Support ?Sized bounds in generic parameters

taiki-e · Jan 20, 2020 · 5eb45b9 · 5eb45b9
1 parent b219910
commit 5eb45b9
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Showing 4 changed files with 84 additions and 32 deletions.
diff --git a/src/lib.rs b/src/lib.rs
@@ -149,7 +149,7 @@ macro_rules! pin_project {
         pub struct $ident:ident
             $(<
                 $( $lifetime:lifetime $(: $lifetime_bound:lifetime)? ),* $(,)?
-                $( $generics:ident $(: $generics_bound:path)? $(: $generics_lifetime_bound:lifetime)? $(= $generics_default:ty)? ),* $(,)?
+                $( $generics:ident $(: $generics_bound:path)? $(: ?$generics_unsized_bound:path)? $(: $generics_lifetime_bound:lifetime)? $(= $generics_default:ty)? ),* $(,)?
             >)?
             $(where
                 $($where_clause_ty:ty : $where_clause_bound:path),* $(,)?
@@ -166,7 +166,7 @@ macro_rules! pin_project {
             pub struct $ident
                 $(<
                     $( $lifetime $(: $lifetime_bound)? ),*
-                    $( $generics $(: $generics_bound)? $(: $generics_lifetime_bound)? $(= $generics_default)? ),*
+                    $( $generics $(: $generics_bound)? $(: ?$generics_unsized_bound)? $(: $generics_lifetime_bound)? $(= $generics_default)? ),*
                 >)?
                 $(where
                     $($where_clause_ty : $where_clause_bound),*
@@ -184,7 +184,7 @@ macro_rules! pin_project {
         $vis:vis struct $ident:ident
             $(<
                 $( $lifetime:lifetime $(: $lifetime_bound:lifetime)? ),* $(,)?
-                $( $generics:ident $(: $generics_bound:path)? $(: $generics_lifetime_bound:lifetime)? $(= $generics_default:ty)? ),* $(,)?
+                $( $generics:ident $(: $generics_bound:path)? $(: ?$generics_unsized_bound:path)? $(: $generics_lifetime_bound:lifetime)? $(= $generics_default:ty)? ),* $(,)?
             >)?
             $(where
                 $($where_clause_ty:ty : $where_clause_bound:path),* $(,)?
@@ -201,7 +201,7 @@ macro_rules! pin_project {
             $vis struct $ident
                 $(<
                     $( $lifetime $(: $lifetime_bound)? ),*
-                    $( $generics $(: $generics_bound)? $(: $generics_lifetime_bound)? $(= $generics_default)? ),*
+                    $( $generics $(: $generics_bound)? $(: ?$generics_unsized_bound)? $(: $generics_lifetime_bound)? $(= $generics_default)? ),*
                 >)?
                 $(where
                     $($where_clause_ty : $where_clause_bound),*
@@ -223,7 +223,7 @@ macro_rules! pin_project {
             $(<
                 $( $lifetime:lifetime $(: $lifetime_bound:lifetime)? ),*
                 // limitation: does not support multiple trait/lifetime bounds and ? trait bounds.
-                $( $generics:ident $(: $generics_bound:path)? $(: $generics_lifetime_bound:lifetime)? $(= $generics_default:ty)? ),*
+                $( $generics:ident $(: $generics_bound:path)? $(: ?$generics_unsized_bound:path)? $(: $generics_lifetime_bound:lifetime)? $(= $generics_default:ty)? ),*
             >)?
             $(where
                 // limitation: does not support multiple trait/lifetime bounds and ? trait bounds.
@@ -239,7 +239,7 @@ macro_rules! pin_project {
     ) => {
         $(#[$attrs])*
         $vis struct $ident
-            $(< $( $lifetime $(: $lifetime_bound)? ,)* $( $generics $(: $generics_bound)? $(: $generics_lifetime_bound)? $(= $generics_default)? ,)* >)?
+            $(< $( $lifetime $(: $lifetime_bound)? ,)* $( $generics $(: $generics_bound)? $(: ?$generics_unsized_bound)? $(: $generics_lifetime_bound)? $(= $generics_default)? ,)* >)?
             $(where
                 $($where_clause_ty: $where_clause_bound),*
             )*
@@ -254,7 +254,7 @@ macro_rules! pin_project {
             #[allow(clippy::mut_mut)] // This lint warns `&mut &mut <ty>`.
             #[allow(dead_code)] // This lint warns unused fields/variants.
             $proj_vis struct Projection
-                <'__pin $(, $( $lifetime $(: $lifetime_bound)? ,)* $( $generics $(: $generics_bound)? $(: $generics_lifetime_bound)? ),* )?>
+                <'__pin $(, $( $lifetime $(: $lifetime_bound)? ,)* $( $generics $(: $generics_bound)? $(: ?$generics_unsized_bound)? $(: $generics_lifetime_bound)? ),* )?>
                 $(where
                     $($where_clause_ty: $where_clause_bound),*
                 )*
@@ -265,7 +265,7 @@ macro_rules! pin_project {
             }
             #[allow(dead_code)] // This lint warns unused fields/variants.
             $proj_vis struct ProjectionRef
-                <'__pin $(, $( $lifetime $(: $lifetime_bound)? ,)* $( $generics $(: $generics_bound)? $(: $generics_lifetime_bound)? ),* )?>
+                <'__pin $(, $( $lifetime $(: $lifetime_bound)? ,)* $( $generics $(: $generics_bound)? $(: ?$generics_unsized_bound)? $(: $generics_lifetime_bound)? ),* )?>
                 $(where
                     $($where_clause_ty: $where_clause_bound),*
                 )*
@@ -275,7 +275,7 @@ macro_rules! pin_project {
                 ),+
             }
 
-            impl $(< $( $lifetime $(: $lifetime_bound)? ,)* $( $generics $(: $generics_bound)? $(: $generics_lifetime_bound)? ),* >)?
+            impl $(< $( $lifetime $(: $lifetime_bound)? ,)* $( $generics $(: $generics_bound)? $(: ?$generics_unsized_bound)? $(: $generics_lifetime_bound)? ),* >)?
                 $ident $(< $($lifetime,)* $($generics),* >)?
                 $(where
                     $($where_clause_ty: $where_clause_bound),*
@@ -333,7 +333,7 @@ macro_rules! pin_project {
             //
             // See also https://github.com/taiki-e/pin-project/pull/53.
             $vis struct __Origin
-                <'__pin $(, $( $lifetime $(: $lifetime_bound)? ,)* $( $generics $(: $generics_bound)? $(: $generics_lifetime_bound)? ),* )?>
+                <'__pin $(, $( $lifetime $(: $lifetime_bound)? ,)* $( $generics $(: $generics_bound)? $(: ?$generics_unsized_bound)? $(: $generics_lifetime_bound)? ),* )?>
                 $(where
                     $($where_clause_ty: $where_clause_bound),*
                 )*
@@ -343,7 +343,7 @@ macro_rules! pin_project {
                     $field: $crate::pin_project!(@make_unpin_bound $(#[$pin])? $field_ty)
                 ),+
             }
-            impl <'__pin $(, $( $lifetime $(: $lifetime_bound)? ,)* $($generics $(: $generics_bound)? $(: $generics_lifetime_bound)? ),* )?> ::core::marker::Unpin
+            impl <'__pin $(, $( $lifetime $(: $lifetime_bound)? ,)* $($generics $(: $generics_bound)? $(: ?$generics_unsized_bound)? $(: $generics_lifetime_bound)? ),* )?> ::core::marker::Unpin
                 for $ident $(< $($lifetime,)* $($generics),* >)?
             where
                 __Origin <'__pin $(, $($lifetime,)* $($generics),* )?>: ::core::marker::Unpin
@@ -366,7 +366,7 @@ macro_rules! pin_project {
             #[allow(clippy::drop_bounds)]
             impl<T: ::core::ops::Drop> MustNotImplDrop for T {}
             #[allow(single_use_lifetimes)]
-            impl $(< $( $lifetime $(: $lifetime_bound)? ,)* $($generics $(: $generics_bound)? $(: $generics_lifetime_bound)? ),*>)? MustNotImplDrop
+            impl $(< $( $lifetime $(: $lifetime_bound)? ,)* $($generics $(: $generics_bound)? $(: ?$generics_unsized_bound)? $(: $generics_lifetime_bound)? ),*>)? MustNotImplDrop
                 for $ident $(< $($lifetime,)* $($generics),* >)?
                 $(where
                     $($where_clause_ty: $where_clause_bound),*
@@ -390,7 +390,7 @@ macro_rules! pin_project {
             #[allow(non_snake_case)]
             #[deny(safe_packed_borrows)]
             fn __assert_not_repr_packed
-                $(< $($lifetime $(: $lifetime_bound)? ,)* $( $generics $(: $generics_bound)? $(: $generics_lifetime_bound)? ),* >)?
+                $(< $($lifetime $(: $lifetime_bound)? ,)* $( $generics $(: $generics_bound)? $(: ?$generics_unsized_bound)? $(: $generics_lifetime_bound)? ),* >)?
             (
                 this: &$ident $(< $($lifetime,)* $($generics),* >)?
             )

diff --git a/tests/test.rs b/tests/test.rs
@@ -80,6 +80,20 @@ fn where_clause_and_associated_type_fields() {
     // impl<T> Static for Struct3<T> {}
 }
 
+// #[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! {
@@ -110,11 +124,11 @@ fn move_out() {
 
 #[test]
 fn trait_bounds_on_type_generics() {
-    // pin_project! {
-    //     pub struct Struct1<'a, T: ?Sized> {
-    //         field: &'a mut T,
-    //     }
-    // }
+    pin_project! {
+        pub struct Struct1<'a, T: ?Sized> {
+            field: &'a mut T,
+        }
+    }
 
     pin_project! {
         pub struct Struct2<'a, T: ::core::fmt::Debug> {
@@ -282,21 +296,23 @@ fn trivial_bounds() {
     }
 }
 
-// #[test]
-// fn dst() {
-//     pin_project! {
-//         pub struct A<T: ?Sized> {
-//             x: T,
-//         }
-//     }
+#[test]
+fn dst() {
+    pin_project! {
+        pub struct A<T: ?Sized> {
+            x: T,
+        }
+    }
 
-//     pin_project! {
-//         pub struct B<T: ?Sized> {
-//             #[pin]
-//             x: T,
-//         }
-//     }
-// }
+    let _: &mut A<dyn core::fmt::Debug> = &mut A { x: 0u8 } as _;
+
+    pin_project! {
+        pub struct B<T: ?Sized> {
+            #[pin]
+            x: T,
+        }
+    }
+}
 
 #[test]
 fn dyn_type() {

diff --git a/tests/ui/invalid-bounds.rs b/tests/ui/invalid-bounds.rs
@@ -0,0 +1,15 @@
+use pin_project_lite::pin_project;
+
+pin_project! {
+    struct A<T: 'static : ?Sized> { //~ ERROR no rules expected the token `:`
+        field: T,
+    }
+}
+
+pin_project! {
+    struct B<T: Sized : 'static> { //~ ERROR expected one of `+`, `,`, `=`, or `>`, found `:`
+        field: T,
+    }
+}
+
+fn main() {}
diff --git a/tests/ui/invalid-bounds.stderr b/tests/ui/invalid-bounds.stderr
@@ -0,0 +1,21 @@
+error: no rules expected the token `:`
+ --> $DIR/invalid-bounds.rs:4:25
+  |
+4 |     struct A<T: 'static : ?Sized> { //~ ERROR no rules expected the token `:`
+  |                         ^ no rules expected this token in macro call
+
+error: expected one of `+`, `,`, `=`, or `>`, found `:`
+  --> $DIR/invalid-bounds.rs:9:1
+   |
+9  | / pin_project! {
+10 | |     struct B<T: Sized : 'static> { //~ ERROR expected one of `+`, `,`, `=`, or `>`, found `:`
+11 | |         field: T,
+12 | |     }
+13 | | }
+   | | ^
+   | | |
+   | | expected one of `+`, `,`, `=`, or `>`
+   | |_unexpected token
+   |   in this macro invocation
+   |
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)