Fix trailing comma support in generics

This reverts commit 950229c.
taiki-e · Sep 29, 2020 · 060656e · 060656e
1 parent b82b312
commit 060656e
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Showing 3 changed files with 91 additions and 26 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -6,6 +6,8 @@ This project adheres to [Semantic Versioning](https://semver.org).
 
 ## [Unreleased]
 
+* Fix trailing comma support in generics
+
 ## [0.1.8] - 2020-09-26
 
 * Fix compatibility of generated code with `forbid(future_incompatible)`

diff --git a/src/lib.rs b/src/lib.rs
@@ -208,6 +208,7 @@ macro_rules! __pin_project_internal {
             ),+
         }
 
+        #[allow(explicit_outlives_requirements)]
         #[allow(single_use_lifetimes)] // https://github.com/rust-lang/rust/issues/55058
         #[allow(clippy::used_underscore_binding)]
         const _: () = {
@@ -460,7 +461,8 @@ macro_rules! __pin_project_internal {
     (
         $(#[$attrs:meta])*
         pub struct $ident:ident $(<
-            $( $generics:tt
+            $( $lifetime:lifetime $(: $lifetime_bound:lifetime)? ),* $(,)?
+            $( $generics:ident
                 $(: $generics_bound:path)?
                 $(: ?$generics_unsized_bound:path)?
                 $(: $generics_lifetime_bound:lifetime)?
@@ -484,18 +486,24 @@ macro_rules! __pin_project_internal {
         $crate::__pin_project_internal! { @struct_internal;
             [pub(crate)]
             [$(#[$attrs])* pub struct $ident]
-            [$(< $( $generics
-                $(: $generics_bound)?
-                $(: ?$generics_unsized_bound)?
-                $(: $generics_lifetime_bound)?
-                $(= $generics_default)?
-            ),* >)?]
-            [$( $( $generics
-                $(: $generics_bound)?
-                $(: ?$generics_unsized_bound)?
-                $(: $generics_lifetime_bound)?
-            ),* )?]
-            [$( $( $generics ),* )?]
+            [$(<
+                $( $lifetime $(: $lifetime_bound)? ,)*
+                $( $generics
+                    $(: $generics_bound)?
+                    $(: ?$generics_unsized_bound)?
+                    $(: $generics_lifetime_bound)?
+                    $(= $generics_default)?
+                ),*
+            >)?]
+            [$(
+                $( $lifetime $(: $lifetime_bound)? ,)*
+                $( $generics
+                    $(: $generics_bound)?
+                    $(: ?$generics_unsized_bound)?
+                    $(: $generics_lifetime_bound)?
+                ),*
+            )?]
+            [$( $( $lifetime ,)* $( $generics ),* )?]
             [$(where $( $where_clause_ty
                 $(: $where_clause_bound)?
                 $(: ?$where_clause_unsized_bound)?
@@ -512,7 +520,8 @@ macro_rules! __pin_project_internal {
     (
         $(#[$attrs:meta])*
         $vis:vis struct $ident:ident $(<
-            $( $generics:tt
+            $( $lifetime:lifetime $(: $lifetime_bound:lifetime)? ),* $(,)?
+            $( $generics:ident
                 $(: $generics_bound:path)?
                 $(: ?$generics_unsized_bound:path)?
                 $(: $generics_lifetime_bound:lifetime)?
@@ -536,18 +545,24 @@ macro_rules! __pin_project_internal {
         $crate::__pin_project_internal! { @struct_internal;
             [$vis]
             [$(#[$attrs])* $vis struct $ident]
-            [$(< $( $generics
-                $(: $generics_bound)?
-                $(: ?$generics_unsized_bound)?
-                $(: $generics_lifetime_bound)?
-                $(= $generics_default)?
-            ),* >)?]
-            [$( $( $generics
-                $(: $generics_bound)?
-                $(: ?$generics_unsized_bound)?
-                $(: $generics_lifetime_bound)?
-            ),* )?]
-            [$( $( $generics ),* )?]
+            [$(<
+                $( $lifetime $(: $lifetime_bound)? ,)*
+                $( $generics
+                    $(: $generics_bound)?
+                    $(: ?$generics_unsized_bound)?
+                    $(: $generics_lifetime_bound)?
+                    $(= $generics_default)?
+                ),*
+            >)?]
+            [$(
+                $( $lifetime $(: $lifetime_bound)? ,)*
+                $( $generics
+                    $(: $generics_bound)?
+                    $(: ?$generics_unsized_bound)?
+                    $(: $generics_lifetime_bound)?
+                ),*
+            )?]
+            [$( $( $lifetime ,)* $( $generics ),* )?]
             [$(where $( $where_clause_ty
                 $(: $where_clause_bound)?
                 $(: ?$where_clause_unsized_bound)?

diff --git a/tests/test.rs b/tests/test.rs
@@ -385,3 +385,51 @@ fn no_infer_outlives() {
         }
     }
 }
+
+// https://github.com/taiki-e/pin-project-lite/issues/31
+#[test]
+fn trailing_comma() {
+    pub trait T {}
+
+    pin_project! {
+        pub struct S1<
+            A: T,
+            B: T,
+        > {
+            f: (A, B),
+        }
+    }
+
+    pin_project! {
+        pub struct S2<
+            A,
+            B,
+        >
+        where
+            A: T,
+            B: T,
+        {
+            f: (A, B),
+        }
+    }
+
+    pin_project! {
+        #[allow(explicit_outlives_requirements)]
+        pub struct S3<
+            'a,
+            A: 'a,
+            B: 'a,
+        > {
+            f: &'a (A, B),
+        }
+    }
+
+    // pin_project! {
+    //     pub struct S4<
+    //         'a,
+    //         'b: 'a, // <-----
+    //     > {
+    //         f: &'a &'b (),
+    //     }
+    // }
+}