attr(feature = "inline-more", inline)]
+        fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+        where
+            S: Serializer,
+        {
+            serializer.collect_seq(self)
+        }
+    }
+
+    impl<'de, T, S> Deserialize<'de> for HashSet<T, S>
+    where
+        T: Deserialize<'de> + Eq + Hash,
+        S: BuildHasher + Default,
+    {
+        fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+        where
+            D: Deserializer<'de>,
+        {
+            struct SeqVisitor<T, S> {
+                marker: PhantomData<HashSet<T, S>>,
+            }
+
+            impl<'de, T, S> Visitor<'de> for SeqVisitor<T, S>
+            where
+                T: Deserialize<'de> + Eq + Hash,
+                S: BuildHasher + Default,
+            {
+                type Value = HashSet<T, S>;
+
+                fn expecting(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
+                    formatter.write_str("a sequence")
+                }
+
+                #[cfg_attr(feature = "inline-more", inline)]
+                fn visit_seq<A>(self, mut seq: A) -> Result<Self::Value, A::Error>
+                where
+                    A: SeqAccess<'de>,
+                {
+                    let mut values = HashSet::with_capacity_and_hasher(
+                        size_hint::cautious(seq.size_hint()),
+                        S::default(),
+                    );
+
+                    while let Some(value) = seq.next_element()? {
+                        values.insert(value);
+                    }
+
+                    Ok(values)
+                }
+            }
+
+            let visitor = SeqVisitor {
+                marker: PhantomData,
+            };
+            deserializer.deserialize_seq(visitor)
+        }
+
+        #[allow(clippy::missing_errors_doc)]
+        fn deserialize_in_place<D>(deserializer: D, place: &mut Self) -> Result<(), D::Error>
+        where
+            D: Deserializer<'de>,
+        {
+            struct SeqInPlaceVisitor<'a, T, S>(&'a mut HashSet<T, S>);
+
+            impl<'a, 'de, T, S> Visitor<'de> for SeqInPlaceVisitor<'a, T, S>
+            where
+                T: Deserialize<'de> + Eq + Hash,
+                S: BuildHasher + Default,
+            {
+                type Value = ();
+
+                fn expecting(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
+                    formatter.write_str("a sequence")
+                }
+
+                #[cfg_attr(feature = "inline-more", inline)]
+                fn visit_seq<A>(self, mut seq: A) -> Result<Self::Value, A::Error>
+                where
+                    A: SeqAccess<'de>,
+                {
+                    self.0.clear();
+                    self.0.reserve(size_hint::cautious(seq.size_hint()));
+
+                    while let Some(value) = seq.next_element()? {
+                        self.0.insert(value);
+                    }
+
+                    Ok(())
+                }
+            }
+
+            deserializer.deserialize_seq(SeqInPlaceVisitor(place))
+        }
+    }
+}
--- a/src/lib.rs
+++ b/src/lib.rs
@ -0,0 +1,150 @@
+//! This crate is a Rust port of Google's high-performance [SwissTable] hash
+//! map, adapted to make it a drop-in replacement for Rust's standard `HashMap`
+//! and `HashSet` types.
+//!
+//! The original C++ version of [SwissTable] can be found [here], and this
+//! [CppCon talk] gives an overview of how the algorithm works.
+//!
+//! [SwissTable]: https://abseil.io/blog/20180927-swisstables
+//! [here]: https://github.com/abseil/abseil-cpp/blob/master/absl/container/internal/raw_hash_set.h
+//! [CppCon talk]: https://www.youtube.com/watch?v=ncHmEUmJZf4
+
+#![no_std]
+#![cfg_attr(
+    feature = "nightly",
+    feature(
+        test,
+        core_intrinsics,
+        dropck_eyepatch,
+        min_specialization,
+        extend_one,
+        allocator_api,
+        slice_ptr_get,
+        nonnull_slice_from_raw_parts,
+        maybe_uninit_array_assume_init,
+        build_hasher_simple_hash_one
+    )
+)]
+#![allow(
+    clippy::doc_markdown,
+    clippy::module_name_repetitions,
+    clippy::must_use_candidate,
+    clippy::option_if_let_else,
+    clippy::redundant_else,
+    clippy::manual_map,
+    clippy::missing_safety_doc,
+    clippy::missing_errors_doc
+)]
+#![warn(missing_docs)]
+#![warn(rust_2018_idioms)]
+
+#[cfg(test)]
+#[macro_use]
+extern crate std;
+
+#[cfg_attr(test, macro_use)]
+extern crate alloc;
+
+#[cfg(feature = "nightly")]
+#[cfg(doctest)]
+doc_comment::doctest!("../README.md");
+
+#[macro_use]
+mod macros;
+
+#[cfg(feature = "raw")]
+/// Experimental and unsafe `RawTable` API. This module is only available if the
+/// `raw` feature is enabled.
+pub mod raw {
+    // The RawTable API is still experimental and is not properly documented yet.
+    #[allow(missing_docs)]
+    #[path = "mod.rs"]
+    mod inner;
+    pub use inner::*;
+
+    #[cfg(feature = "rayon")]
+    /// [rayon]-based parallel iterator types for hash maps.
+    /// You will rarely need to interact with it directly unless you have need
+    /// to name one of the iterator types.
+    ///
+    /// [rayon]: https://docs.rs/rayon/1.0/rayon
+    pub mod rayon {
+        pub use crate::external_trait_impls::rayon::raw::*;
+    }
+}
+#[cfg(not(feature = "raw"))]
+mod raw;
+
+mod external_trait_impls;
+mod map;
+#[cfg(feature = "rustc-internal-api")]
+mod rustc_entry;
+mod scopeguard;
+mod set;
+
+pub mod hash_map {
+    //! A hash map implemented with quadratic probing and SIMD lookup.
+    pub use crate::map::*;
+
+    #[cfg(feature = "rustc-internal-api")]
+    pub use crate::rustc_entry::*;
+
+    #[cfg(feature = "rayon")]
+    /// [rayon]-based parallel iterator types for hash maps.
+    /// You will rarely need to interact with it directly unless you have need
+    /// to name one of the iterator types.
+    ///
+    /// [rayon]: https://docs.rs/rayon/1.0/rayon
+    pub mod rayon {
+        pub use crate::external_trait_impls::rayon::map::*;
+    }
+}
+pub mod hash_set {
+    //! A hash set implemented as a `HashMap` where the value is `()`.
+    pub use crate::set::*;
+
+    #[cfg(feature = "rayon")]
+    /// [rayon]-based parallel iterator types for hash sets.
+    /// You will rarely need to interact with it directly unless you have need
+    /// to name one of the iterator types.
+    ///
+    /// [rayon]: https://docs.rs/rayon/1.0/rayon
+    pub mod rayon {
+        pub use crate::external_trait_impls::rayon::set::*;
+    }
+}
+
+pub use crate::map::HashMap;
+pub use crate::set::HashSet;
+
+/// The error type for `try_reserve` methods.
+#[derive(Clone, PartialEq, Eq, Debug)]
+pub enum TryReserveError {
+    /// Error due to the computed capacity exceeding the collection's maximum
+    /// (usually `isize::MAX` bytes).
+    CapacityOverflow,
+
+    /// The memory allocator returned an error
+    AllocError {
+        /// The layout of the allocation request that failed.
+        layout: alloc::alloc::Layout,
+    },
+}
+
+/// Wrapper around `Bump` which allows it to be used as an allocator for
+/// `HashMap`, `HashSet` and `RawTable`.
+///
+/// `Bump` can be used directly without this wrapper on nightly if you enable
+/// the `allocator-api` feature of the `bumpalo` crate.
+#[cfg(feature = "bumpalo")]
+#[derive(Clone, Copy, Debug)]
+pub struct BumpWrapper<'a>(pub &'a bumpalo::Bump);
+
+#[cfg(feature = "bumpalo")]
+#[test]
+fn test_bumpalo() {
+    use bumpalo::Bump;
+    let bump = Bump::new();
+    let mut map = HashMap::new_in(BumpWrapper(&bump));
+    map.insert(0, 1);
+}
--- a/src/macros.rs
+++ b/src/macros.rs
@ -0,0 +1,70 @@
+// See the cfg-if crate.
+#[allow(unused_macro_rules)]
+macro_rules! cfg_if {
+    // match if/else chains with a final `else`
+    ($(
+        if #[cfg($($meta:meta),*)] { $($it:item)* }
+    ) else * else {
+        $($it2:item)*
+    }) => {
+        cfg_if! {
+            @__items
+            () ;
+            $( ( ($($meta),*) ($($it)*) ), )*
+            ( () ($($it2)*) ),
+        }
+    };
+
+    // match if/else chains lacking a final `else`
+    (
+        if #[cfg($($i_met:meta),*)] { $($i_it:item)* }
+        $(
+            else if #[cfg($($e_met:meta),*)] { $($e_it:item)* }
+        )*
+    ) => {
+        cfg_if! {
+            @__items
+            () ;
+            ( ($($i_met),*) ($($i_it)*) ),
+            $( ( ($($e_met),*) ($($e_it)*) ), )*
+            ( () () ),
+        }
+    };
+
+    // Internal and recursive macro to emit all the items
+    //
+    // Collects all the negated cfgs in a list at the beginning and after the
+    // semicolon is all the remaining items
+    (@__items ($($not:meta,)*) ; ) => {};
+    (@__items ($($not:meta,)*) ; ( ($($m:meta),*) ($($it:item)*) ), $($rest:tt)*) => {
+        // Emit all items within one block, applying an approprate #[cfg]. The
+        // #[cfg] will require all `$m` matchers specified and must also negate
+        // all previous matchers.
+        cfg_if! { @__apply cfg(all($($m,)* not(any($($not),*)))), $($it)* }
+
+        // Recurse to emit all other items in `$rest`, and when we do so add all
+        // our `$m` matchers to the list of `$not` matchers as future emissions
+        // will have to negate everything we just matched as well.
+        cfg_if! { @__items ($($not,)* $($m,)*) ; $($rest)* }
+    };
+
+    // Internal macro to Apply a cfg attribute to a list of items
+    (@__apply $m:meta, $($it:item)*) => {
+        $(#[$m] $it)*
+    };
+}
+
+// Helper macro for specialization. This also helps avoid parse errors if the
+// default fn syntax for specialization changes in the future.
+#[cfg(feature = "nightly")]
+macro_rules! default_fn {
+	(#[$($a:tt)*] $($tt:tt)*) => {
+        #[$($a)*] default $($tt)*
+    }
+}
+#[cfg(not(feature = "nightly"))]
+macro_rules! default_fn {
+	($($tt:tt)*) => {
+        $($tt)*
+    }
+}
--- a/src/map.rs
+++ b/src/map.rs
--- a/src/raw/alloc.rs
+++ b/src/raw/alloc.rs
@ -0,0 +1,73 @@
+pub(crate) use self::inner::{do_alloc, Allocator, Global};
+
+#[cfg(feature = "nightly")]
+mod inner {
+    use crate::alloc::alloc::Layout;
+    pub use crate::alloc::alloc::{Allocator, Global};
+    use core::ptr::NonNull;
+
+    #[allow(clippy::map_err_ignore)]
+    pub fn do_alloc<A: Allocator>(alloc: &A, layout: Layout) -> Result<NonNull<u8>, ()> {
+        match alloc.allocate(layout) {
+            Ok(ptr) => Ok(ptr.as_non_null_ptr()),
+            Err(_) => Err(()),
+        }
+    }
+
+    #[cfg(feature = "bumpalo")]
+    unsafe impl Allocator for crate::BumpWrapper<'_> {
+        #[inline]
+        fn allocate(&self, layout: Layout) -> Result<NonNull<[u8]>, core::alloc::AllocError> {
+            match self.0.try_alloc_layout(layout) {
+                Ok(ptr) => Ok(NonNull::slice_from_raw_parts(ptr, layout.size())),
+                Err(_) => Err(core::alloc::AllocError),
+            }
+        }
+        #[inline]
+        unsafe fn deallocate(&self, _ptr: NonNull<u8>, _layout: Layout) {}
+    }
+}
+
+#[cfg(not(feature = "nightly"))]
+mod inner {
+    use crate::alloc::alloc::{alloc, dealloc, Layout};
+    use core::ptr::NonNull;
+
+    #[allow(clippy::missing_safety_doc)] // not exposed outside of this crate
+    pub unsafe trait Allocator {
+        fn allocate(&self, layout: Layout) -> Result<NonNull<u8>, ()>;
+        unsafe fn deallocate(&self, ptr: NonNull<u8>, layout: Layout);
+    }
+
+    #[derive(Copy, Clone)]
+    pub struct Global;
+    unsafe impl Allocator for Global {
+        #[inline]
+        fn allocate(&self, layout: Layout) -> Result<NonNull<u8>, ()> {
+            unsafe { NonNull::new(alloc(layout)).ok_or(()) }
+        }
+        #[inline]
+        unsafe fn deallocate(&self, ptr: NonNull<u8>, layout: Layout) {
+            dealloc(ptr.as_ptr(), layout);
+        }
+    }
+    impl Default for Global {
+        #[inline]
+        fn default() -> Self {
+            Global
+        }
+    }
+
+    pub fn do_alloc<A: Allocator>(alloc: &A, layout: Layout) -> Result<NonNull<u8>, ()> {
+        alloc.allocate(layout)
+    }
+
+    #[cfg(feature = "bumpalo")]
+    unsafe impl Allocator for crate::BumpWrapper<'_> {
+        #[allow(clippy::map_err_ignore)]
+        fn allocate(&self, layout: Layout) -> Result<NonNull<u8>, ()> {
+            self.0.try_alloc_layout(layout).map_err(|_| ())
+        }
+        unsafe fn deallocate(&self, _ptr: NonNull<u8>, _layout: Layout) {}
+    }
+}
--- a/src/raw/bitmask.rs
+++ b/src/raw/bitmask.rs
@ -0,0 +1,122 @@
+use super::imp::{BitMaskWord, BITMASK_MASK, BITMASK_STRIDE};
+#[cfg(feature = "nightly")]
+use core::intrinsics;
+
+/// A bit mask which contains the result of a `Match` operation on a `Group` and
+/// allows iterating through them.
+///
+/// The bit mask is arranged so that low-order bits represent lower memory
+/// addresses for group match results.
+///
+/// For implementation reasons, the bits in the set may be sparsely packed, so
+/// that there is only one bit-per-byte used (the high bit, 7). If this is the
+/// case, `BITMASK_STRIDE` will be 8 to indicate a divide-by-8 should be
+/// performed on counts/indices to normalize this difference. `BITMASK_MASK` is
+/// similarly a mask of all the actually-used bits.
+#[derive(Copy, Clone)]
+pub struct BitMask(pub BitMaskWord);
+
+#[allow(clippy::use_self)]
+impl BitMask {
+    /// Returns a new `BitMask` with all bits inverted.
+    #[inline]
+    #[must_use]
+    pub fn invert(self) -> Self {
+        BitMask(self.0 ^ BITMASK_MASK)
+    }
+
+    /// Flip the bit in the mask for the entry at the given index.
+    ///
+    /// Returns the bit's previous state.
+    #[inline]
+    #[allow(clippy::cast_ptr_alignment)]
+    #[cfg(feature = "raw")]
+    pub unsafe fn flip(&mut self, index: usize) -> bool {
+        // NOTE: The + BITMASK_STRIDE - 1 is to set the high bit.
+        let mask = 1 << (index * BITMASK_STRIDE + BITMASK_STRIDE - 1);
+        self.0 ^= mask;
+        // The bit was set if the bit is now 0.
+        self.0 & mask == 0
+    }
+
+    /// Returns a new `BitMask` with the lowest bit removed.
+    #[inline]
+    #[must_use]
+    pub fn remove_lowest_bit(self) -> Self {
+        BitMask(self.0 & (self.0 - 1))
+    }
+    /// Returns whether the `BitMask` has at least one set bit.
+    #[inline]
+    pub fn any_bit_set(self) -> bool {
+        self.0 != 0
+    }
+
+    /// Returns the first set bit in the `BitMask`, if there is one.
+    #[inline]
+    pub fn lowest_set_bit(self) -> Option<usize> {
+        if self.0 == 0 {
+            None
+        } else {
+            Some(unsafe { self.lowest_set_bit_nonzero() })
+        }
+    }
+
+    /// Returns the first set bit in the `BitMask`, if there is one. The
+    /// bitmask must not be empty.
+    #[inline]
+    #[cfg(feature = "nightly")]
+    pub unsafe fn lowest_set_bit_nonzero(self) -> usize {
+        intrinsics::cttz_nonzero(self.0) as usize / BITMASK_STRIDE
+    }
+    #[inline]
+    #[cfg(not(feature = "nightly"))]
+    pub unsafe fn lowest_set_bit_nonzero(self) -> usize {
+        self.trailing_zeros()
+    }
+
+    /// Returns the number of trailing zeroes in the `BitMask`.
+    #[inline]
+    pub fn trailing_zeros(self) -> usize {
+        // ARM doesn't have a trailing_zeroes instruction, and instead uses
+        // reverse_bits (RBIT) + leading_zeroes (CLZ). However older ARM
+        // versions (pre-ARMv7) don't have RBIT and need to emulate it
+        // instead. Since we only have 1 bit set in each byte on ARM, we can
+        // use swap_bytes (REV) + leading_zeroes instead.
+        if cfg!(target_arch = "arm") && BITMASK_STRIDE % 8 == 0 {
+            self.0.swap_bytes().leading_zeros() as usize / BITMASK_STRIDE
+        } else {
+            self.0.trailing_zeros() as usize / BITMASK_STRIDE
+        }
+    }
+
+    /// Returns the number of leading zeroes in the `BitMask`.
+    #[inline]
+    pub fn leading_zeros(self) -> usize {
+        self.0.leading_zeros() as usize / BITMASK_STRIDE
+    }
+}
+
+impl IntoIterator for BitMask {
+    type Item = usize;
+    type IntoIter = BitMaskIter;
+
+    #[inline]
+    fn into_iter(self) -> BitMaskIter {
+        BitMaskIter(self)
+    }
+}
+
+/// Iterator over the contents of a `BitMask`, returning the indices of set
+/// bits.
+pub struct BitMaskIter(BitMask);
+
+impl Iterator for BitMaskIter {
+    type Item = usize;
+
+    #[inline]
+    fn next(&mut self) -> Option<usize> {
+        let bit = self.0.lowest_set_bit()?;
+        self.0 = self.0.remove_lowest_bit();
+        Some(bit)
+    }
+}
--- a/src/raw/generic.rs
+++ b/src/raw/generic.rs
@ -0,0 +1,154 @@
+use super::bitmask::BitMask;
+use super::EMPTY;
+use core::{mem, ptr};
+
+// Use the native word size as the group size. Using a 64-bit group size on
+// a 32-bit architecture will just end up being more expensive because
+// shifts and multiplies will need to be emulated.
+#[cfg(any(
+    target_pointer_width = "64",
+    target_arch = "aarch64",
+    target_arch = "x86_64",
+    target_arch = "wasm32",
+))]
+type GroupWord = u64;
+#[cfg(all(
+    target_pointer_width = "32",
+    not(target_arch = "aarch64"),
+    not(target_arch = "x86_64"),
+    not(target_arch = "wasm32"),
+))]
+type GroupWord = u32;
+
+pub type BitMaskWord = GroupWord;
+pub const BITMASK_STRIDE: usize = 8;
+// We only care about the highest bit of each byte for the mask.
+#[allow(clippy::cast_possible_truncation, clippy::unnecessary_cast)]
+pub const BITMASK_MASK: BitMaskWord = 0x8080_8080_8080_8080_u64 as GroupWord;
+
+/// Helper function to replicate a byte across a `GroupWord`.
+#[inline]
+fn repeat(byte: u8) -> GroupWord {
+    GroupWord::from_ne_bytes([byte; Group::WIDTH])
+}
+
+/// Abstraction over a group of control bytes which can be scanned in
+/// parallel.
+///
+/// This implementation uses a word-sized integer.
+#[derive(Copy, Clone)]
+pub struct Group(GroupWord);
+
+// We perform all operations in the native endianness, and convert to
+// little-endian just before creating a BitMask. The can potentially
+// enable the compiler to eliminate unnecessary byte swaps if we are
+// only checking whether a BitMask is empty.
+#[allow(clippy::use_self)]
+impl Group {
+    /// Number of bytes in the group.
+    pub const WIDTH: usize = mem::size_of::<Self>();
+
+    /// Returns a full group of empty bytes, suitable for use as the initial
+    /// value for an empty hash table.
+    ///
+    /// This is guaranteed to be aligned to the group size.
+    #[inline]
+    pub const fn static_empty() -> &'static [u8; Group::WIDTH] {
+        #[repr(C)]
+        struct AlignedBytes {
+            _align: [Group; 0],
+            bytes: [u8; Group::WIDTH],
+        }
+        const ALIGNED_BYTES: AlignedBytes = AlignedBytes {
+            _align: [],
+            bytes: [EMPTY; Group::WIDTH],
+        };
+        &ALIGNED_BYTES.bytes
+    }
+
+    /// Loads a group of bytes starting at the given address.
+    #[inline]
+    #[allow(clippy::cast_ptr_alignment)] // unaligned load
+    pub unsafe fn load(ptr: *const u8) -> Self {
+        Group(ptr::read_unaligned(ptr.cast()))
+    }
+
+    /// Loads a group of bytes starting at the given address, which must be
+    /// aligned to `mem::align_of::<Group>()`.
+    #[inline]
+    #[allow(clippy::cast_ptr_alignment)]
+    pub unsafe fn load_aligned(ptr: *const u8) -> Self {
+        // FIXME: use align_offset once it stabilizes
+        debug_assert_eq!(ptr as usize & (mem::align_of::<Self>() - 1), 0);
+        Group(ptr::read(ptr.cast()))
+    }
+
+    /// Stores the group of bytes to the given address, which must be
+    /// aligned to `mem::align_of::<Group>()`.
+    #[inline]
+    #[allow(clippy::cast_ptr_alignment)]
+    pub unsafe fn store_aligned(self, ptr: *mut u8) {
+        // FIXME: use align_offset once it stabilizes
+        debug_assert_eq!(ptr as usize & (mem::align_of::<Self>() - 1), 0);
+        ptr::write(ptr.cast(), self.0);
+    }
+
+    /// Returns a `BitMask` indicating all bytes in the group which *may*
+    /// have the given value.
+    ///
+    /// This function may return a false positive in certain cases where
+    /// the byte in the group differs from the searched value only in its
+    /// lowest bit. This is fine because:
+    /// - This never happens for `EMPTY` and `DELETED`, only full entries.
+    /// - The check for key equality will catch these.
+    /// - This only happens if there is at least 1 true match.
+    /// - The chance of this happening is very low (< 1% chance per byte).
+    #[inline]
+    pub fn match_byte(self, byte: u8) -> BitMask {
+        // This algorithm is derived from
+        // https://graphics.stanford.edu/~seander/bithacks.html##ValueInWord
+        let cmp = self.0 ^ repeat(byte);
+        BitMask((cmp.wrapping_sub(repeat(0x01)) & !cmp & repeat(0x80)).to_le())
+    }
+
+    /// Returns a `BitMask` indicating all bytes in the group which are
+    /// `EMPTY`.
+    #[inline]
+    pub fn match_empty(self) -> BitMask {
+        // If the high bit is set, then the byte must be either:
+        // 1111_1111 (EMPTY) or 1000_0000 (DELETED).
+        // So we can just check if the top two bits are 1 by ANDing them.
+        BitMask((self.0 & (self.0 << 1) & repeat(0x80)).to_le())
+    }
+
+    /// Returns a `BitMask` indicating all bytes in the group which are
+    /// `EMPTY` or `DELETED`.
+    #[inline]
+    pub fn match_empty_or_deleted(self) -> BitMask {
+        // A byte is EMPTY or DELETED iff the high bit is set
+        BitMask((self.0 & repeat(0x80)).to_le())
+    }
+
+    /// Returns a `BitMask` indicating all bytes in the group which are full.
+    #[inline]
+    pub fn match_full(self) -> BitMask {
+        self.match_empty_or_deleted().invert()
+    }
+
+    /// Performs the following transformation on all bytes in the group:
+    /// - `EMPTY => EMPTY`
+    /// - `DELETED => EMPTY`
+    /// - `FULL => DELETED`
+    #[inline]
+    pub fn convert_special_to_empty_and_full_to_deleted(self) -> Self {
+        // Map high_bit = 1 (EMPTY or DELETED) to 1111_1111
+        // and high_bit = 0 (FULL) to 1000_0000
+        //
+        // Here's this logic expanded to concrete values:
+        //   let full = 1000_0000 (true) or 0000_0000 (false)
+        //   !1000_0000 + 1 = 0111_1111 + 1 = 1000_0000 (no carry)
+        //   !0000_0000 + 0 = 1111_1111 + 0 = 1111_1111 (no carry)
+        let full = !self.0 & repeat(0x80);
+        Group(!full + (full >> 7))
+    }
+}
--- a/src/raw/mod.rs
+++ b/src/raw/mod.rs
--- a/src/raw/sse2.rs
+++ b/src/raw/sse2.rs
@ -0,0 +1,146 @@
+use super::bitmask::BitMask;
+use super::EMPTY;
+use core::mem;
+
+#[cfg(target_arch = "x86")]
+use core::arch::x86;
+#[cfg(target_arch = "x86_64")]
+use core::arch::x86_64 as x86;
+
+pub type BitMaskWord = u16;
+pub const BITMASK_STRIDE: usize = 1;
+pub const BITMASK_MASK: BitMaskWord = 0xffff;
+
+/// Abstraction over a group of control bytes which can be scanned in
+/// parallel.
+///
+/// This implementation uses a 128-bit SSE value.
+#[derive(Copy, Clone)]
+pub struct Group(x86::__m128i);
+
+// FIXME: https://github.com/rust-lang/rust-clippy/issues/3859
+#[allow(clippy::use_self)]
+impl Group {
+    /// Number of bytes in the group.
+    pub const WIDTH: usize = mem::size_of::<Self>();
+
+    /// Returns a full group of empty bytes, suitable for use as the initial
+    /// value for an empty hash table.
+    ///
+    /// This is guaranteed to be aligned to the group size.
+    #[inline]
+    #[allow(clippy::items_after_statements)]
+    pub const fn static_empty() -> &'static [u8; Group::WIDTH] {
+        #[repr(C)]
+        struct AlignedBytes {
+            _align: [Group; 0],
+            bytes: [u8; Group::WIDTH],
+        }
+        const ALIGNED_BYTES: AlignedBytes = AlignedBytes {
+            _align: [],
+            bytes: [EMPTY; Group::WIDTH],
+        };
+        &ALIGNED_BYTES.bytes
+    }
+
+    /// Loads a group of bytes starting at the given address.
+    #[inline]
+    #[allow(clippy::cast_ptr_alignment)] // unaligned load
+    pub unsafe fn load(ptr: *const u8) -> Self {
+        Group(x86::_mm_loadu_si128(ptr.cast()))
+    }
+
+    /// Loads a group of bytes starting at the given address, which must be
+    /// aligned to `mem::align_of::<Group>()`.
+    #[inline]
+    #[allow(clippy::cast_ptr_alignment)]
+    pub unsafe fn load_aligned(ptr: *const u8) -> Self {
+        // FIXME: use align_offset once it stabilizes
+        debug_assert_eq!(ptr as usize & (mem::align_of::<Self>() - 1), 0);
+        Group(x86::_mm_load_si128(ptr.cast()))
+    }
+
+    /// Stores the group of bytes to the given address, which must be
+    /// aligned to `mem::align_of::<Group>()`.
+    #[inline]
+    #[allow(clippy::cast_ptr_alignment)]
+    pub unsafe fn store_aligned(self, ptr: *mut u8) {
+        // FIXME: use align_offset once it stabilizes
+        debug_assert_eq!(ptr as usize & (mem::align_of::<Self>() - 1), 0);
+        x86::_mm_store_si128(ptr.cast(), self.0);
+    }
+
+    /// Returns a `BitMask` indicating all bytes in the group which have
+    /// the given value.
+    #[inline]
+    pub fn match_byte(self, byte: u8) -> BitMask {
+        #[allow(
+            clippy::cast_possible_wrap, // byte: u8 as i8
+            // byte: i32 as u16
+            //   note: _mm_movemask_epi8 returns a 16-bit mask in a i32, the
+            //   upper 16-bits of the i32 are zeroed:
+            clippy::cast_sign_loss,
+            clippy::cast_possible_truncation
+        )]
+        unsafe {
+            let cmp = x86::_mm_cmpeq_epi8(self.0, x86::_mm_set1_epi8(byte as i8));
+            BitMask(x86::_mm_movemask_epi8(cmp) as u16)
+        }
+    }
+
+    /// Returns a `BitMask` indicating all bytes in the group which are
+    /// `EMPTY`.
+    #[inline]
+    pub fn match_empty(self) -> BitMask {
+        self.match_byte(EMPTY)
+    }
+
+    /// Returns a `BitMask` indicating all bytes in the group which are
+    /// `EMPTY` or `DELETED`.
+    #[inline]
+    pub fn match_empty_or_deleted(self) -> BitMask {
+        #[allow(
+            // byte: i32 as u16
+            //   note: _mm_movemask_epi8 returns a 16-bit mask in a i32, the
+            //   upper 16-bits of the i32 are zeroed:
+            clippy::cast_sign_loss,
+            clippy::cast_possible_truncation
+        )]
+        unsafe {
+            // A byte is EMPTY or DELETED iff the high bit is set
+            BitMask(x86::_mm_movemask_epi8(self.0) as u16)
+        }
+    }
+
+    /// Returns a `BitMask` indicating all bytes in the group which are full.
+    #[inline]
+    pub fn match_full(&self) -> BitMask {
+        self.match_empty_or_deleted().invert()
+    }
+
+    /// Performs the following transformation on all bytes in the group:
+    /// - `EMPTY => EMPTY`
+    /// - `DELETED => EMPTY`
+    /// - `FULL => DELETED`
+    #[inline]
+    pub fn convert_special_to_empty_and_full_to_deleted(self) -> Self {
+        // Map high_bit = 1 (EMPTY or DELETED) to 1111_1111
+        // and high_bit = 0 (FULL) to 1000_0000
+        //
+        // Here's this logic expanded to concrete values:
+        //   let special = 0 > byte = 1111_1111 (true) or 0000_0000 (false)
+        //   1111_1111 | 1000_0000 = 1111_1111
+        //   0000_0000 | 1000_0000 = 1000_0000
+        #[allow(
+            clippy::cast_possible_wrap, // byte: 0x80_u8 as i8
+        )]
+        unsafe {
+            let zero = x86::_mm_setzero_si128();
+            let special = x86::_mm_cmpgt_epi8(zero, self.0);
+            Group(x86::_mm_or_si128(
+                special,
+                x86::_mm_set1_epi8(0x80_u8 as i8),
+            ))
+        }
+    }
+}
--- a/src/rustc_entry.rs
+++ b/src/rustc_entry.rs
@ -0,0 +1,630 @@
+use self::RustcEntry::*;
+use crate::map::{make_insert_hash, Drain, HashMap, IntoIter, Iter, IterMut};
+use crate::raw::{Allocator, Bucket, Global, RawTable};
+use core::fmt::{self, Debug};
+use core::hash::{BuildHasher, Hash};
+use core::mem;
+
+impl<K, V, S, A> HashMap<K, V, S, A>
+where
+    K: Eq + Hash,
+    S: BuildHasher,
+    A: Allocator + Clone,
+{
+    /// Gets the given key's corresponding entry in the map for in-place manipulation.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use hashbrown::HashMap;
+    ///
+    /// let mut letters = HashMap::new();
+    ///
+    /// for ch in "a short treatise on fungi".chars() {
+    ///     let counter = letters.rustc_entry(ch).or_insert(0);
+    ///     *counter += 1;
+    /// }
+    ///
+    /// assert_eq!(letters[&'s'], 2);
+    /// assert_eq!(letters[&'t'], 3);
+    /// assert_eq!(letters[&'u'], 1);
+    /// assert_eq!(letters.get(&'y'), None);
+    /// ```
+    #[cfg_attr(feature = "inline-more", inline)]
+    pub fn rustc_entry(&mut self, key: K) -> RustcEntry<'_, K, V, A> {
+        let hash = make_insert_hash(&self.hash_builder, &key);
+        if let Some(elem) = self.table.find(hash, |q| q.0.eq(&key)) {
+            RustcEntry::Occupied(RustcOccupiedEntry {
+                key: Some(key),
+                elem,
+                table: &mut self.table,
+            })
+        } else {
+            // Ideally we would put this in VacantEntry::insert, but Entry is not
+            // generic over the BuildHasher and adding a generic parameter would be
+            // a breaking change.
+            self.reserve(1);
+
+            RustcEntry::Vacant(RustcVacantEntry {
+                hash,
+                key,
+                table: &mut self.table,
+            })
+        }
+    }
+}
+
+/// A view into a single entry in a map, which may either be vacant or occupied.
+///
+/// This `enum` is constructed from the [`rustc_entry`] method on [`HashMap`].
+///
+/// [`HashMap`]: struct.HashMap.html
+/// [`rustc_entry`]: struct.HashMap.html#method.rustc_entry
+pub enum RustcEntry<'a, K, V, A = Global>
+where
+    A: Allocator + Clone,
+{
+    /// An occupied entry.
+    Occupied(RustcOccupiedEntry<'a, K, V, A>),
+
+    /// A vacant entry.
+    Vacant(RustcVacantEntry<'a, K, V, A>),
+}
+
+impl<K: Debug, V: Debug, A: Allocator + Clone> Debug for RustcEntry<'_, K, V, A> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match *self {
+            Vacant(ref v) => f.debug_tuple("Entry").field(v).finish(),
+            Occupied(ref o) => f.debug_tuple("Entry").field(o).finish(),
+        }
+    }
+}
+
+/// A view into an occupied entry in a `HashMap`.
+/// It is part of the [`RustcEntry`] enum.
+///
+/// [`RustcEntry`]: enum.RustcEntry.html
+pub struct RustcOccupiedEntry<'a, K, V, A = Global>
+where
+    A: Allocator + Clone,
+{
+    key: Option<K>,
+    elem: Bucket<(K, V)>,
+    table: &'a mut RawTable<(K, V), A>,
+}
+
+unsafe impl<K, V, A> Send for RustcOccupiedEntry<'_, K, V, A>
+where
+    K: Send,
+    V: Send,
+    A: Allocator + Clone + Send,
+{
+}
+unsafe impl<K, V, A> Sync for RustcOccupiedEntry<'_, K, V, A>
+where
+    K: Sync,
+    V: Sync,
+    A: Allocator + Clone + Sync,
+{
+}
+
+impl<K: Debug, V: Debug, A: Allocator + Clone> Debug for RustcOccupiedEntry<'_, K, V, A> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("OccupiedEntry")
+            .field("key", self.key())
+            .field("value", self.get())
+            .finish()
+    }
+}
+
+/// A view into a vacant entry in a `HashMap`.
+/// It is part of the [`RustcEntry`] enum.
+///
+/// [`RustcEntry`]: enum.RustcEntry.html
+pub struct RustcVacantEntry<'a, K, V, A = Global>
+where
+    A: Allocator + Clone,
+{
+    hash: u64,
+    key: K,
+    table: &'a mut RawTable<(K, V), A>,
+}
+
+impl<K: Debug, V, A: Allocator + Clone> Debug for RustcVacantEntry<'_, K, V, A> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_tuple("VacantEntry").field(self.key()).finish()
+    }
+}
+
+impl<'a, K, V, A: Allocator + Clone> RustcEntry<'a, K, V, A> {
+    /// Sets the value of the entry, and returns a RustcOccupiedEntry.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use hashbrown::HashMap;
+    ///
+    /// let mut map: HashMap<&str, u32> = HashMap::new();
+    /// let entry = map.rustc_entry("horseyland").insert(37);
+    ///
+    /// assert_eq!(entry.key(), &"horseyland");
+    /// ```
+    pub fn insert(self, value: V) -> RustcOccupiedEntry<'a, K, V, A> {
+        match self {
+            Vacant(entry) => entry.insert_entry(value),
+            Occupied(mut entry) => {
+                entry.insert(value);
+                entry
+            }
+        }
+    }
+
+    /// Ensures a value is in the entry by inserting the default if empty, and returns
+    /// a mutable reference to the value in the entry.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use hashbrown::HashMap;
+    ///
+    /// let mut map: HashMap<&str, u32> = HashMap::new();
+    ///
+    /// map.rustc_entry("poneyland").or_insert(3);
+    /// assert_eq!(map["poneyland"], 3);
+    ///
+    /// *map.rustc_entry("poneyland").or_insert(10) *= 2;
+    /// assert_eq!(map["poneyland"], 6);
+    /// ```
+    #[cfg_attr(feature = "inline-more", inline)]
+    pub fn or_insert(self, default: V) -> &'a mut V
+    where
+        K: Hash,
+    {
+        match self {
+            Occupied(entry) => entry.into_mut(),
+            Vacant(entry) => entry.insert(default),
+        }
+    }
+
+    /// Ensures a value is in the entry by inserting the result of the default function if empty,
+    /// and returns a mutable reference to the value in the entry.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use hashbrown::HashMap;
+    ///
+    /// let mut map: HashMap<&str, String> = HashMap::new();
+    /// let s = "hoho".to_string();
+    ///
+    /// map.rustc_entry("poneyland").or_insert_with(|| s);
+    ///
+    /// assert_eq!(map["poneyland"], "hoho".to_string());
+    /// ```
+    #[cfg_attr(feature = "inline-more", inline)]
+    pub fn or_insert_with<F: FnOnce() -> V>(self, default: F) -> &'a mut V
+    where
+        K: Hash,
+    {
+        match self {
+            Occupied(entry) => entry.into_mut(),
+            Vacant(entry) => entry.insert(default()),
+        }
+    }
+
+    /// Returns a reference to this entry's key.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use hashbrown::HashMap;
+    ///
+    /// let mut map: HashMap<&str, u32> = HashMap::new();
+    /// assert_eq!(map.rustc_entry("poneyland").key(), &"poneyland");
+    /// ```
+    #[cfg_attr(feature = "inline-more", inline)]
+    pub fn key(&self) -> &K {
+        match *self {
+            Occupied(ref entry) => entry.key(),
+            Vacant(ref entry) => entry.key(),
+        }
+    }
+
+    /// Provides in-place mutable access to an occupied entry before any
+    /// potential inserts into the map.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use hashbrown::HashMap;
+    ///
+    /// let mut map: HashMap<&str, u32> = HashMap::new();
+    ///
+    /// map.rustc_entry("poneyland")
+    ///    .and_modify(|e| { *e += 1 })
+    ///    .or_insert(42);
+    /// assert_eq!(map["poneyland"], 42);
+    ///
+    /// map.rustc_entry("poneyland")
+    ///    .and_modify(|e| { *e += 1 })
+    ///    .or_insert(42);
+    /// assert_eq!(map["poneyland"], 43);
+    /// ```
+    #[cfg_attr(feature = "inline-more", inline)]
+    pub fn and_modify<F>(self, f: F) -> Self
+    where
+        F: FnOnce(&mut V),
+    {
+        match self {
+            Occupied(mut entry) => {
+                f(entry.get_mut());
+                Occupied(entry)
+            }
+            Vacant(entry) => Vacant(entry),
+        }
+    }
+}
+
+impl<'a, K, V: Default, A: Allocator + Clone> RustcEntry<'a, K, V, A> {
+    /// Ensures a value is in the entry by inserting the default value if empty,
+    /// and returns a mutable reference to the value in the entry.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// # fn main() {
+    /// use hashbrown::HashMap;
+    ///
+    /// let mut map: HashMap<&str, Option<u32>> = HashMap::new();
+    /// map.rustc_entry("poneyland").or_default();
+    ///
+    /// assert_eq!(map["poneyland"], None);
+    /// # }
+    /// ```
+    #[cfg_attr(feature = "inline-more", inline)]
+    pub fn or_default(self) -> &'a mut V
+    where
+        K: Hash,
+    {
+        match self {
+            Occupied(entry) => entry.into_mut(),
+            Vacant(entry) => entry.insert(Default::default()),
+        }
+    }
+}
+
+impl<'a, K, V, A: Allocator + Clone> RustcOccupiedEntry<'a, K, V, A> {
+    /// Gets a reference to the key in the entry.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use hashbrown::HashMap;
+    ///
+    /// let mut map: HashMap<&str, u32> = HashMap::new();
+    /// map.rustc_entry("poneyland").or_insert(12);
+    /// assert_eq!(map.rustc_entry("poneyland").key(), &"poneyland");
+    /// ```
+    #[cfg_attr(feature = "inline-more", inline)]
+    pub fn key(&self) -> &K {
+        unsafe { &self.elem.as_ref().0 }
+    }
+
+    /// Take the ownership of the key and value from the map.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use hashbrown::HashMap;
+    /// use hashbrown::hash_map::RustcEntry;
+    ///
+    /// let mut map: HashMap<&str, u32> = HashMap::new();
+    /// map.rustc_entry("poneyland").or_insert(12);
+    ///
+    /// if let RustcEntry::Occupied(o) = map.rustc_entry("poneyland") {
+    ///     // We delete the entry from the map.
+    ///     o.remove_entry();
+    /// }
+    ///
+    /// assert_eq!(map.contains_key("poneyland"), false);
+    /// ```
+    #[cfg_attr(feature = "inline-more", inline)]
+    pub fn remove_entry(self) -> (K, V) {
+        unsafe { self.table.remove(self.elem) }
+    }
+
+    /// Gets a reference to the value in the entry.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use hashbrown::HashMap;
+    /// use hashbrown::hash_map::RustcEntry;
+    ///
+    /// let mut map: HashMap<&str, u32> = HashMap::new();
+    /// map.rustc_entry("poneyland").or_insert(12);
+    ///
+    /// if let RustcEntry::Occupied(o) = map.rustc_entry("poneyland") {
+    ///     assert_eq!(o.get(), &12);
+    /// }
+    /// ```
+    #[cfg_attr(feature = "inline-more", inline)]
+    pub fn get(&self) -> &V {
+        unsafe { &self.elem.as_ref().1 }
+    }
+
+    /// Gets a mutable reference to the value in the entry.
+    ///
+    /// If you need a reference to the `RustcOccupiedEntry` which may outlive the
+    /// destruction of the `RustcEntry` value, see [`into_mut`].
+    ///
+    /// [`into_mut`]: #method.into_mut
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use hashbrown::HashMap;
+    /// use hashbrown::hash_map::RustcEntry;
+    ///
+    /// let mut map: HashMap<&str, u32> = HashMap::new();
+    /// map.rustc_entry("poneyland").or_insert(12);
+    ///
+    /// assert_eq!(map["poneyland"], 12);
+    /// if let RustcEntry::Occupied(mut o) = map.rustc_entry("poneyland") {
+    ///     *o.get_mut() += 10;
+    ///     assert_eq!(*o.get(), 22);
+    ///
+    ///     // We can use the same RustcEntry multiple times.
+    ///     *o.get_mut() += 2;
+    /// }
+    ///
+    /// assert_eq!(map["poneyland"], 24);
+    /// ```
+    #[cfg_attr(feature = "inline-more", inline)]
+    pub fn get_mut(&mut self) -> &mut V {
+        unsafe { &mut self.elem.as_mut().1 }
+    }
+
+    /// Converts the RustcOccupiedEntry into a mutable reference to the value in the entry
+    /// with a lifetime bound to the map itself.
+    ///
+    /// If you need multiple references to the `RustcOccupiedEntry`, see [`get_mut`].
+    ///
+    /// [`get_mut`]: #method.get_mut
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use hashbrown::HashMap;
+    /// use hashbrown::hash_map::RustcEntry;
+    ///
+    /// let mut map: HashMap<&str, u32> = HashMap::new();
+    /// map.rustc_entry("poneyland").or_insert(12);
+    ///
+    /// assert_eq!(map["poneyland"], 12);
+    /// if let RustcEntry::Occupied(o) = map.rustc_entry("poneyland") {
+    ///     *o.into_mut() += 10;
+    /// }
+    ///
+    /// assert_eq!(map["poneyland"], 22);
+    /// ```
+    #[cfg_attr(feature = "inline-more", inline)]
+    pub fn into_mut(self) -> &'a mut V {
+        unsafe { &mut self.elem.as_mut().1 }
+    }
+
+    /// Sets the value of the entry, and returns the entry's old value.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use hashbrown::HashMap;
+    /// use hashbrown::hash_map::RustcEntry;
+    ///
+    /// let mut map: HashMap<&str, u32> = HashMap::new();
+    /// map.rustc_entry("poneyland").or_insert(12);
+    ///
+    /// if let RustcEntry::Occupied(mut o) = map.rustc_entry("poneyland") {
+    ///     assert_eq!(o.insert(15), 12);
+    /// }
+    ///
+    /// assert_eq!(map["poneyland"], 15);
+    /// ```
+    #[cfg_attr(feature = "inline-more", inline)]
+    pub fn insert(&mut self, value: V) -> V {
+        mem::replace(self.get_mut(), value)
+    }
+
+    /// Takes the value out of the entry, and returns it.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use hashbrown::HashMap;
+    /// use hashbrown::hash_map::RustcEntry;
+    ///
+    /// let mut map: HashMap<&str, u32> = HashMap::new();
+    /// map.rustc_entry("poneyland").or_insert(12);
+    ///
+    /// if let RustcEntry::Occupied(o) = map.rustc_entry("poneyland") {
+    ///     assert_eq!(o.remove(), 12);
+    /// }
+    ///
+    /// assert_eq!(map.contains_key("poneyland"), false);
+    /// ```
+    #[cfg_attr(feature = "inline-more", inline)]
+    pub fn remove(self) -> V {
+        self.remove_entry().1
+    }
+
+    /// Replaces the entry, returning the old key and value. The new key in the hash map will be
+    /// the key used to create this entry.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use hashbrown::hash_map::{RustcEntry, HashMap};
+    /// use std::rc::Rc;
+    ///
+    /// let mut map: HashMap<Rc<String>, u32> = HashMap::new();
+    /// map.insert(Rc::new("Stringthing".to_string()), 15);
+    ///
+    /// let my_key = Rc::new("Stringthing".to_string());
+    ///
+    /// if let RustcEntry::Occupied(entry) = map.rustc_entry(my_key) {
+    ///     // Also replace the key with a handle to our other key.
+    ///     let (old_key, old_value): (Rc<String>, u32) = entry.replace_entry(16);
+    /// }
+    ///
+    /// ```
+    #[cfg_attr(feature = "inline-more", inline)]
+    pub fn replace_entry(self, value: V) -> (K, V) {
+        let entry = unsafe { self.elem.as_mut() };
+
+        let old_key = mem::replace(&mut entry.0, self.key.unwrap());
+        let old_value = mem::replace(&mut entry.1, value);
+
+        (old_key, old_value)
+    }
+
+    /// Replaces the key in the hash map with the key used to create this entry.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use hashbrown::hash_map::{RustcEntry, HashMap};
+    /// use std::rc::Rc;
+    ///
+    /// let mut map: HashMap<Rc<String>, u32> = HashMap::new();
+    /// let mut known_strings: Vec<Rc<String>> = Vec::new();
+    ///
+    /// // Initialise known strings, run program, etc.
+    ///
+    /// reclaim_memory(&mut map, &known_strings);
+    ///
+    /// fn reclaim_memory(map: &mut HashMap<Rc<String>, u32>, known_strings: &[Rc<String>] ) {
+    ///     for s in known_strings {
+    ///         if let RustcEntry::Occupied(entry) = map.rustc_entry(s.clone()) {
+    ///             // Replaces the entry's key with our version of it in `known_strings`.
+    ///             entry.replace_key();
+    ///         }
+    ///     }
+    /// }
+    /// ```
+    #[cfg_attr(feature = "inline-more", inline)]
+    pub fn replace_key(self) -> K {
+        let entry = unsafe { self.elem.as_mut() };
+        mem::replace(&mut entry.0, self.key.unwrap())
+    }
+}
+
+impl<'a, K, V, A: Allocator + Clone> RustcVacantEntry<'a, K, V, A> {
+    /// Gets a reference to the key that would be used when inserting a value
+    /// through the `RustcVacantEntry`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use hashbrown::HashMap;
+    ///
+    /// let mut map: HashMap<&str, u32> = HashMap::new();
+    /// assert_eq!(map.rustc_entry("poneyland").key(), &"poneyland");
+    /// ```
+    #[cfg_attr(feature = "inline-more", inline)]
+    pub fn key(&self) -> &K {
+        &self.key
+    }
+
+    /// Take ownership of the key.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use hashbrown::HashMap;
+    /// use hashbrown::hash_map::RustcEntry;
+    ///
+    /// let mut map: HashMap<&str, u32> = HashMap::new();
+    ///
+    /// if let RustcEntry::Vacant(v) = map.rustc_entry("poneyland") {
+    ///     v.into_key();
+    /// }
+    /// ```
+    #[cfg_attr(feature = "inline-more", inline)]
+    pub fn into_key(self) -> K {
+        self.key
+    }
+
+    /// Sets the value of the entry with the RustcVacantEntry's key,
+    /// and returns a mutable reference to it.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use hashbrown::HashMap;
+    /// use hashbrown::hash_map::RustcEntry;
+    ///
+    /// let mut map: HashMap<&str, u32> = HashMap::new();
+    ///
+    /// if let RustcEntry::Vacant(o) = map.rustc_entry("poneyland") {
+    ///     o.insert(37);
+    /// }
+    /// assert_eq!(map["poneyland"], 37);
+    /// ```
+    #[cfg_attr(feature = "inline-more", inline)]
+    pub fn insert(self, value: V) -> &'a mut V {
+        unsafe {
+            let bucket = self.table.insert_no_grow(self.hash, (self.key, value));
+            &mut bucket.as_mut().1
+        }
+    }
+
+    /// Sets the value of the entry with the RustcVacantEntry's key,
+    /// and returns a RustcOccupiedEntry.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use hashbrown::HashMap;
+    /// use hashbrown::hash_map::RustcEntry;
+    ///
+    /// let mut map: HashMap<&str, u32> = HashMap::new();
+    ///
+    /// if let RustcEntry::Vacant(v) = map.rustc_entry("poneyland") {
+    ///     let o = v.insert_entry(37);
+    ///     assert_eq!(o.get(), &37);
+    /// }
+    /// ```
+    #[cfg_attr(feature = "inline-more", inline)]
+    pub fn insert_entry(self, value: V) -> RustcOccupiedEntry<'a, K, V, A> {
+        let bucket = unsafe { self.table.insert_no_grow(self.hash, (self.key, value)) };
+        RustcOccupiedEntry {
+            key: None,
+            elem: bucket,
+            table: self.table,
+        }
+    }
+}
+
+impl<K, V> IterMut<'_, K, V> {
+    /// Returns a iterator of references over the remaining items.
+    #[cfg_attr(feature = "inline-more", inline)]
+    pub fn rustc_iter(&self) -> Iter<'_, K, V> {
+        self.iter()
+    }
+}
+
+impl<K, V> IntoIter<K, V> {
+    /// Returns a iterator of references over the remaining items.
+    #[cfg_attr(feature = "inline-more", inline)]
+    pub fn rustc_iter(&self) -> Iter<'_, K, V> {
+        self.iter()
+    }
+}
+
+impl<K, V> Drain<'_, K, V> {
+    /// Returns a iterator of references over the remaining items.
+    #[cfg_attr(feature = "inline-more", inline)]
+    pub fn rustc_iter(&self) -> Iter<'_, K, V> {
+        self.iter()
+    }
+}
--- a/src/scopeguard.rs
+++ b/src/scopeguard.rs
@ -0,0 +1,74 @@
+// Extracted from the scopeguard crate
+use core::{
+    mem,
+    ops::{Deref, DerefMut},
+    ptr,
+};
+
+pub struct ScopeGuard<T, F>
+where
+    F: FnMut(&mut T),
+{
+    dropfn: F,
+    value: T,
+}
+
+#[inline]
+pub fn guard<T, F>(value: T, dropfn: F) -> ScopeGuard<T, F>
+where
+    F: FnMut(&mut T),
+{
+    ScopeGuard { dropfn, value }
+}
+
+impl<T, F> ScopeGuard<T, F>
+where
+    F: FnMut(&mut T),
+{
+    #[inline]
+    pub fn into_inner(guard: Self) -> T {
+        // Cannot move out of Drop-implementing types, so
+        // ptr::read the value and forget the guard.
+        unsafe {
+            let value = ptr::read(&guard.value);
+            // read the closure so that it is dropped, and assign it to a local
+            // variable to ensure that it is only dropped after the guard has
+            // been forgotten. (In case the Drop impl of the closure, or that
+            // of any consumed captured variable, panics).
+            let _dropfn = ptr::read(&guard.dropfn);
+            mem::forget(guard);
+            value
+        }
+    }
+}
+
+impl<T, F> Deref for ScopeGuard<T, F>
+where
+    F: FnMut(&mut T),
+{
+    type Target = T;
+    #[inline]
+    fn deref(&self) -> &T {
+        &self.value
+    }
+}
+
+impl<T, F> DerefMut for ScopeGuard<T, F>
+where
+    F: FnMut(&mut T),
+{
+    #[inline]
+    fn deref_mut(&mut self) -> &mut T {
+        &mut self.value
+    }
+}
+
+impl<T, F> Drop for ScopeGuard<T, F>
+where
+    F: FnMut(&mut T),
+{
+    #[inline]
+    fn drop(&mut self) {
+        (self.dropfn)(&mut self.value);
+    }
+}
--- a/src/set.rs
+++ b/src/set.rs
--- a/tests/hasher.rs
+++ b/tests/hasher.rs
@ -0,0 +1,65 @@
+//! Sanity check that alternate hashers work correctly.
+
+#![cfg(not(miri))] // FIXME: takes too long
+
+use hashbrown::HashSet;
+use std::hash::{BuildHasher, BuildHasherDefault, Hasher};
+
+fn check<S: BuildHasher + Default>() {
+    let range = 0..1_000;
+
+    let mut set = HashSet::<i32, S>::default();
+    set.extend(range.clone());
+
+    assert!(!set.contains(&i32::min_value()));
+    assert!(!set.contains(&(range.start - 1)));
+    for i in range.clone() {
+        assert!(set.contains(&i));
+    }
+    assert!(!set.contains(&range.end));
+    assert!(!set.contains(&i32::max_value()));
+}
+
+/// Use hashbrown's default hasher.
+#[test]
+fn default() {
+    check::<hashbrown::hash_map::DefaultHashBuilder>();
+}
+
+/// Use std's default hasher.
+#[test]
+fn random_state() {
+    check::<std::collections::hash_map::RandomState>();
+}
+
+/// Use a constant 0 hash.
+#[test]
+fn zero() {
+    #[derive(Default)]
+    struct ZeroHasher;
+
+    impl Hasher for ZeroHasher {
+        fn finish(&self) -> u64 {
+            0
+        }
+        fn write(&mut self, _: &[u8]) {}
+    }
+
+    check::<BuildHasherDefault<ZeroHasher>>();
+}
+
+/// Use a constant maximum hash.
+#[test]
+fn max() {
+    #[derive(Default)]
+    struct MaxHasher;
+
+    impl Hasher for MaxHasher {
+        fn finish(&self) -> u64 {
+            u64::max_value()
+        }
+        fn write(&mut self, _: &[u8]) {}
+    }
+
+    check::<BuildHasherDefault<MaxHasher>>();
+}
--- a/tests/rayon.rs
+++ b/tests/rayon.rs
@ -0,0 +1,533 @@
+#![cfg(feature = "rayon")]
+
+#[macro_use]
+extern crate lazy_static;
+
+use hashbrown::{HashMap, HashSet};
+use rayon::iter::{
+    IntoParallelIterator, IntoParallelRefIterator, IntoParallelRefMutIterator, ParallelExtend,
+    ParallelIterator,
+};
+
+macro_rules! assert_eq3 {
+    ($e1:expr, $e2:expr, $e3:expr) => {{
+        assert_eq!($e1, $e2);
+        assert_eq!($e1, $e3);
+        assert_eq!($e2, $e3);
+    }};
+}
+
+lazy_static! {
+    static ref MAP_EMPTY: HashMap<char, u32> = HashMap::new();
+    static ref MAP: HashMap<char, u32> = {
+        let mut m = HashMap::new();
+        m.insert('b', 20);
+        m.insert('a', 10);
+        m.insert('c', 30);
+        m.insert('e', 50);
+        m.insert('f', 60);
+        m.insert('d', 40);
+        m
+    };
+}
+
+#[test]
+fn map_seq_par_equivalence_iter_empty() {
+    let vec_seq = MAP_EMPTY.iter().collect::<Vec<_>>();
+    let vec_par = MAP_EMPTY.par_iter().collect::<Vec<_>>();
+
+    assert_eq3!(vec_seq, vec_par, []);
+}
+
+#[test]
+fn map_seq_par_equivalence_iter() {
+    let mut vec_seq = MAP.iter().collect::<Vec<_>>();
+    let mut vec_par = MAP.par_iter().collect::<Vec<_>>();
+
+    assert_eq!(vec_seq, vec_par);
+
+    // Do not depend on the exact order of values
+    let expected_sorted = [
+        (&'a', &10),
+        (&'b', &20),
+        (&'c', &30),
+        (&'d', &40),
+        (&'e', &50),
+        (&'f', &60),
+    ];
+
+    vec_seq.sort_unstable();
+    vec_par.sort_unstable();
+
+    assert_eq3!(vec_seq, vec_par, expected_sorted);
+}
+
+#[test]
+fn map_seq_par_equivalence_keys_empty() {
+    let vec_seq = MAP_EMPTY.keys().collect::<Vec<&char>>();
+    let vec_par = MAP_EMPTY.par_keys().collect::<Vec<&char>>();
+
+    let expected: [&char; 0] = [];
+
+    assert_eq3!(vec_seq, vec_par, expected);
+}
+
+#[test]
+fn map_seq_par_equivalence_keys() {
+    let mut vec_seq = MAP.keys().collect::<Vec<_>>();
+    let mut vec_par = MAP.par_keys().collect::<Vec<_>>();
+
+    assert_eq!(vec_seq, vec_par);
+
+    // Do not depend on the exact order of values
+    let expected_sorted = [&'a', &'b', &'c', &'d', &'e', &'f'];
+
+    vec_seq.sort_unstable();
+    vec_par.sort_unstable();
+
+    assert_eq3!(vec_seq, vec_par, expected_sorted);
+}
+
+#[test]
+fn map_seq_par_equivalence_values_empty() {
+    let vec_seq = MAP_EMPTY.values().collect::<Vec<_>>();
+    let vec_par = MAP_EMPTY.par_values().collect::<Vec<_>>();
+
+    let expected: [&u32; 0] = [];
+
+    assert_eq3!(vec_seq, vec_par, expected);
+}
+
+#[test]
+fn map_seq_par_equivalence_values() {
+    let mut vec_seq = MAP.values().collect::<Vec<_>>();
+    let mut vec_par = MAP.par_values().collect::<Vec<_>>();
+
+    assert_eq!(vec_seq, vec_par);
+
+    // Do not depend on the exact order of values
+    let expected_sorted = [&10, &20, &30, &40, &50, &60];
+
+    vec_seq.sort_unstable();
+    vec_par.sort_unstable();
+
+    assert_eq3!(vec_seq, vec_par, expected_sorted);
+}
+
+#[test]
+fn map_seq_par_equivalence_iter_mut_empty() {
+    let mut map1 = MAP_EMPTY.clone();
+    let mut map2 = MAP_EMPTY.clone();
+
+    let vec_seq = map1.iter_mut().collect::<Vec<_>>();
+    let vec_par = map2.par_iter_mut().collect::<Vec<_>>();
+
+    assert_eq3!(vec_seq, vec_par, []);
+}
+
+#[test]
+fn map_seq_par_equivalence_iter_mut() {
+    let mut map1 = MAP.clone();
+    let mut map2 = MAP.clone();
+
+    let mut vec_seq = map1.iter_mut().collect::<Vec<_>>();
+    let mut vec_par = map2.par_iter_mut().collect::<Vec<_>>();
+
+    assert_eq!(vec_seq, vec_par);
+
+    // Do not depend on the exact order of values
+    let expected_sorted = [
+        (&'a', &mut 10),
+        (&'b', &mut 20),
+        (&'c', &mut 30),
+        (&'d', &mut 40),
+        (&'e', &mut 50),
+        (&'f', &mut 60),
+    ];
+
+    vec_seq.sort_unstable();
+    vec_par.sort_unstable();
+
+    assert_eq3!(vec_seq, vec_par, expected_sorted);
+}
+
+#[test]
+fn map_seq_par_equivalence_values_mut_empty() {
+    let mut map1 = MAP_EMPTY.clone();
+    let mut map2 = MAP_EMPTY.clone();
+
+    let vec_seq = map1.values_mut().collect::<Vec<_>>();
+    let vec_par = map2.par_values_mut().collect::<Vec<_>>();
+
+    let expected: [&u32; 0] = [];
+
+    assert_eq3!(vec_seq, vec_par, expected);
+}
+
+#[test]
+fn map_seq_par_equivalence_values_mut() {
+    let mut map1 = MAP.clone();
+    let mut map2 = MAP.clone();
+
+    let mut vec_seq = map1.values_mut().collect::<Vec<_>>();
+    let mut vec_par = map2.par_values_mut().collect::<Vec<_>>();
+
+    assert_eq!(vec_seq, vec_par);
+
+    // Do not depend on the exact order of values
+    let expected_sorted = [&mut 10, &mut 20, &mut 30, &mut 40, &mut 50, &mut 60];
+
+    vec_seq.sort_unstable();
+    vec_par.sort_unstable();
+
+    assert_eq3!(vec_seq, vec_par, expected_sorted);
+}
+
+#[test]
+fn map_seq_par_equivalence_into_iter_empty() {
+    let vec_seq = MAP_EMPTY.clone().into_iter().collect::<Vec<_>>();
+    let vec_par = MAP_EMPTY.clone().into_par_iter().collect::<Vec<_>>();
+
+    assert_eq3!(vec_seq, vec_par, []);
+}
+
+#[test]
+fn map_seq_par_equivalence_into_iter() {
+    let mut vec_seq = MAP.clone().into_iter().collect::<Vec<_>>();
+    let mut vec_par = MAP.clone().into_par_iter().collect::<Vec<_>>();
+
+    assert_eq!(vec_seq, vec_par);
+
+    // Do not depend on the exact order of values
+    let expected_sorted = [
+        ('a', 10),
+        ('b', 20),
+        ('c', 30),
+        ('d', 40),
+        ('e', 50),
+        ('f', 60),
+    ];
+
+    vec_seq.sort_unstable();
+    vec_par.sort_unstable();
+
+    assert_eq3!(vec_seq, vec_par, expected_sorted);
+}
+
+lazy_static! {
+    static ref MAP_VEC_EMPTY: Vec<(char, u32)> = vec![];
+    static ref MAP_VEC: Vec<(char, u32)> = vec![
+        ('b', 20),
+        ('a', 10),
+        ('c', 30),
+        ('e', 50),
+        ('f', 60),
+        ('d', 40),
+    ];
+}
+
+#[test]
+fn map_seq_par_equivalence_collect_empty() {
+    let map_expected = MAP_EMPTY.clone();
+    let map_seq = MAP_VEC_EMPTY.clone().into_iter().collect::<HashMap<_, _>>();
+    let map_par = MAP_VEC_EMPTY
+        .clone()
+        .into_par_iter()
+        .collect::<HashMap<_, _>>();
+
+    assert_eq!(map_seq, map_par);
+    assert_eq!(map_seq, map_expected);
+    assert_eq!(map_par, map_expected);
+}
+
+#[test]
+fn map_seq_par_equivalence_collect() {
+    let map_expected = MAP.clone();
+    let map_seq = MAP_VEC.clone().into_iter().collect::<HashMap<_, _>>();
+    let map_par = MAP_VEC.clone().into_par_iter().collect::<HashMap<_, _>>();
+
+    assert_eq!(map_seq, map_par);
+    assert_eq!(map_seq, map_expected);
+    assert_eq!(map_par, map_expected);
+}
+
+lazy_static! {
+    static ref MAP_EXISTING_EMPTY: HashMap<char, u32> = HashMap::new();
+    static ref MAP_EXISTING: HashMap<char, u32> = {
+        let mut m = HashMap::new();
+        m.insert('b', 20);
+        m.insert('a', 10);
+        m
+    };
+    static ref MAP_EXTENSION_EMPTY: Vec<(char, u32)> = vec![];
+    static ref MAP_EXTENSION: Vec<(char, u32)> = vec![('c', 30), ('e', 50), ('f', 60), ('d', 40),];
+}
+
+#[test]
+fn map_seq_par_equivalence_existing_empty_extend_empty() {
+    let expected = HashMap::new();
+    let mut map_seq = MAP_EXISTING_EMPTY.clone();
+    let mut map_par = MAP_EXISTING_EMPTY.clone();
+
+    map_seq.extend(MAP_EXTENSION_EMPTY.iter().copied());
+    map_par.par_extend(MAP_EXTENSION_EMPTY.par_iter().copied());
+
+    assert_eq3!(map_seq, map_par, expected);
+}
+
+#[test]
+fn map_seq_par_equivalence_existing_empty_extend() {
+    let expected = MAP_EXTENSION.iter().copied().collect::<HashMap<_, _>>();
+    let mut map_seq = MAP_EXISTING_EMPTY.clone();
+    let mut map_par = MAP_EXISTING_EMPTY.clone();
+
+    map_seq.extend(MAP_EXTENSION.iter().copied());
+    map_par.par_extend(MAP_EXTENSION.par_iter().copied());
+
+    assert_eq3!(map_seq, map_par, expected);
+}
+
+#[test]
+fn map_seq_par_equivalence_existing_extend_empty() {
+    let expected = MAP_EXISTING.clone();
+    let mut map_seq = MAP_EXISTING.clone();
+    let mut map_par = MAP_EXISTING.clone();
+
+    map_seq.extend(MAP_EXTENSION_EMPTY.iter().copied());
+    map_par.par_extend(MAP_EXTENSION_EMPTY.par_iter().copied());
+
+    assert_eq3!(map_seq, map_par, expected);
+}
+
+#[test]
+fn map_seq_par_equivalence_existing_extend() {
+    let expected = MAP.clone();
+    let mut map_seq = MAP_EXISTING.clone();
+    let mut map_par = MAP_EXISTING.clone();
+
+    map_seq.extend(MAP_EXTENSION.iter().copied());
+    map_par.par_extend(MAP_EXTENSION.par_iter().copied());
+
+    assert_eq3!(map_seq, map_par, expected);
+}
+
+lazy_static! {
+    static ref SET_EMPTY: HashSet<char> = HashSet::new();
+    static ref SET: HashSet<char> = {
+        let mut s = HashSet::new();
+        s.insert('b');
+        s.insert('a');
+        s.insert('c');
+        s.insert('e');
+        s.insert('f');
+        s.insert('d');
+        s
+    };
+}
+
+#[test]
+fn set_seq_par_equivalence_iter_empty() {
+    let vec_seq = SET_EMPTY.iter().collect::<Vec<_>>();
+    let vec_par = SET_EMPTY.par_iter().collect::<Vec<_>>();
+
+    let expected: [&char; 0] = [];
+
+    assert_eq3!(vec_seq, vec_par, expected);
+}
+
+#[test]
+fn set_seq_par_equivalence_iter() {
+    let mut vec_seq = SET.iter().collect::<Vec<_>>();
+    let mut vec_par = SET.par_iter().collect::<Vec<_>>();
+
+    assert_eq!(vec_seq, vec_par);
+
+    // Do not depend on the exact order of values
+    let expected_sorted = [&'a', &'b', &'c', &'d', &'e', &'f'];
+
+    vec_seq.sort_unstable();
+    vec_par.sort_unstable();
+
+    assert_eq3!(vec_seq, vec_par, expected_sorted);
+}
+
+#[test]
+fn set_seq_par_equivalence_into_iter_empty() {
+    let vec_seq = SET_EMPTY.clone().into_iter().collect::<Vec<_>>();
+    let vec_par = SET_EMPTY.clone().into_par_iter().collect::<Vec<_>>();
+
+    assert_eq3!(vec_seq, vec_par, []);
+}
+
+#[test]
+fn set_seq_par_equivalence_into_iter() {
+    let mut vec_seq = SET.clone().into_iter().collect::<Vec<_>>();
+    let mut vec_par = SET.clone().into_par_iter().collect::<Vec<_>>();
+
+    assert_eq!(vec_seq, vec_par);
+
+    // Do not depend on the exact order of values
+    let expected_sorted = ['a', 'b', 'c', 'd', 'e', 'f'];
+
+    vec_seq.sort_unstable();
+    vec_par.sort_unstable();
+
+    assert_eq3!(vec_seq, vec_par, expected_sorted);
+}
+
+lazy_static! {
+    static ref SET_VEC_EMPTY: Vec<char> = vec![];
+    static ref SET_VEC: Vec<char> = vec!['b', 'a', 'c', 'e', 'f', 'd',];
+}
+
+#[test]
+fn set_seq_par_equivalence_collect_empty() {
+    let set_expected = SET_EMPTY.clone();
+    let set_seq = SET_VEC_EMPTY.clone().into_iter().collect::<HashSet<_>>();
+    let set_par = SET_VEC_EMPTY
+        .clone()
+        .into_par_iter()
+        .collect::<HashSet<_>>();
+
+    assert_eq!(set_seq, set_par);
+    assert_eq!(set_seq, set_expected);
+    assert_eq!(set_par, set_expected);
+}
+
+#[test]
+fn set_seq_par_equivalence_collect() {
+    let set_expected = SET.clone();
+    let set_seq = SET_VEC.clone().into_iter().collect::<HashSet<_>>();
+    let set_par = SET_VEC.clone().into_par_iter().collect::<HashSet<_>>();
+
+    assert_eq!(set_seq, set_par);
+    assert_eq!(set_seq, set_expected);
+    assert_eq!(set_par, set_expected);
+}
+
+lazy_static! {
+    static ref SET_EXISTING_EMPTY: HashSet<char> = HashSet::new();
+    static ref SET_EXISTING: HashSet<char> = {
+        let mut s = HashSet::new();
+        s.insert('b');
+        s.insert('a');
+        s
+    };
+    static ref SET_EXTENSION_EMPTY: Vec<char> = vec![];
+    static ref SET_EXTENSION: Vec<char> = vec!['c', 'e', 'f', 'd',];
+}
+
+#[test]
+fn set_seq_par_equivalence_existing_empty_extend_empty() {
+    let expected = HashSet::new();
+    let mut set_seq = SET_EXISTING_EMPTY.clone();
+    let mut set_par = SET_EXISTING_EMPTY.clone();
+
+    set_seq.extend(SET_EXTENSION_EMPTY.iter().copied());
+    set_par.par_extend(SET_EXTENSION_EMPTY.par_iter().copied());
+
+    assert_eq3!(set_seq, set_par, expected);
+}
+
+#[test]
+fn set_seq_par_equivalence_existing_empty_extend() {
+    let expected = SET_EXTENSION.iter().copied().collect::<HashSet<_>>();
+    let mut set_seq = SET_EXISTING_EMPTY.clone();
+    let mut set_par = SET_EXISTING_EMPTY.clone();
+
+    set_seq.extend(SET_EXTENSION.iter().copied());
+    set_par.par_extend(SET_EXTENSION.par_iter().copied());
+
+    assert_eq3!(set_seq, set_par, expected);
+}
+
+#[test]
+fn set_seq_par_equivalence_existing_extend_empty() {
+    let expected = SET_EXISTING.clone();
+    let mut set_seq = SET_EXISTING.clone();
+    let mut set_par = SET_EXISTING.clone();
+
+    set_seq.extend(SET_EXTENSION_EMPTY.iter().copied());
+    set_par.par_extend(SET_EXTENSION_EMPTY.par_iter().copied());
+
+    assert_eq3!(set_seq, set_par, expected);
+}
+
+#[test]
+fn set_seq_par_equivalence_existing_extend() {
+    let expected = SET.clone();
+    let mut set_seq = SET_EXISTING.clone();
+    let mut set_par = SET_EXISTING.clone();
+
+    set_seq.extend(SET_EXTENSION.iter().copied());
+    set_par.par_extend(SET_EXTENSION.par_iter().copied());
+
+    assert_eq3!(set_seq, set_par, expected);
+}
+
+lazy_static! {
+    static ref SET_A: HashSet<char> = ['a', 'b', 'c', 'd'].iter().copied().collect();
+    static ref SET_B: HashSet<char> = ['a', 'b', 'e', 'f'].iter().copied().collect();
+    static ref SET_DIFF_AB: HashSet<char> = ['c', 'd'].iter().copied().collect();
+    static ref SET_DIFF_BA: HashSet<char> = ['e', 'f'].iter().copied().collect();
+    static ref SET_SYMM_DIFF_AB: HashSet<char> = ['c', 'd', 'e', 'f'].iter().copied().collect();
+    static ref SET_INTERSECTION_AB: HashSet<char> = ['a', 'b'].iter().copied().collect();
+    static ref SET_UNION_AB: HashSet<char> =
+        ['a', 'b', 'c', 'd', 'e', 'f'].iter().copied().collect();
+}
+
+#[test]
+fn set_seq_par_equivalence_difference() {
+    let diff_ab_seq = SET_A.difference(&*SET_B).copied().collect::<HashSet<_>>();
+    let diff_ab_par = SET_A
+        .par_difference(&*SET_B)
+        .copied()
+        .collect::<HashSet<_>>();
+
+    assert_eq3!(diff_ab_seq, diff_ab_par, *SET_DIFF_AB);
+
+    let diff_ba_seq = SET_B.difference(&*SET_A).copied().collect::<HashSet<_>>();
+    let diff_ba_par = SET_B
+        .par_difference(&*SET_A)
+        .copied()
+        .collect::<HashSet<_>>();
+
+    assert_eq3!(diff_ba_seq, diff_ba_par, *SET_DIFF_BA);
+}
+
+#[test]
+fn set_seq_par_equivalence_symmetric_difference() {
+    let symm_diff_ab_seq = SET_A
+        .symmetric_difference(&*SET_B)
+        .copied()
+        .collect::<HashSet<_>>();
+    let symm_diff_ab_par = SET_A
+        .par_symmetric_difference(&*SET_B)
+        .copied()
+        .collect::<HashSet<_>>();
+
+    assert_eq3!(symm_diff_ab_seq, symm_diff_ab_par, *SET_SYMM_DIFF_AB);
+}
+
+#[test]
+fn set_seq_par_equivalence_intersection() {
+    let intersection_ab_seq = SET_A.intersection(&*SET_B).copied().collect::<HashSet<_>>();
+    let intersection_ab_par = SET_A
+        .par_intersection(&*SET_B)
+        .copied()
+        .collect::<HashSet<_>>();
+
+    assert_eq3!(
+        intersection_ab_seq,
+        intersection_ab_par,
+        *SET_INTERSECTION_AB
+    );
+}
+
+#[test]
+fn set_seq_par_equivalence_union() {
+    let union_ab_seq = SET_A.union(&*SET_B).copied().collect::<HashSet<_>>();
+    let union_ab_par = SET_A.par_union(&*SET_B).copied().collect::<HashSet<_>>();
+
+    assert_eq3!(union_ab_seq, union_ab_par, *SET_UNION_AB);
+}
--- a/tests/serde.rs
+++ b/tests/serde.rs
@ -0,0 +1,65 @@
+#![cfg(feature = "serde")]
+
+use core::hash::BuildHasherDefault;
+use fnv::FnvHasher;
+use hashbrown::{HashMap, HashSet};
+use serde_test::{assert_tokens, Token};
+
+// We use FnvHash for this test because we rely on the ordering
+type FnvHashMap<K, V> = HashMap<K, V, BuildHasherDefault<FnvHasher>>;
+type FnvHashSet<T> = HashSet<T, BuildHasherDefault<FnvHasher>>;
+
+#[test]
+fn map_serde_tokens_empty() {
+    let map = FnvHashMap::<char, u32>::default();
+
+    assert_tokens(&map, &[Token::Map { len: Some(0) }, Token::MapEnd]);
+}
+
+#[test]
+fn map_serde_tokens() {
+    let mut map = FnvHashMap::default();
+    map.insert('b', 20);
+    map.insert('a', 10);
+    map.insert('c', 30);
+
+    assert_tokens(
+        &map,
+        &[
+            Token::Map { len: Some(3) },
+            Token::Char('a'),
+            Token::I32(10),
+            Token::Char('c'),
+            Token::I32(30),
+            Token::Char('b'),
+            Token::I32(20),
+            Token::MapEnd,
+        ],
+    );
+}
+
+#[test]
+fn set_serde_tokens_empty() {
+    let set = FnvHashSet::<u32>::default();
+
+    assert_tokens(&set, &[Token::Seq { len: Some(0) }, Token::SeqEnd]);
+}
+
+#[test]
+fn set_serde_tokens() {
+    let mut set = FnvHashSet::default();
+    set.insert(20);
+    set.insert(10);
+    set.insert(30);
+
+    assert_tokens(
+        &set,
+        &[
+            Token::Seq { len: Some(3) },
+            Token::I32(30),
+            Token::I32(20),
+            Token::I32(10),
+            Token::SeqEnd,
+        ],
+    );
+}
--- a/tests/set.rs
+++ b/tests/set.rs
@ -0,0 +1,34 @@
+#![cfg(not(miri))] // FIXME: takes too long
+
+use hashbrown::HashSet;
+use rand::{distributions::Alphanumeric, rngs::SmallRng, Rng, SeedableRng};
+use std::iter;
+
+#[test]
+fn test_hashset_insert_remove() {
+    let mut m: HashSet<Vec<char>> = HashSet::new();
+    let seed = u64::from_le_bytes(*b"testseed");
+
+    let rng = &mut SmallRng::seed_from_u64(seed);
+    let tx: Vec<Vec<char>> = iter::repeat_with(|| {
+        rng.sample_iter(&Alphanumeric)
+            .take(32)
+            .map(char::from)
+            .collect()
+    })
+    .take(4096)
+    .collect();
+
+    // more readable with explicit `true` / `false`
+    #[allow(clippy::bool_assert_comparison)]
+    for _ in 0..32 {
+        for x in &tx {
+            assert_eq!(m.contains(x), false);
+            assert_eq!(m.insert(x.clone()), true);
+        }
+        for (i, x) in tx.iter().enumerate() {
+            println!("removing {} {:?}", i, x);
+            assert_eq!(m.remove(x), true);
+        }
+    }
+}
				`@ -0,0 +1 @@`
				`doc-valid-idents = [ "CppCon", "SwissTable", "SipHash", "HashDoS" ]`
				`@ -0,0 +1 @@`
				`{"package":"Could not get crate checksum","files":{}}`