Merge pull request #447 from madsmtm/fix-docs

Fix generating documentation for structs containing `objc2::rc::Id`

Author: madsmtm

.github/workflows/ci.yml

@@ -144,9 +144,6 @@ jobs:
         key: cargo-${{ github.job }}-${{ matrix.name }}-${{ hashFiles('**/Cargo.lock') }}
 
     - name: cargo doc
-      # Disable cargo doc checking for now, `NSEnumerator2<'a, T>` is broken
-      # on current nightly.
-      if: false
       run: cargo doc --no-deps --document-private-items ${{ matrix.args }}
 
     - name: cargo clippy

crates/objc2/src/rc/id.rs

@@ -663,6 +663,7 @@ impl<T: ?Sized> fmt::Pointer for Id<T> {
 
 mod private {
     use crate::runtime::Object;
+    use crate::ClassType;
     use core::panic::{RefUnwindSafe, UnwindSafe};
 
     pub struct UnknownStorage<T: ?Sized>(*const T, Object);
@@ -682,6 +683,8 @@ mod private {
 
     #[doc(hidden)]
     pub trait IdSendSyncHelper<T: ?Sized>: mutability::Mutability {
+        // TODO: Move this to be a hidden type under `Mutability` once GATs
+        // are in our MSRV.
         type EquivalentType: ?Sized;
     }
 
@@ -714,6 +717,19 @@ mod private {
     impl<T: ?Sized> IdSendSyncHelper<T> for mutability::MainThreadOnly {
         type EquivalentType = ArcLikeStorage<T>;
     }
+
+    /// Helper struct for avoiding a gnarly ICE in `rustdoc` when generating
+    /// documentation for `icrate` iterator helpers (in particular, it fails
+    /// in generating auto trait implementations).
+    ///
+    /// See related issues:
+    /// - <https://github.com/rust-lang/rust/issues/91380>
+    /// - <https://github.com/rust-lang/rust/issues/107715>
+    pub struct EquivalentType<T: ?Sized + ClassType>(
+        <T::Mutability as IdSendSyncHelper<T>>::EquivalentType,
+    )
+    where
+        T::Mutability: IdSendSyncHelper<T>;
 }
 
 // https://doc.rust-lang.org/nomicon/arc-mutex/arc-base.html#send-and-sync
@@ -732,7 +748,7 @@ mod private {
 unsafe impl<T: ?Sized + ClassType + Send> Send for Id<T>
 where
     T::Mutability: private::IdSendSyncHelper<T>,
-    <T::Mutability as private::IdSendSyncHelper<T>>::EquivalentType: Send,
+    private::EquivalentType<T>: Send,
 {
 }
 
@@ -749,7 +765,7 @@ where
 unsafe impl<T: ?Sized + ClassType + Sync> Sync for Id<T>
 where
     T::Mutability: private::IdSendSyncHelper<T>,
-    <T::Mutability as private::IdSendSyncHelper<T>>::EquivalentType: Sync,
+    private::EquivalentType<T>: Sync,
 {
 }
 

crates/test-ui/ui/nsarray_bound_not_send_sync.stderr

@@ -4,8 +4,9 @@ error[E0277]: `*const NSObject` cannot be shared between threads safely
   |     needs_sync::<NSArray<NSObject>>();
   |                  ^^^^^^^^^^^^^^^^^ `*const NSObject` cannot be shared between threads safely
   |
-  = help: within `icrate::objc2::rc::id::private::UnknownStorage<NSObject>`, the trait `Sync` is not implemented for `*const NSObject`
+  = help: within `icrate::objc2::rc::id::private::EquivalentType<NSObject>`, the trait `Sync` is not implemented for `*const NSObject`
   = note: required because it appears within the type `UnknownStorage<NSObject>`
+  = note: required because it appears within the type `EquivalentType<NSObject>`
   = note: required for `Id<NSObject>` to implement `Sync`
   = note: required because it appears within the type `PhantomData<Id<NSObject>>`
   = note: required because it appears within the type `NSArray<NSObject>`
@@ -40,8 +41,9 @@ error[E0277]: `*const NSObject` cannot be sent between threads safely
   |     needs_send::<NSArray<NSObject>>();
   |                  ^^^^^^^^^^^^^^^^^ `*const NSObject` cannot be sent between threads safely
   |
-  = help: within `icrate::objc2::rc::id::private::UnknownStorage<NSObject>`, the trait `Send` is not implemented for `*const NSObject`
+  = help: within `icrate::objc2::rc::id::private::EquivalentType<NSObject>`, the trait `Send` is not implemented for `*const NSObject`
   = note: required because it appears within the type `UnknownStorage<NSObject>`
+  = note: required because it appears within the type `EquivalentType<NSObject>`
   = note: required for `Id<NSObject>` to implement `Send`
   = note: required because it appears within the type `PhantomData<Id<NSObject>>`
   = note: required because it appears within the type `NSArray<NSObject>`
@@ -79,8 +81,9 @@ error[E0277]: `*const NSObject` cannot be shared between threads safely
   |     needs_sync::<NSMutableArray<NSObject>>();
   |                  ^^^^^^^^^^^^^^^^^^^^^^^^ `*const NSObject` cannot be shared between threads safely
   |
-  = help: within `icrate::objc2::rc::id::private::UnknownStorage<NSObject>`, the trait `Sync` is not implemented for `*const NSObject`
+  = help: within `icrate::objc2::rc::id::private::EquivalentType<NSObject>`, the trait `Sync` is not implemented for `*const NSObject`
   = note: required because it appears within the type `UnknownStorage<NSObject>`
+  = note: required because it appears within the type `EquivalentType<NSObject>`
   = note: required for `Id<NSObject>` to implement `Sync`
   = note: required because it appears within the type `PhantomData<Id<NSObject>>`
   = note: required because it appears within the type `NSArray<NSObject>`
@@ -117,8 +120,9 @@ error[E0277]: `*const NSObject` cannot be sent between threads safely
   |     needs_send::<NSMutableArray<NSObject>>();
   |                  ^^^^^^^^^^^^^^^^^^^^^^^^ `*const NSObject` cannot be sent between threads safely
   |
-  = help: within `icrate::objc2::rc::id::private::UnknownStorage<NSObject>`, the trait `Send` is not implemented for `*const NSObject`
+  = help: within `icrate::objc2::rc::id::private::EquivalentType<NSObject>`, the trait `Send` is not implemented for `*const NSObject`
   = note: required because it appears within the type `UnknownStorage<NSObject>`
+  = note: required because it appears within the type `EquivalentType<NSObject>`
   = note: required for `Id<NSObject>` to implement `Send`
   = note: required because it appears within the type `PhantomData<Id<NSObject>>`
   = note: required because it appears within the type `NSArray<NSObject>`