1 // Original code (./enum-default.rs):
2 //
3 // ```rust
4 // #![allow(dead_code)]
5 //
6 // use pin_project::pin_project;
7 //
8 // #[pin_project(project = EnumProj)]
9 // enum Enum<T, U> {
10 // Pinned(#[pin] T),
11 // Unpinned(U),
12 // }
13 //
14 // fn main() {}
15 // ```
16
17 #![allow(dead_code, unused_imports, unused_parens, unknown_lints, renamed_and_removed_lints)]
18 #![allow(
19 clippy::needless_lifetimes,
20 clippy::just_underscores_and_digits,
21 clippy::used_underscore_binding
22 )]
23
24 use pin_project::pin_project;
25
26 // #[pin_project(project = EnumProj)]
27 enum Enum<T, U> {
28 Pinned(/* #[pin] */ T),
29 Unpinned(U),
30 }
31
32 enum EnumProj<'pin, T, U>
33 where
34 Enum<T, U>: 'pin,
35 {
36 Pinned(::pin_project::__private::Pin<&'pin mut (T)>),
37 Unpinned(&'pin mut (U)),
38 }
39
40 const _: () = {
41 // When `#[pin_project]` is used on enums, only named projection types and
42 // methods are generated because there is no way to access variants of
43 // projected types without naming it.
44 // (When `#[pin_project]` is used on structs, both methods are always generated.)
45
46 impl<T, U> Enum<T, U> {
project<'pin>( self: ::pin_project::__private::Pin<&'pin mut Self>, ) -> EnumProj<'pin, T, U>47 fn project<'pin>(
48 self: ::pin_project::__private::Pin<&'pin mut Self>,
49 ) -> EnumProj<'pin, T, U> {
50 unsafe {
51 match self.get_unchecked_mut() {
52 Self::Pinned(_0) => {
53 EnumProj::Pinned(::pin_project::__private::Pin::new_unchecked(_0))
54 }
55 Self::Unpinned(_0) => EnumProj::Unpinned(_0),
56 }
57 }
58 }
59 }
60
61 // Automatically create the appropriate conditional `Unpin` implementation.
62 //
63 // See ./struct-default-expanded.rs and https://github.com/taiki-e/pin-project/pull/53.
64 // for details.
65 struct __Enum<'pin, T, U> {
66 __pin_project_use_generics: ::pin_project::__private::AlwaysUnpin<
67 'pin,
68 (::pin_project::__private::PhantomData<T>, ::pin_project::__private::PhantomData<U>),
69 >,
70 __field0: T,
71 }
72 impl<'pin, T, U> ::pin_project::__private::Unpin for Enum<T, U> where
73 __Enum<'pin, T, U>: ::pin_project::__private::Unpin
74 {
75 }
76 // A dummy impl of `UnsafeUnpin`, to ensure that the user cannot implement it.
77 #[doc(hidden)]
78 unsafe impl<'pin, T, U> ::pin_project::UnsafeUnpin for Enum<T, U> where
79 __Enum<'pin, T, U>: ::pin_project::__private::Unpin
80 {
81 }
82
83 // Ensure that enum does not implement `Drop`.
84 //
85 // See ./struct-default-expanded.rs for details.
86 trait EnumMustNotImplDrop {}
87 #[allow(clippy::drop_bounds, drop_bounds)]
88 impl<T: ::pin_project::__private::Drop> EnumMustNotImplDrop for T {}
89 impl<T, U> EnumMustNotImplDrop for Enum<T, U> {}
90 // A dummy impl of `PinnedDrop`, to ensure that users don't accidentally
91 // write a non-functional `PinnedDrop` impls.
92 #[doc(hidden)]
93 impl<T, U> ::pin_project::__private::PinnedDrop for Enum<T, U> {
drop(self: ::pin_project::__private::Pin<&mut Self>)94 unsafe fn drop(self: ::pin_project::__private::Pin<&mut Self>) {}
95 }
96
97 // We don't need to check for `#[repr(packed)]`,
98 // since it does not apply to enums.
99 };
100
main()101 fn main() {}
102