// Original code (./struct-default.rs): // // ```rust // #![allow(dead_code)] // // use pin_project::pin_project; // // #[pin_project] // struct Struct { // #[pin] // pinned: T, // unpinned: U, // } // // fn main() {} // ``` #![allow(dead_code, unused_imports, unused_parens, unknown_lints, renamed_and_removed_lints)] #![allow(clippy::needless_lifetimes)] use pin_project::pin_project; // #[pin_project] struct Struct { // #[pin] pinned: T, unpinned: U, } const _: () = { struct __StructProjection<'pin, T, U> where Struct: 'pin, { pinned: ::pin_project::__private::Pin<&'pin mut (T)>, unpinned: &'pin mut (U), } struct __StructProjectionRef<'pin, T, U> where Struct: 'pin, { pinned: ::pin_project::__private::Pin<&'pin (T)>, unpinned: &'pin (U), } impl Struct { fn project<'pin>( self: ::pin_project::__private::Pin<&'pin mut Self>, ) -> __StructProjection<'pin, T, U> { unsafe { let Self { pinned, unpinned } = self.get_unchecked_mut(); __StructProjection { pinned: ::pin_project::__private::Pin::new_unchecked(pinned), unpinned, } } } fn project_ref<'pin>( self: ::pin_project::__private::Pin<&'pin Self>, ) -> __StructProjectionRef<'pin, T, U> { unsafe { let Self { pinned, unpinned } = self.get_ref(); __StructProjectionRef { pinned: ::pin_project::__private::Pin::new_unchecked(pinned), unpinned, } } } } // Ensure that it's impossible to use pin projections on a #[repr(packed)] // struct. // // Taking a reference to a packed field is UB, and applying // `#[forbid(unaligned_references)]` makes sure that doing this 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. #[forbid(unaligned_references, safe_packed_borrows)] fn __assert_not_repr_packed(this: &Struct) { let _ = &this.pinned; let _ = &this.unpinned; } // Automatically create the appropriate conditional `Unpin` implementation. // // Basically this is equivalent to the following code: // // ```rust // impl Unpin for Struct 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. struct __Struct<'pin, T, U> { __pin_project_use_generics: ::pin_project::__private::AlwaysUnpin< 'pin, (::pin_project::__private::PhantomData, ::pin_project::__private::PhantomData), >, __field0: T, } impl<'pin, T, U> ::pin_project::__private::Unpin for Struct where __Struct<'pin, T, U>: ::pin_project::__private::Unpin { } // A dummy impl of `UnsafeUnpin`, to ensure that the user cannot implement it. // // To ensure that users don't accidentally write a non-functional `UnsafeUnpin` // impls, we emit one ourselves. If the user ends up writing an `UnsafeUnpin` // impl, they'll get a "conflicting implementations of trait" error when // coherence checks are run. #[doc(hidden)] unsafe impl<'pin, T, U> ::pin_project::UnsafeUnpin for Struct where __Struct<'pin, T, U>: ::pin_project::__private::Unpin { } // Ensure that struct does not implement `Drop`. // // If you attempt to provide an Drop impl, the blanket impl will // then apply to your type, causing a compile-time error due to // the conflict with the second impl. trait StructMustNotImplDrop {} #[allow(clippy::drop_bounds, drop_bounds)] impl StructMustNotImplDrop for T {} impl StructMustNotImplDrop for Struct {} // A dummy impl of `PinnedDrop`, to ensure that users don't accidentally // write a non-functional `PinnedDrop` impls. #[doc(hidden)] impl ::pin_project::__private::PinnedDrop for Struct { unsafe fn drop(self: ::pin_project::__private::Pin<&mut Self>) {} } }; fn main() {}