Change self argument of project method to self: Pin<&mut Self>

taiki-e · Sep 4, 2019 · 8735be8 · 8735be8
1 parent 5317091
commit 8735be8
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Showing 10 changed files with 89 additions and 62 deletions.
diff --git a/pin-project-internal/src/lib.rs b/pin-project-internal/src/lib.rs
@@ -2,7 +2,10 @@
 
 #![recursion_limit = "256"]
 #![doc(html_root_url = "https://docs.rs/pin-project-internal/0.4.0-alpha.8")]
-#![doc(test(no_crate_inject, attr(deny(warnings, rust_2018_idioms), allow(dead_code))))]
+#![doc(test(
+    no_crate_inject,
+    attr(deny(warnings, rust_2018_idioms, single_use_lifetimes), allow(dead_code))
+))]
 #![warn(unsafe_code)]
 #![warn(rust_2018_idioms, unreachable_pub, single_use_lifetimes)]
 #![warn(clippy::all, clippy::pedantic)]
@@ -104,7 +107,7 @@ use syn::parse::Nothing;
 /// }
 ///
 /// impl<T, U> Foo<T, U> {
-///     fn baz(mut self: Pin<&mut Self>) {
+///     fn baz(self: Pin<&mut Self>) {
 ///         let this = self.project();
 ///         let _: Pin<&mut T> = this.future; // Pinned reference to the field
 ///         let _: &mut U = this.field; // Normal reference to the field
@@ -127,7 +130,7 @@ use syn::parse::Nothing;
 /// }
 ///
 /// impl<T, U> Foo<T, U> {
-///     fn baz(mut self: Pin<&mut Self>) {
+///     fn baz(self: Pin<&mut Self>) {
 ///         let this = self.project();
 ///         let _: Pin<&mut T> = this.future; // Pinned reference to the field
 ///         let _: &mut U = this.field; // Normal reference to the field
@@ -174,7 +177,7 @@ use syn::parse::Nothing;
 /// }
 ///
 /// #[pinned_drop]
-/// fn my_drop_fn<T: Debug, U: Debug>(mut foo: Pin<&mut Foo<T, U>>) {
+/// fn my_drop_fn<T: Debug, U: Debug>(foo: Pin<&mut Foo<T, U>>) {
 ///     let foo = foo.project();
 ///     println!("Dropping pinned field: {:?}", foo.pinned_field);
 ///     println!("Dropping unpin field: {:?}", foo.unpin_field);
@@ -205,7 +208,7 @@ use syn::parse::Nothing;
 /// }
 ///
 /// impl<T, U> Foo<T, U> {
-///     fn baz(mut self: Pin<&mut Self>) {
+///     fn baz(self: Pin<&mut Self>) {
 ///         let this = self.project();
 ///         let _: Pin<&mut T> = this.future;
 ///         let _: &mut U = this.field;
@@ -223,7 +226,7 @@ use syn::parse::Nothing;
 /// struct Foo<T, U>(#[pin] T, U);
 ///
 /// impl<T, U> Foo<T, U> {
-///     fn baz(mut self: Pin<&mut Self>) {
+///     fn baz(self: Pin<&mut Self>) {
 ///         let this = self.project();
 ///         let _: Pin<&mut T> = this.0;
 ///         let _: &mut U = this.1;
@@ -262,7 +265,7 @@ use syn::parse::Nothing;
 /// # #[cfg(feature = "project_attr")]
 /// impl<A, B, C> Foo<A, B, C> {
 ///     #[project] // Nightly does not need a dummy attribute to the function.
-///     fn baz(mut self: Pin<&mut Self>) {
+///     fn baz(self: Pin<&mut Self>) {
 ///         #[project]
 ///         match self.project() {
 ///             Foo::Tuple(x, y) => {
@@ -363,7 +366,7 @@ pub fn pinned_drop(args: TokenStream, input: TokenStream) -> TokenStream {
 ///
 /// // impl for the original type
 /// impl<T, U> Foo<T, U> {
-///     fn bar(mut self: Pin<&mut Self>) {
+///     fn bar(self: Pin<&mut Self>) {
 ///         self.project().baz()
 ///     }
 /// }
@@ -400,7 +403,7 @@ pub fn pinned_drop(args: TokenStream, input: TokenStream) -> TokenStream {
 ///
 /// impl<T, U> Foo<T, U> {
 ///     #[project] // Nightly does not need a dummy attribute to the function.
-///     fn baz(mut self: Pin<&mut Self>) {
+///     fn baz(self: Pin<&mut Self>) {
 ///         #[project]
 ///         let Foo { future, field } = self.project();
 ///
@@ -430,7 +433,7 @@ pub fn pinned_drop(args: TokenStream, input: TokenStream) -> TokenStream {
 ///
 /// impl<A, B, C> Foo<A, B, C> {
 ///     #[project] // Nightly does not need a dummy attribute to the function.
-///     fn baz(mut self: Pin<&mut Self>) {
+///     fn baz(self: Pin<&mut Self>) {
 ///         #[project]
 ///         match self.project() {
 ///             Foo::Tuple(x, y) => {

diff --git a/pin-project-internal/src/pin_project/enums.rs b/pin-project-internal/src/pin_project/enums.rs
@@ -31,21 +31,23 @@ pub(super) fn parse(cx: &mut Context, mut item: ItemEnum) -> Result<TokenStream>
 
     let (proj_variants, proj_arms) = variants(cx, &mut item)?;
 
-    let Context { proj_ident, proj_trait, orig_ident, lifetime, .. } = &cx;
+    let Context { proj_ident, orig_ident, lifetime, .. } = &cx;
     let proj_generics = cx.proj_generics();
     let proj_ty_generics = proj_generics.split_for_impl().1;
-    let (impl_generics, ty_generics, where_clause) = item.generics.split_for_impl();
+    let (orig_impl_generics, orig_ty_generics, where_clause) = item.generics.split_for_impl();
 
     let mut proj_items = quote! {
         #[allow(clippy::mut_mut)]
         #[allow(dead_code)]
         enum #proj_ident #proj_generics #where_clause { #(#proj_variants,)* }
     };
     proj_items.extend(quote! {
-        impl #impl_generics #proj_trait #ty_generics for ::core::pin::Pin<&mut #orig_ident #ty_generics> #where_clause {
-            fn project<#lifetime>(&#lifetime mut self) -> #proj_ident #proj_ty_generics #where_clause {
+        impl #orig_impl_generics #orig_ident #orig_ty_generics #where_clause {
+            fn project<#lifetime>(
+                self: ::core::pin::Pin<&#lifetime mut Self>,
+            ) -> #proj_ident #proj_ty_generics {
                 unsafe {
-                    match self.as_mut().get_unchecked_mut() {
+                    match self.get_unchecked_mut() {
                         #(#proj_arms,)*
                     }
                 }

diff --git a/pin-project-internal/src/pin_project/mod.rs b/pin-project-internal/src/pin_project/mod.rs
@@ -6,9 +6,7 @@ use syn::{
     *,
 };
 
-use crate::utils::{
-    self, crate_path, proj_ident, proj_lifetime_name, proj_trait_ident, DEFAULT_LIFETIME_NAME,
-};
+use crate::utils::{self, crate_path, proj_ident, proj_lifetime_name, DEFAULT_LIFETIME_NAME};
 
 mod enums;
 mod structs;
@@ -56,9 +54,6 @@ struct Context {
     orig_ident: Ident,
     /// Name of the projected type.
     proj_ident: Ident,
-    /// Name of the trait generated
-    /// to provide a 'project' method
-    proj_trait: Ident,
 
     /// Visibility of original type.
     vis: Visibility,
@@ -86,7 +81,6 @@ impl Context {
     ) -> Result<Self> {
         let Args { pinned_drop, unsafe_unpin } = syn::parse2(args)?;
         let proj_ident = proj_ident(orig_ident);
-        let proj_trait = proj_trait_ident(orig_ident);
 
         let mut lifetime_name = String::from(DEFAULT_LIFETIME_NAME);
         proj_lifetime_name(&mut lifetime_name, &generics.params);
@@ -107,7 +101,6 @@ impl Context {
         Ok(Self {
             orig_ident: orig_ident.clone(),
             proj_ident,
-            proj_trait,
             vis: vis.clone(),
             generics,
             lifetime,
@@ -339,20 +332,6 @@ impl Context {
             }
         }
     }
-
-    fn make_proj_trait(&self) -> TokenStream {
-        let Self { proj_ident, proj_trait, lifetime, .. } = self;
-        let proj_generics = self.proj_generics();
-        let proj_ty_generics = proj_generics.split_for_impl().1;
-
-        let (orig_generics, _, orig_where_clause) = self.generics.split_for_impl();
-
-        quote! {
-            trait #proj_trait #orig_generics {
-                fn project<#lifetime>(&#lifetime mut self) -> #proj_ident #proj_ty_generics #orig_where_clause;
-            }
-        }
-    }
 }
 
 fn parse(args: TokenStream, input: TokenStream) -> Result<TokenStream> {
@@ -365,7 +344,6 @@ fn parse(args: TokenStream, input: TokenStream) -> Result<TokenStream> {
             res.extend(packed_check);
             res.extend(cx.make_drop_impl());
             res.extend(cx.make_unpin_impl());
-            res.extend(cx.make_proj_trait());
             Ok(res)
         }
         Item::Enum(item) => {
@@ -376,7 +354,6 @@ fn parse(args: TokenStream, input: TokenStream) -> Result<TokenStream> {
             let mut res = enums::parse(&mut cx, item)?;
             res.extend(cx.make_drop_impl());
             res.extend(cx.make_unpin_impl());
-            res.extend(cx.make_proj_trait());
             Ok(res)
         }
         item => Err(error!(item, "#[pin_project] attribute may only be used on structs or enums")),

diff --git a/pin-project-internal/src/pin_project/structs.rs b/pin-project-internal/src/pin_project/structs.rs
@@ -28,21 +28,23 @@ pub(super) fn parse(cx: &mut Context, mut item: ItemStruct) -> Result<TokenStrea
         Fields::Unnamed(fields) => unnamed(cx, fields)?,
     };
 
-    let Context { proj_ident, proj_trait, orig_ident, lifetime, .. } = &cx;
+    let Context { proj_ident, orig_ident, lifetime, .. } = &cx;
     let proj_generics = cx.proj_generics();
     let proj_ty_generics = proj_generics.split_for_impl().1;
-    let (impl_generics, ty_generics, where_clause) = item.generics.split_for_impl();
+    let (orig_impl_generics, orig_ty_generics, where_clause) = item.generics.split_for_impl();
 
     let mut proj_items = quote! {
         #[allow(clippy::mut_mut)]
         #[allow(dead_code)]
         struct #proj_ident #proj_generics #where_clause #proj_fields
     };
     proj_items.extend(quote! {
-        impl #impl_generics #proj_trait #ty_generics for ::core::pin::Pin<&mut #orig_ident #ty_generics> #where_clause {
-            fn project<#lifetime>(&#lifetime mut self) -> #proj_ident #proj_ty_generics #where_clause {
+        impl #orig_impl_generics #orig_ident #orig_ty_generics #where_clause {
+            fn project<#lifetime>(
+                self: ::core::pin::Pin<&#lifetime mut Self>,
+            ) -> #proj_ident #proj_ty_generics {
                 unsafe {
-                    let this = self.as_mut().get_unchecked_mut();
+                    let this = self.get_unchecked_mut();
                     #proj_ident #proj_init
                 }
             }

diff --git a/pin-project-internal/src/utils.rs b/pin-project-internal/src/utils.rs
@@ -12,10 +12,6 @@ pub(crate) fn proj_ident(ident: &Ident) -> Ident {
     format_ident!("__{}Projection", ident)
 }
 
-pub(crate) fn proj_trait_ident(ident: &Ident) -> Ident {
-    format_ident!("__{}ProjectionTrait", ident)
-}
-
 /// Determine the lifetime names. Ensure it doesn't overlap with any existing lifetime names.
 pub(crate) fn proj_lifetime_name(
     lifetime_name: &mut String,

diff --git a/src/lib.rs b/src/lib.rs
@@ -28,7 +28,7 @@
 //! }
 //!
 //! impl<T, U> Foo<T, U> {
-//!     fn baz(mut self: Pin<&mut Self>) {
+//!     fn baz(self: Pin<&mut Self>) {
 //!         let this = self.project();
 //!         let _: Pin<&mut T> = this.future; // Pinned reference to the field
 //!         let _: &mut U = this.field; // Normal reference to the field
@@ -86,7 +86,10 @@
 
 #![recursion_limit = "256"]
 #![doc(html_root_url = "https://docs.rs/pin-project/0.4.0-alpha.8")]
-#![doc(test(no_crate_inject, attr(deny(warnings, rust_2018_idioms), allow(dead_code))))]
+#![doc(test(
+    no_crate_inject,
+    attr(deny(warnings, rust_2018_idioms, single_use_lifetimes), allow(dead_code))
+))]
 #![no_std]
 #![warn(unsafe_code)]
 #![warn(rust_2018_idioms, unreachable_pub, single_use_lifetimes)]

diff --git a/tests/pin_project.rs b/tests/pin_project.rs
@@ -20,7 +20,7 @@ fn test_pin_project() {
     let mut foo = Foo { field1: 1, field2: 2 };
 
     let mut foo_orig = Pin::new(&mut foo);
-    let foo = foo_orig.project();
+    let foo = foo_orig.as_mut().project();
 
     let x: Pin<&mut i32> = foo.field1;
     assert_eq!(*x, 1);
@@ -33,7 +33,7 @@ fn test_pin_project() {
 
     let mut foo = Foo { field1: 1, field2: 2 };
 
-    let mut foo = Pin::new(&mut foo);
+    let foo = Pin::new(&mut foo);
     let foo = foo.project();
 
     let __FooProjection { field1, field2 } = foo;
@@ -47,7 +47,7 @@ fn test_pin_project() {
 
     let mut bar = Bar(1, 2);
 
-    let mut bar = Pin::new(&mut bar);
+    let bar = Pin::new(&mut bar);
     let bar = bar.project();
 
     let x: Pin<&mut i32> = bar.0;
@@ -73,7 +73,7 @@ fn test_pin_project() {
     let mut baz = Baz::Variant1(1, 2);
 
     let mut baz_orig = Pin::new(&mut baz);
-    let baz = baz_orig.project();
+    let baz = baz_orig.as_mut().project();
 
     match baz {
         __BazProjection::Variant1(x, y) => {
@@ -94,7 +94,7 @@ fn test_pin_project() {
 
     let mut baz = Baz::Variant2 { field1: 3, field2: 4 };
 
-    let mut baz = Pin::new(&mut baz);
+    let baz = Pin::new(&mut baz);
     let mut baz = baz.project();
 
     match &mut baz {
@@ -132,7 +132,7 @@ fn enum_project_set() {
 
     let mut bar = Bar::Variant1(25);
     let mut bar_orig = Pin::new(&mut bar);
-    let bar_proj = bar_orig.project();
+    let bar_proj = bar_orig.as_mut().project();
 
     match bar_proj {
         __BarProjection::Variant1(val) => {
@@ -239,11 +239,11 @@ fn combine() {
     unsafe impl<T: Unpin> UnsafeUnpin for Foo<T> {}
 }
 
-#[test]
 // This 'allow' is unrelated to the code
 // generated by pin-project - it's just to
 // allow us to put a private enum in a public enum
 #[allow(private_in_public)]
+#[test]
 fn test_private_type_in_public_type() {
     #[pin_project]
     pub struct PublicStruct<T> {
@@ -262,3 +262,47 @@ fn test_private_type_in_public_type() {
         OtherVariant(u8),
     }
 }
+
+// https://github.com/taiki-e/pin-project/issues/65
+#[test]
+fn test_lifetime_project() {
+    #[pin_project]
+    struct Struct<T, U> {
+        #[pin]
+        pinned: T,
+        unpinned: U,
+    }
+
+    #[pin_project]
+    enum Enum<T, U> {
+        Variant {
+            #[pin]
+            pinned: T,
+            unpinned: U,
+        },
+    }
+
+    impl<T, U> Struct<T, U> {
+        fn get_pin_mut<'a>(self: Pin<&'a mut Self>) -> Pin<&'a mut T> {
+            self.project().pinned
+        }
+
+        fn get_pin_mut_elided(self: Pin<&mut Self>) -> Pin<&mut T> {
+            self.project().pinned
+        }
+    }
+
+    impl<T, U> Enum<T, U> {
+        fn get_pin_mut<'a>(self: Pin<&'a mut Self>) -> Pin<&'a mut T> {
+            match self.project() {
+                __EnumProjection::Variant { pinned, .. } => pinned,
+            }
+        }
+
+        fn get_pin_mut_elided(self: Pin<&mut Self>) -> Pin<&mut T> {
+            match self.project() {
+                __EnumProjection::Variant { pinned, .. } => pinned,
+            }
+        }
+    }
+}
diff --git a/tests/pinned_drop.rs b/tests/pinned_drop.rs
@@ -14,7 +14,7 @@ pub struct Foo<'a> {
 }
 
 #[pinned_drop]
-fn do_drop(mut foo: Pin<&mut Foo<'_>>) {
+fn do_drop(foo: Pin<&mut Foo<'_>>) {
     **foo.project().was_dropped = true;
 }