Merge #77

77: Move automatic generation of Unpin implementation to proc-macro-derive r=taiki-e a=taiki-e

To generate the correct `Unpin` implementation, we need to collect the
types of the pinned fields. However, since proc-macro-attribute is
applied before cfg, we cannot be collecting field types at this timing.
So instead of generating the `Unpin` implementation here, we need to
delegate automatic generation of the `Unpin` implementation to
proc-macro-derive.

Fixes #68

Co-authored-by: Taiki Endo <te316e89@gmail.com>

azure-pipelines.yml

@@ -39,6 +39,7 @@ jobs:
   parameters:
     toolchain: nightly
     name: nightly
+    cross: true
 
 - job: compiletest
   pool:
@@ -49,7 +50,9 @@ jobs:
         toolchain: nightly
     - script: |
         cargo clean
-        RUSTFLAGS='--cfg compiletest --cfg pin_project_show_unpin_struct' cargo test -p pin-project --all-features --test compiletest
+        cargo test -p pin-project --all-features --test compiletest
+      env:
+        RUSTFLAGS: -Dwarnings --cfg compiletest --cfg pin_project_show_unpin_struct
       displayName: compiletest
 
 - job: clippy
@@ -122,5 +125,7 @@ jobs:
       parameters:
         toolchain: nightly
     - script: |
-        RUSTDOCFLAGS=-Dwarnings cargo doc --no-deps --all --all-features
+        cargo doc --no-deps --all --all-features
+      env:
+        RUSTDOCFLAGS: -Dwarnings
       displayName: cargo doc

ci/azure-test.yml

@@ -1,11 +1,19 @@
 parameters:
-  vmImage: ubuntu-16.04
   cmd: test
 
 jobs:
 - job: ${{ parameters.name }}
+  strategy:
+    matrix:
+      Linux:
+        vmImage: ubuntu-16.04
+      ${{ if parameters.cross }}:
+        MacOS:
+          vmImage: macOS-10.13
+        Windows:
+          vmImage: vs2017-win2016
   pool:
-    vmImage: ${{ parameters.vmImage }}
+    vmImage: $(vmImage)
 
   steps:
     - template: azure-install-rust.yml

compiletest.sh

@@ -0,0 +1,5 @@
+#!/bin/bash
+
+# A script to run compile tests with the same condition that pin-project executes with CI.
+
+rm -rf target/debug/deps/libpin_project* && RUSTFLAGS='--cfg compiletest --cfg pin_project_show_unpin_struct' cargo test -p pin-project --all-features --test compiletest

examples/struct-default.rs

@@ -33,19 +33,19 @@ impl<'_outer_pin, T, U> __StructProjectionTrait<'_outer_pin, T, U>
 {
     fn project<'_pin>(&'_pin mut self) -> __StructProjection<'_pin, T, U> {
         unsafe {
-            let this = self.as_mut().get_unchecked_mut();
+            let Struct { pinned, unpinned } = self.as_mut().get_unchecked_mut();
             __StructProjection {
-                pinned: ::core::pin::Pin::new_unchecked(&mut this.pinned),
-                unpinned: &mut this.unpinned,
+                pinned: ::core::pin::Pin::new_unchecked(pinned),
+                unpinned: unpinned,
             }
         }
     }
     fn project_into(self) -> __StructProjection<'_outer_pin, T, U> {
         unsafe {
-            let this = self.get_unchecked_mut();
+            let Struct { pinned, unpinned } = self.get_unchecked_mut();
             __StructProjection {
-                pinned: ::core::pin::Pin::new_unchecked(&mut this.pinned),
-                unpinned: &mut this.unpinned,
+                pinned: ::core::pin::Pin::new_unchecked(pinned),
+                unpinned: unpinned,
             }
         }
     }
@@ -91,8 +91,12 @@ impl<T, U> StructMustNotImplDrop for Struct<T, U> {}
 #[allow(non_snake_case)]
 #[deny(safe_packed_borrows)]
 fn __pin_project_assert_not_repr_packed_Struct<T, U>(val: Struct<T, U>) {
-    &val.pinned;
-    &val.unpinned;
+    {
+        &val.pinned;
+    }
+    {
+        &val.unpinned;
+    }
 }
 
 fn main() {}

pin-project-internal/src/lib.rs

@@ -333,7 +333,8 @@ use syn::parse::Nothing;
 /// [`pinned_drop`]: ./attr.pinned_drop.html
 #[proc_macro_attribute]
 pub fn pin_project(args: TokenStream, input: TokenStream) -> TokenStream {
-    pin_project::attribute(args.into(), input.into()).into()
+    let input = syn::parse_macro_input!(input);
+    pin_project::attribute(args.into(), input).into()
 }
 
 // TODO: Move this doc into pin-project crate when https://github.com/rust-lang/rust/pull/62855 merged.
@@ -372,7 +373,8 @@ pub fn pin_project(args: TokenStream, input: TokenStream) -> TokenStream {
 #[proc_macro_attribute]
 pub fn pinned_drop(args: TokenStream, input: TokenStream) -> TokenStream {
     let _: Nothing = syn::parse_macro_input!(args);
-    pinned_drop::attribute(input.into()).into()
+    let input = syn::parse_macro_input!(input);
+    pinned_drop::attribute(&input).into()
 }
 
 // TODO: Move this doc into pin-project crate when https://github.com/rust-lang/rust/pull/62855 merged.
@@ -493,7 +495,15 @@ pub fn pinned_drop(args: TokenStream, input: TokenStream) -> TokenStream {
 #[proc_macro_attribute]
 pub fn project(args: TokenStream, input: TokenStream) -> TokenStream {
     let _: Nothing = syn::parse_macro_input!(args);
-    project::attribute(input.into()).into()
+    let input = syn::parse_macro_input!(input);
+    project::attribute(input).into()
+}
+
+#[doc(hidden)]
+#[proc_macro_derive(__PinProjectAutoImplUnpin, attributes(pin))]
+pub fn derive_unpin(input: TokenStream) -> TokenStream {
+    let input = syn::parse_macro_input!(input);
+    pin_project::derive(input).into()
 }
 
 #[cfg(feature = "renamed")]