Adding upstream version 86.0.1.upstream/86.0.1upstream

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

125 files changed, 5583 insertions, 0 deletions

diff --git a/third_party/rust/pin-project/.cargo-checksum.json b/third_party/rust/pin-project/.cargo-checksum.json
new file mode 100644
index 0000000000..05286ce214
--- /dev/null
+++ b/third_party/rust/pin-project/.cargo-checksum.json
@@ -0,0 +1 @@
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.rs":"56d8f0eb22d547f5f9954bd37ca31c5b58b9d60bc5dc5b8c70f7d73cf8844649","tests/ui/pin_project/conflict-unpin.stderr":"3aed74d6895be645c3c81cdfc5f9a6ebfe3e7fa92713998b1a5dadf9b26c9709","tests/ui/pin_project/duplicate-argument.rs":"e4e3109d9afc23ebf1cbc5f87d5fb4749a460b1a2c6a583ca9c6ac6f9e163736","tests/ui/pin_project/duplicate-argument.stderr":"a44525259d06247b194f3906d90b7fb409fc9d49e0e1446a3dc53c147868938d","tests/ui/pin_project/invalid.rs":"11bbdcf64d87d42b8a26b5ae48139df1320b047f4b2b7dba19228531d60ac16e","tests/ui/pin_project/invalid.stderr":"24aef9cadd25685c4afbeff7d88a985e1c9fa873e300ad725143af6d5678b689","tests/ui/pin_project/overlapping_unpin_struct.rs":"d563525d945e970841002cc1f93822f50cfb9c81586363e2038a9aabf0a66ad3","tests/ui/pin_project/overlapping_unpin_struct.stderr":"223abbb21ae2dcc6711e0dc813c70dcb38f750ab001964ca0530622834a12d75","tests/ui/pin_project/packed.rs":"279fe7005a0a69bbafd2adc1d4b1e444c0e7dd284e101d0986190039bbb05017","tests/ui/pin_project/packed.stderr":"e71e8148eeb4ffe4d8e8fce0ab8d33da0bf7de993a64df0977bb473413773b62","tests/ui/pin_project/packed_sneaky-1.rs":"203499e8143f40fdcc61dbca31f96dbf3fa1bb91233dcc712be298b7765fc46f","tests/ui/pin_project/packed_sneaky-1.stderr":"ac490bd0b67b3740e9bac68115c07826ee9b6e6b99b35f9374f8ee7c6dfef7a8","tests/ui/pin_project/packed_sneaky-2.rs":"0716a5a40005b3ac558871804ed9ef809565fda35eef24c1c95d97ea5e9be6d7","tests/ui/pin_project/packed_sneaky-2.stderr":"7d9a3be663ed010b2d510c0d5a5a719df282630362786d73832c90276417b140","tests/ui/pin_project/private_in_public-enum.rs":"cf9b494164733abf98b9324141cfe666e734bb9d105166bd0f944d49452072ba","tests/ui/pin_project/private_in_public-enum.stderr":"ce58e5f6fd0d38e8f4d4215206aa341f11288442243715ca25803ab850ce3764","tests/ui/pin_project/proper_unpin.rs":"acc73e5f22373f4e91f1cfe652fd4ef27413e2dd0d5aa954b707aaa6ef15ec15","tests/ui/pin_project/proper_unpin.stderr":"69f80463679a6e899206ddd95438e12ba669060d0e957e87fc679ce9dd97269f","tests/ui/pin_project/remove-attr-from-field.rs":"e99ac2d655bde1a98e422fc1a0f7469eccbc0854abfe483c30b8464f30569533","tests/ui/pin_project/remove-attr-from-field.stderr":"bbf41a598b03a19dbd329affe7be05ad8f9c33071a5d805d2566f2c66303af00","tests/ui/pin_project/remove-attr-from-struct.rs":"2ecf262048e41551cde96f1fc419c89b93ba0bf15bd30eb13744e469655fb44b","tests/ui/pin_project/remove-attr-from-struct.stderr":"53527fbce3fe824952da9a6a4324dc46f0484452ac043cf1260de5193b7b0688","tests/ui/pin_project/safe_packed_borrows.rs":"01fae92d21252650befaaaac567b518641d45638a203a454a6735661f5f9d1b5","tests/ui/pin_project/safe_packed_borrows.stderr":"554bc0f7587ff26b22f51ca5de9786422fdb2a0bc4ea16c66b979bf0181e7cc6","tests/ui/pin_project/unpin_sneaky.rs":"7920d4e05142a0277bd9daeb40457586ec3be27372d797087aa9b693607efacd","tests/ui/pin_project/unpin_sneaky.stderr":"9e550974a9a5543749cbf4f2053ce3ed1bc2fbef95cc325e8cb5c7e9a09770e4","tests/ui/pin_project/unsupported.rs":"f10b8566fc25e971ebd16e0ec3be4e7371db637e3848d19840f11fef0cf0fc3d","tests/ui/pin_project/unsupported.stderr":"26cfc632dcef0bcf7f9cddb9db785f0931984f733224723e58f9490b2035e0d7","tests/ui/pinned_drop/forget-pinned-drop-impl.rs":"abea9c1477e0cd589c05b4405ecbf6f2b03e4de4ce36e57ea3c309e1e5db1a7a","tests/ui/pinned_drop/forget-pinned-drop-impl.stderr":"05d0eedce594fd5d4d204403bf1d5d62881c816449e31093fa4f90ed9d73b258","tests/ui/pinned_drop/invalid.rs":"80c3f83df81b2ebc0df4f31894f32c13813e1dcb0a08004f4d8777b4cacb258e","tests/ui/pinned_drop/invalid.stderr":"cb71637d4fd4e203897a281f7321e0e2ab604fabef1d390999d9dad84bc133d3","tests/ui/pinned_drop/pinned-drop-no-attr-arg.rs":"6097441094e69ae18887171c8528900ae018707d3cfa03e2d3dc13fd06c58837","tests/ui/pinned_drop/pinned-drop-no-attr-arg.stderr":"af119418b4a88f62d538e248313596b0c528ceedaf79b94f99207f00860a634d","tests/ui/pinned_drop/ref-self.rs":"1252d4f1fd70cdff7b0fe3a105d99f5b5b6d1ccedff4f8b8b72a8c472a41a8bf","tests/ui/pinned_drop/ref-self.stderr":"ce4ae36ed0748d98e86971cd2cf1e78cc1a41b856d18ae3810a5c225a117d974","tests/ui/pinned_drop/self.rs":"4d059f302103eb6edc5a1f0a7d60a22c51612d8049ac16655ea4e80b9e532d09","tests/ui/pinned_drop/self.stderr":"5b4aede646efac30bd4b7fa4c40645c6ea1cdb733db15b6498631a7d9f2a2c59","tests/ui/pinned_drop/unsafe-code.rs":"8d0602d5f06ae3760caf094a6a211e9cc8526c261d6c39085d3f9a3c0ef6dd75","tests/ui/pinned_drop/unsafe-code.stderr":"ab3e8552f1643feacac3546b4f87ea87d59debc8b873d9002a5536ec248de090","tests/ui/project/ambiguous-let.rs":"151baeb436ddd82fcbe0892468400ffa8ed3edde7f722429d90fe916287d18cf","tests/ui/project/ambiguous-let.stderr":"e08aa651e416d9d410deef4f1b91b6204c107ca50a66ec17858c20c2e67c8db3","tests/ui/project/invalid.rs":"aa3f4f0a4b74ba92896f0b08ff8bd50ead31f9ebf4e4ed146b8b9e3c6666d365","tests/ui/project/invalid.stderr":"6b58ebe69f02dd9ce02c059197954f565e71d9f12d42572f89d5770d340130bc","tests/ui/project/type-mismatch.rs":"b358d3ea01a1a7434c23cb787e53179ee913b39173e55d3175d8782bee896312","tests/ui/project/type-mismatch.stderr":"dcebbb50aaa638d650dca10701df52e8d38baa01c801c32d5c20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\ No newline at end of file
diff --git a/third_party/rust/pin-project/CHANGELOG.md b/third_party/rust/pin-project/CHANGELOG.md
new file mode 100644
index 0000000000..195948ac30
--- /dev/null
+++ b/third_party/rust/pin-project/CHANGELOG.md
@@ -0,0 +1,363 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+This project adheres to [Semantic Versioning](https://semver.org).
+
+## [Unreleased]
+
+## [0.4.9] - 2020-04-14
+
+* [Fixed lifetime inference error when associated types are used in fields.][188]
+
+* [Fixed compile error with tuple structs with `where` clauses.][186]
+
+* [`#[project]` attribute can now be used for `if let` expressions.][181]
+
+[188]: https://github.com/taiki-e/pin-project/pull/188
+[186]: https://github.com/taiki-e/pin-project/pull/186
+[181]: https://github.com/taiki-e/pin-project/pull/181
+
+## [0.4.8] - 2020-01-27
+
+* [Ensured that users cannot implement `PinnedDrop` without proper attribute argument.][180]
+
+[180]: https://github.com/taiki-e/pin-project/pull/180
+
+## [0.4.7] - 2020-01-20
+
+* [Fixed support for lifetime bounds.][176]
+
+[176]: https://github.com/taiki-e/pin-project/pull/176
+
+## [0.4.6] - 2019-11-20
+
+* [Fixed compile error when there is `Self` in the where clause.][169]
+
+[169]: https://github.com/taiki-e/pin-project/pull/169
+
+## [0.4.5] - 2019-10-21
+
+* [Fixed compile error with `dyn` types.][158]
+
+[158]: https://github.com/taiki-e/pin-project/pull/158
+
+## [0.4.4] - 2019-10-17
+
+* [Fixed an issue where `PinnedDrop` implementations can call unsafe code without an unsafe block.][149]
+
+[149]: https://github.com/taiki-e/pin-project/pull/149
+
+## [0.4.3] - 2019-10-15 - YANKED
+
+* [`#[pin_project]` can now interoperate with `#[cfg_attr()]`.][135]
+
+* [`#[pin_project]` can now interoperate with `#[cfg()]` on tuple structs and tuple variants.][135]
+
+* [Fixed support for DSTs(Dynamically Sized Types) on `#[pin_project(UnsafeUnpin)]`][120]
+
+[120]: https://github.com/taiki-e/pin-project/pull/120
+[135]: https://github.com/taiki-e/pin-project/pull/135
+
+## [0.4.2] - 2019-09-29 - YANKED
+
+* [Fixed support for DSTs(Dynamically Sized Types).][113]
+
+[113]: https://github.com/taiki-e/pin-project/pull/113
+
+## [0.4.1] - 2019-09-26 - YANKED
+
+* [Fixed an issue that caused an error when using `#[pin_project]` on a type that has `#[pin]` + `!Unpin` field with no generics or lifetime.][111]
+
+[111]: https://github.com/taiki-e/pin-project/pull/111
+
+## [0.4.0] - 2019-09-25 - YANKED
+
+* [**Pin projection has become a safe operation.**][18] In the absence of other unsafe code that you write, it is impossible to cause undefined behavior.
+
+* `#[unsafe_project]` attribute has been replaced with `#[pin_project]` attribute. ([#18][18], [#33][33])
+
+* [The `Unpin` argument has been removed - an `Unpin` impl is now generated by default.][18]
+
+* Drop impls must be specified with `#[pinned_drop]` instead of via a normal `Drop` impl. ([#18][18], [#33][33], [#86][86])
+
+* [`Unpin` impls must be specified with an impl of `UnsafeUnpin`, instead of implementing the normal `Unpin` trait.][18]
+
+* [`#[pin_project]` attribute now determines the visibility of the projection type/method is based on the original type.][96]
+
+* [`#[pin_project]` can now be used for public type with private field types.][53]
+
+* [`#[pin_project]` can now interoperate with `#[cfg()]`.][77]
+
+* [Added `project_ref` method to `#[pin_project]` types.][93]
+
+* [Added `#[project_ref]` attribute.][93]
+
+* [Removed "project_attr" feature and always enable `#[project]` attribute.][94]
+
+* [`#[project]` attribute can now be used for `impl` blocks.][46]
+
+* [`#[project]` attribute can now be used for `use` statements.][85]
+
+* [`#[project]` attribute now supports `match` expressions at the position of the initializer expression of `let` expressions.][51]
+
+Changes since the 0.4.0-beta.1 release:
+
+* [Fixed an issue that caused an error when using `#[pin_project(UnsafeUnpin)]` and not providing a manual `UnsafeUnpin` implementation on a type with no generics or lifetime.][107]
+
+[18]: https://github.com/taiki-e/pin-project/pull/18
+[33]: https://github.com/taiki-e/pin-project/pull/107
+[107]: https://github.com/taiki-e/pin-project/pull/107
+
+## [0.4.0-beta.1] - 2019-09-21
+
+* [Changed the argument type of project method back to `self: Pin<&mut Self>`.][90]
+
+* [Removed "project_attr" feature and always enable `#[project]` attribute.][94]
+
+* [Removed "renamed" feature.][100]
+
+* [`#[project]` attribute can now be used for `use` statements.][85]
+
+* [Added `project_ref` method and `#[project_ref]` attribute.][93]
+
+* [`#[pin_project]` attribute now determines the visibility of the projection type/method is based on the original type.][96]
+
+[85]: https://github.com/taiki-e/pin-project/pull/85
+[90]: https://github.com/taiki-e/pin-project/pull/90
+[93]: https://github.com/taiki-e/pin-project/pull/93
+[94]: https://github.com/taiki-e/pin-project/pull/94
+[96]: https://github.com/taiki-e/pin-project/pull/96
+[100]: https://github.com/taiki-e/pin-project/pull/100
+
+## [0.4.0-alpha.11] - 2019-09-11
+
+* [Changed #[pinned_drop] to trait implementation.][86]
+
+  ```rust
+  #[pinned_drop]
+  impl<T> PinnedDrop for Foo<'_, T> {
+      fn drop(mut self: Pin<&mut Self>) {
+          **self.project().was_dropped = true;
+      }
+  }
+  ```
+
+* Added some examples and generated code.
+
+* Improve error messages.
+
+[86]: https://github.com/taiki-e/pin-project/pull/86
+
+## [0.4.0-alpha.10] - 2019-09-07
+
+* [`#[pin_project]` can now interoperate with `#[cfg()]`.][77]
+
+* Improved documentation.
+
+[77]: https://github.com/taiki-e/pin-project/pull/77
+
+## [0.4.0-alpha.9] - 2019-09-05
+
+* [Added 'project_into' method to #[pin_project] types][69]. This can be useful when returning a pin projection from a method.
+  ```rust
+  fn get_pin_mut(self: Pin<&mut Self>) -> Pin<&mut T> {
+      self.project_into().pinned
+  }
+  ```
+
+* [Prevented UnpinStruct from appearing in the document by default.][71] See [taiki-e/pin-project#71][71] for more details.
+
+[69]: https://github.com/taiki-e/pin-project/pull/69
+[71]: https://github.com/taiki-e/pin-project/pull/69
+
+## [0.4.0-alpha.8] - 2019-09-03
+
+* [Improved document of generated code.][62]. Also added an option to control the document of generated code. See [taiki-e/pin-project#62][62] for more details.
+
+* [Improved error messages][61]
+
+[61]: https://github.com/taiki-e/pin-project/pull/61
+[62]: https://github.com/taiki-e/pin-project/pull/62
+
+## [0.4.0-alpha.7] - 2019-09-02
+
+* [Applied `#[allow(dead_code)]` to generated types.][57]
+
+[57]: https://github.com/taiki-e/pin-project/pull/57
+
+## [0.4.0-alpha.6] - 2019-09-01
+
+* [Allowed using `#[pin_project]` type with private field types][53]
+
+[53]: https://github.com/taiki-e/pin-project/pull/53
+
+## [0.4.0-alpha.5] - 2019-08-24
+
+* [`#[project]` attribute now supports `match` expressions at the position of the initializer expression of `let` expressions.][51]
+
+[51]: https://github.com/taiki-e/pin-project/pull/51
+
+## [0.4.0-alpha.4] - 2019-08-23
+
+* Avoided clippy::drop_bounds lint in generated code.
+
+## [0.4.0-alpha.3] - 2019-08-23
+
+* [Changed `project` method generated by `#[pin_project]` attribute to take an `&mut Pin<&mut Self>` argument.][47]
+
+* [`#[project]` attribute can now be used for impl blocks.][46]
+
+* [`#[pin_project]` attribute can now detect that the type used does not have its own drop implementation without actually implementing drop.][48] This removed some restrictions.
+
+[46]: https://github.com/taiki-e/pin-project/pull/46
+[47]: https://github.com/taiki-e/pin-project/pull/47
+[48]: https://github.com/taiki-e/pin-project/pull/48
+
+## [0.4.0-alpha.2] - 2019-08-13
+
+* Updated `proc-macro2`, `syn`, and `quote` to 1.0.
+
+## [0.4.0-alpha.1] - 2019-08-11
+
+* **Pin projection has become a safe operation.**
+
+* `#[unsafe_project]` has been replaced with `#[pin_project]`.
+
+* The `Unpin` argument has been removed - an `Unpin` impl is now generated by default.
+
+* Drop impls must be specified with `#[pinned_drop]` instead of via a normal `Drop` impl.
+
+* `Unpin` impls must be specified with an impl of `UnsafeUnpin`, instead of implementing the normal `Unpin` trait.
+
+* Made `#[project]` attribute disabled by default.
+
+See also [tracking issue for 0.4 release][21].
+
+[21]: https://github.com/taiki-e/pin-project/issues/21
+
+## [0.3.5] - 2019-08-14
+
+* Updated `proc-macro2`, `syn`, and `quote` to 1.0.
+
+## [0.3.4] - 2019-07-21
+
+* Improved error messages.
+
+## [0.3.3] - 2019-07-15 - YANKED
+
+* Improved error messages.
+
+## [0.3.2] - 2019-03-30
+
+* Avoided suffixes on tuple index.
+
+## [0.3.1] - 2019-03-02
+
+* Improved documentation.
+
+* Updated minimum `syn` version to 0.15.22.
+
+## [0.3.0] - 2019-02-20
+
+* Removed `unsafe_fields` attribute.
+
+* Removed `unsafe_variants` attribute.
+
+## [0.2.2] - 2019-02-20
+
+* Fixed a bug that generates incorrect code for the some structures with trait bounds on type generics.
+
+## [0.2.1] - 2019-02-20
+
+* Fixed a bug that generates incorrect code for the structures with where clause and associated type fields.
+
+## [0.2.0] - 2019-02-11
+
+* Made `unsafe_fields` optional.
+
+* Improved documentation.
+
+## [0.1.8] - 2019-02-02
+
+* Added the feature to create projected enums to `unsafe_project`.
+
+* Added `project` attribute to support pattern matching.
+
+## [0.1.7] - 2019-01-19
+
+* Fixed documentation.
+
+## [0.1.6] - 2019-01-19
+
+* `unsafe_fields` can now opt-out.
+
+* Added `unsafe_variants` attribute. This attribute is available if pin-project is built with the "unsafe_variants" feature.
+
+## [0.1.5] - 2019-01-17
+
+* Added support for tuple struct to `unsafe_project`.
+
+## [0.1.4] - 2019-01-12
+
+* Added options for automatically implementing `Unpin` to both `unsafe_project` and `unsafe_fields`.
+
+## [0.1.3] - 2019-01-11
+
+* Fixed dependencies.
+
+* Added `unsafe_fields` attribute.
+
+## [0.1.2] - 2019-01-09
+
+* Improved documentation.
+
+## [0.1.1] - 2019-01-08
+
+* Renamed from `unsafe_pin_project` to `unsafe_project`.
+
+## [0.1.0] - 2019-01-08 - YANKED
+
+Initial release
+
+[Unreleased]: https://github.com/taiki-e/pin-project/compare/v0.4.9...HEAD
+[0.4.9]: https://github.com/taiki-e/pin-project/compare/v0.4.8...v0.4.9
+[0.4.8]: https://github.com/taiki-e/pin-project/compare/v0.4.7...v0.4.8
+[0.4.7]: https://github.com/taiki-e/pin-project/compare/v0.4.6...v0.4.7
+[0.4.6]: https://github.com/taiki-e/pin-project/compare/v0.4.5...v0.4.6
+[0.4.5]: https://github.com/taiki-e/pin-project/compare/v0.4.4...v0.4.5
+[0.4.4]: https://github.com/taiki-e/pin-project/compare/v0.4.3...v0.4.4
+[0.4.3]: https://github.com/taiki-e/pin-project/compare/v0.4.2...v0.4.3
+[0.4.2]: https://github.com/taiki-e/pin-project/compare/v0.4.1...v0.4.2
+[0.4.1]: https://github.com/taiki-e/pin-project/compare/v0.4.0...v0.4.1
+[0.4.0]: https://github.com/taiki-e/pin-project/compare/v0.4.0-beta.1...v0.4.0
+[0.4.0-beta.1]: https://github.com/taiki-e/pin-project/compare/v0.4.0-alpha.11...v0.4.0-beta.1
+[0.4.0-alpha.11]: https://github.com/taiki-e/pin-project/compare/v0.4.0-alpha.10...v0.4.0-alpha.11
+[0.4.0-alpha.10]: https://github.com/taiki-e/pin-project/compare/v0.4.0-alpha.9...v0.4.0-alpha.10
+[0.4.0-alpha.9]: https://github.com/taiki-e/pin-project/compare/v0.4.0-alpha.8...v0.4.0-alpha.9
+[0.4.0-alpha.8]: https://github.com/taiki-e/pin-project/compare/v0.4.0-alpha.7...v0.4.0-alpha.8
+[0.4.0-alpha.7]: https://github.com/taiki-e/pin-project/compare/v0.4.0-alpha.6...v0.4.0-alpha.7
+[0.4.0-alpha.6]: https://github.com/taiki-e/pin-project/compare/v0.4.0-alpha.5...v0.4.0-alpha.6
+[0.4.0-alpha.5]: https://github.com/taiki-e/pin-project/compare/v0.4.0-alpha.4...v0.4.0-alpha.5
+[0.4.0-alpha.4]: https://github.com/taiki-e/pin-project/compare/v0.4.0-alpha.3...v0.4.0-alpha.4
+[0.4.0-alpha.3]: https://github.com/taiki-e/pin-project/compare/v0.4.0-alpha.2...v0.4.0-alpha.3
+[0.4.0-alpha.2]: https://github.com/taiki-e/pin-project/compare/v0.4.0-alpha.1...v0.4.0-alpha.2
+[0.4.0-alpha.1]: https://github.com/taiki-e/pin-project/compare/v0.3.5...v0.4.0-alpha.1
+[0.3.5]: https://github.com/taiki-e/pin-project/compare/v0.3.4...v0.3.5
+[0.3.4]: https://github.com/taiki-e/pin-project/compare/v0.3.3...v0.3.4
+[0.3.3]: https://github.com/taiki-e/pin-project/compare/v0.3.2...v0.3.3
+[0.3.2]: https://github.com/taiki-e/pin-project/compare/v0.3.1...v0.3.2
+[0.3.1]: https://github.com/taiki-e/pin-project/compare/v0.3.0...v0.3.1
+[0.3.0]: https://github.com/taiki-e/pin-project/compare/v0.2.2...v0.3.0
+[0.2.2]: https://github.com/taiki-e/pin-project/compare/v0.2.1...v0.2.2
+[0.2.1]: https://github.com/taiki-e/pin-project/compare/v0.2.0...v0.2.1
+[0.2.0]: https://github.com/taiki-e/pin-project/compare/v0.1.8...v0.2.0
+[0.1.8]: https://github.com/taiki-e/pin-project/compare/v0.1.7...v0.1.8
+[0.1.7]: https://github.com/taiki-e/pin-project/compare/v0.1.6...v0.1.7
+[0.1.6]: https://github.com/taiki-e/pin-project/compare/v0.1.5...v0.1.6
+[0.1.5]: https://github.com/taiki-e/pin-project/compare/v0.1.4...v0.1.5
+[0.1.4]: https://github.com/taiki-e/pin-project/compare/v0.1.3...v0.1.4
+[0.1.3]: https://github.com/taiki-e/pin-project/compare/v0.1.2...v0.1.3
+[0.1.2]: https://github.com/taiki-e/pin-project/compare/v0.1.1...v0.1.2
+[0.1.1]: https://github.com/taiki-e/pin-project/compare/v0.1.0...v0.1.1
+[0.1.0]: https://github.com/taiki-e/pin-project/releases/tag/v0.1.0
diff --git a/third_party/rust/pin-project/Cargo.lock b/third_party/rust/pin-project/Cargo.lock
new file mode 100644
index 0000000000..2db8002ba9
--- /dev/null
+++ b/third_party/rust/pin-project/Cargo.lock
@@ -0,0 +1,56 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "pin-project"
+version = "0.4.9"
+dependencies = [
+ "pin-project-internal 0.4.9 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "pin-project-internal"
+version = "0.4.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "proc-macro2 1.0.10 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.17 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "proc-macro2"
+version = "1.0.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "unicode-xid 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "quote"
+version = "1.0.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "proc-macro2 1.0.10 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "syn"
+version = "1.0.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "proc-macro2 1.0.10 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "unicode-xid 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "unicode-xid"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[metadata]
+"checksum pin-project-internal 0.4.9 (registry+https://github.com/rust-lang/crates.io-index)" = "8988430ce790d8682672117bc06dda364c0be32d3abd738234f19f3240bad99a"
+"checksum proc-macro2 1.0.10 (registry+https://github.com/rust-lang/crates.io-index)" = "df246d292ff63439fea9bc8c0a270bed0e390d5ebd4db4ba15aba81111b5abe3"
+"checksum quote 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)" = "2bdc6c187c65bca4260c9011c9e3132efe4909da44726bad24cf7572ae338d7f"
+"checksum syn 1.0.17 (registry+https://github.com/rust-lang/crates.io-index)" = "0df0eb663f387145cab623dea85b09c2c5b4b0aef44e945d928e682fce71bb03"
+"checksum unicode-xid 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "826e7639553986605ec5979c7dd957c7895e93eabed50ab2ffa7f6128a75097c"
diff --git a/third_party/rust/pin-project/Cargo.toml b/third_party/rust/pin-project/Cargo.toml
new file mode 100644
index 0000000000..b3ef6db911
--- /dev/null
+++ b/third_party/rust/pin-project/Cargo.toml
@@ -0,0 +1,28 @@
+# 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 believe there's an error in this file please file an
+# issue against the rust-lang/cargo repository. If you're
+# editing this file be aware that the upstream Cargo.toml
+# will likely look very different (and much more reasonable)
+
+[package]
+edition = "2018"
+name = "pin-project"
+version = "0.4.9"
+authors = ["Taiki Endo <te316e89@gmail.com>"]
+description = "A crate for safe and ergonomic pin-projection.\n"
+homepage = "https://github.com/taiki-e/pin-project"
+documentation = "https://docs.rs/pin-project"
+readme = "README.md"
+keywords = ["pin", "macros", "attribute"]
+categories = ["no-std", "rust-patterns"]
+license = "Apache-2.0 OR MIT"
+repository = "https://github.com/taiki-e/pin-project"
+[dependencies.pin-project-internal]
+version = "=0.4.9"
+default-features = false
diff --git a/third_party/rust/pin-project/LICENSE-APACHE b/third_party/rust/pin-project/LICENSE-APACHE
new file mode 100644
index 0000000000..d645695673
--- /dev/null
+++ b/third_party/rust/pin-project/LICENSE-APACHE
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
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+
+      "You" (or "Your") shall mean an individual or Legal Entity
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+      "Work" shall mean the work of authorship, whether in Source or
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+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
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+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
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+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
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+      origin of the Work and reproducing the content of the NOTICE file.
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+   7. Disclaimer of Warranty. Unless required by applicable law or
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+      Contributor provides its Contributions) on an "AS IS" BASIS,
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+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
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+      Work (including but not limited to damages for loss of goodwill,
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+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   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
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
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+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
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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.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/third_party/rust/pin-project/LICENSE-MIT b/third_party/rust/pin-project/LICENSE-MIT
new file mode 100644
index 0000000000..31aa79387f
--- /dev/null
+++ b/third_party/rust/pin-project/LICENSE-MIT
@@ -0,0 +1,23 @@
+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.
diff --git a/third_party/rust/pin-project/README.md b/third_party/rust/pin-project/README.md
new file mode 100644
index 0000000000..a8bc573dcf
--- /dev/null
+++ b/third_party/rust/pin-project/README.md
@@ -0,0 +1,77 @@
+# pin-project
+
+[![crates-badge]][crates-url]
+[![docs-badge]][docs-url]
+[![license-badge]][license]
+[![rustc-badge]][rustc-url]
+
+[crates-badge]: https://img.shields.io/crates/v/pin-project.svg
+[crates-url]: https://crates.io/crates/pin-project
+[docs-badge]: https://docs.rs/pin-project/badge.svg
+[docs-url]: https://docs.rs/pin-project
+[license-badge]: https://img.shields.io/crates/l/pin-project.svg
+[license]: #license
+[rustc-badge]: https://img.shields.io/badge/rustc-1.33+-lightgray.svg
+[rustc-url]: https://blog.rust-lang.org/2019/02/28/Rust-1.33.0.html
+
+A crate for safe and ergonomic pin-projection.
+
+[Documentation][docs-url]
+
+[Examples](examples/README.md)
+
+## Usage
+
+Add this to your `Cargo.toml`:
+
+```toml
+[dependencies]
+pin-project = "0.4"
+```
+
+The current pin-project requires Rust 1.33 or later.
+
+## Examples
+
+[`pin_project`] attribute creates a projection struct covering all the fields.
+
+```rust
+use pin_project::pin_project;
+use std::pin::Pin;
+
+#[pin_project]
+struct Struct<T, U> {
+    #[pin]
+    pinned: T,
+    unpinned: U,
+}
+
+impl<T, U> Struct<T, U> {
+    fn foo(self: Pin<&mut Self>) {
+        let this = self.project();
+        let _: Pin<&mut T> = this.pinned; // Pinned reference to the field
+        let _: &mut U = this.unpinned; // Normal reference to the field
+    }
+}
+```
+
+[Code like this will be generated](examples/struct-default-expanded.rs)
+
+See [API documentation][docs-url] for more details.
+
+Also, there are examples and generated code of each feature in [examples](examples/README.md) directory.
+
+[`pin_project`]: https://docs.rs/pin-project/0.4/pin_project/attr.pin_project.html
+
+## License
+
+Licensed under either of
+
+* Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or <http://www.apache.org/licenses/LICENSE-2.0>)
+* MIT license ([LICENSE-MIT](LICENSE-MIT) or <http://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.
diff --git a/third_party/rust/pin-project/ci.sh b/third_party/rust/pin-project/ci.sh
new file mode 100644
index 0000000000..016481d23b
--- /dev/null
+++ b/third_party/rust/pin-project/ci.sh
@@ -0,0 +1,24 @@
+#!/bin/bash
+
+# A script to run a simplified version of the checks done by CI.
+#
+# Usage
+#
+# ```sh
+# . ./ci.sh
+# ```
+
+echo "Running 'cargo fmt -- --check'"
+cargo +nightly fmt --all -- --check
+
+echo "Running 'cargo clippy'"
+cargo +nightly clippy --all --all-features
+
+echo "Running 'cargo test'"
+cargo +nightly test --all --all-features
+
+echo "Running 'cargo doc'"
+cargo +nightly doc --no-deps --all --all-features
+
+echo "Running 'compiletest'"
+. ./compiletest.sh
diff --git a/third_party/rust/pin-project/ci/install-component.sh b/third_party/rust/pin-project/ci/install-component.sh
new file mode 100644
index 0000000000..943755c5b2
--- /dev/null
+++ b/third_party/rust/pin-project/ci/install-component.sh
@@ -0,0 +1,29 @@
+#!/bin/bash
+
+set -euo pipefail
+
+component="${1}"
+
+if ! rustup component add "${component}" 2>/dev/null; then
+    # If the component is unavailable on the latest nightly,
+    # use the latest toolchain with the component available.
+    # Refs: https://github.com/rust-lang/rustup-components-history#the-web-part
+    target=$(curl -sSf "https://rust-lang.github.io/rustup-components-history/x86_64-unknown-linux-gnu/${component}")
+    echo "'${component}' is unavailable on the default toolchain, use the toolchain 'nightly-${target}' instead"
+
+    rustup update "nightly-${target}" --no-self-update
+    rustup default "nightly-${target}"
+
+    echo "Query rust and cargo versions:"
+    rustup -V
+    rustc -V
+    cargo -V
+
+    rustup component add "${component}"
+fi
+
+echo "Query component versions:"
+case "${component}" in
+    clippy | miri) cargo "${component}" -V ;;
+    rustfmt) "${component}" -V ;;
+esac
diff --git a/third_party/rust/pin-project/ci/install-rust.sh b/third_party/rust/pin-project/ci/install-rust.sh
new file mode 100644
index 0000000000..3e0b27ae84
--- /dev/null
+++ b/third_party/rust/pin-project/ci/install-rust.sh
@@ -0,0 +1,20 @@
+#!/bin/bash
+
+set -euo pipefail
+
+toolchain="${1:-nightly}"
+
+if rustup -V 2>/dev/null; then
+    rustup set profile minimal
+    rustup update "${toolchain}" --no-self-update
+    rustup default "${toolchain}"
+else
+    curl -sSf https://sh.rustup.rs | sh -s -- -y --profile minimal --default-toolchain "${toolchain}"
+    export PATH=${PATH}:${HOME}/.cargo/bin
+    echo "##[add-path]${HOME}/.cargo/bin"
+fi
+
+echo "Query rust and cargo versions:"
+rustup -V
+rustc -V
+cargo -V
diff --git a/third_party/rust/pin-project/compiletest.sh b/third_party/rust/pin-project/compiletest.sh
new file mode 100644
index 0000000000..21351a50a9
--- /dev/null
+++ b/third_party/rust/pin-project/compiletest.sh
@@ -0,0 +1,12 @@
+#!/bin/bash
+
+# A script to run compile tests with the same condition of the checks done by CI.
+#
+# Usage
+#
+# ```sh
+# . ./compiletest.sh
+# ```
+
+TRYBUILD=overwrite RUSTFLAGS='--cfg pin_project_show_unpin_struct' cargo +nightly test -p pin-project --all-features --test compiletest -- --ignored
+# RUSTFLAGS='--cfg pin_project_show_unpin_struct' cargo +nightly test -p pin-project --all-features --test compiletest -- --ignored
diff --git a/third_party/rust/pin-project/examples/README.md b/third_party/rust/pin-project/examples/README.md
new file mode 100644
index 0000000000..6234900131
--- /dev/null
+++ b/third_party/rust/pin-project/examples/README.md
@@ -0,0 +1,9 @@
+## Examples and generated code of each feature of pin-project
+
+* [Basic usage of `#[pin_project]` on structs.](struct-default.rs) -- [generated code](struct-default-expanded.rs)
+
+* [Basic usage of `#[pin_project]` on enums.](enum-default.rs) -- [generated code](enum-default-expanded.rs)
+
+* [Manual implementation of `Unpin` by `UnsafeUnpin`.](unsafe_unpin.rs) -- [generated code](unsafe_unpin-expanded.rs)
+
+* [Manual implementation of `Drop` by `#[pinned_drop]`.](pinned_drop.rs) -- [generated code](pinned_drop-expanded.rs)
diff --git a/third_party/rust/pin-project/examples/enum-default-expanded.rs b/third_party/rust/pin-project/examples/enum-default-expanded.rs
new file mode 100644
index 0000000000..568f9b2c23
--- /dev/null
+++ b/third_party/rust/pin-project/examples/enum-default-expanded.rs
@@ -0,0 +1,86 @@
+// Original code (./enum-default.rs):
+//
+// ```rust
+// #![allow(dead_code)]
+//
+// use pin_project::pin_project;
+//
+// #[pin_project]
+// enum Enum<T, U> {
+//     Pinned(#[pin] T),
+//     Unpinned(U),
+// }
+//
+// fn main() {}
+// ```
+
+#![allow(dead_code, unused_imports, unused_parens)]
+
+use pin_project::pin_project;
+
+enum Enum<T, U> {
+    Pinned(/* #[pin] */ T),
+    Unpinned(U),
+}
+
+#[allow(clippy::mut_mut)] // This lint warns `&mut &mut <ty>`.
+#[allow(dead_code)] // This lint warns unused fields/variants.
+enum __EnumProjection<'pin, T, U> {
+    Pinned(::core::pin::Pin<&'pin mut (T)>),
+    Unpinned(&'pin mut (U)),
+}
+
+#[allow(dead_code)] // This lint warns unused fields/variants.
+enum __EnumProjectionRef<'pin, T, U> {
+    Pinned(::core::pin::Pin<&'pin (T)>),
+    Unpinned(&'pin (U)),
+}
+
+impl<T, U> Enum<T, U> {
+    fn project<'pin>(self: ::core::pin::Pin<&'pin mut Self>) -> __EnumProjection<'pin, T, U> {
+        unsafe {
+            match self.get_unchecked_mut() {
+                Enum::Pinned(_0) => __EnumProjection::Pinned(::core::pin::Pin::new_unchecked(_0)),
+                Enum::Unpinned(_0) => __EnumProjection::Unpinned(_0),
+            }
+        }
+    }
+    fn project_ref<'pin>(self: ::core::pin::Pin<&'pin Self>) -> __EnumProjectionRef<'pin, T, U> {
+        unsafe {
+            match self.get_ref() {
+                Enum::Pinned(_0) => {
+                    __EnumProjectionRef::Pinned(::core::pin::Pin::new_unchecked(_0))
+                }
+                Enum::Unpinned(_0) => __EnumProjectionRef::Unpinned(_0),
+            }
+        }
+    }
+}
+
+// Automatically create the appropriate conditional `Unpin` implementation.
+//
+// See ./struct-default-expanded.rs and https://github.com/taiki-e/pin-project/pull/53.
+// for details.
+#[allow(non_snake_case)]
+fn __unpin_scope_Enum() {
+    struct __Enum<'pin, T, U> {
+        __pin_project_use_generics: ::pin_project::__private::AlwaysUnpin<'pin, (T, U)>,
+        __field0: T,
+    }
+    impl<'pin, T, U> ::core::marker::Unpin for Enum<T, U> where __Enum<'pin, T, U>: ::core::marker::Unpin
+    {}
+}
+
+// Ensure that enum does not implement `Drop`.
+//
+// See ./struct-default-expanded.rs for details.
+trait EnumMustNotImplDrop {}
+#[allow(clippy::drop_bounds)]
+impl<T: ::core::ops::Drop> EnumMustNotImplDrop for T {}
+#[allow(single_use_lifetimes)]
+impl<T, U> EnumMustNotImplDrop for Enum<T, U> {}
+
+// We don't need to check for '#[repr(packed)]',
+// since it does not apply to enums.
+
+fn main() {}
diff --git a/third_party/rust/pin-project/examples/enum-default.rs b/third_party/rust/pin-project/examples/enum-default.rs
new file mode 100644
index 0000000000..ab5a4bc2a5
--- /dev/null
+++ b/third_party/rust/pin-project/examples/enum-default.rs
@@ -0,0 +1,13 @@
+// See ./enum-default-expanded.rs for generated code.
+
+#![allow(dead_code)]
+
+use pin_project::pin_project;
+
+#[pin_project]
+enum Enum<T, U> {
+    Pinned(#[pin] T),
+    Unpinned(U),
+}
+
+fn main() {}
diff --git a/third_party/rust/pin-project/examples/pinned_drop-expanded.rs b/third_party/rust/pin-project/examples/pinned_drop-expanded.rs
new file mode 100644
index 0000000000..d96dd98e12
--- /dev/null
+++ b/third_party/rust/pin-project/examples/pinned_drop-expanded.rs
@@ -0,0 +1,133 @@
+// Original code (./pinned_drop.rs):
+//
+// ```rust
+// #![allow(dead_code)]
+//
+// use pin_project::{pin_project, pinned_drop};
+// use std::pin::Pin;
+//
+// #[pin_project(PinnedDrop)]
+// pub struct Foo<'a, T> {
+//     was_dropped: &'a mut bool,
+//     #[pin]
+//     field: T,
+// }
+//
+// #[pinned_drop]
+// fn drop_foo<T>(mut this: Pin<&mut Foo<'_, T>>) {
+//     **this.project().was_dropped = true;
+// }
+//
+// fn main() {}
+// ```
+
+#![allow(dead_code, unused_imports, unused_parens)]
+
+use pin_project::{pin_project, pinned_drop};
+use std::pin::Pin;
+
+pub struct Foo<'a, T> {
+    was_dropped: &'a mut bool,
+    // #[pin]
+    field: T,
+}
+
+#[allow(clippy::mut_mut)] // This lint warns `&mut &mut <ty>`.
+#[allow(dead_code)] // This lint warns unused fields/variants.
+pub(crate) struct __FooProjection<'pin, 'a, T> {
+    was_dropped: &'pin mut (&'a mut bool),
+    field: ::core::pin::Pin<&'pin mut (T)>,
+}
+
+#[allow(dead_code)] // This lint warns unused fields/variants.
+pub(crate) struct __FooProjectionRef<'pin, 'a, T> {
+    was_dropped: &'pin (&'a mut bool),
+    field: ::core::pin::Pin<&'pin (T)>,
+}
+
+impl<'a, T> Foo<'a, T> {
+    pub(crate) fn project<'pin>(
+        self: ::core::pin::Pin<&'pin mut Self>,
+    ) -> __FooProjection<'pin, 'a, T> {
+        unsafe {
+            let Foo { was_dropped, field } = self.get_unchecked_mut();
+            __FooProjection { was_dropped, field: ::core::pin::Pin::new_unchecked(field) }
+        }
+    }
+    pub(crate) fn project_ref<'pin>(
+        self: ::core::pin::Pin<&'pin Self>,
+    ) -> __FooProjectionRef<'pin, 'a, T> {
+        unsafe {
+            let Foo { was_dropped, field } = self.get_ref();
+            __FooProjectionRef { was_dropped, field: ::core::pin::Pin::new_unchecked(field) }
+        }
+    }
+}
+
+#[allow(single_use_lifetimes)]
+impl<'a, T> ::core::ops::Drop for Foo<'a, T> {
+    fn drop(&mut self) {
+        // Safety - we're in 'drop', so we know that 'self' will
+        // never move again.
+        let pinned_self = unsafe { ::core::pin::Pin::new_unchecked(self) };
+        // We call `pinned_drop` only once. Since `PinnedDrop::drop`
+        // is an unsafe function and a private API, it is never called again in safe
+        // code *unless the user uses a maliciously crafted macro*.
+        unsafe {
+            ::pin_project::__private::PinnedDrop::drop(pinned_self);
+        }
+    }
+}
+
+// It is safe to implement PinnedDrop::drop, but it is not safe to call it.
+// This is because destructors can be called multiple times (double dropping
+// is unsound: rust-lang/rust#62360).
+//
+// Ideally, it would be desirable to be able to prohibit manual calls in the
+// same way as Drop::drop, but the library cannot. So, by using macros and
+// replacing them with private traits, we prevent users from calling
+// PinnedDrop::drop.
+//
+// Users can implement `Drop` safely using `#[pinned_drop]`.
+// **Do not call or implement this trait directly.**
+impl<T> ::pin_project::__private::PinnedDrop for Foo<'_, T> {
+    // Since calling it twice on the same object would be UB,
+    // this method is unsafe.
+    unsafe fn drop(self: Pin<&mut Self>) {
+        fn __drop_inner<T>(__self: Pin<&mut Foo<'_, T>>) {
+            **__self.project().was_dropped = true;
+        }
+        __drop_inner(self);
+    }
+}
+
+// Automatically create the appropriate conditional `Unpin` implementation.
+//
+// See ./struct-default-expanded.rs and https://github.com/taiki-e/pin-project/pull/53.
+// for details.
+#[allow(non_snake_case)]
+fn __unpin_scope_Foo() {
+    pub struct __Foo<'pin, 'a, T> {
+        __pin_project_use_generics: ::pin_project::__private::AlwaysUnpin<'pin, (T)>,
+        __field0: T,
+        __lifetime0: &'a (),
+    }
+    impl<'pin, 'a, T> ::core::marker::Unpin for Foo<'a, T> where
+        __Foo<'pin, 'a, T>: ::core::marker::Unpin
+    {
+    }
+}
+
+// Ensure that it's impossible to use pin projections on a #[repr(packed)] struct.
+//
+// See ./struct-default-expanded.rs and https://github.com/taiki-e/pin-project/pull/34
+// for details.
+#[allow(single_use_lifetimes)]
+#[allow(non_snake_case)]
+#[deny(safe_packed_borrows)]
+fn __pin_project_assert_not_repr_packed_Foo<'a, T>(val: &Foo<'a, T>) {
+    &val.was_dropped;
+    &val.field;
+}
+
+fn main() {}
diff --git a/third_party/rust/pin-project/examples/pinned_drop.rs b/third_party/rust/pin-project/examples/pinned_drop.rs
new file mode 100644
index 0000000000..3dcfc6afe9
--- /dev/null
+++ b/third_party/rust/pin-project/examples/pinned_drop.rs
@@ -0,0 +1,22 @@
+// See ./pinned_drop-expanded.rs for generated code.
+
+#![allow(dead_code)]
+
+use pin_project::{pin_project, pinned_drop};
+use std::pin::Pin;
+
+#[pin_project(PinnedDrop)]
+pub struct Foo<'a, T> {
+    was_dropped: &'a mut bool,
+    #[pin]
+    field: T,
+}
+
+#[pinned_drop]
+impl<T> PinnedDrop for Foo<'_, T> {
+    fn drop(self: Pin<&mut Self>) {
+        **self.project().was_dropped = true;
+    }
+}
+
+fn main() {}
diff --git a/third_party/rust/pin-project/examples/struct-default-expanded.rs b/third_party/rust/pin-project/examples/struct-default-expanded.rs
new file mode 100644
index 0000000000..ec454b7971
--- /dev/null
+++ b/third_party/rust/pin-project/examples/struct-default-expanded.rs
@@ -0,0 +1,128 @@
+// Original code (./struct-default.rs):
+//
+// ```rust
+// #![allow(dead_code)]
+//
+// use pin_project::pin_project;
+//
+// #[pin_project]
+// struct Struct<T, U> {
+//     #[pin]
+//     pinned: T,
+//     unpinned: U,
+// }
+//
+// fn main() {}
+// ```
+
+#![allow(dead_code, unused_imports, unused_parens)]
+
+use pin_project::pin_project;
+
+struct Struct<T, U> {
+    // #[pin]
+    pinned: T,
+    unpinned: U,
+}
+
+#[allow(clippy::mut_mut)] // This lint warns `&mut &mut <ty>`.
+#[allow(dead_code)] // This lint warns unused fields/variants.
+struct __StructProjection<'pin, T, U> {
+    pinned: ::core::pin::Pin<&'pin mut (T)>,
+    unpinned: &'pin mut (U),
+}
+#[allow(dead_code)] // This lint warns unused fields/variants.
+struct __StructProjectionRef<'pin, T, U> {
+    pinned: ::core::pin::Pin<&'pin (T)>,
+    unpinned: &'pin (U),
+}
+
+impl<T, U> Struct<T, U> {
+    fn project<'pin>(self: ::core::pin::Pin<&'pin mut Self>) -> __StructProjection<'pin, T, U> {
+        unsafe {
+            let Struct { pinned, unpinned } = self.get_unchecked_mut();
+            __StructProjection { pinned: ::core::pin::Pin::new_unchecked(pinned), unpinned }
+        }
+    }
+    fn project_ref<'pin>(self: ::core::pin::Pin<&'pin Self>) -> __StructProjectionRef<'pin, T, U> {
+        unsafe {
+            let Struct { pinned, unpinned } = self.get_ref();
+            __StructProjectionRef { pinned: ::core::pin::Pin::new_unchecked(pinned), unpinned }
+        }
+    }
+}
+
+// Automatically create the appropriate conditional `Unpin` implementation.
+//
+// Basically this is equivalent to the following code:
+// ```rust
+// impl<T, U> Unpin for Struct<T, U> where T: Unpin {}
+// ```
+//
+// However, if struct is public and there is a private type field,
+// this would cause an E0446 (private type in public interface).
+//
+// When RFC 2145 is implemented (rust-lang/rust#48054),
+// this will become a lint, rather then a hard error.
+//
+// As a workaround for this, we generate a new struct, containing all of the pinned
+// fields from our #[pin_project] type. This struct is declared within
+// a function, which makes it impossible to be named by user code.
+// This guarantees that it will use the default auto-trait impl for Unpin -
+// that is, it will implement Unpin iff all of its fields implement Unpin.
+// This type can be safely declared as 'public', satisfying the privacy
+// checker without actually allowing user code to access it.
+//
+// This allows users to apply the #[pin_project] attribute to types
+// regardless of the privacy of the types of their fields.
+//
+// See also https://github.com/taiki-e/pin-project/pull/53.
+#[allow(non_snake_case)]
+fn __unpin_scope_Struct() {
+    struct __Struct<'pin, T, U> {
+        __pin_project_use_generics: ::pin_project::__private::AlwaysUnpin<'pin, (T, U)>,
+        __field0: T,
+    }
+    impl<'pin, T, U> ::core::marker::Unpin for Struct<T, U> where
+        __Struct<'pin, T, U>: ::core::marker::Unpin
+    {
+    }
+}
+
+// Ensure that struct does not implement `Drop`.
+//
+// There are two possible cases:
+// 1. The user type does not implement Drop. In this case,
+// the first blanked impl will not apply to it. This code
+// will compile, as there is only one impl of MustNotImplDrop for the user type
+// 2. The user type does impl Drop. This will make the blanket impl applicable,
+// which will then conflict with the explicit MustNotImplDrop impl below.
+// This will result in a compilation error, which is exactly what we want.
+trait StructMustNotImplDrop {}
+#[allow(clippy::drop_bounds)]
+impl<T: ::core::ops::Drop> StructMustNotImplDrop for T {}
+#[allow(single_use_lifetimes)]
+impl<T, U> StructMustNotImplDrop for Struct<T, U> {}
+
+// Ensure that it's impossible to use pin projections on a #[repr(packed)] struct.
+//
+// Taking a reference to a packed field is unsafe, and applying
+// #[deny(safe_packed_borrows)] makes sure that doing this without
+// an 'unsafe' block (which we deliberately do not generate)
+// is a hard error.
+//
+// If the struct ends up having #[repr(packed)] applied somehow,
+// this will generate an (unfriendly) error message. Under all reasonable
+// circumstances, we'll detect the #[repr(packed)] attribute, and generate
+// a much nicer error above.
+//
+// See https://github.com/taiki-e/pin-project/pull/34 for more details.
+#[allow(single_use_lifetimes)]
+#[allow(non_snake_case)]
+#[deny(safe_packed_borrows)]
+fn __pin_project_assert_not_repr_packed_Struct<T, U>(val: &Struct<T, U>) {
+    &val.pinned;
+    &val.unpinned;
+}
+
+fn main() {}
diff --git a/third_party/rust/pin-project/examples/struct-default.rs b/third_party/rust/pin-project/examples/struct-default.rs
new file mode 100644
index 0000000000..46808a5827
--- /dev/null
+++ b/third_party/rust/pin-project/examples/struct-default.rs
@@ -0,0 +1,14 @@
+// See ./struct-default-expanded.rs for generated code.
+
+#![allow(dead_code)]
+
+use pin_project::pin_project;
+
+#[pin_project]
+struct Struct<T, U> {
+    #[pin]
+    pinned: T,
+    unpinned: U,
+}
+
+fn main() {}
diff --git a/third_party/rust/pin-project/examples/unsafe_unpin-expanded.rs b/third_party/rust/pin-project/examples/unsafe_unpin-expanded.rs
new file mode 100644
index 0000000000..acb3ee8316
--- /dev/null
+++ b/third_party/rust/pin-project/examples/unsafe_unpin-expanded.rs
@@ -0,0 +1,90 @@
+// Original code (./unsafe_unpin.rs):
+//
+// ```rust
+// #![allow(dead_code)]
+//
+// use pin_project::{pin_project, UnsafeUnpin};
+//
+// #[pin_project(UnsafeUnpin)]
+// pub struct Foo<T, U> {
+//     #[pin]
+//     pinned: T,
+//     unpinned: U,
+// }
+//
+// unsafe impl<T: Unpin, U> UnsafeUnpin for Foo<T, U> {}
+//
+// fn main() {}
+// ```
+
+#![allow(dead_code, unused_imports, unused_parens)]
+
+use pin_project::{pin_project, UnsafeUnpin};
+
+pub struct Foo<T, U> {
+    // #[pin]
+    pinned: T,
+    unpinned: U,
+}
+
+#[allow(clippy::mut_mut)] // This lint warns `&mut &mut <ty>`.
+#[allow(dead_code)] // This lint warns unused fields/variants.
+pub(crate) struct __FooProjection<'pin, T, U> {
+    pinned: ::core::pin::Pin<&'pin mut (T)>,
+    unpinned: &'pin mut (U),
+}
+#[allow(dead_code)] // This lint warns unused fields/variants.
+pub(crate) struct __FooProjectionRef<'pin, T, U> {
+    pinned: ::core::pin::Pin<&'pin (T)>,
+    unpinned: &'pin (U),
+}
+
+impl<T, U> Foo<T, U> {
+    pub(crate) fn project<'pin>(
+        self: ::core::pin::Pin<&'pin mut Self>,
+    ) -> __FooProjection<'pin, T, U> {
+        unsafe {
+            let Foo { pinned, unpinned } = self.get_unchecked_mut();
+            __FooProjection { pinned: ::core::pin::Pin::new_unchecked(pinned), unpinned }
+        }
+    }
+    pub(crate) fn project_ref<'pin>(
+        self: ::core::pin::Pin<&'pin Self>,
+    ) -> __FooProjectionRef<'pin, T, U> {
+        unsafe {
+            let Foo { pinned, unpinned } = self.get_ref();
+            __FooProjectionRef { pinned: ::core::pin::Pin::new_unchecked(pinned), unpinned }
+        }
+    }
+}
+
+unsafe impl<T: Unpin, U> UnsafeUnpin for Foo<T, U> {}
+
+#[allow(single_use_lifetimes)]
+impl<'pin, T, U> ::core::marker::Unpin for Foo<T, U> where
+    ::pin_project::__private::Wrapper<'pin, Self>: ::pin_project::UnsafeUnpin
+{
+}
+
+// Ensure that struct does not implement `Drop`.
+//
+// See ./struct-default-expanded.rs for details.
+trait FooMustNotImplDrop {}
+#[allow(clippy::drop_bounds)]
+impl<T: ::core::ops::Drop> FooMustNotImplDrop for T {}
+#[allow(single_use_lifetimes)]
+impl<T, U> FooMustNotImplDrop for Foo<T, U> {}
+
+// Ensure that it's impossible to use pin projections on a #[repr(packed)] struct.
+//
+// See ./struct-default-expanded.rs and https://github.com/taiki-e/pin-project/pull/34
+// for details.
+#[allow(single_use_lifetimes)]
+#[allow(non_snake_case)]
+#[deny(safe_packed_borrows)]
+fn __pin_project_assert_not_repr_packed_Foo<T, U>(val: &Foo<T, U>) {
+    &val.pinned;
+    &val.unpinned;
+}
+
+fn main() {}
diff --git a/third_party/rust/pin-project/examples/unsafe_unpin.rs b/third_party/rust/pin-project/examples/unsafe_unpin.rs
new file mode 100644
index 0000000000..9056808d6f
--- /dev/null
+++ b/third_party/rust/pin-project/examples/unsafe_unpin.rs
@@ -0,0 +1,16 @@
+// See ./pinned_drop-expanded.rs for generated code.
+
+#![allow(dead_code)]
+
+use pin_project::{pin_project, UnsafeUnpin};
+
+#[pin_project(UnsafeUnpin)]
+pub struct Foo<T, U> {
+    #[pin]
+    pinned: T,
+    unpinned: U,
+}
+
+unsafe impl<T: Unpin, U> UnsafeUnpin for Foo<T, U> {}
+
+fn main() {}
diff --git a/third_party/rust/pin-project/src/lib.rs b/third_party/rust/pin-project/src/lib.rs
new file mode 100644
index 0000000000..7d2de26614
--- /dev/null
+++ b/third_party/rust/pin-project/src/lib.rs
@@ -0,0 +1,205 @@
+//! A crate for safe and ergonomic pin-projection.
+//!
+//! ## Examples
+//!
+//! [`pin_project`] attribute creates a projection struct covering all the fields.
+//!
+//! ```rust
+//! use pin_project::pin_project;
+//! use std::pin::Pin;
+//!
+//! #[pin_project]
+//! struct Struct<T, U> {
+//!     #[pin]
+//!     pinned: T,
+//!     unpinned: U,
+//! }
+//!
+//! impl<T, U> Struct<T, U> {
+//!     fn foo(self: Pin<&mut Self>) {
+//!         let this = self.project();
+//!         let _: Pin<&mut T> = this.pinned; // Pinned reference to the field
+//!         let _: &mut U = this.unpinned; // Normal reference to the field
+//!     }
+//! }
+//! ```
+//!
+//! [Code like this will be generated](https://github.com/taiki-e/pin-project/blob/master/examples/struct-default-expanded.rs)
+//!
+//! See [`pin_project`] attribute for more details.
+//!
+//! Also, there are examples and generated code of each feature in [examples](https://github.com/taiki-e/pin-project/blob/master/examples/README.md) directory.
+//!
+//! [`pin_project`]: attr.pin_project.html
+
+#![no_std]
+#![recursion_limit = "256"]
+#![doc(html_root_url = "https://docs.rs/pin-project/0.4.9")]
+#![doc(test(
+    no_crate_inject,
+    attr(deny(warnings, rust_2018_idioms, single_use_lifetimes), allow(dead_code))
+))]
+#![warn(unsafe_code)]
+#![warn(missing_docs, rust_2018_idioms, single_use_lifetimes, unreachable_pub)]
+#![warn(clippy::all)]
+// mem::take requires Rust 1.40
+#![allow(clippy::mem_replace_with_default)]
+#![allow(clippy::needless_doctest_main)]
+
+#[doc(inline)]
+pub use pin_project_internal::pin_project;
+
+#[doc(inline)]
+pub use pin_project_internal::pinned_drop;
+
+#[doc(inline)]
+pub use pin_project_internal::project;
+
+#[doc(inline)]
+pub use pin_project_internal::project_ref;
+
+/// A trait used for custom implementations of [`Unpin`].
+/// This trait is used in conjunction with the `UnsafeUnpin`
+/// argument to [`pin_project`]
+///
+/// The Rust [`Unpin`] trait is safe to implement - by itself,
+/// implementing it cannot lead to undefined behavior. Undefined
+/// behavior can only occur when other unsafe code is used.
+///
+/// It turns out that using pin projections, which requires unsafe code,
+/// imposes additional requirements on an [`Unpin`] impl. Normally, all of this
+/// unsafety is contained within this crate, ensuring that it's impossible for
+/// you to violate any of the guarantees required by pin projection.
+///
+/// However, things change if you want to provide a custom [`Unpin`] impl
+/// for your `#[pin_project]` type. As stated in [the Rust
+/// documentation](https://doc.rust-lang.org/nightly/std/pin/index.html#projections-and-structural-pinning),
+/// you must be sure to only implement [`Unpin`] when all of your `#[pin]` fields (i.e. structurally
+/// pinned fields) are also [`Unpin`].
+///
+/// To help highlight this unsafety, the `UnsafeUnpin` trait is provided.
+/// Implementing this trait is logically equivalent to implementing [`Unpin`] -
+/// this crate will generate an [`Unpin`] impl for your type that 'forwards' to
+/// your `UnsafeUnpin` impl. However, this trait is `unsafe` - since your type
+/// uses structural pinning (otherwise, you wouldn't be using this crate!),
+/// you must be sure that your `UnsafeUnpin` impls follows all of
+/// the requirements for an [`Unpin`] impl of a structurally-pinned type.
+///
+/// Note that if you specify `#[pin_project(UnsafeUnpin)]`, but do *not*
+/// provide an impl of `UnsafeUnpin`, your type will never implement [`Unpin`].
+/// This is effectively the same thing as adding a [`PhantomPinned`] to your type
+///
+/// Since this trait is `unsafe`, impls of it will be detected by the `unsafe_code` lint,
+/// and by tools like `cargo geiger`.
+///
+/// ## Examples
+///
+/// An `UnsafeUnpin` impl which, in addition to requiring that structurally pinned
+/// fields be [`Unpin`], imposes an additional requirement:
+///
+/// ```rust
+/// use pin_project::{pin_project, UnsafeUnpin};
+///
+/// #[pin_project(UnsafeUnpin)]
+/// struct Foo<K, V> {
+///     #[pin]
+///     field_1: K,
+///     field_2: V,
+/// }
+///
+/// unsafe impl<K, V> UnsafeUnpin for Foo<K, V> where K: Unpin + Clone {}
+/// ```
+///
+/// [`PhantomPinned`]: core::marker::PhantomPinned
+/// [`pin_project`]: attr.pin_project.html
+#[allow(unsafe_code)]
+pub unsafe trait UnsafeUnpin {}
+
+// Not public API.
+#[doc(hidden)]
+pub mod __private {
+    use super::UnsafeUnpin;
+    use core::{marker::PhantomData, pin::Pin};
+
+    #[doc(hidden)]
+    pub use pin_project_internal::__PinProjectInternalDerive;
+
+    // It is safe to implement PinnedDrop::drop, but it is not safe to call it.
+    // This is because destructors can be called multiple times (double dropping
+    // is unsound: rust-lang/rust#62360).
+    //
+    // Ideally, it would be desirable to be able to prohibit manual calls in the
+    // same way as Drop::drop, but the library cannot. So, by using macros and
+    // replacing them with private traits, we prevent users from calling
+    // PinnedDrop::drop.
+    //
+    // Users can implement `Drop` safely using `#[pinned_drop]`.
+    // **Do not call or implement this trait directly.**
+    #[doc(hidden)]
+    pub trait PinnedDrop {
+        // Since calling it twice on the same object would be UB,
+        // this method is unsafe.
+        #[allow(unsafe_code)]
+        #[doc(hidden)]
+        unsafe fn drop(self: Pin<&mut Self>);
+    }
+
+    // This is an internal helper struct used by `pin-project-internal`.
+    // This allows us to force an error if the user tries to provide
+    // a regular `Unpin` impl when they specify the `UnsafeUnpin` argument.
+    // This is why we need Wrapper:
+    //
+    // Supposed we have the following code:
+    //
+    // #[pin_project(UnsafeUnpin)]
+    // struct MyStruct<T> {
+    //     #[pin] field: T
+    // }
+    //
+    // impl<T> Unpin for MyStruct<T> where MyStruct<T>: UnsafeUnpin {} // generated by pin-project-internal
+    // impl<T> Unpin for MyStruct<T> where T: Copy // written by the user
+    //
+    // We want this code to be rejected - the user is completely bypassing `UnsafeUnpin`,
+    // and providing an unsound Unpin impl in safe code!
+    //
+    // Unfortunately, the Rust compiler will accept the above code.
+    // Because MyStruct is declared in the same crate as the user-provided impl,
+    // the compiler will notice that 'MyStruct<T>: UnsafeUnpin' never holds.
+    //
+    // The solution is to introduce the 'Wrapper' struct, which is defined
+    // in the 'pin-project' crate.
+    //
+    // We now have code that looks like this:
+    //
+    // impl<T> Unpin for MyStruct<T> where Wrapper<MyStruct<T>>: UnsafeUnpin {} // generated by pin-project-internal
+    // impl<T> Unpin for MyStruct<T> where T: Copy // written by the user
+    //
+    // We also have 'unsafe impl<T> UnsafeUnpin for Wrapper<T> where T: UnsafeUnpin {}' in the
+    // 'pin-project' crate.
+    //
+    // Now, our generated impl has a bound involving a type defined in another crate - Wrapper.
+    // This will cause rust to conservatively assume that 'Wrapper<MyStruct<T>>: UnsafeUnpin'
+    // holds, in the interest of preserving forwards compatibility (in case such an impl is added
+    // for Wrapper<T> in a new version of the crate).
+    //
+    // This will cause rust to reject any other Unpin impls for MyStruct<T>, since it will
+    // assume that our generated impl could potentially apply in any situation.
+    //
+    // This achieves the desired effect - when the user writes `#[pin_project(UnsafeUnpin)]`,
+    // the user must either provide no impl of `UnsafeUnpin` (which is equivalent
+    // to making the type never implement Unpin), or provide an impl of `UnsafeUnpin`.
+    // It is impossible for them to provide an impl of `Unpin`
+    #[doc(hidden)]
+    pub struct Wrapper<'a, T: ?Sized>(PhantomData<&'a ()>, T);
+
+    #[allow(unsafe_code)]
+    unsafe impl<T: ?Sized> UnsafeUnpin for Wrapper<'_, T> where T: UnsafeUnpin {}
+
+    // This is an internal helper struct used by `pin-project-internal`.
+    //
+    // See https://github.com/taiki-e/pin-project/pull/53 for more details.
+    #[doc(hidden)]
+    pub struct AlwaysUnpin<'a, T: ?Sized>(PhantomData<&'a ()>, PhantomData<T>);
+
+    impl<T: ?Sized> Unpin for AlwaysUnpin<'_, T> {}
+}
diff --git a/third_party/rust/pin-project/tests/cfg.rs b/third_party/rust/pin-project/tests/cfg.rs
new file mode 100644
index 0000000000..fa63227549
--- /dev/null
+++ b/third_party/rust/pin-project/tests/cfg.rs
@@ -0,0 +1,243 @@
+#![warn(unsafe_code)]
+#![warn(rust_2018_idioms, single_use_lifetimes)]
+#![allow(dead_code)]
+
+// Refs: https://doc.rust-lang.org/nightly/reference/attributes.html
+
+use pin_project::pin_project;
+use std::{marker::PhantomPinned, pin::Pin};
+
+fn is_unpin<T: Unpin>() {}
+
+#[cfg(target_os = "linux")]
+pub struct Linux;
+#[cfg(not(target_os = "linux"))]
+pub struct Other;
+
+// Use this type to check that `cfg(any())` is working properly.
+// If `cfg(any())` is not working properly, `is_unpin` will fail.
+pub struct Any(PhantomPinned);
+
+#[test]
+fn cfg() {
+    // structs
+
+    #[pin_project]
+    pub struct SameName {
+        #[cfg(target_os = "linux")]
+        #[pin]
+        inner: Linux,
+        #[cfg(not(target_os = "linux"))]
+        #[pin]
+        inner: Other,
+        #[cfg(any())]
+        #[pin]
+        any: Any,
+    }
+
+    is_unpin::<SameName>();
+
+    #[cfg(target_os = "linux")]
+    let _x = SameName { inner: Linux };
+    #[cfg(not(target_os = "linux"))]
+    let _x = SameName { inner: Other };
+
+    #[pin_project]
+    pub struct DifferentName {
+        #[cfg(target_os = "linux")]
+        #[pin]
+        l: Linux,
+        #[cfg(not(target_os = "linux"))]
+        #[pin]
+        o: Other,
+        #[cfg(any())]
+        #[pin]
+        a: Any,
+    }
+
+    is_unpin::<DifferentName>();
+
+    #[cfg(target_os = "linux")]
+    let _x = DifferentName { l: Linux };
+    #[cfg(not(target_os = "linux"))]
+    let _x = DifferentName { o: Other };
+
+    #[pin_project]
+    pub struct TupleStruct(
+        #[cfg(target_os = "linux")]
+        #[pin]
+        Linux,
+        #[cfg(not(target_os = "linux"))]
+        #[pin]
+        Other,
+        #[cfg(any())]
+        #[pin]
+        Any,
+    );
+
+    is_unpin::<TupleStruct>();
+
+    #[cfg(target_os = "linux")]
+    let _x = TupleStruct(Linux);
+    #[cfg(not(target_os = "linux"))]
+    let _x = TupleStruct(Other);
+
+    // enums
+
+    #[pin_project]
+    pub enum Variant {
+        #[cfg(target_os = "linux")]
+        Inner(#[pin] Linux),
+        #[cfg(not(target_os = "linux"))]
+        Inner(#[pin] Other),
+
+        #[cfg(target_os = "linux")]
+        Linux(#[pin] Linux),
+        #[cfg(not(target_os = "linux"))]
+        Other(#[pin] Other),
+        #[cfg(any())]
+        Any(#[pin] Any),
+    }
+
+    is_unpin::<Variant>();
+
+    #[cfg(target_os = "linux")]
+    let _x = Variant::Inner(Linux);
+    #[cfg(not(target_os = "linux"))]
+    let _x = Variant::Inner(Other);
+
+    #[cfg(target_os = "linux")]
+    let _x = Variant::Linux(Linux);
+    #[cfg(not(target_os = "linux"))]
+    let _x = Variant::Other(Other);
+
+    #[pin_project]
+    pub enum Field {
+        SameName {
+            #[cfg(target_os = "linux")]
+            #[pin]
+            inner: Linux,
+            #[cfg(not(target_os = "linux"))]
+            #[pin]
+            inner: Other,
+            #[cfg(any())]
+            #[pin]
+            any: Any,
+        },
+        DifferentName {
+            #[cfg(target_os = "linux")]
+            #[pin]
+            l: Linux,
+            #[cfg(not(target_os = "linux"))]
+            #[pin]
+            w: Other,
+            #[cfg(any())]
+            #[pin]
+            any: Any,
+        },
+        TupleVariant(
+            #[cfg(target_os = "linux")]
+            #[pin]
+            Linux,
+            #[cfg(not(target_os = "linux"))]
+            #[pin]
+            Other,
+            #[cfg(any())]
+            #[pin]
+            Any,
+        ),
+    }
+
+    is_unpin::<Field>();
+
+    #[cfg(target_os = "linux")]
+    let _x = Field::SameName { inner: Linux };
+    #[cfg(not(target_os = "linux"))]
+    let _x = Field::SameName { inner: Other };
+
+    #[cfg(target_os = "linux")]
+    let _x = Field::DifferentName { l: Linux };
+    #[cfg(not(target_os = "linux"))]
+    let _x = Field::DifferentName { w: Other };
+
+    #[cfg(target_os = "linux")]
+    let _x = Field::TupleVariant(Linux);
+    #[cfg(not(target_os = "linux"))]
+    let _x = Field::TupleVariant(Other);
+}
+
+#[test]
+fn cfg_attr() {
+    #[pin_project]
+    pub struct SameCfg {
+        #[cfg(target_os = "linux")]
+        #[cfg_attr(target_os = "linux", pin)]
+        inner: Linux,
+        #[cfg(not(target_os = "linux"))]
+        #[cfg_attr(not(target_os = "linux"), pin)]
+        inner: Other,
+        #[cfg(any())]
+        #[cfg_attr(any(), pin)]
+        any: Any,
+    }
+
+    is_unpin::<SameCfg>();
+
+    #[cfg(target_os = "linux")]
+    let mut x = SameCfg { inner: Linux };
+    #[cfg(not(target_os = "linux"))]
+    let mut x = SameCfg { inner: Other };
+
+    let x = Pin::new(&mut x).project();
+    #[cfg(target_os = "linux")]
+    let _: Pin<&mut Linux> = x.inner;
+    #[cfg(not(target_os = "linux"))]
+    let _: Pin<&mut Other> = x.inner;
+
+    #[pin_project]
+    pub struct DifferentCfg {
+        #[cfg(target_os = "linux")]
+        #[cfg_attr(target_os = "linux", pin)]
+        inner: Linux,
+        #[cfg(not(target_os = "linux"))]
+        #[cfg_attr(target_os = "linux", pin)]
+        inner: Other,
+        #[cfg(any())]
+        #[cfg_attr(any(), pin)]
+        any: Any,
+    }
+
+    is_unpin::<DifferentCfg>();
+
+    #[cfg(target_os = "linux")]
+    let mut x = DifferentCfg { inner: Linux };
+    #[cfg(not(target_os = "linux"))]
+    let mut x = DifferentCfg { inner: Other };
+
+    let x = Pin::new(&mut x).project();
+    #[cfg(target_os = "linux")]
+    let _: Pin<&mut Linux> = x.inner;
+    #[cfg(not(target_os = "linux"))]
+    let _: &mut Other = x.inner;
+
+    #[cfg_attr(not(any()), pin_project)]
+    struct Foo<T> {
+        #[cfg_attr(not(any()), pin)]
+        inner: T,
+    }
+
+    let mut x = Foo { inner: 0_u8 };
+    let x = Pin::new(&mut x).project();
+    let _: Pin<&mut u8> = x.inner;
+}
+
+#[test]
+fn cfg_attr_any_packed() {
+    // Since `cfg(any())` can never be true, it is okay for this to pass.
+    #[pin_project]
+    #[cfg_attr(any(), repr(packed))]
+    struct Struct {
+        #[pin]
+        field: u32,
+    }
+}
diff --git a/third_party/rust/pin-project/tests/compiletest.rs b/third_party/rust/pin-project/tests/compiletest.rs
new file mode 100644
index 0000000000..cf3986fcb1
--- /dev/null
+++ b/third_party/rust/pin-project/tests/compiletest.rs
@@ -0,0 +1,16 @@
+#![cfg(pin_project_show_unpin_struct)]
+#![warn(unsafe_code)]
+#![warn(rust_2018_idioms, single_use_lifetimes)]
+
+#[ignore]
+#[test]
+fn ui() {
+    let t = trybuild::TestCases::new();
+    t.compile_fail("tests/ui/cfg/*.rs");
+    t.compile_fail("tests/ui/pin_project/*.rs");
+    t.compile_fail("tests/ui/pinned_drop/*.rs");
+    t.compile_fail("tests/ui/project/*.rs");
+    t.compile_fail("tests/ui/unsafe_unpin/*.rs");
+    t.compile_fail("tests/ui/unstable-features/*.rs");
+    t.pass("tests/ui/unstable-features/run-pass/*.rs");
+}
diff --git a/third_party/rust/pin-project/tests/no_infer_outlives.rs b/third_party/rust/pin-project/tests/no_infer_outlives.rs
new file mode 100644
index 0000000000..6602b62c99
--- /dev/null
+++ b/third_party/rust/pin-project/tests/no_infer_outlives.rs
@@ -0,0 +1,19 @@
+use pin_project::{pin_project, project};
+
+trait Bar<X> {
+    type Y;
+}
+
+struct Example<A>(A);
+
+impl<X, T> Bar<X> for Example<T> {
+    type Y = Option<T>;
+}
+
+#[pin_project]
+struct Foo<A, B> {
+    _x: <Example<A> as Bar<B>>::Y,
+}
+
+#[project]
+impl<A, B> Foo<A, B> {}
diff --git a/third_party/rust/pin-project/tests/pin_project.rs b/third_party/rust/pin-project/tests/pin_project.rs
new file mode 100644
index 0000000000..45f761a4ad
--- /dev/null
+++ b/third_party/rust/pin-project/tests/pin_project.rs
@@ -0,0 +1,552 @@
+#![no_std]
+#![warn(unsafe_code)]
+#![warn(rust_2018_idioms, single_use_lifetimes)]
+#![allow(dead_code)]
+
+use core::{marker::PhantomPinned, pin::Pin};
+use pin_project::{pin_project, pinned_drop, UnsafeUnpin};
+
+#[test]
+fn test_pin_project() {
+    #[pin_project]
+    struct Struct<T, U> {
+        #[pin]
+        field1: T,
+        field2: U,
+    }
+
+    let mut foo = Struct { field1: 1, field2: 2 };
+
+    let mut foo_orig = Pin::new(&mut foo);
+    let foo = foo_orig.as_mut().project();
+
+    let x: Pin<&mut i32> = foo.field1;
+    assert_eq!(*x, 1);
+
+    let y: &mut i32 = foo.field2;
+    assert_eq!(*y, 2);
+
+    assert_eq!(foo_orig.as_ref().field1, 1);
+    assert_eq!(foo_orig.as_ref().field2, 2);
+
+    let mut foo = Struct { field1: 1, field2: 2 };
+
+    let foo = Pin::new(&mut foo).project();
+
+    let __StructProjection { field1, field2 } = foo;
+    let _: Pin<&mut i32> = field1;
+    let _: &mut i32 = field2;
+
+    #[pin_project]
+    struct TupleStruct<T, U>(#[pin] T, U);
+
+    let mut bar = TupleStruct(1, 2);
+
+    let bar = Pin::new(&mut bar).project();
+
+    let x: Pin<&mut i32> = bar.0;
+    assert_eq!(*x, 1);
+
+    let y: &mut i32 = bar.1;
+    assert_eq!(*y, 2);
+
+    #[pin_project]
+    #[derive(Eq, PartialEq, Debug)]
+    enum Enum<A, B, C, D> {
+        Variant1(#[pin] A, B),
+        Variant2 {
+            #[pin]
+            field1: C,
+            field2: D,
+        },
+        None,
+    }
+
+    let mut baz = Enum::Variant1(1, 2);
+
+    let mut baz_orig = Pin::new(&mut baz);
+    let baz = baz_orig.as_mut().project();
+
+    match baz {
+        __EnumProjection::Variant1(x, y) => {
+            let x: Pin<&mut i32> = x;
+            assert_eq!(*x, 1);
+
+            let y: &mut i32 = y;
+            assert_eq!(*y, 2);
+        }
+        __EnumProjection::Variant2 { field1, field2 } => {
+            let _x: Pin<&mut i32> = field1;
+            let _y: &mut i32 = field2;
+        }
+        __EnumProjection::None => {}
+    }
+
+    assert_eq!(Pin::into_ref(baz_orig).get_ref(), &Enum::Variant1(1, 2));
+
+    let mut baz = Enum::Variant2 { field1: 3, field2: 4 };
+
+    let mut baz = Pin::new(&mut baz).project();
+
+    match &mut baz {
+        __EnumProjection::Variant1(x, y) => {
+            let _x: &mut Pin<&mut i32> = x;
+            let _y: &mut &mut i32 = y;
+        }
+        __EnumProjection::Variant2 { field1, field2 } => {
+            let x: &mut Pin<&mut i32> = field1;
+            assert_eq!(**x, 3);
+
+            let y: &mut &mut i32 = field2;
+            assert_eq!(**y, 4);
+        }
+        __EnumProjection::None => {}
+    }
+
+    if let __EnumProjection::Variant2 { field1, field2 } = baz {
+        let x: Pin<&mut i32> = field1;
+        assert_eq!(*x, 3);
+
+        let y: &mut i32 = field2;
+        assert_eq!(*y, 4);
+    }
+}
+
+#[test]
+fn enum_project_set() {
+    #[pin_project]
+    #[derive(Eq, PartialEq, Debug)]
+    enum Bar {
+        Variant1(#[pin] u8),
+        Variant2(bool),
+    }
+
+    let mut bar = Bar::Variant1(25);
+    let mut bar_orig = Pin::new(&mut bar);
+    let bar_proj = bar_orig.as_mut().project();
+
+    match bar_proj {
+        __BarProjection::Variant1(val) => {
+            let new_bar = Bar::Variant2(val.as_ref().get_ref() == &25);
+            bar_orig.set(new_bar);
+        }
+        _ => unreachable!(),
+    }
+
+    assert_eq!(bar, Bar::Variant2(true));
+}
+
+#[test]
+fn where_clause_and_associated_type_fields() {
+    #[pin_project]
+    struct Struct1<I>
+    where
+        I: Iterator,
+    {
+        #[pin]
+        field1: I,
+        field2: I::Item,
+    }
+
+    #[pin_project]
+    struct Struct2<I, J>
+    where
+        I: Iterator<Item = J>,
+    {
+        #[pin]
+        field1: I,
+        field2: J,
+    }
+
+    #[pin_project]
+    pub struct Struct3<T>
+    where
+        T: 'static,
+    {
+        field: T,
+    }
+
+    trait Static: 'static {}
+
+    impl<T> Static for Struct3<T> {}
+
+    #[pin_project]
+    enum Enum<I>
+    where
+        I: Iterator,
+    {
+        Variant1(#[pin] I),
+        Variant2(I::Item),
+    }
+}
+
+#[allow(explicit_outlives_requirements)] // https://github.com/rust-lang/rust/issues/60993
+#[test]
+fn unsized_in_where_clause() {
+    #[pin_project]
+    struct Struct<I>
+    where
+        I: ?Sized,
+    {
+        #[pin]
+        field: I,
+    }
+}
+
+#[test]
+fn derive_copy() {
+    #[pin_project]
+    #[derive(Clone, Copy)]
+    struct Struct<T> {
+        val: T,
+    }
+
+    fn is_copy<T: Copy>() {}
+
+    is_copy::<Struct<u8>>();
+}
+
+#[test]
+fn move_out() {
+    struct NotCopy;
+
+    #[pin_project]
+    struct Struct {
+        val: NotCopy,
+    }
+
+    let foo = Struct { val: NotCopy };
+    let _val: NotCopy = foo.val;
+
+    #[pin_project]
+    enum Enum {
+        Variant(NotCopy),
+    }
+
+    let bar = Enum::Variant(NotCopy);
+    let _val: NotCopy = match bar {
+        Enum::Variant(val) => val,
+    };
+}
+
+#[test]
+fn trait_bounds_on_type_generics() {
+    #[pin_project]
+    pub struct Struct1<'a, T: ?Sized> {
+        field: &'a mut T,
+    }
+
+    #[pin_project]
+    pub struct Struct2<'a, T: ::core::fmt::Debug> {
+        field: &'a mut T,
+    }
+
+    #[pin_project]
+    pub struct Struct3<'a, T: core::fmt::Debug> {
+        field: &'a mut T,
+    }
+
+    #[pin_project]
+    pub struct Struct4<'a, T: core::fmt::Debug + core::fmt::Display> {
+        field: &'a mut T,
+    }
+
+    #[pin_project]
+    pub struct Struct5<'a, T: core::fmt::Debug + ?Sized> {
+        field: &'a mut T,
+    }
+
+    #[pin_project]
+    pub struct Struct6<'a, T: core::fmt::Debug = [u8; 16]> {
+        field: &'a mut T,
+    }
+
+    let _: Struct6<'_> = Struct6 { field: &mut [0u8; 16] };
+
+    #[pin_project]
+    pub struct Struct7<T: 'static> {
+        field: T,
+    }
+
+    trait Static: 'static {}
+
+    impl<T> Static for Struct7<T> {}
+
+    #[pin_project]
+    pub struct Struct8<'a, 'b: 'a> {
+        field1: &'a u8,
+        field2: &'b u8,
+    }
+
+    #[pin_project]
+    pub struct TupleStruct<'a, T: ?Sized>(&'a mut T);
+
+    #[pin_project]
+    enum Enum<'a, T: ?Sized> {
+        Variant(&'a mut T),
+    }
+}
+
+#[test]
+fn overlapping_lifetime_names() {
+    #[pin_project]
+    pub struct Foo<'pin, T> {
+        #[pin]
+        field: &'pin mut T,
+    }
+}
+
+#[test]
+fn combine() {
+    #[pin_project(PinnedDrop, UnsafeUnpin)]
+    pub struct Foo<T> {
+        field1: u8,
+        #[pin]
+        field2: T,
+    }
+
+    #[pinned_drop]
+    impl<T> PinnedDrop for Foo<T> {
+        fn drop(self: Pin<&mut Self>) {}
+    }
+
+    #[allow(unsafe_code)]
+    unsafe impl<T: Unpin> UnsafeUnpin for Foo<T> {}
+}
+
+#[test]
+fn private_type_in_public_type() {
+    #[pin_project]
+    pub struct PublicStruct<T> {
+        #[pin]
+        inner: PrivateStruct<T>,
+    }
+
+    struct PrivateStruct<T>(T);
+}
+
+#[test]
+fn lifetime_project() {
+    #[pin_project]
+    struct Struct1<T, U> {
+        #[pin]
+        pinned: T,
+        unpinned: U,
+    }
+
+    #[pin_project]
+    struct Struct2<'a, T, U> {
+        #[pin]
+        pinned: &'a mut T,
+        unpinned: U,
+    }
+
+    #[pin_project]
+    enum Enum<T, U> {
+        Variant {
+            #[pin]
+            pinned: T,
+            unpinned: U,
+        },
+    }
+
+    impl<T, U> Struct1<T, U> {
+        fn get_pin_ref<'a>(self: Pin<&'a Self>) -> Pin<&'a T> {
+            self.project_ref().pinned
+        }
+        fn get_pin_mut<'a>(self: Pin<&'a mut Self>) -> Pin<&'a mut T> {
+            self.project().pinned
+        }
+    }
+
+    impl<'b, T, U> Struct2<'b, T, U> {
+        fn get_pin_ref<'a>(self: Pin<&'a Self>) -> Pin<&'a &'b mut T> {
+            self.project_ref().pinned
+        }
+        fn get_pin_mut<'a>(self: Pin<&'a mut Self>) -> Pin<&'a mut &'b mut T> {
+            self.project().pinned
+        }
+    }
+
+    impl<T, U> Enum<T, U> {
+        fn get_pin_ref<'a>(self: Pin<&'a Self>) -> Pin<&'a T> {
+            match self.project_ref() {
+                __EnumProjectionRef::Variant { pinned, .. } => pinned,
+            }
+        }
+        fn get_pin_mut<'a>(self: Pin<&'a mut Self>) -> Pin<&'a mut T> {
+            match self.project() {
+                __EnumProjection::Variant { pinned, .. } => pinned,
+            }
+        }
+    }
+}
+
+#[rustversion::since(1.36)]
+#[test]
+fn lifetime_project_elided() {
+    #[pin_project]
+    struct Struct1<T, U> {
+        #[pin]
+        pinned: T,
+        unpinned: U,
+    }
+
+    #[pin_project]
+    struct Struct2<'a, T, U> {
+        #[pin]
+        pinned: &'a mut T,
+        unpinned: U,
+    }
+
+    #[pin_project]
+    enum Enum<T, U> {
+        Variant {
+            #[pin]
+            pinned: T,
+            unpinned: U,
+        },
+    }
+
+    impl<T, U> Struct1<T, U> {
+        fn get_pin_ref(self: Pin<&Self>) -> Pin<&T> {
+            self.project_ref().pinned
+        }
+        fn get_pin_mut(self: Pin<&mut Self>) -> Pin<&mut T> {
+            self.project().pinned
+        }
+    }
+
+    impl<'b, T, U> Struct2<'b, T, U> {
+        fn get_pin_ref(self: Pin<&Self>) -> Pin<&&'b mut T> {
+            self.project_ref().pinned
+        }
+        fn get_pin_mut(self: Pin<&mut Self>) -> Pin<&mut &'b mut T> {
+            self.project().pinned
+        }
+    }
+
+    impl<T, U> Enum<T, U> {
+        fn get_pin_ref(self: Pin<&Self>) -> Pin<&T> {
+            match self.project_ref() {
+                __EnumProjectionRef::Variant { pinned, .. } => pinned,
+            }
+        }
+        fn get_pin_mut(self: Pin<&mut Self>) -> Pin<&mut T> {
+            match self.project() {
+                __EnumProjection::Variant { pinned, .. } => pinned,
+            }
+        }
+    }
+}
+
+mod visibility {
+    use pin_project::pin_project;
+
+    #[pin_project]
+    pub(crate) struct A {
+        pub b: u8,
+    }
+}
+
+#[test]
+fn visibility() {
+    let mut x = visibility::A { b: 0 };
+    let x = Pin::new(&mut x);
+    let y = x.as_ref().project_ref();
+    let _: &u8 = y.b;
+    let y = x.project();
+    let _: &mut u8 = y.b;
+}
+
+#[test]
+fn trivial_bounds() {
+    #[pin_project]
+    pub struct NoGenerics {
+        #[pin]
+        field: PhantomPinned,
+    }
+}
+
+#[test]
+fn dst() {
+    #[pin_project]
+    pub struct A<T: ?Sized> {
+        x: T,
+    }
+
+    let _: &mut A<dyn core::fmt::Debug> = &mut A { x: 0u8 } as _;
+
+    #[pin_project]
+    pub struct B<T: ?Sized> {
+        #[pin]
+        x: T,
+    }
+
+    #[pin_project]
+    pub struct C<T: ?Sized>(T);
+
+    #[pin_project]
+    pub struct D<T: ?Sized>(#[pin] T);
+}
+
+#[test]
+fn dyn_type() {
+    #[pin_project]
+    struct Struct1 {
+        a: i32,
+        f: dyn core::fmt::Debug,
+    }
+
+    #[pin_project]
+    struct Struct2 {
+        a: i32,
+        #[pin]
+        f: dyn core::fmt::Debug,
+    }
+
+    #[pin_project]
+    struct Struct3 {
+        a: i32,
+        f: dyn core::fmt::Debug + Send,
+    }
+
+    #[pin_project]
+    struct Struct4 {
+        a: i32,
+        #[pin]
+        f: dyn core::fmt::Debug + Send,
+    }
+}
+
+#[test]
+fn self_in_where_clause() {
+    pub trait Trait {}
+
+    #[pin_project]
+    pub struct Struct1<T>
+    where
+        Self: Trait,
+    {
+        x: T,
+    }
+
+    impl<T> Trait for Struct1<T> {}
+
+    pub trait Trait2 {
+        type Foo;
+    }
+
+    #[pin_project]
+    pub struct Struct2<T>
+    where
+        Self: Trait2<Foo = Struct1<T>>,
+        <Self as Trait2>::Foo: Trait,
+    {
+        x: T,
+    }
+
+    impl<T> Trait2 for Struct2<T> {
+        type Foo = Struct1<T>;
+    }
+}
diff --git a/third_party/rust/pin-project/tests/pinned_drop.rs b/third_party/rust/pin-project/tests/pinned_drop.rs
new file mode 100644
index 0000000000..932f636000
--- /dev/null
+++ b/third_party/rust/pin-project/tests/pinned_drop.rs
@@ -0,0 +1,210 @@
+#![warn(unsafe_code)]
+#![warn(rust_2018_idioms, single_use_lifetimes)]
+#![allow(dead_code)]
+
+use pin_project::{pin_project, pinned_drop};
+use std::pin::Pin;
+
+#[test]
+fn safe_project() {
+    #[pin_project(PinnedDrop)]
+    pub struct Struct<'a> {
+        was_dropped: &'a mut bool,
+        #[pin]
+        field: u8,
+    }
+
+    #[pinned_drop]
+    impl PinnedDrop for Struct<'_> {
+        fn drop(self: Pin<&mut Self>) {
+            **self.project().was_dropped = true;
+        }
+    }
+
+    let mut was_dropped = false;
+    drop(Struct { was_dropped: &mut was_dropped, field: 42 });
+    assert!(was_dropped);
+}
+
+#[test]
+fn mut_self_argument() {
+    #[pin_project(PinnedDrop)]
+    struct Struct {
+        data: usize,
+    }
+
+    #[pinned_drop]
+    impl PinnedDrop for Struct {
+        fn drop(mut self: Pin<&mut Self>) {
+            let _: &mut _ = &mut self.data;
+        }
+    }
+}
+
+#[test]
+fn self_in_vec() {
+    #[pin_project(PinnedDrop)]
+    struct Struct {
+        data: usize,
+    }
+
+    #[pinned_drop]
+    impl PinnedDrop for Struct {
+        fn drop(self: Pin<&mut Self>) {
+            let _: Vec<_> = vec![self.data];
+        }
+    }
+}
+
+#[test]
+fn self_in_macro_containing_fn() {
+    #[pin_project(PinnedDrop)]
+    pub struct Struct {
+        data: usize,
+    }
+
+    macro_rules! emit {
+        ($($tt:tt)*) => {
+            $($tt)*
+        };
+    }
+
+    #[pinned_drop]
+    impl PinnedDrop for Struct {
+        fn drop(self: Pin<&mut Self>) {
+            let _ = emit!({
+                impl Struct {
+                    pub fn f(self) {}
+                }
+            });
+            self.data;
+        }
+    }
+}
+
+#[test]
+fn self_call() {
+    #[pin_project(PinnedDrop)]
+    pub struct Struct {
+        data: usize,
+    }
+
+    trait Trait {
+        fn self_ref(&self) {}
+        fn self_pin_ref(self: Pin<&Self>) {}
+        fn self_mut(&mut self) {}
+        fn self_pin_mut(self: Pin<&mut Self>) {}
+        fn assoc_fn(_this: Pin<&mut Self>) {}
+    }
+
+    impl Trait for Struct {}
+
+    #[pinned_drop]
+    impl PinnedDrop for Struct {
+        fn drop(mut self: Pin<&mut Self>) {
+            self.self_ref();
+            self.as_ref().self_pin_ref();
+            self.self_mut();
+            self.as_mut().self_pin_mut();
+            Self::assoc_fn(self.as_mut());
+            <Self>::assoc_fn(self.as_mut());
+        }
+    }
+}
+
+// See also `ui/pinned_drop/self.rs`.
+#[test]
+fn self_expr() {
+    #[pin_project(PinnedDrop)]
+    pub struct Struct {
+        x: usize,
+    }
+
+    #[pinned_drop]
+    impl PinnedDrop for Struct {
+        fn drop(mut self: Pin<&mut Self>) {
+            let _: Self = Self { x: 0 };
+        }
+    }
+
+    #[pin_project(PinnedDrop)]
+    pub struct TupleStruct(usize);
+
+    #[pinned_drop]
+    impl PinnedDrop for TupleStruct {
+        fn drop(mut self: Pin<&mut Self>) {
+            let _: Self = Self(0);
+        }
+    }
+
+    #[rustversion::since(1.37)]
+    #[pin_project(PinnedDrop)]
+    pub enum Enum {
+        StructVariant { x: usize },
+        TupleVariant(usize),
+    }
+
+    #[rustversion::since(1.37)]
+    #[pinned_drop]
+    impl PinnedDrop for Enum {
+        fn drop(mut self: Pin<&mut Self>) {
+            // let _: Self = Self::StructVariant { x: 0 }; //~ ERROR can't use generic parameters from outer function [E0401]
+            let _: Self = Self::TupleVariant(0);
+        }
+    }
+}
+
+// See also `ui/pinned_drop/self.rs`.
+#[test]
+fn self_pat() {
+    #[pin_project(PinnedDrop)]
+    pub struct Struct {
+        x: usize,
+    }
+
+    #[pinned_drop]
+    impl PinnedDrop for Struct {
+        fn drop(mut self: Pin<&mut Self>) {
+            // match *self {
+            //     Self { x: _ } => {} //~ ERROR can't use generic parameters from outer function [E0401]
+            // }
+            // if let Self { x: _ } = *self {} //~ ERROR can't use generic parameters from outer function [E0401]
+            // let Self { x: _ } = *self; //~ ERROR can't use generic parameters from outer function [E0401]
+        }
+    }
+
+    #[pin_project(PinnedDrop)]
+    pub struct TupleStruct(usize);
+
+    #[pinned_drop]
+    impl PinnedDrop for TupleStruct {
+        #[allow(irrefutable_let_patterns)]
+        fn drop(mut self: Pin<&mut Self>) {
+            match *self {
+                Self(_) => {}
+            }
+            if let Self(_) = *self {}
+            let Self(_) = *self;
+        }
+    }
+
+    #[rustversion::since(1.37)]
+    #[pin_project(PinnedDrop)]
+    pub enum Enum {
+        StructVariant { x: usize },
+        TupleVariant(usize),
+    }
+
+    #[rustversion::since(1.37)]
+    #[pinned_drop]
+    impl PinnedDrop for Enum {
+        fn drop(mut self: Pin<&mut Self>) {
+            // match *self {
+            //     Self::StructVariant { x: _ } => {} //~ ERROR can't use generic parameters from outer function [E0401]
+            //     Self::TupleVariant(_) => {} //~ ERROR can't use generic parameters from outer function [E0401]
+            // }
+            // if let Self::StructVariant { x: _ } = *self {} //~ ERROR can't use generic parameters from outer function [E0401]
+            // if let Self::TupleVariant(_) = *self {} //~ ERROR can't use generic parameters from outer function [E0401]
+        }
+    }
+}
diff --git a/third_party/rust/pin-project/tests/project.rs b/third_party/rust/pin-project/tests/project.rs
new file mode 100644
index 0000000000..b88ccd839e
--- /dev/null
+++ b/third_party/rust/pin-project/tests/project.rs
@@ -0,0 +1,217 @@
+#![warn(unsafe_code)]
+#![warn(rust_2018_idioms, single_use_lifetimes)]
+#![allow(dead_code)]
+
+// This hack is needed until https://github.com/rust-lang/rust/pull/69201
+// makes it way into stable.
+// Ceurrently, `#[attr] if true {}` doesn't even *parse* on stable,
+// which means that it will error even behind a `#[rustversion::nightly]`
+//
+// This trick makes sure that we don't even attempt to parse
+// the `#[project] if let _` test on stable.
+#[rustversion::nightly]
+include!("project_if_attr.rs.in");
+
+use pin_project::{pin_project, project};
+use std::pin::Pin;
+
+#[project] // Nightly does not need a dummy attribute to the function.
+#[test]
+fn project_stmt_expr() {
+    // struct
+
+    #[pin_project]
+    struct Foo<T, U> {
+        #[pin]
+        field1: T,
+        field2: U,
+    }
+
+    let mut foo = Foo { field1: 1, field2: 2 };
+
+    #[project]
+    let Foo { field1, field2 } = Pin::new(&mut foo).project();
+
+    let x: Pin<&mut i32> = field1;
+    assert_eq!(*x, 1);
+
+    let y: &mut i32 = field2;
+    assert_eq!(*y, 2);
+
+    // tuple struct
+
+    #[pin_project]
+    struct Bar<T, U>(#[pin] T, U);
+
+    let mut bar = Bar(1, 2);
+
+    #[project]
+    let Bar(x, y) = Pin::new(&mut bar).project();
+
+    let x: Pin<&mut i32> = x;
+    assert_eq!(*x, 1);
+
+    let y: &mut i32 = y;
+    assert_eq!(*y, 2);
+
+    // enum
+
+    #[pin_project]
+    enum Baz<A, B, C, D> {
+        Variant1(#[pin] A, B),
+        Variant2 {
+            #[pin]
+            field1: C,
+            field2: D,
+        },
+        None,
+    }
+
+    let mut baz = Baz::Variant1(1, 2);
+
+    let mut baz = Pin::new(&mut baz).project();
+
+    #[project]
+    match &mut baz {
+        Baz::Variant1(x, y) => {
+            let x: &mut Pin<&mut i32> = x;
+            assert_eq!(**x, 1);
+
+            let y: &mut &mut i32 = y;
+            assert_eq!(**y, 2);
+        }
+        Baz::Variant2 { field1, field2 } => {
+            let _x: &mut Pin<&mut i32> = field1;
+            let _y: &mut &mut i32 = field2;
+        }
+        Baz::None => {}
+    }
+
+    #[project]
+    let val = match &mut baz {
+        Baz::Variant1(_, _) => true,
+        Baz::Variant2 { .. } => false,
+        Baz::None => false,
+    };
+    assert_eq!(val, true);
+}
+
+#[test]
+fn project_impl() {
+    #[pin_project]
+    struct HasGenerics<T, U> {
+        #[pin]
+        field1: T,
+        field2: U,
+    }
+
+    #[project]
+    impl<T, U> HasGenerics<T, U> {
+        fn a(self) {
+            let Self { field1, field2 } = self;
+
+            let _x: Pin<&mut T> = field1;
+            let _y: &mut U = field2;
+        }
+    }
+
+    #[pin_project]
+    struct NoneGenerics {
+        #[pin]
+        field1: i32,
+        field2: u32,
+    }
+
+    #[project]
+    impl NoneGenerics {}
+
+    #[pin_project]
+    struct HasLifetimes<'a, T, U> {
+        #[pin]
+        field1: &'a mut T,
+        field2: U,
+    }
+
+    #[project]
+    impl<T, U> HasLifetimes<'_, T, U> {}
+
+    #[pin_project]
+    struct HasOverlappingLifetimes<'pin, T, U> {
+        #[pin]
+        field1: &'pin mut T,
+        field2: U,
+    }
+
+    #[allow(single_use_lifetimes)]
+    #[project]
+    impl<'pin, T, U> HasOverlappingLifetimes<'pin, T, U> {}
+
+    #[pin_project]
+    struct HasOverlappingLifetimes2<T, U> {
+        #[pin]
+        field1: T,
+        field2: U,
+    }
+
+    #[allow(single_use_lifetimes)]
+    #[project]
+    impl<T, U> HasOverlappingLifetimes2<T, U> {
+        fn foo<'pin>(&'pin self) {}
+    }
+}
+
+#[pin_project]
+struct A {
+    #[pin]
+    field: u8,
+}
+
+mod project_use_1 {
+    use crate::A;
+    use core::pin::Pin;
+    use pin_project::project;
+
+    #[project]
+    use crate::A;
+
+    #[project]
+    #[test]
+    fn project_use() {
+        let mut x = A { field: 0 };
+        #[project]
+        let A { field } = Pin::new(&mut x).project();
+        let _: Pin<&mut u8> = field;
+    }
+}
+
+mod project_use_2 {
+    #[project]
+    use crate::A;
+    use pin_project::project;
+
+    #[project]
+    impl A {
+        fn project_use(self) {}
+    }
+}
+
+#[pin_project]
+struct StructWhereClause<T>
+where
+    T: Copy,
+{
+    field: T,
+}
+
+#[pin_project]
+struct TupleStructWhereClause<T>(T)
+where
+    T: Copy;
+
+#[pin_project]
+enum EnumWhereClause<T>
+where
+    T: Copy,
+{
+    Variant(T),
+}
diff --git a/third_party/rust/pin-project/tests/project_if_attr.rs.in b/third_party/rust/pin-project/tests/project_if_attr.rs.in
new file mode 100644
index 0000000000..2d1eb26785
--- /dev/null
+++ b/third_party/rust/pin-project/tests/project_if_attr.rs.in
@@ -0,0 +1,29 @@
+// FIXME: Once https://github.com/rust-lang/rust/pull/69201 makes its
+// way into stable, move this back into `project.rs
+
+#[test]
+#[project]
+fn project_if_let() {
+    #[pin_project]
+    enum Foo<A, B> {
+        Variant1(#[pin] A),
+        Variant2(u8),
+        Variant3 {
+            #[pin] field: B
+        }
+    }
+
+    let mut foo: Foo<bool, f32> = Foo::Variant1(true);
+    let foo = Pin::new(&mut foo).project();
+
+    #[project]
+    if let Foo::Variant1(a) = foo {
+        let a: Pin<&mut bool> = a;
+        assert_eq!(*a, true);
+    } else if let Foo::Variant2(_) = foo {
+        unreachable!();
+    } else if let Foo::Variant3 { .. } = foo {
+        unreachable!();
+    }
+}
+
diff --git a/third_party/rust/pin-project/tests/project_ref.rs b/third_party/rust/pin-project/tests/project_ref.rs
new file mode 100644
index 0000000000..a90e016100
--- /dev/null
+++ b/third_party/rust/pin-project/tests/project_ref.rs
@@ -0,0 +1,151 @@
+#![warn(unsafe_code)]
+#![warn(rust_2018_idioms, single_use_lifetimes)]
+#![allow(dead_code)]
+
+use pin_project::{pin_project, project_ref};
+use std::pin::Pin;
+
+#[project_ref] // Nightly does not need a dummy attribute to the function.
+#[test]
+fn project_stmt_expr() {
+    // struct
+
+    #[pin_project]
+    struct Foo<T, U> {
+        #[pin]
+        field1: T,
+        field2: U,
+    }
+
+    let foo = Foo { field1: 1, field2: 2 };
+
+    #[project_ref]
+    let Foo { field1, field2 } = Pin::new(&foo).project_ref();
+
+    let x: Pin<&i32> = field1;
+    assert_eq!(*x, 1);
+
+    let y: &i32 = field2;
+    assert_eq!(*y, 2);
+
+    // tuple struct
+
+    #[pin_project]
+    struct Bar<T, U>(#[pin] T, U);
+
+    let bar = Bar(1, 2);
+
+    #[project_ref]
+    let Bar(x, y) = Pin::new(&bar).project_ref();
+
+    let x: Pin<&i32> = x;
+    assert_eq!(*x, 1);
+
+    let y: &i32 = y;
+    assert_eq!(*y, 2);
+
+    // enum
+
+    #[pin_project]
+    enum Baz<A, B, C, D> {
+        Variant1(#[pin] A, B),
+        Variant2 {
+            #[pin]
+            field1: C,
+            field2: D,
+        },
+        None,
+    }
+
+    let baz = Baz::Variant1(1, 2);
+
+    let baz = Pin::new(&baz).project_ref();
+
+    #[project_ref]
+    match &baz {
+        Baz::Variant1(x, y) => {
+            let x: &Pin<&i32> = x;
+            assert_eq!(**x, 1);
+
+            let y: &&i32 = y;
+            assert_eq!(**y, 2);
+        }
+        Baz::Variant2 { field1, field2 } => {
+            let _x: &Pin<&i32> = field1;
+            let _y: &&i32 = field2;
+        }
+        Baz::None => {}
+    }
+
+    #[project_ref]
+    let val = match &baz {
+        Baz::Variant1(_, _) => true,
+        Baz::Variant2 { .. } => false,
+        Baz::None => false,
+    };
+    assert_eq!(val, true);
+}
+
+#[test]
+fn project_impl() {
+    #[pin_project]
+    struct HasGenerics<T, U> {
+        #[pin]
+        field1: T,
+        field2: U,
+    }
+
+    #[project_ref]
+    impl<T, U> HasGenerics<T, U> {
+        fn a(self) {
+            let Self { field1, field2 } = self;
+
+            let _x: Pin<&T> = field1;
+            let _y: &U = field2;
+        }
+    }
+
+    #[pin_project]
+    struct NoneGenerics {
+        #[pin]
+        field1: i32,
+        field2: u32,
+    }
+
+    #[project_ref]
+    impl NoneGenerics {}
+
+    #[pin_project]
+    struct HasLifetimes<'a, T, U> {
+        #[pin]
+        field1: &'a mut T,
+        field2: U,
+    }
+
+    #[project_ref]
+    impl<T, U> HasLifetimes<'_, T, U> {}
+
+    #[pin_project]
+    struct HasOverlappingLifetimes<'pin, T, U> {
+        #[pin]
+        field1: &'pin mut T,
+        field2: U,
+    }
+
+    #[allow(single_use_lifetimes)]
+    #[project_ref]
+    impl<'pin, T, U> HasOverlappingLifetimes<'pin, T, U> {}
+
+    #[pin_project]
+    struct HasOverlappingLifetimes2<T, U> {
+        #[pin]
+        field1: T,
+        field2: U,
+    }
+
+    #[allow(single_use_lifetimes)]
+    #[project_ref]
+    impl<T, U> HasOverlappingLifetimes2<T, U> {
+        fn foo<'pin>(&'pin self) {}
+    }
+}
diff --git a/third_party/rust/pin-project/tests/repr_packed.rs b/third_party/rust/pin-project/tests/repr_packed.rs
new file mode 100644
index 0000000000..3b196511b7
--- /dev/null
+++ b/third_party/rust/pin-project/tests/repr_packed.rs
@@ -0,0 +1,50 @@
+#![warn(unsafe_code)]
+#![warn(rust_2018_idioms, single_use_lifetimes)]
+#![allow(dead_code)]
+#![deny(safe_packed_borrows)]
+
+use std::cell::Cell;
+
+// Ensure that the compiler doesn't copy the fields
+// of #[repr(packed)] types during drop, if the field has alignment 1
+// (that is, any reference to the field is guaranteed to have proper alignment)
+// We are currently unable to statically prevent the usage of #[pin_project]
+// on #[repr(packed)] types composed entirely of fields of alignment 1.
+// This shouldn't lead to undefined behavior, as long as the compiler doesn't
+// try to move the field anyway during drop.
+//
+// This tests validates that the compiler is doing what we expect.
+#[test]
+fn weird_repr_packed() {
+    // We keep track of the field address during
+    // drop using a thread local, to avoid changing
+    // the layout of our #[repr(packed)] type.
+    thread_local! {
+        static FIELD_ADDR: Cell<usize> = Cell::new(0);
+    }
+
+    #[repr(packed)]
+    struct Foo {
+        field: u8,
+    }
+
+    impl Drop for Foo {
+        fn drop(&mut self) {
+            FIELD_ADDR.with(|f| {
+                f.set(&self.field as *const u8 as usize);
+            })
+        }
+    }
+
+    let field_addr = {
+        // We let this field drop by going out of scope,
+        // rather than explicitly calling drop(foo).
+        // Calling drop(foo) causes 'foo' to be moved
+        // into the 'drop' function, resulting in a different
+        // address.
+        let foo = Foo { field: 27 };
+        let field_addr = &foo.field as *const u8 as usize;
+        field_addr
+    };
+    assert_eq!(field_addr, FIELD_ADDR.with(|f| f.get()));
+}
diff --git a/third_party/rust/pin-project/tests/ui/cfg/cfg_attr-resolve.rs b/third_party/rust/pin-project/tests/ui/cfg/cfg_attr-resolve.rs
new file mode 100644
index 0000000000..e16f3e8de2
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/cfg/cfg_attr-resolve.rs
@@ -0,0 +1,11 @@
+use std::pin::Pin;
+
+#[cfg_attr(any(), pin_project::pin_project)]
+struct Foo<T> {
+    inner: T,
+}
+
+fn main() {
+    let mut x = Foo { inner: 0_u8 };
+    let _x = Pin::new(&mut x).project(); //~ ERROR E0599
+}
diff --git a/third_party/rust/pin-project/tests/ui/cfg/cfg_attr-resolve.stderr b/third_party/rust/pin-project/tests/ui/cfg/cfg_attr-resolve.stderr
new file mode 100644
index 0000000000..45af3ae05a
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/cfg/cfg_attr-resolve.stderr
@@ -0,0 +1,5 @@
+error[E0599]: no method named `project` found for struct `std::pin::Pin<&mut Foo<u8>>` in the current scope
+  --> $DIR/cfg_attr-resolve.rs:10:31
+   |
+10 |     let _x = Pin::new(&mut x).project(); //~ ERROR E0599
+   |                               ^^^^^^^ method not found in `std::pin::Pin<&mut Foo<u8>>`
diff --git a/third_party/rust/pin-project/tests/ui/cfg/cfg_attr-type-mismatch.rs b/third_party/rust/pin-project/tests/ui/cfg/cfg_attr-type-mismatch.rs
new file mode 100644
index 0000000000..2807c8768b
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/cfg/cfg_attr-type-mismatch.rs
@@ -0,0 +1,24 @@
+use pin_project::pin_project;
+use std::pin::Pin;
+
+#[cfg_attr(not(any()), pin_project)]
+struct Foo<T> {
+    #[cfg_attr(any(), pin)]
+    inner: T,
+}
+
+#[cfg_attr(not(any()), pin_project)]
+struct Bar<T> {
+    #[cfg_attr(not(any()), pin)]
+    inner: T,
+}
+
+fn main() {
+    let mut x = Foo { inner: 0_u8 };
+    let x = Pin::new(&mut x).project();
+    let _: Pin<&mut u8> = x.inner; //~ ERROR E0308
+
+    let mut x = Bar { inner: 0_u8 };
+    let x = Pin::new(&mut x).project();
+    let _: &mut u8 = x.inner; //~ ERROR E0308
+}
diff --git a/third_party/rust/pin-project/tests/ui/cfg/cfg_attr-type-mismatch.stderr b/third_party/rust/pin-project/tests/ui/cfg/cfg_attr-type-mismatch.stderr
new file mode 100644
index 0000000000..286829911f
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/cfg/cfg_attr-type-mismatch.stderr
@@ -0,0 +1,23 @@
+error[E0308]: mismatched types
+  --> $DIR/cfg_attr-type-mismatch.rs:19:27
+   |
+19 |     let _: Pin<&mut u8> = x.inner; //~ ERROR E0308
+   |            ------------   ^^^^^^^ expected struct `std::pin::Pin`, found `&mut u8`
+   |            |
+   |            expected due to this
+   |
+   = note:         expected struct `std::pin::Pin<&mut u8>`
+           found mutable reference `&mut u8`
+
+error[E0308]: mismatched types
+  --> $DIR/cfg_attr-type-mismatch.rs:23:22
+   |
+23 |     let _: &mut u8 = x.inner; //~ ERROR E0308
+   |            -------   ^^^^^^^
+   |            |         |
+   |            |         expected `&mut u8`, found struct `std::pin::Pin`
+   |            |         help: consider mutably borrowing here: `&mut x.inner`
+   |            expected due to this
+   |
+   = note: expected mutable reference `&mut u8`
+                         found struct `std::pin::Pin<&mut u8>`
diff --git a/third_party/rust/pin-project/tests/ui/cfg/cfg_attr-unpin.rs b/third_party/rust/pin-project/tests/ui/cfg/cfg_attr-unpin.rs
new file mode 100644
index 0000000000..7b88205542
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/cfg/cfg_attr-unpin.rs
@@ -0,0 +1,21 @@
+use pin_project::pin_project;
+use std::marker::PhantomPinned;
+
+#[cfg_attr(any(), pin_project)]
+struct Foo<T> {
+    inner: T,
+}
+
+#[cfg_attr(not(any()), pin_project)]
+struct Bar<T> {
+    #[cfg_attr(not(any()), pin)]
+    inner: T,
+}
+
+fn is_unpin<T: Unpin>() {}
+
+fn main() {
+    is_unpin::<Foo<PhantomPinned>>(); // ERROR E0277
+    is_unpin::<Bar<()>>(); // Ok
+    is_unpin::<Bar<PhantomPinned>>(); //~ ERROR E0277
+}
diff --git a/third_party/rust/pin-project/tests/ui/cfg/cfg_attr-unpin.stderr b/third_party/rust/pin-project/tests/ui/cfg/cfg_attr-unpin.stderr
new file mode 100644
index 0000000000..8879d020e8
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/cfg/cfg_attr-unpin.stderr
@@ -0,0 +1,22 @@
+error[E0277]: `std::marker::PhantomPinned` cannot be unpinned
+  --> $DIR/cfg_attr-unpin.rs:18:5
+   |
+15 | fn is_unpin<T: Unpin>() {}
+   |                ----- required by this bound in `is_unpin`
+...
+18 |     is_unpin::<Foo<PhantomPinned>>(); // ERROR E0277
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ within `Foo<std::marker::PhantomPinned>`, the trait `std::marker::Unpin` is not implemented for `std::marker::PhantomPinned`
+   |
+   = note: required because it appears within the type `Foo<std::marker::PhantomPinned>`
+
+error[E0277]: `std::marker::PhantomPinned` cannot be unpinned
+  --> $DIR/cfg_attr-unpin.rs:20:5
+   |
+15 | fn is_unpin<T: Unpin>() {}
+   |                ----- required by this bound in `is_unpin`
+...
+20 |     is_unpin::<Bar<PhantomPinned>>(); //~ ERROR E0277
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ within `__Bar<'_, std::marker::PhantomPinned>`, the trait `std::marker::Unpin` is not implemented for `std::marker::PhantomPinned`
+   |
+   = note: required because it appears within the type `__Bar<'_, std::marker::PhantomPinned>`
+   = note: required because of the requirements on the impl of `std::marker::Unpin` for `Bar<std::marker::PhantomPinned>`
diff --git a/third_party/rust/pin-project/tests/ui/cfg/packed_sneaky-span-issue-1.rs b/third_party/rust/pin-project/tests/ui/cfg/packed_sneaky-span-issue-1.rs
new file mode 100644
index 0000000000..3776dac3df
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/cfg/packed_sneaky-span-issue-1.rs
@@ -0,0 +1,18 @@
+use auxiliary_macros::hidden_repr;
+use pin_project::pin_project;
+
+//~ ERROR may not be used on #[repr(packed)] types
+// span is lost.
+// Refs: https://github.com/rust-lang/rust/issues/43081
+#[pin_project]
+#[hidden_repr(packed)]
+struct Foo {
+    #[cfg(not(any()))]
+    #[pin]
+    field: u32,
+    #[cfg(any())]
+    #[pin]
+    field: u8,
+}
+
+fn main() {}
diff --git a/third_party/rust/pin-project/tests/ui/cfg/packed_sneaky-span-issue-1.stderr b/third_party/rust/pin-project/tests/ui/cfg/packed_sneaky-span-issue-1.stderr
new file mode 100644
index 0000000000..f4d7dee6b7
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/cfg/packed_sneaky-span-issue-1.stderr
@@ -0,0 +1 @@
+error: #[pin_project] attribute may not be used on #[repr(packed)] types
diff --git a/third_party/rust/pin-project/tests/ui/cfg/packed_sneaky-span-issue-2.rs b/third_party/rust/pin-project/tests/ui/cfg/packed_sneaky-span-issue-2.rs
new file mode 100644
index 0000000000..aa65d33149
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/cfg/packed_sneaky-span-issue-2.rs
@@ -0,0 +1,18 @@
+use auxiliary_macros::hidden_repr;
+use pin_project::pin_project;
+
+//~ ERROR may not be used on #[repr(packed)] types
+// span is lost.
+// Refs: https://github.com/rust-lang/rust/issues/43081
+#[pin_project]
+#[hidden_repr(packed)]
+struct Foo {
+    #[cfg(any())]
+    #[pin]
+    field: u32,
+    #[cfg(not(any()))]
+    #[pin]
+    field: u8,
+}
+
+fn main() {}
diff --git a/third_party/rust/pin-project/tests/ui/cfg/packed_sneaky-span-issue-2.stderr b/third_party/rust/pin-project/tests/ui/cfg/packed_sneaky-span-issue-2.stderr
new file mode 100644
index 0000000000..f4d7dee6b7
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/cfg/packed_sneaky-span-issue-2.stderr
@@ -0,0 +1 @@
+error: #[pin_project] attribute may not be used on #[repr(packed)] types
diff --git a/third_party/rust/pin-project/tests/ui/cfg/packed_sneaky.rs b/third_party/rust/pin-project/tests/ui/cfg/packed_sneaky.rs
new file mode 100644
index 0000000000..3305ed39c5
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/cfg/packed_sneaky.rs
@@ -0,0 +1,12 @@
+use auxiliary_macros::hidden_repr_cfg_not_any;
+use pin_project::pin_project;
+
+// `#[hidden_repr_cfg_not_any(packed)]` generates `#[cfg_attr(not(any()), repr(packed))]`.
+#[pin_project]
+#[hidden_repr_cfg_not_any(packed)] //~ ERROR may not be used on #[repr(packed)] types
+struct Foo {
+    #[pin]
+    field: u32,
+}
+
+fn main() {}
diff --git a/third_party/rust/pin-project/tests/ui/cfg/packed_sneaky.stderr b/third_party/rust/pin-project/tests/ui/cfg/packed_sneaky.stderr
new file mode 100644
index 0000000000..5910cf4b64
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/cfg/packed_sneaky.stderr
@@ -0,0 +1,7 @@
+error: #[pin_project] attribute may not be used on #[repr(packed)] types
+ --> $DIR/packed_sneaky.rs:6:1
+  |
+6 | #[hidden_repr_cfg_not_any(packed)] //~ ERROR may not be used on #[repr(packed)] types
+  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+  |
+  = note: this error originates in an attribute macro (in Nightly builds, run with -Z macro-backtrace for more info)
diff --git a/third_party/rust/pin-project/tests/ui/cfg/proper_unpin.rs b/third_party/rust/pin-project/tests/ui/cfg/proper_unpin.rs
new file mode 100644
index 0000000000..b7bb04de80
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/cfg/proper_unpin.rs
@@ -0,0 +1,28 @@
+use pin_project::pin_project;
+use std::marker::PhantomPinned;
+
+#[pin_project]
+struct Foo<T> {
+    #[cfg(any())]
+    #[pin]
+    inner: T,
+    #[cfg(not(any()))]
+    inner: T,
+}
+
+#[pin_project]
+struct Bar<T> {
+    #[cfg(any())]
+    inner: T,
+    #[cfg(not(any()))]
+    #[pin]
+    inner: T,
+}
+
+fn is_unpin<T: Unpin>() {}
+
+fn main() {
+    is_unpin::<Foo<PhantomPinned>>(); // Ok
+    is_unpin::<Bar<()>>(); // Ok
+    is_unpin::<Bar<PhantomPinned>>(); //~ ERROR E0277
+}
diff --git a/third_party/rust/pin-project/tests/ui/cfg/proper_unpin.stderr b/third_party/rust/pin-project/tests/ui/cfg/proper_unpin.stderr
new file mode 100644
index 0000000000..1f58ea218b
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/cfg/proper_unpin.stderr
@@ -0,0 +1,11 @@
+error[E0277]: `std::marker::PhantomPinned` cannot be unpinned
+  --> $DIR/proper_unpin.rs:27:5
+   |
+22 | fn is_unpin<T: Unpin>() {}
+   |                ----- required by this bound in `is_unpin`
+...
+27 |     is_unpin::<Bar<PhantomPinned>>(); //~ ERROR E0277
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ within `__Bar<'_, std::marker::PhantomPinned>`, the trait `std::marker::Unpin` is not implemented for `std::marker::PhantomPinned`
+   |
+   = note: required because it appears within the type `__Bar<'_, std::marker::PhantomPinned>`
+   = note: required because of the requirements on the impl of `std::marker::Unpin` for `Bar<std::marker::PhantomPinned>`
diff --git a/third_party/rust/pin-project/tests/ui/cfg/unsupported.rs b/third_party/rust/pin-project/tests/ui/cfg/unsupported.rs
new file mode 100644
index 0000000000..5205307d22
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/cfg/unsupported.rs
@@ -0,0 +1,13 @@
+use pin_project::pin_project;
+
+//~ ERROR may not be used on structs with zero fields
+// span is lost.
+// Refs: https://github.com/rust-lang/rust/issues/43081
+#[pin_project]
+struct Struct {
+    #[cfg(any())]
+    #[pin]
+    f: u8,
+}
+
+fn main() {}
diff --git a/third_party/rust/pin-project/tests/ui/cfg/unsupported.stderr b/third_party/rust/pin-project/tests/ui/cfg/unsupported.stderr
new file mode 100644
index 0000000000..0ee8676705
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/cfg/unsupported.stderr
@@ -0,0 +1 @@
+error: #[pin_project] attribute may not be used on structs with zero fields
diff --git a/third_party/rust/pin-project/tests/ui/pin_project/add-attr-to-struct.rs b/third_party/rust/pin-project/tests/ui/pin_project/add-attr-to-struct.rs
new file mode 100644
index 0000000000..ea7c917d54
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pin_project/add-attr-to-struct.rs
@@ -0,0 +1,19 @@
+use auxiliary_macros::add_attr;
+use pin_project::pin_project;
+use std::marker::PhantomPinned;
+
+#[pin_project]
+#[add_attr(struct)] //~ ERROR duplicate #[pin] attribute
+struct Foo {
+    #[pin]
+    field: PhantomPinned,
+}
+
+#[add_attr(struct)] //~ ERROR #[pin] attribute may only be used on fields of structs or variants
+#[pin_project]
+struct Bar {
+    #[pin]
+    field: PhantomPinned,
+}
+
+fn main() {}
diff --git a/third_party/rust/pin-project/tests/ui/pin_project/add-attr-to-struct.stderr b/third_party/rust/pin-project/tests/ui/pin_project/add-attr-to-struct.stderr
new file mode 100644
index 0000000000..cb2c9638bb
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pin_project/add-attr-to-struct.stderr
@@ -0,0 +1,15 @@
+error: duplicate #[pin] attribute
+ --> $DIR/add-attr-to-struct.rs:6:1
+  |
+6 | #[add_attr(struct)] //~ ERROR duplicate #[pin] attribute
+  | ^^^^^^^^^^^^^^^^^^^
+  |
+  = note: this error originates in an attribute macro (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: #[pin] attribute may only be used on fields of structs or variants
+  --> $DIR/add-attr-to-struct.rs:12:1
+   |
+12 | #[add_attr(struct)] //~ ERROR #[pin] attribute may only be used on fields of structs or variants
+   | ^^^^^^^^^^^^^^^^^^^
+   |
+   = note: this error originates in an attribute macro (in Nightly builds, run with -Z macro-backtrace for more info)
diff --git a/third_party/rust/pin-project/tests/ui/pin_project/add-pinned-field.rs b/third_party/rust/pin-project/tests/ui/pin_project/add-pinned-field.rs
new file mode 100644
index 0000000000..76394cf506
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pin_project/add-pinned-field.rs
@@ -0,0 +1,23 @@
+use auxiliary_macros::add_pinned_field;
+use pin_project::pin_project;
+
+fn is_unpin<T: Unpin>() {}
+
+#[pin_project]
+#[add_pinned_field]
+struct Foo {
+    #[pin]
+    field: u32,
+}
+
+#[add_pinned_field]
+#[pin_project]
+struct Bar {
+    #[pin]
+    field: u32,
+}
+
+fn main() {
+    is_unpin::<Foo>(); //~ ERROR E0277
+    is_unpin::<Bar>(); //~ ERROR E0277
+}
diff --git a/third_party/rust/pin-project/tests/ui/pin_project/add-pinned-field.stderr b/third_party/rust/pin-project/tests/ui/pin_project/add-pinned-field.stderr
new file mode 100644
index 0000000000..3de6f4ac5a
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pin_project/add-pinned-field.stderr
@@ -0,0 +1,23 @@
+error[E0277]: `std::marker::PhantomPinned` cannot be unpinned
+  --> $DIR/add-pinned-field.rs:21:5
+   |
+4  | fn is_unpin<T: Unpin>() {}
+   |                ----- required by this bound in `is_unpin`
+...
+21 |     is_unpin::<Foo>(); //~ ERROR E0277
+   |     ^^^^^^^^^^^^^^^ within `__Foo<'_>`, the trait `std::marker::Unpin` is not implemented for `std::marker::PhantomPinned`
+   |
+   = note: required because it appears within the type `__Foo<'_>`
+   = note: required because of the requirements on the impl of `std::marker::Unpin` for `Foo`
+
+error[E0277]: `std::marker::PhantomPinned` cannot be unpinned
+  --> $DIR/add-pinned-field.rs:22:5
+   |
+4  | fn is_unpin<T: Unpin>() {}
+   |                ----- required by this bound in `is_unpin`
+...
+22 |     is_unpin::<Bar>(); //~ ERROR E0277
+   |     ^^^^^^^^^^^^^^^ within `__Bar<'_>`, the trait `std::marker::Unpin` is not implemented for `std::marker::PhantomPinned`
+   |
+   = note: required because it appears within the type `__Bar<'_>`
+   = note: required because of the requirements on the impl of `std::marker::Unpin` for `Bar`
diff --git a/third_party/rust/pin-project/tests/ui/pin_project/conflict-drop.rs b/third_party/rust/pin-project/tests/ui/pin_project/conflict-drop.rs
new file mode 100644
index 0000000000..c9651848a4
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pin_project/conflict-drop.rs
@@ -0,0 +1,31 @@
+use pin_project::{pin_project, pinned_drop};
+use std::pin::Pin;
+
+#[pin_project] //~ ERROR E0119
+struct Foo<T, U> {
+    #[pin]
+    future: T,
+    field: U,
+}
+
+impl<T, U> Drop for Foo<T, U> {
+    fn drop(&mut self) {}
+}
+
+#[pin_project(PinnedDrop)] //~ ERROR E0119
+struct Bar<T, U> {
+    #[pin]
+    future: T,
+    field: U,
+}
+
+#[pinned_drop]
+impl<T, U> PinnedDrop for Bar<T, U> {
+    fn drop(self: Pin<&mut Self>) {}
+}
+
+impl<T, U> Drop for Bar<T, U> {
+    fn drop(&mut self) {}
+}
+
+fn main() {}
diff --git a/third_party/rust/pin-project/tests/ui/pin_project/conflict-drop.stderr b/third_party/rust/pin-project/tests/ui/pin_project/conflict-drop.stderr
new file mode 100644
index 0000000000..1724fcc07d
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pin_project/conflict-drop.stderr
@@ -0,0 +1,21 @@
+error[E0119]: conflicting implementations of trait `FooMustNotImplDrop` for type `Foo<_, _>`:
+ --> $DIR/conflict-drop.rs:4:1
+  |
+4 | #[pin_project] //~ ERROR E0119
+  | ^^^^^^^^^^^^^^
+  | |
+  | first implementation here
+  | conflicting implementation for `Foo<_, _>`
+  |
+  = note: this error originates in a derive macro (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error[E0119]: conflicting implementations of trait `std::ops::Drop` for type `Bar<_, _>`:
+  --> $DIR/conflict-drop.rs:15:1
+   |
+15 | #[pin_project(PinnedDrop)] //~ ERROR E0119
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `Bar<_, _>`
+...
+27 | impl<T, U> Drop for Bar<T, U> {
+   | ----------------------------- first implementation here
+   |
+   = note: this error originates in a derive macro (in Nightly builds, run with -Z macro-backtrace for more info)
diff --git a/third_party/rust/pin-project/tests/ui/pin_project/conflict-unpin.rs b/third_party/rust/pin-project/tests/ui/pin_project/conflict-unpin.rs
new file mode 100644
index 0000000000..0c48d27907
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pin_project/conflict-unpin.rs
@@ -0,0 +1,37 @@
+use pin_project::pin_project;
+
+// The same implementation.
+
+#[pin_project] //~ ERROR E0119
+struct Foo<T, U> {
+    #[pin]
+    future: T,
+    field: U,
+}
+
+// conflicting implementations
+impl<T, U> Unpin for Foo<T, U> where T: Unpin {} // Conditional Unpin impl
+
+// The implementation that under different conditions.
+
+#[pin_project] //~ ERROR E0119
+struct Bar<T, U> {
+    #[pin]
+    future: T,
+    field: U,
+}
+
+// conflicting implementations
+impl<T, U> Unpin for Bar<T, U> {} // Non-conditional Unpin impl
+
+#[pin_project] //~ ERROR E0119
+struct Baz<T, U> {
+    #[pin]
+    future: T,
+    field: U,
+}
+
+// conflicting implementations
+impl<T: Unpin, U: Unpin> Unpin for Baz<T, U> {} // Conditional Unpin impl
+
+fn main() {}
diff --git a/third_party/rust/pin-project/tests/ui/pin_project/conflict-unpin.stderr b/third_party/rust/pin-project/tests/ui/pin_project/conflict-unpin.stderr
new file mode 100644
index 0000000000..0d6f439b8b
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pin_project/conflict-unpin.stderr
@@ -0,0 +1,32 @@
+error[E0119]: conflicting implementations of trait `std::marker::Unpin` for type `Foo<_, _>`:
+  --> $DIR/conflict-unpin.rs:5:1
+   |
+5  | #[pin_project] //~ ERROR E0119
+   | ^^^^^^^^^^^^^^ conflicting implementation for `Foo<_, _>`
+...
+13 | impl<T, U> Unpin for Foo<T, U> where T: Unpin {} // Conditional Unpin impl
+   | --------------------------------------------- first implementation here
+   |
+   = note: this error originates in a derive macro (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error[E0119]: conflicting implementations of trait `std::marker::Unpin` for type `Bar<_, _>`:
+  --> $DIR/conflict-unpin.rs:17:1
+   |
+17 | #[pin_project] //~ ERROR E0119
+   | ^^^^^^^^^^^^^^ conflicting implementation for `Bar<_, _>`
+...
+25 | impl<T, U> Unpin for Bar<T, U> {} // Non-conditional Unpin impl
+   | ------------------------------ first implementation here
+   |
+   = note: this error originates in a derive macro (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error[E0119]: conflicting implementations of trait `std::marker::Unpin` for type `Baz<_, _>`:
+  --> $DIR/conflict-unpin.rs:27:1
+   |
+27 | #[pin_project] //~ ERROR E0119
+   | ^^^^^^^^^^^^^^ conflicting implementation for `Baz<_, _>`
+...
+35 | impl<T: Unpin, U: Unpin> Unpin for Baz<T, U> {} // Conditional Unpin impl
+   | -------------------------------------------- first implementation here
+   |
+   = note: this error originates in a derive macro (in Nightly builds, run with -Z macro-backtrace for more info)
diff --git a/third_party/rust/pin-project/tests/ui/pin_project/duplicate-argument.rs b/third_party/rust/pin-project/tests/ui/pin_project/duplicate-argument.rs
new file mode 100644
index 0000000000..df8bf1b751
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pin_project/duplicate-argument.rs
@@ -0,0 +1,27 @@
+use pin_project::pin_project;
+
+#[pin_project(UnsafeUnpin, UnsafeUnpin)] //~ ERROR duplicate `UnsafeUnpin` argument
+struct UnsafeUnpin<T> {
+    #[pin]
+    pinned: T,
+}
+
+#[pin_project(PinnedDrop, PinnedDrop)] //~ ERROR duplicate `PinnedDrop` argument
+struct PinnedDrop<T> {
+    #[pin]
+    pinned: T,
+}
+
+#[pin_project(PinnedDrop, UnsafeUnpin, UnsafeUnpin)] //~ ERROR duplicate `UnsafeUnpin` argument
+struct Duplicate3<T> {
+    #[pin]
+    pinned: T,
+}
+
+#[pin_project(PinnedDrop, UnsafeUnpin, PinnedDrop, PinnedDrop)] //~ ERROR duplicate `PinnedDrop` argument
+struct Duplicate4<T> {
+    #[pin]
+    pinned: T,
+}
+
+fn main() {}
diff --git a/third_party/rust/pin-project/tests/ui/pin_project/duplicate-argument.stderr b/third_party/rust/pin-project/tests/ui/pin_project/duplicate-argument.stderr
new file mode 100644
index 0000000000..338e3f4e2d
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pin_project/duplicate-argument.stderr
@@ -0,0 +1,23 @@
+error: duplicate `UnsafeUnpin` argument
+ --> $DIR/duplicate-argument.rs:3:28
+  |
+3 | #[pin_project(UnsafeUnpin, UnsafeUnpin)] //~ ERROR duplicate `UnsafeUnpin` argument
+  |                            ^^^^^^^^^^^
+
+error: duplicate `PinnedDrop` argument
+ --> $DIR/duplicate-argument.rs:9:27
+  |
+9 | #[pin_project(PinnedDrop, PinnedDrop)] //~ ERROR duplicate `PinnedDrop` argument
+  |                           ^^^^^^^^^^
+
+error: duplicate `UnsafeUnpin` argument
+  --> $DIR/duplicate-argument.rs:15:40
+   |
+15 | #[pin_project(PinnedDrop, UnsafeUnpin, UnsafeUnpin)] //~ ERROR duplicate `UnsafeUnpin` argument
+   |                                        ^^^^^^^^^^^
+
+error: duplicate `PinnedDrop` argument
+  --> $DIR/duplicate-argument.rs:21:40
+   |
+21 | #[pin_project(PinnedDrop, UnsafeUnpin, PinnedDrop, PinnedDrop)] //~ ERROR duplicate `PinnedDrop` argument
+   |                                        ^^^^^^^^^^
diff --git a/third_party/rust/pin-project/tests/ui/pin_project/invalid.rs b/third_party/rust/pin-project/tests/ui/pin_project/invalid.rs
new file mode 100644
index 0000000000..f545018c1e
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pin_project/invalid.rs
@@ -0,0 +1,56 @@
+use pin_project::pin_project;
+
+#[pin_project]
+struct A<T> {
+    #[pin()] //~ ERROR unexpected token
+    pinned: T,
+}
+
+#[pin_project]
+struct B<T>(#[pin(foo)] T); //~ ERROR unexpected token
+
+#[pin_project]
+enum C<T> {
+    A(#[pin(foo)] T), //~ ERROR unexpected token
+}
+
+#[pin_project]
+enum D<T> {
+    A {
+        #[pin(foo)] //~ ERROR unexpected token
+        pinned: T,
+    },
+}
+
+#[pin_project(UnsafeUnpin,,)] //~ ERROR expected identifier
+struct E<T> {
+    #[pin]
+    pinned: T,
+}
+
+#[pin_project(Foo)] //~ ERROR unexpected argument
+struct F<T> {
+    #[pin]
+    pinned: T,
+}
+
+#[pin_project]
+enum G<T> {
+    #[pin] //~ ERROR may only be used on fields of structs or variants
+    A(T),
+}
+
+#[pin_project]
+#[pin] //~ ERROR may only be used on fields of structs or variants
+enum H<T> {
+    A(T),
+}
+
+#[pin_project]
+struct I<T> {
+    #[pin]
+    #[pin] //~ ERROR duplicate #[pin] attribute
+    pinned: T,
+}
+
+fn main() {}
diff --git a/third_party/rust/pin-project/tests/ui/pin_project/invalid.stderr b/third_party/rust/pin-project/tests/ui/pin_project/invalid.stderr
new file mode 100644
index 0000000000..308d476670
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pin_project/invalid.stderr
@@ -0,0 +1,53 @@
+error: unexpected token: ()
+ --> $DIR/invalid.rs:5:10
+  |
+5 |     #[pin()] //~ ERROR unexpected token
+  |          ^^
+
+error: unexpected token: (foo)
+  --> $DIR/invalid.rs:10:18
+   |
+10 | struct B<T>(#[pin(foo)] T); //~ ERROR unexpected token
+   |                  ^^^^^
+
+error: unexpected token: (foo)
+  --> $DIR/invalid.rs:14:12
+   |
+14 |     A(#[pin(foo)] T), //~ ERROR unexpected token
+   |            ^^^^^
+
+error: unexpected token: (foo)
+  --> $DIR/invalid.rs:20:14
+   |
+20 |         #[pin(foo)] //~ ERROR unexpected token
+   |              ^^^^^
+
+error: expected identifier
+  --> $DIR/invalid.rs:25:27
+   |
+25 | #[pin_project(UnsafeUnpin,,)] //~ ERROR expected identifier
+   |                           ^
+
+error: unexpected argument: Foo
+  --> $DIR/invalid.rs:31:15
+   |
+31 | #[pin_project(Foo)] //~ ERROR unexpected argument
+   |               ^^^
+
+error: #[pin] attribute may only be used on fields of structs or variants
+  --> $DIR/invalid.rs:39:5
+   |
+39 |     #[pin] //~ ERROR may only be used on fields of structs or variants
+   |     ^^^^^^
+
+error: #[pin] attribute may only be used on fields of structs or variants
+  --> $DIR/invalid.rs:44:1
+   |
+44 | #[pin] //~ ERROR may only be used on fields of structs or variants
+   | ^^^^^^
+
+error: duplicate #[pin] attribute
+  --> $DIR/invalid.rs:52:5
+   |
+52 |     #[pin] //~ ERROR duplicate #[pin] attribute
+   |     ^^^^^^
diff --git a/third_party/rust/pin-project/tests/ui/pin_project/overlapping_unpin_struct.rs b/third_party/rust/pin-project/tests/ui/pin_project/overlapping_unpin_struct.rs
new file mode 100644
index 0000000000..00fef3cc3b
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pin_project/overlapping_unpin_struct.rs
@@ -0,0 +1,18 @@
+use pin_project::pin_project;
+use std::marker::PhantomPinned;
+
+#[pin_project]
+struct Foo<T> {
+    #[pin]
+    inner: T,
+}
+
+struct __Foo {}
+
+impl Unpin for __Foo {}
+
+fn is_unpin<T: Unpin>() {}
+
+fn main() {
+    is_unpin::<Foo<PhantomPinned>>(); //~ ERROR E0277
+}
diff --git a/third_party/rust/pin-project/tests/ui/pin_project/overlapping_unpin_struct.stderr b/third_party/rust/pin-project/tests/ui/pin_project/overlapping_unpin_struct.stderr
new file mode 100644
index 0000000000..60f4116dbd
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pin_project/overlapping_unpin_struct.stderr
@@ -0,0 +1,11 @@
+error[E0277]: `std::marker::PhantomPinned` cannot be unpinned
+  --> $DIR/overlapping_unpin_struct.rs:17:5
+   |
+14 | fn is_unpin<T: Unpin>() {}
+   |                ----- required by this bound in `is_unpin`
+...
+17 |     is_unpin::<Foo<PhantomPinned>>(); //~ ERROR E0277
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ within `__Foo<'_, std::marker::PhantomPinned>`, the trait `std::marker::Unpin` is not implemented for `std::marker::PhantomPinned`
+   |
+   = note: required because it appears within the type `__Foo<'_, std::marker::PhantomPinned>`
+   = note: required because of the requirements on the impl of `std::marker::Unpin` for `Foo<std::marker::PhantomPinned>`
diff --git a/third_party/rust/pin-project/tests/ui/pin_project/packed.rs b/third_party/rust/pin-project/tests/ui/pin_project/packed.rs
new file mode 100644
index 0000000000..86f3ecf33d
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pin_project/packed.rs
@@ -0,0 +1,25 @@
+use pin_project::pin_project;
+
+#[pin_project]
+#[repr(packed, C)] //~ ERROR may not be used on #[repr(packed)] types
+struct A {
+    #[pin]
+    field: u8,
+}
+
+// Test putting 'repr' before the 'pin_project' attribute
+#[repr(packed, C)] //~ ERROR may not be used on #[repr(packed)] types
+#[pin_project]
+struct B {
+    #[pin]
+    field: u8,
+}
+
+#[pin_project]
+#[repr(packed(2))] //~ ERROR may not be used on #[repr(packed)] types
+struct C {
+    #[pin]
+    field: u32,
+}
+
+fn main() {}
diff --git a/third_party/rust/pin-project/tests/ui/pin_project/packed.stderr b/third_party/rust/pin-project/tests/ui/pin_project/packed.stderr
new file mode 100644
index 0000000000..969faea211
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pin_project/packed.stderr
@@ -0,0 +1,17 @@
+error: #[pin_project] attribute may not be used on #[repr(packed)] types
+ --> $DIR/packed.rs:4:8
+  |
+4 | #[repr(packed, C)] //~ ERROR may not be used on #[repr(packed)] types
+  |        ^^^^^^
+
+error: #[pin_project] attribute may not be used on #[repr(packed)] types
+  --> $DIR/packed.rs:11:8
+   |
+11 | #[repr(packed, C)] //~ ERROR may not be used on #[repr(packed)] types
+   |        ^^^^^^
+
+error: #[pin_project] attribute may not be used on #[repr(packed)] types
+  --> $DIR/packed.rs:19:8
+   |
+19 | #[repr(packed(2))] //~ ERROR may not be used on #[repr(packed)] types
+   |        ^^^^^^^^^
diff --git a/third_party/rust/pin-project/tests/ui/pin_project/packed_sneaky-1.rs b/third_party/rust/pin-project/tests/ui/pin_project/packed_sneaky-1.rs
new file mode 100644
index 0000000000..dcf5464e4c
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pin_project/packed_sneaky-1.rs
@@ -0,0 +1,33 @@
+use auxiliary_macros::hidden_repr;
+use pin_project::{pin_project, pinned_drop, UnsafeUnpin};
+use std::pin::Pin;
+
+#[pin_project] //~ ERROR may not be used on #[repr(packed)] types
+#[hidden_repr(packed)]
+struct A {
+    #[pin]
+    field: u32,
+}
+
+#[pin_project(UnsafeUnpin)] //~ ERROR may not be used on #[repr(packed)] types
+#[hidden_repr(packed)]
+struct C {
+    #[pin]
+    field: u32,
+}
+
+unsafe impl UnsafeUnpin for C {}
+
+#[pin_project(PinnedDrop)] //~ ERROR may not be used on #[repr(packed)] types
+#[hidden_repr(packed)]
+struct D {
+    #[pin]
+    field: u32,
+}
+
+#[pinned_drop]
+impl PinnedDrop for D {
+    fn drop(self: Pin<&mut Self>) {}
+}
+
+fn main() {}
diff --git a/third_party/rust/pin-project/tests/ui/pin_project/packed_sneaky-1.stderr b/third_party/rust/pin-project/tests/ui/pin_project/packed_sneaky-1.stderr
new file mode 100644
index 0000000000..06a4f6266c
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pin_project/packed_sneaky-1.stderr
@@ -0,0 +1,23 @@
+error: #[pin_project] attribute may not be used on #[repr(packed)] types
+ --> $DIR/packed_sneaky-1.rs:6:1
+  |
+6 | #[hidden_repr(packed)]
+  | ^^^^^^^^^^^^^^^^^^^^^^
+  |
+  = note: this error originates in an attribute macro (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: #[pin_project] attribute may not be used on #[repr(packed)] types
+  --> $DIR/packed_sneaky-1.rs:13:1
+   |
+13 | #[hidden_repr(packed)]
+   | ^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: this error originates in an attribute macro (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: #[pin_project] attribute may not be used on #[repr(packed)] types
+  --> $DIR/packed_sneaky-1.rs:22:1
+   |
+22 | #[hidden_repr(packed)]
+   | ^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: this error originates in an attribute macro (in Nightly builds, run with -Z macro-backtrace for more info)
diff --git a/third_party/rust/pin-project/tests/ui/pin_project/packed_sneaky-2.rs b/third_party/rust/pin-project/tests/ui/pin_project/packed_sneaky-2.rs
new file mode 100644
index 0000000000..d16270635e
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pin_project/packed_sneaky-2.rs
@@ -0,0 +1,12 @@
+use auxiliary_macros::hidden_repr_macro;
+use pin_project::pin_project;
+
+hidden_repr_macro! { //~ ERROR may not be used on #[repr(packed)] types
+    #[pin_project]
+    struct B {
+        #[pin]
+        field: u32,
+    }
+}
+
+fn main() {}
diff --git a/third_party/rust/pin-project/tests/ui/pin_project/packed_sneaky-2.stderr b/third_party/rust/pin-project/tests/ui/pin_project/packed_sneaky-2.stderr
new file mode 100644
index 0000000000..d653a4d29f
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pin_project/packed_sneaky-2.stderr
@@ -0,0 +1,13 @@
+error: #[pin_project] attribute may not be used on #[repr(packed)] types
+  --> $DIR/packed_sneaky-2.rs:4:1
+   |
+4  | / hidden_repr_macro! { //~ ERROR may not be used on #[repr(packed)] types
+5  | |     #[pin_project]
+6  | |     struct B {
+7  | |         #[pin]
+8  | |         field: u32,
+9  | |     }
+10 | | }
+   | |_^
+   |
+   = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
diff --git a/third_party/rust/pin-project/tests/ui/pin_project/private_in_public-enum.rs b/third_party/rust/pin-project/tests/ui/pin_project/private_in_public-enum.rs
new file mode 100644
index 0000000000..66ddefa4d8
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pin_project/private_in_public-enum.rs
@@ -0,0 +1,23 @@
+// Even if allows private_in_public, these are errors.
+
+#![allow(private_in_public)]
+
+pub enum PublicEnum {
+    Variant(PrivateEnum),
+}
+
+enum PrivateEnum {
+    Variant(u8),
+}
+
+mod foo {
+    pub(crate) enum CrateEnum {
+        Variant(PrivateEnum),
+    }
+
+    enum PrivateEnum {
+        Variant(u8),
+    }
+}
+
+fn main() {}
diff --git a/third_party/rust/pin-project/tests/ui/pin_project/private_in_public-enum.stderr b/third_party/rust/pin-project/tests/ui/pin_project/private_in_public-enum.stderr
new file mode 100644
index 0000000000..2a5ae992c0
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pin_project/private_in_public-enum.stderr
@@ -0,0 +1,17 @@
+error[E0446]: private type `PrivateEnum` in public interface
+ --> $DIR/private_in_public-enum.rs:6:13
+  |
+6 |     Variant(PrivateEnum),
+  |             ^^^^^^^^^^^ can't leak private type
+...
+9 | enum PrivateEnum {
+  | - `PrivateEnum` declared as private
+
+error[E0446]: private type `foo::PrivateEnum` in public interface
+  --> $DIR/private_in_public-enum.rs:15:17
+   |
+15 |         Variant(PrivateEnum),
+   |                 ^^^^^^^^^^^ can't leak private type
+...
+18 |     enum PrivateEnum {
+   |     - `foo::PrivateEnum` declared as private
diff --git a/third_party/rust/pin-project/tests/ui/pin_project/proper_unpin.rs b/third_party/rust/pin-project/tests/ui/pin_project/proper_unpin.rs
new file mode 100644
index 0000000000..7121cc84a3
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pin_project/proper_unpin.rs
@@ -0,0 +1,38 @@
+use pin_project::pin_project;
+use std::marker::PhantomPinned;
+
+struct Inner<T> {
+    val: T,
+}
+
+#[pin_project]
+struct Foo<T, U> {
+    #[pin]
+    inner: Inner<T>,
+    other: U,
+}
+
+#[pin_project]
+pub struct TrivialBounds {
+    #[pin]
+    field1: PhantomPinned,
+}
+
+#[pin_project]
+struct Bar<'a, T, U> {
+    #[pin]
+    inner: &'a mut Inner<T>,
+    other: U,
+}
+
+fn is_unpin<T: Unpin>() {}
+
+fn main() {
+    is_unpin::<Foo<PhantomPinned, ()>>(); //~ ERROR E0277
+    is_unpin::<Foo<(), PhantomPinned>>(); // Ok
+    is_unpin::<Foo<PhantomPinned, PhantomPinned>>(); //~ ERROR E0277
+
+    is_unpin::<TrivialBounds>(); //~ ERROR E0277
+
+    is_unpin::<Bar<'_, PhantomPinned, PhantomPinned>>(); //~ Ok
+}
diff --git a/third_party/rust/pin-project/tests/ui/pin_project/proper_unpin.stderr b/third_party/rust/pin-project/tests/ui/pin_project/proper_unpin.stderr
new file mode 100644
index 0000000000..73fd289438
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pin_project/proper_unpin.stderr
@@ -0,0 +1,37 @@
+error[E0277]: `std::marker::PhantomPinned` cannot be unpinned
+  --> $DIR/proper_unpin.rs:31:5
+   |
+28 | fn is_unpin<T: Unpin>() {}
+   |                ----- required by this bound in `is_unpin`
+...
+31 |     is_unpin::<Foo<PhantomPinned, ()>>(); //~ ERROR E0277
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ within `__Foo<'_, std::marker::PhantomPinned, ()>`, the trait `std::marker::Unpin` is not implemented for `std::marker::PhantomPinned`
+   |
+   = note: required because it appears within the type `Inner<std::marker::PhantomPinned>`
+   = note: required because it appears within the type `__Foo<'_, std::marker::PhantomPinned, ()>`
+   = note: required because of the requirements on the impl of `std::marker::Unpin` for `Foo<std::marker::PhantomPinned, ()>`
+
+error[E0277]: `std::marker::PhantomPinned` cannot be unpinned
+  --> $DIR/proper_unpin.rs:33:5
+   |
+28 | fn is_unpin<T: Unpin>() {}
+   |                ----- required by this bound in `is_unpin`
+...
+33 |     is_unpin::<Foo<PhantomPinned, PhantomPinned>>(); //~ ERROR E0277
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ within `__Foo<'_, std::marker::PhantomPinned, std::marker::PhantomPinned>`, the trait `std::marker::Unpin` is not implemented for `std::marker::PhantomPinned`
+   |
+   = note: required because it appears within the type `Inner<std::marker::PhantomPinned>`
+   = note: required because it appears within the type `__Foo<'_, std::marker::PhantomPinned, std::marker::PhantomPinned>`
+   = note: required because of the requirements on the impl of `std::marker::Unpin` for `Foo<std::marker::PhantomPinned, std::marker::PhantomPinned>`
+
+error[E0277]: `std::marker::PhantomPinned` cannot be unpinned
+  --> $DIR/proper_unpin.rs:35:5
+   |
+28 | fn is_unpin<T: Unpin>() {}
+   |                ----- required by this bound in `is_unpin`
+...
+35 |     is_unpin::<TrivialBounds>(); //~ ERROR E0277
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^ within `__TrivialBounds<'_>`, the trait `std::marker::Unpin` is not implemented for `std::marker::PhantomPinned`
+   |
+   = note: required because it appears within the type `__TrivialBounds<'_>`
+   = note: required because of the requirements on the impl of `std::marker::Unpin` for `TrivialBounds`
diff --git a/third_party/rust/pin-project/tests/ui/pin_project/remove-attr-from-field.rs b/third_party/rust/pin-project/tests/ui/pin_project/remove-attr-from-field.rs
new file mode 100644
index 0000000000..eebd3cd27f
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pin_project/remove-attr-from-field.rs
@@ -0,0 +1,32 @@
+use auxiliary_macros::remove_attr;
+use pin_project::pin_project;
+use std::{marker::PhantomPinned, pin::Pin};
+
+fn is_unpin<T: Unpin>() {}
+
+#[pin_project]
+#[remove_attr(field)]
+struct Foo {
+    #[pin]
+    field: PhantomPinned,
+}
+
+#[remove_attr(field)]
+#[pin_project]
+struct Bar {
+    #[pin]
+    field: PhantomPinned,
+}
+
+fn main() {
+    is_unpin::<Foo>();
+    is_unpin::<Bar>();
+
+    let mut x = Foo { field: PhantomPinned };
+    let x = Pin::new(&mut x).project();
+    let _: Pin<&mut PhantomPinned> = x.field; //~ ERROR E0308
+
+    let mut x = Bar { field: PhantomPinned };
+    let x = Pin::new(&mut x).project();
+    let _: Pin<&mut PhantomPinned> = x.field; //~ ERROR E0308
+}
diff --git a/third_party/rust/pin-project/tests/ui/pin_project/remove-attr-from-field.stderr b/third_party/rust/pin-project/tests/ui/pin_project/remove-attr-from-field.stderr
new file mode 100644
index 0000000000..15195e7737
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pin_project/remove-attr-from-field.stderr
@@ -0,0 +1,21 @@
+error[E0308]: mismatched types
+  --> $DIR/remove-attr-from-field.rs:27:38
+   |
+27 |     let _: Pin<&mut PhantomPinned> = x.field; //~ ERROR E0308
+   |            -----------------------   ^^^^^^^ expected struct `std::pin::Pin`, found `&mut std::marker::PhantomPinned`
+   |            |
+   |            expected due to this
+   |
+   = note:         expected struct `std::pin::Pin<&mut std::marker::PhantomPinned>`
+           found mutable reference `&mut std::marker::PhantomPinned`
+
+error[E0308]: mismatched types
+  --> $DIR/remove-attr-from-field.rs:31:38
+   |
+31 |     let _: Pin<&mut PhantomPinned> = x.field; //~ ERROR E0308
+   |            -----------------------   ^^^^^^^ expected struct `std::pin::Pin`, found `&mut std::marker::PhantomPinned`
+   |            |
+   |            expected due to this
+   |
+   = note:         expected struct `std::pin::Pin<&mut std::marker::PhantomPinned>`
+           found mutable reference `&mut std::marker::PhantomPinned`
diff --git a/third_party/rust/pin-project/tests/ui/pin_project/remove-attr-from-struct.rs b/third_party/rust/pin-project/tests/ui/pin_project/remove-attr-from-struct.rs
new file mode 100644
index 0000000000..b395a42354
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pin_project/remove-attr-from-struct.rs
@@ -0,0 +1,30 @@
+use auxiliary_macros::remove_attr;
+use pin_project::pin_project;
+use std::{marker::PhantomPinned, pin::Pin};
+
+fn is_unpin<T: Unpin>() {}
+
+#[pin_project]
+#[remove_attr(struct)]
+struct Foo {
+    #[pin] //~ ERROR cannot find attribute `pin` in this scope
+    field: PhantomPinned,
+}
+
+#[remove_attr(struct)]
+#[pin_project]
+struct Bar {
+    #[pin] //~ ERROR cannot find attribute `pin` in this scope
+    field: PhantomPinned,
+}
+
+fn main() {
+    is_unpin::<Foo>(); //~ ERROR E0277
+    is_unpin::<Bar>(); //~ ERROR E0277
+
+    let mut x = Foo { field: PhantomPinned };
+    let _x = Pin::new(&mut x).project(); //~ ERROR E0277,E0599
+
+    let mut x = Bar { field: PhantomPinned };
+    let _x = Pin::new(&mut x).project(); //~ ERROR E0277,E0599
+}
diff --git a/third_party/rust/pin-project/tests/ui/pin_project/remove-attr-from-struct.stderr b/third_party/rust/pin-project/tests/ui/pin_project/remove-attr-from-struct.stderr
new file mode 100644
index 0000000000..3173248daa
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pin_project/remove-attr-from-struct.stderr
@@ -0,0 +1,63 @@
+error: cannot find attribute `pin` in this scope
+  --> $DIR/remove-attr-from-struct.rs:10:7
+   |
+10 |     #[pin] //~ ERROR cannot find attribute `pin` in this scope
+   |       ^^^
+
+error: cannot find attribute `pin` in this scope
+  --> $DIR/remove-attr-from-struct.rs:17:7
+   |
+17 |     #[pin] //~ ERROR cannot find attribute `pin` in this scope
+   |       ^^^
+
+error[E0277]: `std::marker::PhantomPinned` cannot be unpinned
+  --> $DIR/remove-attr-from-struct.rs:22:5
+   |
+5  | fn is_unpin<T: Unpin>() {}
+   |                ----- required by this bound in `is_unpin`
+...
+22 |     is_unpin::<Foo>(); //~ ERROR E0277
+   |     ^^^^^^^^^^^^^^^ within `Foo`, the trait `std::marker::Unpin` is not implemented for `std::marker::PhantomPinned`
+   |
+   = note: required because it appears within the type `Foo`
+
+error[E0277]: `std::marker::PhantomPinned` cannot be unpinned
+  --> $DIR/remove-attr-from-struct.rs:23:5
+   |
+5  | fn is_unpin<T: Unpin>() {}
+   |                ----- required by this bound in `is_unpin`
+...
+23 |     is_unpin::<Bar>(); //~ ERROR E0277
+   |     ^^^^^^^^^^^^^^^ within `Bar`, the trait `std::marker::Unpin` is not implemented for `std::marker::PhantomPinned`
+   |
+   = note: required because it appears within the type `Bar`
+
+error[E0277]: `std::marker::PhantomPinned` cannot be unpinned
+  --> $DIR/remove-attr-from-struct.rs:26:14
+   |
+26 |     let _x = Pin::new(&mut x).project(); //~ ERROR E0277,E0599
+   |              ^^^^^^^^ within `Foo`, the trait `std::marker::Unpin` is not implemented for `std::marker::PhantomPinned`
+   |
+   = note: required because it appears within the type `Foo`
+   = note: required by `std::pin::Pin::<P>::new`
+
+error[E0599]: no method named `project` found for struct `std::pin::Pin<&mut Foo>` in the current scope
+  --> $DIR/remove-attr-from-struct.rs:26:31
+   |
+26 |     let _x = Pin::new(&mut x).project(); //~ ERROR E0277,E0599
+   |                               ^^^^^^^ method not found in `std::pin::Pin<&mut Foo>`
+
+error[E0277]: `std::marker::PhantomPinned` cannot be unpinned
+  --> $DIR/remove-attr-from-struct.rs:29:14
+   |
+29 |     let _x = Pin::new(&mut x).project(); //~ ERROR E0277,E0599
+   |              ^^^^^^^^ within `Bar`, the trait `std::marker::Unpin` is not implemented for `std::marker::PhantomPinned`
+   |
+   = note: required because it appears within the type `Bar`
+   = note: required by `std::pin::Pin::<P>::new`
+
+error[E0599]: no method named `project` found for struct `std::pin::Pin<&mut Bar>` in the current scope
+  --> $DIR/remove-attr-from-struct.rs:29:31
+   |
+29 |     let _x = Pin::new(&mut x).project(); //~ ERROR E0277,E0599
+   |                               ^^^^^^^ method not found in `std::pin::Pin<&mut Bar>`
diff --git a/third_party/rust/pin-project/tests/ui/pin_project/safe_packed_borrows.rs b/third_party/rust/pin-project/tests/ui/pin_project/safe_packed_borrows.rs
new file mode 100644
index 0000000000..c1a7d55dda
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pin_project/safe_packed_borrows.rs
@@ -0,0 +1,21 @@
+#![deny(safe_packed_borrows)]
+
+// Refs: https://github.com/rust-lang/rust/issues/46043
+
+#[repr(packed)]
+struct A {
+    field: u32,
+}
+
+#[repr(packed(2))]
+struct B {
+    field: u32,
+}
+
+fn main() {
+    let a = A { field: 1 };
+    &a.field; //~ ERROR borrow of packed field is unsafe and requires unsafe function or block
+
+    let b = B { field: 1 };
+    &b.field; //~ ERROR borrow of packed field is unsafe and requires unsafe function or block
+}
diff --git a/third_party/rust/pin-project/tests/ui/pin_project/safe_packed_borrows.stderr b/third_party/rust/pin-project/tests/ui/pin_project/safe_packed_borrows.stderr
new file mode 100644
index 0000000000..7b4cc08ec6
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pin_project/safe_packed_borrows.stderr
@@ -0,0 +1,24 @@
+error: borrow of packed field is unsafe and requires unsafe function or block (error E0133)
+  --> $DIR/safe_packed_borrows.rs:17:5
+   |
+17 |     &a.field; //~ ERROR borrow of packed field is unsafe and requires unsafe function or block
+   |     ^^^^^^^^
+   |
+note: the lint level is defined here
+  --> $DIR/safe_packed_borrows.rs:1:9
+   |
+1  | #![deny(safe_packed_borrows)]
+   |         ^^^^^^^^^^^^^^^^^^^
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #46043 <https://github.com/rust-lang/rust/issues/46043>
+   = note: fields of packed structs might be misaligned: dereferencing a misaligned pointer or even just creating a misaligned reference is undefined behavior
+
+error: borrow of packed field is unsafe and requires unsafe function or block (error E0133)
+  --> $DIR/safe_packed_borrows.rs:20:5
+   |
+20 |     &b.field; //~ ERROR borrow of packed field is unsafe and requires unsafe function or block
+   |     ^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #46043 <https://github.com/rust-lang/rust/issues/46043>
+   = note: fields of packed structs might be misaligned: dereferencing a misaligned pointer or even just creating a misaligned reference is undefined behavior
diff --git a/third_party/rust/pin-project/tests/ui/pin_project/unpin_sneaky.rs b/third_party/rust/pin-project/tests/ui/pin_project/unpin_sneaky.rs
new file mode 100644
index 0000000000..3ccb1a95d1
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pin_project/unpin_sneaky.rs
@@ -0,0 +1,11 @@
+use pin_project::pin_project;
+
+#[pin_project]
+struct Foo {
+    #[pin]
+    inner: u8,
+}
+
+impl Unpin for __Foo {} //~ ERROR E0412,E0321
+
+fn main() {}
diff --git a/third_party/rust/pin-project/tests/ui/pin_project/unpin_sneaky.stderr b/third_party/rust/pin-project/tests/ui/pin_project/unpin_sneaky.stderr
new file mode 100644
index 0000000000..d96050bb54
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pin_project/unpin_sneaky.stderr
@@ -0,0 +1,16 @@
+error[E0412]: cannot find type `__Foo` in this scope
+ --> $DIR/unpin_sneaky.rs:9:16
+  |
+9 | impl Unpin for __Foo {} //~ ERROR E0412,E0321
+  |                ^^^^^ not found in this scope
+  |
+help: possible candidate is found in another module, you can import it into scope
+  |
+1 | use crate::__Foo;
+  |
+
+error[E0321]: cross-crate traits with a default impl, like `std::marker::Unpin`, can only be implemented for a struct/enum type, not `[type error]`
+ --> $DIR/unpin_sneaky.rs:9:1
+  |
+9 | impl Unpin for __Foo {} //~ ERROR E0412,E0321
+  | ^^^^^^^^^^^^^^^^^^^^ can't implement cross-crate trait with a default impl for non-struct/enum type
diff --git a/third_party/rust/pin-project/tests/ui/pin_project/unsupported.rs b/third_party/rust/pin-project/tests/ui/pin_project/unsupported.rs
new file mode 100644
index 0000000000..f7b8eb94a0
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pin_project/unsupported.rs
@@ -0,0 +1,32 @@
+use pin_project::pin_project;
+
+#[pin_project]
+struct Struct1 {} //~ ERROR may not be used on structs with zero fields
+
+#[pin_project]
+struct Struct2(); //~ ERROR may not be used on structs with zero fields
+
+#[pin_project]
+struct Struct3; //~ ERROR may not be used on structs with units
+
+#[pin_project]
+enum Enum1 {} //~ ERROR may not be used on enums without variants
+
+#[pin_project]
+enum Enum2 {
+    A = 2, //~ ERROR may not be used on enums with discriminants
+}
+
+#[pin_project]
+enum Enum3 {
+    A, //~ ERROR may not be used on enums that have no field
+    B,
+}
+
+#[pin_project]
+union Union {
+    //~^ ERROR may only be used on structs or enums
+    x: u8,
+}
+
+fn main() {}
diff --git a/third_party/rust/pin-project/tests/ui/pin_project/unsupported.stderr b/third_party/rust/pin-project/tests/ui/pin_project/unsupported.stderr
new file mode 100644
index 0000000000..89ffd949f5
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pin_project/unsupported.stderr
@@ -0,0 +1,45 @@
+error: #[pin_project] attribute may not be used on structs with zero fields
+ --> $DIR/unsupported.rs:4:16
+  |
+4 | struct Struct1 {} //~ ERROR may not be used on structs with zero fields
+  |                ^^
+
+error: #[pin_project] attribute may not be used on structs with zero fields
+ --> $DIR/unsupported.rs:7:15
+  |
+7 | struct Struct2(); //~ ERROR may not be used on structs with zero fields
+  |               ^^
+
+error: #[pin_project] attribute may not be used on structs with units
+  --> $DIR/unsupported.rs:10:8
+   |
+10 | struct Struct3; //~ ERROR may not be used on structs with units
+   |        ^^^^^^^
+
+error: #[pin_project] attribute may not be used on enums without variants
+  --> $DIR/unsupported.rs:13:12
+   |
+13 | enum Enum1 {} //~ ERROR may not be used on enums without variants
+   |            ^^
+
+error: #[pin_project] attribute may not be used on enums with discriminants
+  --> $DIR/unsupported.rs:17:9
+   |
+17 |     A = 2, //~ ERROR may not be used on enums with discriminants
+   |         ^
+
+error: #[pin_project] attribute may not be used on enums that have no field
+  --> $DIR/unsupported.rs:22:5
+   |
+22 | /     A, //~ ERROR may not be used on enums that have no field
+23 | |     B,
+   | |______^
+
+error: #[pin_project] attribute may only be used on structs or enums
+  --> $DIR/unsupported.rs:27:1
+   |
+27 | / union Union {
+28 | |     //~^ ERROR may only be used on structs or enums
+29 | |     x: u8,
+30 | | }
+   | |_^
diff --git a/third_party/rust/pin-project/tests/ui/pinned_drop/forget-pinned-drop-impl.rs b/third_party/rust/pin-project/tests/ui/pinned_drop/forget-pinned-drop-impl.rs
new file mode 100644
index 0000000000..b291fbae54
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pinned_drop/forget-pinned-drop-impl.rs
@@ -0,0 +1,9 @@
+use pin_project::pin_project;
+
+#[pin_project(PinnedDrop)] //~ ERROR E0277
+pub struct Struct {
+    #[pin]
+    field: u8,
+}
+
+fn main() {}
diff --git a/third_party/rust/pin-project/tests/ui/pinned_drop/forget-pinned-drop-impl.stderr b/third_party/rust/pin-project/tests/ui/pinned_drop/forget-pinned-drop-impl.stderr
new file mode 100644
index 0000000000..67bdbe11bd
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pinned_drop/forget-pinned-drop-impl.stderr
@@ -0,0 +1,7 @@
+error[E0277]: the trait bound `Struct: pin_project::__private::PinnedDrop` is not satisfied
+ --> $DIR/forget-pinned-drop-impl.rs:3:15
+  |
+3 | #[pin_project(PinnedDrop)] //~ ERROR E0277
+  |               ^^^^^^^^^^ the trait `pin_project::__private::PinnedDrop` is not implemented for `Struct`
+  |
+  = note: required by `pin_project::__private::PinnedDrop::drop`
diff --git a/third_party/rust/pin-project/tests/ui/pinned_drop/invalid.rs b/third_party/rust/pin-project/tests/ui/pinned_drop/invalid.rs
new file mode 100644
index 0000000000..651d76856e
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pinned_drop/invalid.rs
@@ -0,0 +1,152 @@
+use pin_project::{pin_project, pinned_drop};
+
+#[pin_project(PinnedDrop)]
+pub struct A {
+    #[pin]
+    field: u8,
+}
+
+#[pinned_drop(foo)] //~ ERROR unexpected token
+impl PinnedDrop for A {
+    fn drop(self: Pin<&mut Self>) {}
+}
+
+#[pin_project(PinnedDrop)]
+pub struct B {
+    #[pin]
+    field: u8,
+}
+
+#[pinned_drop]
+impl Drop for B {
+    //~^ ERROR #[pinned_drop] may only be used on implementation for the `PinnedDrop` trait
+    fn drop(&mut self) {}
+}
+
+#[pin_project(PinnedDrop)]
+pub struct C {
+    #[pin]
+    field: u8,
+}
+
+#[pinned_drop]
+impl C {
+    //~^ ERROR #[pinned_drop] may only be used on implementation for the `PinnedDrop` trait
+    fn drop(&mut self) {}
+}
+
+#[pin_project(PinnedDrop)]
+pub struct D {
+    #[pin]
+    field: u8,
+}
+
+#[pinned_drop]
+impl PinnedDrop for D {
+    fn drop(&mut self) {} //~ ERROR method `drop` must take an argument `self: Pin<&mut Self>`
+}
+
+#[pin_project(PinnedDrop)]
+pub struct E {
+    #[pin]
+    field: u8,
+}
+
+#[pinned_drop]
+impl PinnedDrop for E {
+    fn drop_baz(&mut self) {} //~ ERROR method `drop_baz` is not a member of trait `PinnedDrop
+}
+
+#[pin_project(PinnedDrop)]
+pub struct F {
+    #[pin]
+    field: u8,
+}
+
+#[pinned_drop]
+unsafe impl PinnedDrop for F {
+    //~^ ERROR implementing the trait `PinnedDrop` is not unsafe
+    fn drop(self: Pin<&mut Self>) {}
+}
+
+#[pin_project(PinnedDrop)]
+pub struct G {
+    #[pin]
+    field: u8,
+}
+
+#[pinned_drop]
+impl PinnedDrop for G {
+    unsafe fn drop(self: Pin<&mut Self>) {} //~ ERROR implementing the method `drop` is not unsafe
+}
+
+#[pin_project(PinnedDrop)]
+pub struct H {
+    #[pin]
+    field: u8,
+}
+
+#[pinned_drop]
+impl PinnedDrop for H {
+    const A: u8 = 0; //~ ERROR const `A` is not a member of trait `PinnedDrop`
+    fn drop(self: Pin<&mut Self>) {}
+}
+
+#[pin_project(PinnedDrop)]
+pub struct I {
+    #[pin]
+    field: u8,
+}
+
+#[pinned_drop]
+impl PinnedDrop for I {
+    fn drop(self: Pin<&mut Self>) {}
+    const A: u8 = 0; //~ ERROR const `A` is not a member of trait `PinnedDrop`
+}
+
+#[pin_project(PinnedDrop)]
+pub struct J {
+    #[pin]
+    field: u8,
+}
+
+#[pinned_drop]
+impl PinnedDrop for J {
+    type A = u8; //~ ERROR type `A` is not a member of trait `PinnedDrop`
+    fn drop(self: Pin<&mut Self>) {}
+}
+
+#[pin_project(PinnedDrop)]
+pub struct K {
+    #[pin]
+    field: u8,
+}
+
+#[pinned_drop]
+impl PinnedDrop for K {
+    fn drop(self: Pin<&mut Self>) {}
+    type A = u8; //~ ERROR type `A` is not a member of trait `PinnedDrop`
+}
+
+#[pin_project(PinnedDrop)]
+pub struct L {
+    #[pin]
+    field: u8,
+}
+
+#[pinned_drop]
+impl PinnedDrop for L {
+    fn drop(self: Pin<&mut Self>) {}
+    fn drop(self: Pin<&mut Self>) {} //~ ERROR duplicate definitions with name `drop`
+}
+
+#[pin_project(PinnedDrop)] //~ ERROR E0277
+pub struct M {
+    #[pin]
+    field: u8,
+}
+
+#[pinned_drop]
+fn drop(_this: Pin<&mut M>) {} //~ ERROR expected `impl`
+
+fn main() {}
diff --git a/third_party/rust/pin-project/tests/ui/pinned_drop/invalid.stderr b/third_party/rust/pin-project/tests/ui/pinned_drop/invalid.stderr
new file mode 100644
index 0000000000..c767fbb113
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pinned_drop/invalid.stderr
@@ -0,0 +1,85 @@
+error: unexpected token: foo
+ --> $DIR/invalid.rs:9:15
+  |
+9 | #[pinned_drop(foo)] //~ ERROR unexpected token
+  |               ^^^
+
+error: #[pinned_drop] may only be used on implementation for the `PinnedDrop` trait
+  --> $DIR/invalid.rs:21:6
+   |
+21 | impl Drop for B {
+   |      ^^^^
+
+error: #[pinned_drop] may only be used on implementation for the `PinnedDrop` trait
+  --> $DIR/invalid.rs:33:6
+   |
+33 | impl C {
+   |      ^
+
+error: method `drop` must take an argument `self: Pin<&mut Self>`
+  --> $DIR/invalid.rs:46:13
+   |
+46 |     fn drop(&mut self) {} //~ ERROR method `drop` must take an argument `self: Pin<&mut Self>`
+   |             ^^^^^^^^^
+
+error: method `drop_baz` is not a member of trait `PinnedDrop
+  --> $DIR/invalid.rs:57:8
+   |
+57 |     fn drop_baz(&mut self) {} //~ ERROR method `drop_baz` is not a member of trait `PinnedDrop
+   |        ^^^^^^^^
+
+error: implementing the trait `PinnedDrop` is not unsafe
+  --> $DIR/invalid.rs:67:1
+   |
+67 | unsafe impl PinnedDrop for F {
+   | ^^^^^^
+
+error: implementing the method `drop` is not unsafe
+  --> $DIR/invalid.rs:80:5
+   |
+80 |     unsafe fn drop(self: Pin<&mut Self>) {} //~ ERROR implementing the method `drop` is not unsafe
+   |     ^^^^^^
+
+error: const `A` is not a member of trait `PinnedDrop`
+  --> $DIR/invalid.rs:91:5
+   |
+91 |     const A: u8 = 0; //~ ERROR const `A` is not a member of trait `PinnedDrop`
+   |     ^^^^^^^^^^^^^^^^
+
+error: const `A` is not a member of trait `PinnedDrop`
+   --> $DIR/invalid.rs:104:5
+    |
+104 |     const A: u8 = 0; //~ ERROR const `A` is not a member of trait `PinnedDrop`
+    |     ^^^^^^^^^^^^^^^^
+
+error: type `A` is not a member of trait `PinnedDrop`
+   --> $DIR/invalid.rs:115:5
+    |
+115 |     type A = u8; //~ ERROR type `A` is not a member of trait `PinnedDrop`
+    |     ^^^^^^^^^^^^
+
+error: type `A` is not a member of trait `PinnedDrop`
+   --> $DIR/invalid.rs:128:5
+    |
+128 |     type A = u8; //~ ERROR type `A` is not a member of trait `PinnedDrop`
+    |     ^^^^^^^^^^^^
+
+error: duplicate definitions with name `drop`
+   --> $DIR/invalid.rs:140:5
+    |
+140 |     fn drop(self: Pin<&mut Self>) {} //~ ERROR duplicate definitions with name `drop`
+    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: expected `impl`
+   --> $DIR/invalid.rs:150:1
+    |
+150 | fn drop(_this: Pin<&mut M>) {} //~ ERROR expected `impl`
+    | ^^
+
+error[E0277]: the trait bound `M: pin_project::__private::PinnedDrop` is not satisfied
+   --> $DIR/invalid.rs:143:15
+    |
+143 | #[pin_project(PinnedDrop)] //~ ERROR E0277
+    |               ^^^^^^^^^^ the trait `pin_project::__private::PinnedDrop` is not implemented for `M`
+    |
+    = note: required by `pin_project::__private::PinnedDrop::drop`
diff --git a/third_party/rust/pin-project/tests/ui/pinned_drop/pinned-drop-no-attr-arg.rs b/third_party/rust/pin-project/tests/ui/pinned_drop/pinned-drop-no-attr-arg.rs
new file mode 100644
index 0000000000..1241b5be84
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pinned_drop/pinned-drop-no-attr-arg.rs
@@ -0,0 +1,15 @@
+use pin_project::{pin_project, pinned_drop};
+use std::pin::Pin;
+
+#[pin_project]
+struct Foo {
+    #[pin]
+    field: u8,
+}
+
+#[pinned_drop]
+impl PinnedDrop for Foo { //~ ERROR E0119
+    fn drop(self: Pin<&mut Self>) {}
+}
+
+fn main() {}
diff --git a/third_party/rust/pin-project/tests/ui/pinned_drop/pinned-drop-no-attr-arg.stderr b/third_party/rust/pin-project/tests/ui/pinned_drop/pinned-drop-no-attr-arg.stderr
new file mode 100644
index 0000000000..7353dc483b
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pinned_drop/pinned-drop-no-attr-arg.stderr
@@ -0,0 +1,8 @@
+error[E0119]: conflicting implementations of trait `pin_project::__private::PinnedDrop` for type `Foo`:
+  --> $DIR/pinned-drop-no-attr-arg.rs:11:1
+   |
+4  | #[pin_project]
+   | -------------- first implementation here
+...
+11 | impl PinnedDrop for Foo { //~ ERROR E0119
+   | ^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `Foo`
diff --git a/third_party/rust/pin-project/tests/ui/pinned_drop/ref-self.rs b/third_party/rust/pin-project/tests/ui/pinned_drop/ref-self.rs
new file mode 100644
index 0000000000..79ae05cd7e
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pinned_drop/ref-self.rs
@@ -0,0 +1,14 @@
+// `ref (mut) self` are rejected by rustc.
+
+use std::pin::Pin;
+
+pub struct Struct {
+    field: u8,
+}
+
+impl Struct {
+    fn method_ref(ref self: Pin<&mut Self>) {} //~ ERROR expected identifier, found keyword `self`
+    fn method_ref_mut(ref mut self: Pin<&mut Self>) {} //~ ERROR expected identifier, found keyword `self`
+}
+
+fn main() {}
diff --git a/third_party/rust/pin-project/tests/ui/pinned_drop/ref-self.stderr b/third_party/rust/pin-project/tests/ui/pinned_drop/ref-self.stderr
new file mode 100644
index 0000000000..3ab489813c
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pinned_drop/ref-self.stderr
@@ -0,0 +1,11 @@
+error: expected identifier, found keyword `self`
+  --> $DIR/ref-self.rs:10:23
+   |
+10 |     fn method_ref(ref self: Pin<&mut Self>) {} //~ ERROR expected identifier, found keyword `self`
+   |                       ^^^^ expected identifier, found keyword
+
+error: expected identifier, found keyword `self`
+  --> $DIR/ref-self.rs:11:31
+   |
+11 |     fn method_ref_mut(ref mut self: Pin<&mut Self>) {} //~ ERROR expected identifier, found keyword `self`
+   |                               ^^^^ expected identifier, found keyword
diff --git a/third_party/rust/pin-project/tests/ui/pinned_drop/self.rs b/third_party/rust/pin-project/tests/ui/pinned_drop/self.rs
new file mode 100644
index 0000000000..6d552a71a6
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pinned_drop/self.rs
@@ -0,0 +1,93 @@
+use pin_project::{pin_project, pinned_drop};
+use std::pin::Pin;
+
+fn self_expr() {
+    #[pin_project(PinnedDrop)]
+    pub struct Struct {
+        x: usize,
+    }
+
+    #[pinned_drop]
+    impl PinnedDrop for Struct {
+        fn drop(mut self: Pin<&mut Self>) {
+            let _: Self = Self { x: 0 };
+        }
+    }
+
+    #[pin_project(PinnedDrop)]
+    pub struct TupleStruct(usize);
+
+    #[pinned_drop]
+    impl PinnedDrop for TupleStruct {
+        fn drop(mut self: Pin<&mut Self>) {
+            let _: Self = Self(0);
+        }
+    }
+
+    #[pin_project(PinnedDrop)]
+    pub enum Enum {
+        StructVariant { x: usize },
+        TupleVariant(usize),
+    }
+
+    #[pinned_drop]
+    impl PinnedDrop for Enum {
+        fn drop(mut self: Pin<&mut Self>) {
+            let _: Self = Self::StructVariant { x: 0 }; //~ ERROR can't use generic parameters from outer function [E0401]
+            let _: Self = Self::TupleVariant(0);
+        }
+    }
+}
+
+fn self_pat() {
+    #[pin_project(PinnedDrop)]
+    pub struct Struct {
+        x: usize,
+    }
+
+    #[pinned_drop]
+    impl PinnedDrop for Struct {
+        fn drop(mut self: Pin<&mut Self>) {
+            match *self {
+                Self { x: _ } => {} //~ ERROR can't use generic parameters from outer function [E0401]
+            }
+            if let Self { x: _ } = *self {} //~ ERROR can't use generic parameters from outer function [E0401]
+            let Self { x: _ } = *self; //~ ERROR can't use generic parameters from outer function [E0401]
+        }
+    }
+
+    #[pin_project(PinnedDrop)]
+    pub struct TupleStruct(usize);
+
+    #[pinned_drop]
+    impl PinnedDrop for TupleStruct {
+        #[allow(irrefutable_let_patterns)]
+        fn drop(mut self: Pin<&mut Self>) {
+            match *self {
+                Self(_) => {}
+            }
+            if let Self(_) = *self {}
+            let Self(_) = *self;
+        }
+    }
+
+    #[pin_project(PinnedDrop)]
+    pub enum Enum {
+        StructVariant { x: usize },
+        TupleVariant(usize),
+    }
+
+    #[pinned_drop]
+    impl PinnedDrop for Enum {
+        fn drop(mut self: Pin<&mut Self>) {
+            match *self {
+                Self::StructVariant { x: _ } => {} //~ ERROR can't use generic parameters from outer function [E0401]
+                Self::TupleVariant(_) => {} //~ ERROR can't use generic parameters from outer function [E0401]
+            }
+            if let Self::StructVariant { x: _ } = *self {} //~ ERROR can't use generic parameters from outer function [E0401]
+            if let Self::TupleVariant(_) = *self {} //~ ERROR can't use generic parameters from outer function [E0401]
+        }
+    }
+}
+
+fn main() {}
diff --git a/third_party/rust/pin-project/tests/ui/pinned_drop/self.stderr b/third_party/rust/pin-project/tests/ui/pinned_drop/self.stderr
new file mode 100644
index 0000000000..54c7b676a3
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pinned_drop/self.stderr
@@ -0,0 +1,95 @@
+error[E0401]: can't use generic parameters from outer function
+  --> $DIR/self.rs:36:27
+   |
+34 |     impl PinnedDrop for Enum {
+   |     ---- `Self` type implicitly declared here, by this `impl`
+35 |         fn drop(mut self: Pin<&mut Self>) {
+36 |             let _: Self = Self::StructVariant { x: 0 }; //~ ERROR can't use generic parameters from outer function [E0401]
+   |                           ^^^^^^^^^^^^^^^^^^^
+   |                           |
+   |                           use of generic parameter from outer function
+   |                           use a type here instead
+
+error[E0401]: can't use generic parameters from outer function
+  --> $DIR/self.rs:52:17
+   |
+49 |     impl PinnedDrop for Struct {
+   |     ---- `Self` type implicitly declared here, by this `impl`
+...
+52 |                 Self { x: _ } => {} //~ ERROR can't use generic parameters from outer function [E0401]
+   |                 ^^^^
+   |                 |
+   |                 use of generic parameter from outer function
+   |                 use a type here instead
+
+error[E0401]: can't use generic parameters from outer function
+  --> $DIR/self.rs:54:20
+   |
+49 |     impl PinnedDrop for Struct {
+   |     ---- `Self` type implicitly declared here, by this `impl`
+...
+54 |             if let Self { x: _ } = *self {} //~ ERROR can't use generic parameters from outer function [E0401]
+   |                    ^^^^
+   |                    |
+   |                    use of generic parameter from outer function
+   |                    use a type here instead
+
+error[E0401]: can't use generic parameters from outer function
+  --> $DIR/self.rs:55:17
+   |
+49 |     impl PinnedDrop for Struct {
+   |     ---- `Self` type implicitly declared here, by this `impl`
+...
+55 |             let Self { x: _ } = *self; //~ ERROR can't use generic parameters from outer function [E0401]
+   |                 ^^^^
+   |                 |
+   |                 use of generic parameter from outer function
+   |                 use a type here instead
+
+error[E0401]: can't use generic parameters from outer function
+  --> $DIR/self.rs:84:17
+   |
+81 |     impl PinnedDrop for Enum {
+   |     ---- `Self` type implicitly declared here, by this `impl`
+...
+84 |                 Self::StructVariant { x: _ } => {} //~ ERROR can't use generic parameters from outer function [E0401]
+   |                 ^^^^^^^^^^^^^^^^^^^
+   |                 |
+   |                 use of generic parameter from outer function
+   |                 use a type here instead
+
+error[E0401]: can't use generic parameters from outer function
+  --> $DIR/self.rs:85:17
+   |
+81 |     impl PinnedDrop for Enum {
+   |     ---- `Self` type implicitly declared here, by this `impl`
+...
+85 |                 Self::TupleVariant(_) => {} //~ ERROR can't use generic parameters from outer function [E0401]
+   |                 ^^^^^^^^^^^^^^^^^^
+   |                 |
+   |                 use of generic parameter from outer function
+   |                 use a type here instead
+
+error[E0401]: can't use generic parameters from outer function
+  --> $DIR/self.rs:87:20
+   |
+81 |     impl PinnedDrop for Enum {
+   |     ---- `Self` type implicitly declared here, by this `impl`
+...
+87 |             if let Self::StructVariant { x: _ } = *self {} //~ ERROR can't use generic parameters from outer function [E0401]
+   |                    ^^^^^^^^^^^^^^^^^^^
+   |                    |
+   |                    use of generic parameter from outer function
+   |                    use a type here instead
+
+error[E0401]: can't use generic parameters from outer function
+  --> $DIR/self.rs:88:20
+   |
+81 |     impl PinnedDrop for Enum {
+   |     ---- `Self` type implicitly declared here, by this `impl`
+...
+88 |             if let Self::TupleVariant(_) = *self {} //~ ERROR can't use generic parameters from outer function [E0401]
+   |                    ^^^^^^^^^^^^^^^^^^
+   |                    |
+   |                    use of generic parameter from outer function
+   |                    use a type here instead
diff --git a/third_party/rust/pin-project/tests/ui/pinned_drop/unsafe-code.rs b/third_party/rust/pin-project/tests/ui/pinned_drop/unsafe-code.rs
new file mode 100644
index 0000000000..78f8a11ced
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pinned_drop/unsafe-code.rs
@@ -0,0 +1,17 @@
+use pin_project::{pin_project, pinned_drop};
+use std::pin::Pin;
+
+#[pin_project(PinnedDrop)]
+pub struct Struct {
+    #[pin]
+    field: u8,
+}
+
+#[pinned_drop]
+impl PinnedDrop for Struct {
+    fn drop(self: Pin<&mut Self>) {
+        self.project().field.get_unchecked_mut(); //~ ERROR call to unsafe function is unsafe and requires unsafe function or block [E0133]
+    }
+}
+
+fn main() {}
diff --git a/third_party/rust/pin-project/tests/ui/pinned_drop/unsafe-code.stderr b/third_party/rust/pin-project/tests/ui/pinned_drop/unsafe-code.stderr
new file mode 100644
index 0000000000..98a945f6eb
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/pinned_drop/unsafe-code.stderr
@@ -0,0 +1,7 @@
+error[E0133]: call to unsafe function is unsafe and requires unsafe function or block
+  --> $DIR/unsafe-code.rs:13:9
+   |
+13 |         self.project().field.get_unchecked_mut(); //~ ERROR call to unsafe function is unsafe and requires unsafe function or block [E0133]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ call to unsafe function
+   |
+   = note: consult the function's documentation for information on how to avoid undefined behavior
diff --git a/third_party/rust/pin-project/tests/ui/project/ambiguous-let.rs b/third_party/rust/pin-project/tests/ui/project/ambiguous-let.rs
new file mode 100644
index 0000000000..a7067494ec
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/project/ambiguous-let.rs
@@ -0,0 +1,24 @@
+use pin_project::{pin_project, project};
+
+#[pin_project]
+enum Enum<A, B> {
+    A(#[pin] A),
+    B(B),
+}
+
+struct Struct<T>(T);
+
+#[project]
+fn foo() {
+    let mut foo: Enum<bool, bool> = Enum::A(true);
+
+    #[project]
+    let Struct(x) = match Pin::new(&mut foo).project() {
+        //~^ ERROR Both initializer expression and pattern are replaceable, you need to split the initializer expression into separate let bindings to avoid ambiguity
+        Enum::A(_) => Struct(true),
+        Enum::B(_) => unreachable!(),
+    };
+    assert!(x);
+}
+
+fn main() {}
diff --git a/third_party/rust/pin-project/tests/ui/project/ambiguous-let.stderr b/third_party/rust/pin-project/tests/ui/project/ambiguous-let.stderr
new file mode 100644
index 0000000000..e6552c83ec
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/project/ambiguous-let.stderr
@@ -0,0 +1,5 @@
+error: Both initializer expression and pattern are replaceable, you need to split the initializer expression into separate let bindings to avoid ambiguity
+  --> $DIR/ambiguous-let.rs:16:9
+   |
+16 |     let Struct(x) = match Pin::new(&mut foo).project() {
+   |         ^^^^^^^^^
diff --git a/third_party/rust/pin-project/tests/ui/project/invalid.rs b/third_party/rust/pin-project/tests/ui/project/invalid.rs
new file mode 100644
index 0000000000..bc7226deb2
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/project/invalid.rs
@@ -0,0 +1,24 @@
+use pin_project::{pin_project, project};
+
+#[pin_project]
+struct A<T> {
+    #[pin]
+    future: T,
+}
+
+#[project]
+fn foo() {
+    let mut x = A { future: 0 };
+    #[project(foo)] //~ ERROR unexpected token
+    let A { future } = Pin::new(&mut x).project();
+}
+
+#[project]
+fn bar() {
+    let mut x = A { future: 0 };
+    #[project]
+    #[project] //~ ERROR duplicate #[project] attribute
+    let A { future } = Pin::new(&mut x).project();
+}
+
+fn main() {}
diff --git a/third_party/rust/pin-project/tests/ui/project/invalid.stderr b/third_party/rust/pin-project/tests/ui/project/invalid.stderr
new file mode 100644
index 0000000000..a361b72aa3
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/project/invalid.stderr
@@ -0,0 +1,11 @@
+error: unexpected token: (foo)
+  --> $DIR/invalid.rs:12:14
+   |
+12 |     #[project(foo)] //~ ERROR unexpected token
+   |              ^^^^^
+
+error: duplicate #[project] attribute
+  --> $DIR/invalid.rs:20:5
+   |
+20 |     #[project] //~ ERROR duplicate #[project] attribute
+   |     ^^^^^^^^^^
diff --git a/third_party/rust/pin-project/tests/ui/project/type-mismatch.rs b/third_party/rust/pin-project/tests/ui/project/type-mismatch.rs
new file mode 100644
index 0000000000..41a70eb87b
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/project/type-mismatch.rs
@@ -0,0 +1,74 @@
+#![feature(proc_macro_hygiene, stmt_expr_attributes)]
+
+use pin_project::{pin_project, project};
+use std::pin::Pin;
+
+#[project]
+fn type_mismatch() {
+    #[pin_project]
+    enum Enum<A, B, C, D> {
+        Variant1(#[pin] A, B),
+        Variant2 {
+            #[pin]
+            field1: C,
+            field2: D,
+        },
+        None,
+    }
+
+    let mut foo = Enum::Variant1(1, 2);
+    let mut foo = Pin::new(&mut foo).project();
+
+    #[project]
+    match &mut foo {
+        Enum::Variant1(x, y) => {
+            let x: &mut Pin<&mut i32> = x;
+            assert_eq!(**x, 1);
+
+            let y: &mut &mut i32 = y;
+            assert_eq!(**y, 2);
+        }
+        Enum::Variant2 { field1, field2 } => {
+            let _x: &mut Pin<&mut i32> = field1;
+            let _y: &mut &mut i32 = field2;
+        }
+        None => {} //~ ERROR mismatched types
+    }
+}
+
+//~ ERROR mismatched types
+// span is lost.
+// Refs: https://github.com/rust-lang/rust/issues/43081
+fn type_mismatch_span_issue() {
+    #[pin_project]
+    enum Enum<A, B, C, D> {
+        Variant1(#[pin] A, B),
+        Variant2 {
+            #[pin]
+            field1: C,
+            field2: D,
+        },
+        None,
+    }
+
+    let mut foo = Enum::Variant1(1, 2);
+    let mut foo = Pin::new(&mut foo).project();
+
+    #[project]
+    match &mut foo {
+        Enum::Variant1(x, y) => {
+            let x: &mut Pin<&mut i32> = x;
+            assert_eq!(**x, 1);
+
+            let y: &mut &mut i32 = y;
+            assert_eq!(**y, 2);
+        }
+        Enum::Variant2 { field1, field2 } => {
+            let _x: &mut Pin<&mut i32> = field1;
+            let _y: &mut &mut i32 = field2;
+        }
+        None => {}
+    }
+}
+
+fn main() {}
diff --git a/third_party/rust/pin-project/tests/ui/project/type-mismatch.stderr b/third_party/rust/pin-project/tests/ui/project/type-mismatch.stderr
new file mode 100644
index 0000000000..b4c97d5a99
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/project/type-mismatch.stderr
@@ -0,0 +1,16 @@
+error[E0308]: mismatched types
+  --> $DIR/type-mismatch.rs:35:9
+   |
+23 |     match &mut foo {
+   |           -------- this expression has type `&mut type_mismatch::__EnumProjection<'_, {integer}, {integer}, _, _>`
+...
+35 |         None => {} //~ ERROR mismatched types
+   |         ^^^^ expected enum `type_mismatch::__EnumProjection`, found enum `std::option::Option`
+   |
+   = note: expected enum `type_mismatch::__EnumProjection<'_, {integer}, {integer}, _, _>`
+              found enum `std::option::Option<_>`
+
+error[E0308]: mismatched types
+  |
+  = note: expected enum `type_mismatch_span_issue::__EnumProjection<'_, {integer}, {integer}, _, _>`
+             found enum `std::option::Option<_>`
diff --git a/third_party/rust/pin-project/tests/ui/project/use-public.rs b/third_party/rust/pin-project/tests/ui/project/use-public.rs
new file mode 100644
index 0000000000..23c9b89d00
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/project/use-public.rs
@@ -0,0 +1,15 @@
+use pin_project::pin_project;
+
+#[pin_project]
+struct A {
+    field: u8,
+}
+
+pub mod b {
+    use pin_project::project;
+
+    #[project]
+    pub use crate::A; //~ ERROR E0365
+}
+
+fn main() {}
diff --git a/third_party/rust/pin-project/tests/ui/project/use-public.stderr b/third_party/rust/pin-project/tests/ui/project/use-public.stderr
new file mode 100644
index 0000000000..7919d65cbe
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/project/use-public.stderr
@@ -0,0 +1,7 @@
+error[E0365]: `__AProjection` is private, and cannot be re-exported
+  --> $DIR/use-public.rs:12:13
+   |
+12 |     pub use crate::A; //~ ERROR E0365
+   |             ^^^^^^^^ re-export of private `__AProjection`
+   |
+   = note: consider declaring type or module `__AProjection` with `pub`
diff --git a/third_party/rust/pin-project/tests/ui/project/use.rs b/third_party/rust/pin-project/tests/ui/project/use.rs
new file mode 100644
index 0000000000..d4b02c1d60
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/project/use.rs
@@ -0,0 +1,17 @@
+use pin_project::pin_project;
+
+#[pin_project]
+struct A {
+    field: u8,
+}
+
+mod b {
+    use pin_project::project;
+
+    #[project]
+    use crate::A as B; //~ ERROR #[project] attribute may not be used on renamed imports
+    #[project]
+    use crate::*; //~ ERROR #[project] attribute may not be used on glob imports
+}
+
+fn main() {}
diff --git a/third_party/rust/pin-project/tests/ui/project/use.stderr b/third_party/rust/pin-project/tests/ui/project/use.stderr
new file mode 100644
index 0000000000..07d024160b
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/project/use.stderr
@@ -0,0 +1,11 @@
+error: #[project] attribute may not be used on renamed imports
+  --> $DIR/use.rs:12:16
+   |
+12 |     use crate::A as B; //~ ERROR #[project] attribute may not be used on renamed imports
+   |                ^^^^^^
+
+error: #[project] attribute may not be used on glob imports
+  --> $DIR/use.rs:14:16
+   |
+14 |     use crate::*; //~ ERROR #[project] attribute may not be used on glob imports
+   |                ^
diff --git a/third_party/rust/pin-project/tests/ui/unsafe_unpin/not-implement-unsafe-unpin.rs b/third_party/rust/pin-project/tests/ui/unsafe_unpin/not-implement-unsafe-unpin.rs
new file mode 100644
index 0000000000..429d60f044
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/unsafe_unpin/not-implement-unsafe-unpin.rs
@@ -0,0 +1,14 @@
+use pin_project::pin_project;
+
+#[pin_project(UnsafeUnpin)]
+struct Struct<T, U> {
+    #[pin]
+    inner: T,
+    other: U,
+}
+
+fn is_unpin<T: Unpin>() {}
+
+fn main() {
+    is_unpin::<Struct<(), ()>>(); //~ ERROR E0277
+}
diff --git a/third_party/rust/pin-project/tests/ui/unsafe_unpin/not-implement-unsafe-unpin.stderr b/third_party/rust/pin-project/tests/ui/unsafe_unpin/not-implement-unsafe-unpin.stderr
new file mode 100644
index 0000000000..0baefe3e1a
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/unsafe_unpin/not-implement-unsafe-unpin.stderr
@@ -0,0 +1,11 @@
+error[E0277]: the trait bound `Struct<(), ()>: pin_project::UnsafeUnpin` is not satisfied
+  --> $DIR/not-implement-unsafe-unpin.rs:13:16
+   |
+10 | fn is_unpin<T: Unpin>() {}
+   |                ----- required by this bound in `is_unpin`
+...
+13 |     is_unpin::<Struct<(), ()>>(); //~ ERROR E0277
+   |                ^^^^^^^^^^^^^^ the trait `pin_project::UnsafeUnpin` is not implemented for `Struct<(), ()>`
+   |
+   = note: required because of the requirements on the impl of `pin_project::UnsafeUnpin` for `pin_project::__private::Wrapper<'_, Struct<(), ()>>`
+   = note: required because of the requirements on the impl of `std::marker::Unpin` for `Struct<(), ()>`
diff --git a/third_party/rust/pin-project/tests/ui/unsafe_unpin/proper_unpin.rs b/third_party/rust/pin-project/tests/ui/unsafe_unpin/proper_unpin.rs
new file mode 100644
index 0000000000..8896bfd2ae
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/unsafe_unpin/proper_unpin.rs
@@ -0,0 +1,43 @@
+use pin_project::{pin_project, UnsafeUnpin};
+use std::marker::PhantomPinned;
+
+fn is_unpin<T: Unpin>() {}
+
+#[pin_project(UnsafeUnpin)]
+pub struct Blah<T, U> {
+    field1: U,
+    #[pin]
+    field2: T,
+}
+
+#[allow(unsafe_code)]
+unsafe impl<T: Unpin, U> UnsafeUnpin for Blah<T, U> {}
+
+#[pin_project(UnsafeUnpin)]
+pub struct TrivialBounds {
+    #[pin]
+    field1: PhantomPinned,
+}
+
+#[pin_project(UnsafeUnpin)]
+pub struct OverlappingLifetimeNames<'pin, T, U> {
+    #[pin]
+    field1: U,
+    #[pin]
+    field2: Option<T>,
+    field3: &'pin (),
+}
+
+#[allow(unsafe_code)]
+unsafe impl<T: Unpin, U: Unpin> UnsafeUnpin for OverlappingLifetimeNames<'_, T, U> {}
+
+fn main() {
+    is_unpin::<Blah<PhantomPinned, ()>>(); //~ ERROR E0277
+    is_unpin::<Blah<(), PhantomPinned>>(); // Ok
+    is_unpin::<Blah<PhantomPinned, PhantomPinned>>(); //~ ERROR E0277
+
+    is_unpin::<TrivialBounds>(); //~ ERROR E0277
+
+    is_unpin::<OverlappingLifetimeNames<'_, PhantomPinned, ()>>(); //~ ERROR E0277
+    is_unpin::<OverlappingLifetimeNames<'_, (), PhantomPinned>>(); //~ ERROR E0277
+}
diff --git a/third_party/rust/pin-project/tests/ui/unsafe_unpin/proper_unpin.stderr b/third_party/rust/pin-project/tests/ui/unsafe_unpin/proper_unpin.stderr
new file mode 100644
index 0000000000..5494666ecc
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/unsafe_unpin/proper_unpin.stderr
@@ -0,0 +1,63 @@
+error[E0277]: `std::marker::PhantomPinned` cannot be unpinned
+  --> $DIR/proper_unpin.rs:35:5
+   |
+4  | fn is_unpin<T: Unpin>() {}
+   |                ----- required by this bound in `is_unpin`
+...
+35 |     is_unpin::<Blah<PhantomPinned, ()>>(); //~ ERROR E0277
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `std::marker::Unpin` is not implemented for `std::marker::PhantomPinned`
+   |
+   = note: required because of the requirements on the impl of `pin_project::UnsafeUnpin` for `Blah<std::marker::PhantomPinned, ()>`
+   = note: required because of the requirements on the impl of `pin_project::UnsafeUnpin` for `pin_project::__private::Wrapper<'_, Blah<std::marker::PhantomPinned, ()>>`
+   = note: required because of the requirements on the impl of `std::marker::Unpin` for `Blah<std::marker::PhantomPinned, ()>`
+
+error[E0277]: `std::marker::PhantomPinned` cannot be unpinned
+  --> $DIR/proper_unpin.rs:37:5
+   |
+4  | fn is_unpin<T: Unpin>() {}
+   |                ----- required by this bound in `is_unpin`
+...
+37 |     is_unpin::<Blah<PhantomPinned, PhantomPinned>>(); //~ ERROR E0277
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `std::marker::Unpin` is not implemented for `std::marker::PhantomPinned`
+   |
+   = note: required because of the requirements on the impl of `pin_project::UnsafeUnpin` for `Blah<std::marker::PhantomPinned, std::marker::PhantomPinned>`
+   = note: required because of the requirements on the impl of `pin_project::UnsafeUnpin` for `pin_project::__private::Wrapper<'_, Blah<std::marker::PhantomPinned, std::marker::PhantomPinned>>`
+   = note: required because of the requirements on the impl of `std::marker::Unpin` for `Blah<std::marker::PhantomPinned, std::marker::PhantomPinned>`
+
+error[E0277]: the trait bound `TrivialBounds: pin_project::UnsafeUnpin` is not satisfied
+  --> $DIR/proper_unpin.rs:39:16
+   |
+4  | fn is_unpin<T: Unpin>() {}
+   |                ----- required by this bound in `is_unpin`
+...
+39 |     is_unpin::<TrivialBounds>(); //~ ERROR E0277
+   |                ^^^^^^^^^^^^^ the trait `pin_project::UnsafeUnpin` is not implemented for `TrivialBounds`
+   |
+   = note: required because of the requirements on the impl of `pin_project::UnsafeUnpin` for `pin_project::__private::Wrapper<'_, TrivialBounds>`
+   = note: required because of the requirements on the impl of `std::marker::Unpin` for `TrivialBounds`
+
+error[E0277]: `std::marker::PhantomPinned` cannot be unpinned
+  --> $DIR/proper_unpin.rs:41:5
+   |
+4  | fn is_unpin<T: Unpin>() {}
+   |                ----- required by this bound in `is_unpin`
+...
+41 |     is_unpin::<OverlappingLifetimeNames<'_, PhantomPinned, ()>>(); //~ ERROR E0277
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `std::marker::Unpin` is not implemented for `std::marker::PhantomPinned`
+   |
+   = note: required because of the requirements on the impl of `pin_project::UnsafeUnpin` for `OverlappingLifetimeNames<'_, std::marker::PhantomPinned, ()>`
+   = note: required because of the requirements on the impl of `pin_project::UnsafeUnpin` for `pin_project::__private::Wrapper<'_, OverlappingLifetimeNames<'_, std::marker::PhantomPinned, ()>>`
+   = note: required because of the requirements on the impl of `std::marker::Unpin` for `OverlappingLifetimeNames<'_, std::marker::PhantomPinned, ()>`
+
+error[E0277]: `std::marker::PhantomPinned` cannot be unpinned
+  --> $DIR/proper_unpin.rs:42:5
+   |
+4  | fn is_unpin<T: Unpin>() {}
+   |                ----- required by this bound in `is_unpin`
+...
+42 |     is_unpin::<OverlappingLifetimeNames<'_, (), PhantomPinned>>(); //~ ERROR E0277
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `std::marker::Unpin` is not implemented for `std::marker::PhantomPinned`
+   |
+   = note: required because of the requirements on the impl of `pin_project::UnsafeUnpin` for `OverlappingLifetimeNames<'_, (), std::marker::PhantomPinned>`
+   = note: required because of the requirements on the impl of `pin_project::UnsafeUnpin` for `pin_project::__private::Wrapper<'_, OverlappingLifetimeNames<'_, (), std::marker::PhantomPinned>>`
+   = note: required because of the requirements on the impl of `std::marker::Unpin` for `OverlappingLifetimeNames<'_, (), std::marker::PhantomPinned>`
diff --git a/third_party/rust/pin-project/tests/ui/unstable-features/README.md b/third_party/rust/pin-project/tests/ui/unstable-features/README.md
new file mode 100644
index 0000000000..b9215b6500
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/unstable-features/README.md
@@ -0,0 +1,5 @@
+# UI tests for unstable features
+
+These tests check how the guarantees and features provided by pin-project interact with unstable language features.
+
+The names of the files contained in this directory need to begin with the name of the feature.
diff --git a/third_party/rust/pin-project/tests/ui/unstable-features/marker_trait_attr-feature-gate.rs b/third_party/rust/pin-project/tests/ui/unstable-features/marker_trait_attr-feature-gate.rs
new file mode 100644
index 0000000000..22185eeaf4
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/unstable-features/marker_trait_attr-feature-gate.rs
@@ -0,0 +1,19 @@
+// NB: If you change this test, change 'marker_trait_attr.rs' at the same time.
+
+use pin_project::pin_project;
+use std::marker::PhantomPinned;
+
+#[pin_project] //~ ERROR E0119
+struct Foo<T> {
+    #[pin]
+    x: T,
+}
+
+// unsound Unpin impl
+impl<T> Unpin for Foo<T> {}
+
+fn is_unpin<T: Unpin>() {}
+
+fn main() {
+    is_unpin::<Foo<PhantomPinned>>()
+}
diff --git a/third_party/rust/pin-project/tests/ui/unstable-features/marker_trait_attr-feature-gate.stderr b/third_party/rust/pin-project/tests/ui/unstable-features/marker_trait_attr-feature-gate.stderr
new file mode 100644
index 0000000000..da2c8ea695
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/unstable-features/marker_trait_attr-feature-gate.stderr
@@ -0,0 +1,10 @@
+error[E0119]: conflicting implementations of trait `std::marker::Unpin` for type `Foo<_>`:
+  --> $DIR/marker_trait_attr-feature-gate.rs:6:1
+   |
+6  | #[pin_project] //~ ERROR E0119
+   | ^^^^^^^^^^^^^^ conflicting implementation for `Foo<_>`
+...
+13 | impl<T> Unpin for Foo<T> {}
+   | ------------------------ first implementation here
+   |
+   = note: this error originates in a derive macro (in Nightly builds, run with -Z macro-backtrace for more info)
diff --git a/third_party/rust/pin-project/tests/ui/unstable-features/marker_trait_attr.rs b/third_party/rust/pin-project/tests/ui/unstable-features/marker_trait_attr.rs
new file mode 100644
index 0000000000..0b8b30ad64
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/unstable-features/marker_trait_attr.rs
@@ -0,0 +1,25 @@
+// NB: If you change this test, change 'marker_trait_attr-feature-gate.rs' at the same time.
+
+// marker_trait_attr
+// Tracking issue: https://github.com/rust-lang/rust/issues/29864
+#![feature(marker_trait_attr)]
+
+// See https://github.com/taiki-e/pin-project/issues/105#issuecomment-535355974
+
+use pin_project::pin_project;
+use std::marker::PhantomPinned;
+
+#[pin_project] //~ ERROR E0119
+struct Struct<T> {
+    #[pin]
+    x: T,
+}
+
+// unsound Unpin impl
+impl<T> Unpin for Struct<T> {}
+
+fn is_unpin<T: Unpin>() {}
+
+fn main() {
+    is_unpin::<Struct<PhantomPinned>>()
+}
diff --git a/third_party/rust/pin-project/tests/ui/unstable-features/marker_trait_attr.stderr b/third_party/rust/pin-project/tests/ui/unstable-features/marker_trait_attr.stderr
new file mode 100644
index 0000000000..9b3ec57ea4
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/unstable-features/marker_trait_attr.stderr
@@ -0,0 +1,10 @@
+error[E0119]: conflicting implementations of trait `std::marker::Unpin` for type `Struct<_>`:
+  --> $DIR/marker_trait_attr.rs:12:1
+   |
+12 | #[pin_project] //~ ERROR E0119
+   | ^^^^^^^^^^^^^^ conflicting implementation for `Struct<_>`
+...
+19 | impl<T> Unpin for Struct<T> {}
+   | --------------------------- first implementation here
+   |
+   = note: this error originates in a derive macro (in Nightly builds, run with -Z macro-backtrace for more info)
diff --git a/third_party/rust/pin-project/tests/ui/unstable-features/overlapping_marker_traits-feature-gate.rs b/third_party/rust/pin-project/tests/ui/unstable-features/overlapping_marker_traits-feature-gate.rs
new file mode 100644
index 0000000000..0bd4a32cc1
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/unstable-features/overlapping_marker_traits-feature-gate.rs
@@ -0,0 +1,19 @@
+// NB: If you change this test, change 'overlapping_marker_traits.rs' at the same time.
+
+use pin_project::pin_project;
+use std::marker::PhantomPinned;
+
+#[pin_project] //~ ERROR E0119
+struct Struct<T> {
+    #[pin]
+    x: T,
+}
+
+// unsound Unpin impl
+impl<T> Unpin for Struct<T> {}
+
+fn is_unpin<T: Unpin>() {}
+
+fn main() {
+    is_unpin::<Struct<PhantomPinned>>()
+}
diff --git a/third_party/rust/pin-project/tests/ui/unstable-features/overlapping_marker_traits-feature-gate.stderr b/third_party/rust/pin-project/tests/ui/unstable-features/overlapping_marker_traits-feature-gate.stderr
new file mode 100644
index 0000000000..4a8e23843c
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/unstable-features/overlapping_marker_traits-feature-gate.stderr
@@ -0,0 +1,10 @@
+error[E0119]: conflicting implementations of trait `std::marker::Unpin` for type `Struct<_>`:
+  --> $DIR/overlapping_marker_traits-feature-gate.rs:6:1
+   |
+6  | #[pin_project] //~ ERROR E0119
+   | ^^^^^^^^^^^^^^ conflicting implementation for `Struct<_>`
+...
+13 | impl<T> Unpin for Struct<T> {}
+   | --------------------------- first implementation here
+   |
+   = note: this error originates in a derive macro (in Nightly builds, run with -Z macro-backtrace for more info)
diff --git a/third_party/rust/pin-project/tests/ui/unstable-features/overlapping_marker_traits.rs b/third_party/rust/pin-project/tests/ui/unstable-features/overlapping_marker_traits.rs
new file mode 100644
index 0000000000..28b23fe394
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/unstable-features/overlapping_marker_traits.rs
@@ -0,0 +1,29 @@
+// NB: If you change this test, change 'overlapping_marker_traits-feature-gate.rs' at the same time.
+
+// This feature could break the guarantee for Unpin provided by pin-project,
+// but was removed in https://github.com/rust-lang/rust/pull/68544 (nightly-2020-02-06).
+// Refs:
+// * https://github.com/rust-lang/rust/issues/29864#issuecomment-515780867.
+// * https://github.com/taiki-e/pin-project/issues/105
+
+// overlapping_marker_traits
+// Tracking issue: https://github.com/rust-lang/rust/issues/29864
+#![feature(overlapping_marker_traits)]
+
+use pin_project::pin_project;
+use std::marker::PhantomPinned;
+
+#[pin_project]
+struct Foo<T> {
+    #[pin]
+    x: T,
+}
+
+// unsound Unpin impl
+impl<T> Unpin for Foo<T> {}
+
+fn is_unpin<T: Unpin>() {}
+
+fn main() {
+    is_unpin::<Foo<PhantomPinned>>()
+}
diff --git a/third_party/rust/pin-project/tests/ui/unstable-features/overlapping_marker_traits.stderr b/third_party/rust/pin-project/tests/ui/unstable-features/overlapping_marker_traits.stderr
new file mode 100644
index 0000000000..13ad810f69
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/unstable-features/overlapping_marker_traits.stderr
@@ -0,0 +1,18 @@
+error[E0557]: feature has been removed
+  --> $DIR/overlapping_marker_traits.rs:11:12
+   |
+11 | #![feature(overlapping_marker_traits)]
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^ feature has been removed
+   |
+   = note: removed in favor of `#![feature(marker_trait_attr)]`
+
+error[E0119]: conflicting implementations of trait `std::marker::Unpin` for type `Foo<_>`:
+  --> $DIR/overlapping_marker_traits.rs:16:1
+   |
+16 | #[pin_project]
+   | ^^^^^^^^^^^^^^ conflicting implementation for `Foo<_>`
+...
+23 | impl<T> Unpin for Foo<T> {}
+   | ------------------------ first implementation here
+   |
+   = note: this error originates in a derive macro (in Nightly builds, run with -Z macro-backtrace for more info)
diff --git a/third_party/rust/pin-project/tests/ui/unstable-features/run-pass/stmt_expr_attributes.rs b/third_party/rust/pin-project/tests/ui/unstable-features/run-pass/stmt_expr_attributes.rs
new file mode 100644
index 0000000000..8ad8e41bb1
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/unstable-features/run-pass/stmt_expr_attributes.rs
@@ -0,0 +1,62 @@
+// NB: If you change this test, change 'stmt_expr_attributes-feature-gate.rs' at the same time.
+
+// proc_macro_hygiene
+// Tracking issue: https://github.com/rust-lang/rust/issues/54727
+#![feature(proc_macro_hygiene)]
+// stmt_expr_attributes
+// Tracking issue: https://github.com/rust-lang/rust/issues/15701
+#![feature(stmt_expr_attributes)]
+
+use pin_project::{pin_project, project};
+use std::pin::Pin;
+
+fn project_stmt_expr_nightly() {
+    #[pin_project]
+    enum Baz<A, B, C, D> {
+        Variant1(#[pin] A, B),
+        Variant2 {
+            #[pin]
+            field1: C,
+            field2: D,
+        },
+        None,
+    }
+
+    let mut baz = Baz::Variant1(1, 2);
+
+    let mut baz = Pin::new(&mut baz).project();
+
+    #[project]
+    match &mut baz {
+        Baz::Variant1(x, y) => {
+            let x: &mut Pin<&mut i32> = x;
+            assert_eq!(**x, 1);
+
+            let y: &mut &mut i32 = y;
+            assert_eq!(**y, 2);
+        }
+        Baz::Variant2 { field1, field2 } => {
+            let _x: &mut Pin<&mut i32> = field1;
+            let _y: &mut &mut i32 = field2;
+        }
+        Baz::None => {}
+    }
+
+    let () = #[project]
+    match &mut baz {
+        Baz::Variant1(x, y) => {
+            let x: &mut Pin<&mut i32> = x;
+            assert_eq!(**x, 1);
+
+            let y: &mut &mut i32 = y;
+            assert_eq!(**y, 2);
+        }
+        Baz::Variant2 { field1, field2 } => {
+            let _x: &mut Pin<&mut i32> = field1;
+            let _y: &mut &mut i32 = field2;
+        }
+        Baz::None => {}
+    };
+}
+
+fn main() {}
diff --git a/third_party/rust/pin-project/tests/ui/unstable-features/stmt_expr_attributes-feature-gate.rs b/third_party/rust/pin-project/tests/ui/unstable-features/stmt_expr_attributes-feature-gate.rs
new file mode 100644
index 0000000000..82267238f4
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/unstable-features/stmt_expr_attributes-feature-gate.rs
@@ -0,0 +1,55 @@
+// NB: If you change this test, change 'stmt_expr_attributes.rs' at the same time.
+
+use pin_project::{pin_project, project};
+use std::pin::Pin;
+
+fn project_stmt_expr_nightly() {
+    #[pin_project]
+    enum Enum<A, B, C, D> {
+        Variant1(#[pin] A, B),
+        Variant2 {
+            #[pin]
+            field1: C,
+            field2: D,
+        },
+        None,
+    }
+
+    let mut baz = Enum::Variant1(1, 2);
+
+    let mut baz = Pin::new(&mut baz).project();
+
+    #[project] //~ ERROR E0658
+    match &mut baz {
+        Enum::Variant1(x, y) => {
+            let x: &mut Pin<&mut i32> = x;
+            assert_eq!(**x, 1);
+
+            let y: &mut &mut i32 = y;
+            assert_eq!(**y, 2);
+        }
+        Enum::Variant2 { field1, field2 } => {
+            let _x: &mut Pin<&mut i32> = field1;
+            let _y: &mut &mut i32 = field2;
+        }
+        Enum::None => {}
+    }
+
+    let () = #[project] //~ ERROR E0658
+    match &mut baz {
+        Enum::Variant1(x, y) => {
+            let x: &mut Pin<&mut i32> = x;
+            assert_eq!(**x, 1);
+
+            let y: &mut &mut i32 = y;
+            assert_eq!(**y, 2);
+        }
+        Enum::Variant2 { field1, field2 } => {
+            let _x: &mut Pin<&mut i32> = field1;
+            let _y: &mut &mut i32 = field2;
+        }
+        Enum::None => {}
+    };
+}
+
+fn main() {}
diff --git a/third_party/rust/pin-project/tests/ui/unstable-features/stmt_expr_attributes-feature-gate.stderr b/third_party/rust/pin-project/tests/ui/unstable-features/stmt_expr_attributes-feature-gate.stderr
new file mode 100644
index 0000000000..6510ec760b
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/unstable-features/stmt_expr_attributes-feature-gate.stderr
@@ -0,0 +1,35 @@
+error[E0658]: attributes on expressions are experimental
+  --> $DIR/stmt_expr_attributes-feature-gate.rs:22:5
+   |
+22 |     #[project] //~ ERROR E0658
+   |     ^^^^^^^^^^
+   |
+   = note: see issue #15701 <https://github.com/rust-lang/rust/issues/15701> for more information
+   = help: add `#![feature(stmt_expr_attributes)]` to the crate attributes to enable
+
+error[E0658]: attributes on expressions are experimental
+  --> $DIR/stmt_expr_attributes-feature-gate.rs:38:14
+   |
+38 |     let () = #[project] //~ ERROR E0658
+   |              ^^^^^^^^^^
+   |
+   = note: see issue #15701 <https://github.com/rust-lang/rust/issues/15701> for more information
+   = help: add `#![feature(stmt_expr_attributes)]` to the crate attributes to enable
+
+error[E0658]: custom attributes cannot be applied to expressions
+  --> $DIR/stmt_expr_attributes-feature-gate.rs:22:5
+   |
+22 |     #[project] //~ ERROR E0658
+   |     ^^^^^^^^^^
+   |
+   = note: see issue #54727 <https://github.com/rust-lang/rust/issues/54727> for more information
+   = help: add `#![feature(proc_macro_hygiene)]` to the crate attributes to enable
+
+error[E0658]: custom attributes cannot be applied to expressions
+  --> $DIR/stmt_expr_attributes-feature-gate.rs:38:14
+   |
+38 |     let () = #[project] //~ ERROR E0658
+   |              ^^^^^^^^^^
+   |
+   = note: see issue #54727 <https://github.com/rust-lang/rust/issues/54727> for more information
+   = help: add `#![feature(proc_macro_hygiene)]` to the crate attributes to enable
diff --git a/third_party/rust/pin-project/tests/ui/unstable-features/trivial_bounds-bug.rs b/third_party/rust/pin-project/tests/ui/unstable-features/trivial_bounds-bug.rs
new file mode 100644
index 0000000000..66e0ec4a4f
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/unstable-features/trivial_bounds-bug.rs
@@ -0,0 +1,33 @@
+// NB: If you change this test, change 'trivial_bounds-feature-gate.rs' at the same time.
+
+// trivial_bounds
+// Tracking issue: https://github.com/rust-lang/rust/issues/48214
+#![feature(trivial_bounds)]
+
+use std::marker::{PhantomData, PhantomPinned};
+
+fn phantom_pinned() {
+    struct A(PhantomPinned);
+
+    // bug of trivial_bounds?
+    impl Unpin for A where PhantomPinned: Unpin {} //~ ERROR E0277
+
+    struct Wrapper<T>(T);
+
+    impl<T> Unpin for Wrapper<T> where T: Unpin {}
+
+    struct B(PhantomPinned);
+
+    impl Unpin for B where Wrapper<PhantomPinned>: Unpin {} //~ Ok
+
+    struct WrapperWithLifetime<'a, T>(PhantomData<&'a ()>, T);
+
+    impl<T> Unpin for WrapperWithLifetime<'_, T> where T: Unpin {}
+
+    struct C(PhantomPinned);
+
+    impl<'a> Unpin for C where WrapperWithLifetime<'a, PhantomPinned>: Unpin {}
+    // Ok
+}
+
+fn main() {}
diff --git a/third_party/rust/pin-project/tests/ui/unstable-features/trivial_bounds-bug.stderr b/third_party/rust/pin-project/tests/ui/unstable-features/trivial_bounds-bug.stderr
new file mode 100644
index 0000000000..8370c456cc
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/unstable-features/trivial_bounds-bug.stderr
@@ -0,0 +1,5 @@
+error[E0277]: `std::marker::PhantomPinned` cannot be unpinned
+   --> $DIR/trivial_bounds-bug.rs:13:43
+    |
+13  |     impl Unpin for A where PhantomPinned: Unpin {} //~ ERROR E0277
+    |                                           ^^^^^ the trait `std::marker::Unpin` is not implemented for `std::marker::PhantomPinned`
diff --git a/third_party/rust/pin-project/tests/ui/unstable-features/trivial_bounds-feature-gate.rs b/third_party/rust/pin-project/tests/ui/unstable-features/trivial_bounds-feature-gate.rs
new file mode 100644
index 0000000000..a6a4d84e61
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/unstable-features/trivial_bounds-feature-gate.rs
@@ -0,0 +1,52 @@
+// NB: If you change this test, change 'trivial_bounds.rs' at the same time.
+
+use std::marker::{PhantomData, PhantomPinned};
+
+fn phantom_pinned() {
+    struct A(PhantomPinned);
+
+    impl Unpin for A where PhantomPinned: Unpin {} //~ ERROR E0277
+
+    struct Wrapper<T>(T);
+
+    impl<T> Unpin for Wrapper<T> where T: Unpin {}
+
+    struct B(PhantomPinned);
+
+    impl Unpin for B where Wrapper<PhantomPinned>: Unpin {} //~ ERROR E0277
+
+    struct WrapperWithLifetime<'a, T>(PhantomData<&'a ()>, T);
+
+    impl<T> Unpin for WrapperWithLifetime<'_, T> where T: Unpin {}
+
+    struct C(PhantomPinned);
+
+    impl<'a> Unpin for C where WrapperWithLifetime<'a, PhantomPinned>: Unpin {}
+    // Ok
+}
+
+fn inner() {
+    struct Inner(PhantomPinned);
+
+    struct A(Inner);
+
+    impl Unpin for A where Inner: Unpin {} //~ ERROR E0277
+
+    struct Wrapper<T>(T);
+
+    impl<T> Unpin for Wrapper<T> where T: Unpin {}
+
+    struct B(Inner);
+
+    impl Unpin for B where Wrapper<Inner>: Unpin {} //~ ERROR E0277
+
+    struct WrapperWithLifetime<'a, T>(PhantomData<&'a ()>, T);
+
+    impl<T> Unpin for WrapperWithLifetime<'_, T> where T: Unpin {}
+
+    struct C(Inner);
+
+    impl<'a> Unpin for C where WrapperWithLifetime<'a, Inner>: Unpin {} // Ok
+}
+
+fn main() {}
diff --git a/third_party/rust/pin-project/tests/ui/unstable-features/trivial_bounds-feature-gate.stderr b/third_party/rust/pin-project/tests/ui/unstable-features/trivial_bounds-feature-gate.stderr
new file mode 100644
index 0000000000..f8ef886065
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/unstable-features/trivial_bounds-feature-gate.stderr
@@ -0,0 +1,45 @@
+error[E0277]: `std::marker::PhantomPinned` cannot be unpinned
+ --> $DIR/trivial_bounds-feature-gate.rs:8:5
+  |
+8 |     impl Unpin for A where PhantomPinned: Unpin {} //~ ERROR E0277
+  |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `std::marker::Unpin` is not implemented for `std::marker::PhantomPinned`
+  |
+  = help: see issue #48214
+  = help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
+
+error[E0277]: `std::marker::PhantomPinned` cannot be unpinned
+   --> $DIR/trivial_bounds-feature-gate.rs:8:43
+    |
+8   |     impl Unpin for A where PhantomPinned: Unpin {} //~ ERROR E0277
+    |                                           ^^^^^ the trait `std::marker::Unpin` is not implemented for `std::marker::PhantomPinned`
+
+error[E0277]: `std::marker::PhantomPinned` cannot be unpinned
+  --> $DIR/trivial_bounds-feature-gate.rs:16:5
+   |
+16 |     impl Unpin for B where Wrapper<PhantomPinned>: Unpin {} //~ ERROR E0277
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `std::marker::Unpin` is not implemented for `std::marker::PhantomPinned`
+   |
+   = note: required because of the requirements on the impl of `std::marker::Unpin` for `phantom_pinned::Wrapper<std::marker::PhantomPinned>`
+   = help: see issue #48214
+   = help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
+
+error[E0277]: `std::marker::PhantomPinned` cannot be unpinned
+  --> $DIR/trivial_bounds-feature-gate.rs:33:5
+   |
+33 |     impl Unpin for A where Inner: Unpin {} //~ ERROR E0277
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ within `inner::Inner`, the trait `std::marker::Unpin` is not implemented for `std::marker::PhantomPinned`
+   |
+   = note: required because it appears within the type `inner::Inner`
+   = help: see issue #48214
+   = help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
+
+error[E0277]: `std::marker::PhantomPinned` cannot be unpinned
+  --> $DIR/trivial_bounds-feature-gate.rs:41:5
+   |
+41 |     impl Unpin for B where Wrapper<Inner>: Unpin {} //~ ERROR E0277
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ within `inner::Inner`, the trait `std::marker::Unpin` is not implemented for `std::marker::PhantomPinned`
+   |
+   = note: required because it appears within the type `inner::Inner`
+   = note: required because of the requirements on the impl of `std::marker::Unpin` for `inner::Wrapper<inner::Inner>`
+   = help: see issue #48214
+   = help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
diff --git a/third_party/rust/pin-project/tests/ui/unstable-features/trivial_bounds.rs b/third_party/rust/pin-project/tests/ui/unstable-features/trivial_bounds.rs
new file mode 100644
index 0000000000..680effe61d
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/unstable-features/trivial_bounds.rs
@@ -0,0 +1,34 @@
+// NB: If you change this test, change 'trivial_bounds-feature-gate.rs' at the same time.
+
+// trivial_bounds
+// Tracking issue: https://github.com/rust-lang/rust/issues/48214
+#![feature(trivial_bounds)]
+#![deny(trivial_bounds)]
+
+use std::marker::{PhantomData, PhantomPinned};
+
+fn inner() {
+    struct Inner(PhantomPinned);
+
+    struct A(Inner);
+
+    impl Unpin for A where Inner: Unpin {} //~ ERROR std::marker::Unpin does not depend on any type or lifetime parameters
+
+    struct Wrapper<T>(T);
+
+    impl<T> Unpin for Wrapper<T> where T: Unpin {}
+
+    struct B(Inner);
+
+    impl Unpin for B where Wrapper<Inner>: Unpin {} //~ ERROR std::marker::Unpin does not depend on any type or lifetime parameters
+
+    struct WrapperWithLifetime<'a, T>(PhantomData<&'a ()>, T);
+
+    impl<T> Unpin for WrapperWithLifetime<'_, T> where T: Unpin {}
+
+    struct C(Inner);
+
+    impl<'a> Unpin for C where WrapperWithLifetime<'a, Inner>: Unpin {} // Ok
+}
+
+fn main() {}
diff --git a/third_party/rust/pin-project/tests/ui/unstable-features/trivial_bounds.stderr b/third_party/rust/pin-project/tests/ui/unstable-features/trivial_bounds.stderr
new file mode 100644
index 0000000000..03d0161443
--- /dev/null
+++ b/third_party/rust/pin-project/tests/ui/unstable-features/trivial_bounds.stderr
@@ -0,0 +1,17 @@
+error: Trait bound inner::Inner: std::marker::Unpin does not depend on any type or lifetime parameters
+  --> $DIR/trivial_bounds.rs:15:35
+   |
+15 |     impl Unpin for A where Inner: Unpin {} //~ ERROR std::marker::Unpin does not depend on any type or lifetime parameters
+   |                                   ^^^^^
+   |
+note: the lint level is defined here
+  --> $DIR/trivial_bounds.rs:6:9
+   |
+6  | #![deny(trivial_bounds)]
+   |         ^^^^^^^^^^^^^^
+
+error: Trait bound inner::Wrapper<inner::Inner>: std::marker::Unpin does not depend on any type or lifetime parameters
+  --> $DIR/trivial_bounds.rs:23:44
+   |
+23 |     impl Unpin for B where Wrapper<Inner>: Unpin {} //~ ERROR std::marker::Unpin does not depend on any type or lifetime parameters
+   |                                            ^^^^^
diff --git a/third_party/rust/pin-project/tests/unsafe_unpin.rs b/third_party/rust/pin-project/tests/unsafe_unpin.rs
new file mode 100644
index 0000000000..74673ca126
--- /dev/null
+++ b/third_party/rust/pin-project/tests/unsafe_unpin.rs
@@ -0,0 +1,76 @@
+#![warn(unsafe_code)]
+#![warn(rust_2018_idioms, single_use_lifetimes)]
+#![allow(dead_code)]
+
+use pin_project::{pin_project, UnsafeUnpin};
+use std::{marker::PhantomPinned, pin::Pin};
+
+fn is_unpin<T: Unpin>() {}
+
+#[pin_project(UnsafeUnpin)]
+pub struct Blah<T, U> {
+    field1: U,
+    #[pin]
+    field2: T,
+}
+
+#[allow(unsafe_code)]
+unsafe impl<T: Unpin, U> UnsafeUnpin for Blah<T, U> {}
+
+#[pin_project(UnsafeUnpin)]
+pub struct OverlappingLifetimeNames<'pin, T, U> {
+    #[pin]
+    field1: T,
+    field2: U,
+    field3: &'pin (),
+}
+
+#[allow(unsafe_code)]
+unsafe impl<T: Unpin, U> UnsafeUnpin for OverlappingLifetimeNames<'_, T, U> {}
+
+#[test]
+fn unsafe_unpin() {
+    is_unpin::<Blah<(), PhantomPinned>>();
+    is_unpin::<OverlappingLifetimeNames<'_, (), ()>>();
+}
+
+#[test]
+fn trivial_bounds() {
+    #[pin_project(UnsafeUnpin)]
+    pub struct NotImplementUnsafUnpin {
+        #[pin]
+        field: PhantomPinned,
+    }
+}
+
+#[test]
+fn dst() {
+    #[pin_project(UnsafeUnpin)]
+    pub struct A<T: ?Sized> {
+        x: T,
+    }
+
+    #[pin_project(UnsafeUnpin)]
+    pub struct B<T: ?Sized> {
+        #[pin]
+        x: T,
+    }
+
+    #[pin_project(UnsafeUnpin)]
+    pub struct C<T: ?Sized>(T);
+
+    #[pin_project(UnsafeUnpin)]
+    pub struct D<T: ?Sized>(#[pin] T);
+}
+
+#[test]
+fn test() {
+    let mut x = OverlappingLifetimeNames { field1: 0, field2: 1, field3: &() };
+    let x = Pin::new(&mut x);
+    let y = x.as_ref().project_ref();
+    let _: Pin<&u8> = y.field1;
+    let _: &u8 = y.field2;
+    let y = x.project();
+    let _: Pin<&mut u8> = y.field1;
+    let _: &mut u8 = y.field2;
+}