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> { |
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> { |
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 | |
101 | fn main() {} |
102 | |