Merge #192

192: Hide all generated items except for projected types from calling code r=taiki-e a=taiki-e Generate all items except for projected types inside a `const` scope. This makes it impossible for user code to refer to these types. This removes redundant prefix/postfix based on the original type from many generate types. This also remove the `pin_project_show_unpin_struct` flag. Co-authored-by: Taiki Endo <[email protected]>
taiki-e · Apr 19, 2020 · f21de9f · f21de9f
2 parents fc7630a + fd1924d
commit f21de9f
Show file tree

Hide file tree

Showing 16 changed files with 396 additions and 377 deletions.
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
@@ -72,12 +72,10 @@ jobs:
       - name: cargo test
         run: |
           cargo test --all
-      - name: cargo test --cfg pin_project_show_unpin_struct
+      - name: cargo test -- --ignored
         if: matrix.rust == 'nightly'
-        env:
-          RUSTFLAGS: -Dwarnings --cfg pin_project_show_unpin_struct
         run: |
-          cargo test --all --all-features -- -Zunstable-options --include-ignored
+          cargo test --all -- --ignored
       # Refs: https://github.com/rust-lang/cargo/issues/5657
       - name: cargo check -Zminimal-versions
         if: matrix.rust == 'nightly'

diff --git a/compiletest.sh b/compiletest.sh
@@ -8,5 +8,5 @@
 # . ./compiletest.sh
 # ```
 
-TRYBUILD=overwrite RUSTFLAGS='--cfg pin_project_show_unpin_struct' cargo +nightly test -p pin-project --all-features --test compiletest -- --ignored
-# RUSTFLAGS='--cfg pin_project_show_unpin_struct' cargo +nightly test -p pin-project --all-features --test compiletest -- --ignored
+TRYBUILD=overwrite cargo +nightly test -p pin-project --all-features --test compiletest -- --ignored
+# cargo +nightly test -p pin-project --all-features --test compiletest -- --ignored
diff --git a/examples/enum-default-expanded.rs b/examples/enum-default-expanded.rs
@@ -25,62 +25,75 @@ enum Enum<T, U> {
 
 #[allow(clippy::mut_mut)] // This lint warns `&mut &mut <ty>`.
 #[allow(dead_code)] // This lint warns unused fields/variants.
-enum __EnumProjection<'pin, T, U> {
+enum __EnumProjection<'pin, T, U>
+where
+    Enum<T, U>: 'pin,
+{
     Pinned(::core::pin::Pin<&'pin mut (T)>),
     Unpinned(&'pin mut (U)),
 }
-
 #[allow(dead_code)] // This lint warns unused fields/variants.
-enum __EnumProjectionRef<'pin, T, U> {
+enum __EnumProjectionRef<'pin, T, U>
+where
+    Enum<T, U>: 'pin,
+{
     Pinned(::core::pin::Pin<&'pin (T)>),
     Unpinned(&'pin (U)),
 }
 
-impl<T, U> Enum<T, U> {
-    fn project<'pin>(self: ::core::pin::Pin<&'pin mut Self>) -> __EnumProjection<'pin, T, U> {
-        unsafe {
-            match self.get_unchecked_mut() {
-                Enum::Pinned(_0) => __EnumProjection::Pinned(::core::pin::Pin::new_unchecked(_0)),
-                Enum::Unpinned(_0) => __EnumProjection::Unpinned(_0),
+#[allow(non_upper_case_globals)]
+const __SCOPE_Enum: () = {
+    impl<T, U> Enum<T, U> {
+        fn project<'pin>(self: ::core::pin::Pin<&'pin mut Self>) -> __EnumProjection<'pin, T, U> {
+            unsafe {
+                match self.get_unchecked_mut() {
+                    Enum::Pinned(_0) => {
+                        __EnumProjection::Pinned(::core::pin::Pin::new_unchecked(_0))
+                    }
+                    Enum::Unpinned(_0) => __EnumProjection::Unpinned(_0),
+                }
             }
         }
-    }
-    fn project_ref<'pin>(self: ::core::pin::Pin<&'pin Self>) -> __EnumProjectionRef<'pin, T, U> {
-        unsafe {
-            match self.get_ref() {
-                Enum::Pinned(_0) => {
-                    __EnumProjectionRef::Pinned(::core::pin::Pin::new_unchecked(_0))
+        fn project_ref<'pin>(
+            self: ::core::pin::Pin<&'pin Self>,
+        ) -> __EnumProjectionRef<'pin, T, U> {
+            unsafe {
+                match self.get_ref() {
+                    Enum::Pinned(_0) => {
+                        __EnumProjectionRef::Pinned(::core::pin::Pin::new_unchecked(_0))
+                    }
+                    Enum::Unpinned(_0) => __EnumProjectionRef::Unpinned(_0),
                 }
-                Enum::Unpinned(_0) => __EnumProjectionRef::Unpinned(_0),
             }
         }
     }
-}
 
-// Automatically create the appropriate conditional `Unpin` implementation.
-//
-// See ./struct-default-expanded.rs and https://github.com/taiki-e/pin-project/pull/53.
-// for details.
-#[allow(non_snake_case)]
-fn __unpin_scope_Enum() {
+    // Automatically create the appropriate conditional `Unpin` implementation.
+    //
+    // See ./struct-default-expanded.rs and https://github.com/taiki-e/pin-project/pull/53.
+    // for details.
     struct __Enum<'pin, T, U> {
         __pin_project_use_generics: ::pin_project::__private::AlwaysUnpin<'pin, (T, U)>,
         __field0: T,
     }
     impl<'pin, T, U> ::core::marker::Unpin for Enum<T, U> where __Enum<'pin, T, U>: ::core::marker::Unpin
     {}
-}
 
-// Ensure that enum does not implement `Drop`.
-//
-// See ./struct-default-expanded.rs for details.
-trait EnumMustNotImplDrop {}
-#[allow(clippy::drop_bounds)]
-impl<T: ::core::ops::Drop> EnumMustNotImplDrop for T {}
-#[allow(single_use_lifetimes)]
-impl<T, U> EnumMustNotImplDrop for Enum<T, U> {}
+    // Ensure that enum does not implement `Drop`.
+    //
+    // See ./struct-default-expanded.rs for details.
+    trait EnumMustNotImplDrop {}
+    #[allow(clippy::drop_bounds)]
+    impl<T: ::core::ops::Drop> EnumMustNotImplDrop for T {}
+    #[allow(single_use_lifetimes)]
+    impl<T, U> EnumMustNotImplDrop for Enum<T, U> {}
+    #[allow(single_use_lifetimes)]
+    impl<T, U> ::pin_project::__private::PinnedDrop for Enum<T, U> {
+        unsafe fn drop(self: ::core::pin::Pin<&mut Self>) {}
+    }
 
-// We don't need to check for '#[repr(packed)]',
-// since it does not apply to enums.
+    // We don't need to check for `#[repr(packed)]`,
+    // since it does not apply to enums.
+};
 
 fn main() {}
diff --git a/examples/pinned_drop-expanded.rs b/examples/pinned_drop-expanded.rs
@@ -34,79 +34,84 @@ pub struct Foo<'a, T> {
 
 #[allow(clippy::mut_mut)] // This lint warns `&mut &mut <ty>`.
 #[allow(dead_code)] // This lint warns unused fields/variants.
-pub(crate) struct __FooProjection<'pin, 'a, T> {
+pub(crate) struct __FooProjection<'pin, 'a, T>
+where
+    Foo<'a, T>: 'pin,
+{
     was_dropped: &'pin mut (&'a mut bool),
     field: ::core::pin::Pin<&'pin mut (T)>,
 }
-
 #[allow(dead_code)] // This lint warns unused fields/variants.
-pub(crate) struct __FooProjectionRef<'pin, 'a, T> {
+pub(crate) struct __FooProjectionRef<'pin, 'a, T>
+where
+    Foo<'a, T>: 'pin,
+{
     was_dropped: &'pin (&'a mut bool),
     field: ::core::pin::Pin<&'pin (T)>,
 }
 
-impl<'a, T> Foo<'a, T> {
-    pub(crate) fn project<'pin>(
-        self: ::core::pin::Pin<&'pin mut Self>,
-    ) -> __FooProjection<'pin, 'a, T> {
-        unsafe {
-            let Foo { was_dropped, field } = self.get_unchecked_mut();
-            __FooProjection { was_dropped, field: ::core::pin::Pin::new_unchecked(field) }
+#[allow(non_upper_case_globals)]
+const __SCOPE_Foo: () = {
+    impl<'a, T> Foo<'a, T> {
+        pub(crate) fn project<'pin>(
+            self: ::core::pin::Pin<&'pin mut Self>,
+        ) -> __FooProjection<'pin, 'a, T> {
+            unsafe {
+                let Foo { was_dropped, field } = self.get_unchecked_mut();
+                __FooProjection { was_dropped, field: ::core::pin::Pin::new_unchecked(field) }
+            }
         }
-    }
-    pub(crate) fn project_ref<'pin>(
-        self: ::core::pin::Pin<&'pin Self>,
-    ) -> __FooProjectionRef<'pin, 'a, T> {
-        unsafe {
-            let Foo { was_dropped, field } = self.get_ref();
-            __FooProjectionRef { was_dropped, field: ::core::pin::Pin::new_unchecked(field) }
+        pub(crate) fn project_ref<'pin>(
+            self: ::core::pin::Pin<&'pin Self>,
+        ) -> __FooProjectionRef<'pin, 'a, T> {
+            unsafe {
+                let Foo { was_dropped, field } = self.get_ref();
+                __FooProjectionRef { was_dropped, field: ::core::pin::Pin::new_unchecked(field) }
+            }
         }
     }
-}
 
-#[allow(single_use_lifetimes)]
-impl<'a, T> ::core::ops::Drop for Foo<'a, T> {
-    fn drop(&mut self) {
-        // Safety - we're in 'drop', so we know that 'self' will
-        // never move again.
-        let pinned_self = unsafe { ::core::pin::Pin::new_unchecked(self) };
-        // We call `pinned_drop` only once. Since `PinnedDrop::drop`
-        // is an unsafe function and a private API, it is never called again in safe
-        // code *unless the user uses a maliciously crafted macro*.
-        unsafe {
-            ::pin_project::__private::PinnedDrop::drop(pinned_self);
+    #[allow(single_use_lifetimes)]
+    impl<'a, T> ::core::ops::Drop for Foo<'a, T> {
+        fn drop(&mut self) {
+            // Safety - we're in 'drop', so we know that 'self' will
+            // never move again.
+            let pinned_self = unsafe { ::core::pin::Pin::new_unchecked(self) };
+            // We call `pinned_drop` only once. Since `PinnedDrop::drop`
+            // is an unsafe method and a private API, it is never called again in safe
+            // code *unless the user uses a maliciously crafted macro*.
+            unsafe {
+                ::pin_project::__private::PinnedDrop::drop(pinned_self);
+            }
         }
     }
-}
 
-// It is safe to implement PinnedDrop::drop, but it is not safe to call it.
-// This is because destructors can be called multiple times (double dropping
-// is unsound: rust-lang/rust#62360).
-//
-// Ideally, it would be desirable to be able to prohibit manual calls in the
-// same way as Drop::drop, but the library cannot. So, by using macros and
-// replacing them with private traits, we prevent users from calling
-// PinnedDrop::drop.
-//
-// Users can implement `Drop` safely using `#[pinned_drop]`.
-// **Do not call or implement this trait directly.**
-impl<T> ::pin_project::__private::PinnedDrop for Foo<'_, T> {
-    // Since calling it twice on the same object would be UB,
-    // this method is unsafe.
-    unsafe fn drop(self: Pin<&mut Self>) {
-        fn __drop_inner<T>(__self: Pin<&mut Foo<'_, T>>) {
-            **__self.project().was_dropped = true;
+    // It is safe to implement PinnedDrop::drop, but it is not safe to call it.
+    // This is because destructors can be called multiple times (double dropping
+    // is unsound: rust-lang/rust#62360).
+    //
+    // Ideally, it would be desirable to be able to prohibit manual calls in the
+    // same way as Drop::drop, but the library cannot. So, by using macros and
+    // replacing them with private traits, we prevent users from calling
+    // PinnedDrop::drop.
+    //
+    // Users can implement `Drop` safely using `#[pinned_drop]`.
+    // **Do not call or implement this trait directly.**
+    impl<T> ::pin_project::__private::PinnedDrop for Foo<'_, T> {
+        // Since calling it twice on the same object would be UB,
+        // this method is unsafe.
+        unsafe fn drop(self: Pin<&mut Self>) {
+            fn __drop_inner<T>(__self: Pin<&mut Foo<'_, T>>) {
+                **__self.project().was_dropped = true;
+            }
+            __drop_inner(self);
         }
-        __drop_inner(self);
     }
-}
 
-// Automatically create the appropriate conditional `Unpin` implementation.
-//
-// See ./struct-default-expanded.rs and https://github.com/taiki-e/pin-project/pull/53.
-// for details.
-#[allow(non_snake_case)]
-fn __unpin_scope_Foo() {
+    // Automatically create the appropriate conditional `Unpin` implementation.
+    //
+    // See ./struct-default-expanded.rs and https://github.com/taiki-e/pin-project/pull/53.
+    // for details.
     pub struct __Foo<'pin, 'a, T> {
         __pin_project_use_generics: ::pin_project::__private::AlwaysUnpin<'pin, (T)>,
         __field0: T,
@@ -116,18 +121,17 @@ fn __unpin_scope_Foo() {
         __Foo<'pin, 'a, T>: ::core::marker::Unpin
     {
     }
-}
 
-// Ensure that it's impossible to use pin projections on a #[repr(packed)] struct.
-//
-// See ./struct-default-expanded.rs and https://github.com/taiki-e/pin-project/pull/34
-// for details.
-#[allow(single_use_lifetimes)]
-#[allow(non_snake_case)]
-#[deny(safe_packed_borrows)]
-fn __pin_project_assert_not_repr_packed_Foo<'a, T>(val: &Foo<'a, T>) {
-    &val.was_dropped;
-    &val.field;
-}
+    // Ensure that it's impossible to use pin projections on a #[repr(packed)] struct.
+    //
+    // See ./struct-default-expanded.rs and https://github.com/taiki-e/pin-project/pull/34
+    // for details.
+    #[allow(single_use_lifetimes)]
+    #[deny(safe_packed_borrows)]
+    fn __assert_not_repr_packed<'a, T>(val: &Foo<'a, T>) {
+        &val.was_dropped;
+        &val.field;
+    }
+};
 
 fn main() {}