1 files changed, 154 insertions, 0 deletions
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..82207b60b1
--- /dev/null
+++ b/third_party/rust/pin-project/examples/pinned_drop-expanded.rs
@@ -0,0 +1,154 @@
+// Original code (./pinned_drop.rs):
+//
+// ```rust
+// #![allow(dead_code)]
+//
+// use std::pin::Pin;
+//
+// use pin_project::{pin_project, pinned_drop};
+//
+// #[pin_project(PinnedDrop)]
+// pub struct Struct<'a, T> {
+//     was_dropped: &'a mut bool,
+//     #[pin]
+//     field: T,
+// }
+//
+// #[pinned_drop]
+// fn drop_Struct<T>(mut this: Pin<&mut Struct<'_, T>>) {
+//     **this.project().was_dropped = true;
+// }
+//
+// fn main() {}
+// ```
+
+#![allow(dead_code, unused_imports, unused_parens, unknown_lints, renamed_and_removed_lints)]
+#![allow(clippy::needless_lifetimes, clippy::mut_mut)]
+
+use std::pin::Pin;
+
+use pin_project::{pin_project, pinned_drop};
+
+// #[pin_project(PinnedDrop)]
+pub struct Struct<'a, T> {
+    was_dropped: &'a mut bool,
+    // #[pin]
+    field: T,
+}
+
+const _: () = {
+    pub(crate) struct __StructProjection<'pin, 'a, T>
+    where
+        Struct<'a, T>: 'pin,
+    {
+        was_dropped: &'pin mut (&'a mut bool),
+        field: ::pin_project::__private::Pin<&'pin mut (T)>,
+    }
+    pub(crate) struct __StructProjectionRef<'pin, 'a, T>
+    where
+        Struct<'a, T>: 'pin,
+    {
+        was_dropped: &'pin (&'a mut bool),
+        field: ::pin_project::__private::Pin<&'pin (T)>,
+    }
+
+    impl<'a, T> Struct<'a, T> {
+        pub(crate) fn project<'pin>(
+            self: ::pin_project::__private::Pin<&'pin mut Self>,
+        ) -> __StructProjection<'pin, 'a, T> {
+            unsafe {
+                let Self { was_dropped, field } = self.get_unchecked_mut();
+                __StructProjection {
+                    was_dropped,
+                    field: ::pin_project::__private::Pin::new_unchecked(field),
+                }
+            }
+        }
+        pub(crate) fn project_ref<'pin>(
+            self: ::pin_project::__private::Pin<&'pin Self>,
+        ) -> __StructProjectionRef<'pin, 'a, T> {
+            unsafe {
+                let Self { was_dropped, field } = self.get_ref();
+                __StructProjectionRef {
+                    was_dropped,
+                    field: ::pin_project::__private::Pin::new_unchecked(field),
+                }
+            }
+        }
+    }
+
+    // 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.
+    #[forbid(unaligned_references, safe_packed_borrows)]
+    fn __assert_not_repr_packed<'a, T>(this: &Struct<'a, T>) {
+        let _ = &this.was_dropped;
+        let _ = &this.field;
+    }
+
+    impl<'a, T> ::pin_project::__private::Drop for Struct<'a, T> {
+        fn drop(&mut self) {
+            // Safety - we're in 'drop', so we know that 'self' will
+            // never move again.
+            let pinned_self = unsafe { ::pin_project::__private::Pin::new_unchecked(self) };
+            // We call `pinned_drop` only once. Since `PinnedDrop::drop`
+            // is an unsafe method 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);
+            }
+        }
+    }
+
+    // Automatically create the appropriate conditional `Unpin` implementation.
+    //
+    // See ./struct-default-expanded.rs and https://github.com/taiki-e/pin-project/pull/53.
+    // for details.
+    pub struct __Struct<'pin, 'a, T> {
+        __pin_project_use_generics: ::pin_project::__private::AlwaysUnpin<'pin, (T)>,
+        __field0: T,
+        __lifetime0: &'a (),
+    }
+    impl<'pin, 'a, T> ::pin_project::__private::Unpin for Struct<'a, T> where
+        __Struct<'pin, 'a, T>: ::pin_project::__private::Unpin
+    {
+    }
+    // A dummy impl of `UnsafeUnpin`, to ensure that the user cannot implement it.
+    #[doc(hidden)]
+    unsafe impl<'pin, 'a, T> ::pin_project::UnsafeUnpin for Struct<'a, T> where
+        __Struct<'pin, 'a, T>: ::pin_project::__private::Unpin
+    {
+    }
+};
+
+// Implementing `PinnedDrop::drop` is safe, but calling it is not safe.
+// This is because destructors can be called multiple times in safe code and
+// [double dropping is unsound](https://github.com/rust-lang/rust/pull/62360).
+//
+// Ideally, it would be desirable to be able to forbid manual calls in
+// the same way as `Drop::drop`, but the library cannot do it. 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]` and can drop a
+// type that implements `PinnedDrop` using the [`drop`] function safely.
+// **Do not call or implement this trait directly.**
+#[doc(hidden)]
+impl<T> ::pin_project::__private::PinnedDrop for Struct<'_, T> {
+    // Since calling it twice on the same object would be UB,
+    // this method is unsafe.
+    unsafe fn drop(self: Pin<&mut Self>) {
+        #[allow(clippy::needless_pass_by_value)]
+        fn __drop_inner<T>(__self: Pin<&mut Struct<'_, T>>) {
+            // A dummy `__drop_inner` function to prevent users call outer `__drop_inner`.
+            fn __drop_inner() {}
+
+            **__self.project().was_dropped = true;
+        }
+        __drop_inner(self);
+    }
+}
+
+fn main() {}