commit 95dab1db60d5ace5803f2132255d575d233ae8a8
author David Tolnay <dtolnay@gmail.com> Sun Nov 15 14:32:37 2020 -0800
committer David Tolnay <dtolnay@gmail.com> Sun Nov 15 14:50:58 2020 -0800
tree 8975fdf6d6771f1b457b1c379c8d88a978706926
parent cf9aed6fd90c5197a61f4e3c135302a963b7252e

Ensure opaque types are !Unpin

src/cxx_string.rs

diff --git a/src/cxx_string.rs b/src/cxx_string.rs
index 5010175..7ee8987 100644
--- a/src/cxx_string.rs
+++ b/src/cxx_string.rs
@@ -1,6 +1,7 @@
 use alloc::borrow::Cow;
 use alloc::string::String;
 use core::fmt::{self, Debug, Display};
+use core::marker::{PhantomData, PhantomPinned};
 use core::slice;
 use core::str::{self, Utf8Error};
 
@@ -26,6 +27,7 @@
 #[repr(C)]
 pub struct CxxString {
     _private: [u8; 0],
+    _pinned: PhantomData<PhantomPinned>,
 }
 
 impl CxxString {

src/cxx_vector.rs

diff --git a/src/cxx_vector.rs b/src/cxx_vector.rs
index 5fb0807..d25ea91 100644
--- a/src/cxx_vector.rs
+++ b/src/cxx_vector.rs
@@ -1,7 +1,7 @@
 use crate::cxx_string::CxxString;
 use core::ffi::c_void;
 use core::fmt::{self, Display};
-use core::marker::PhantomData;
+use core::marker::{PhantomData, PhantomPinned};
 use core::mem;
 use core::ptr;
 use core::slice;
@@ -17,6 +17,7 @@
 #[repr(C, packed)]
 pub struct CxxVector<T> {
     _private: [T; 0],
+    _pinned: PhantomData<PhantomPinned>,
 }
 
 impl<T> CxxVector<T>

src/opaque.rs

diff --git a/src/opaque.rs b/src/opaque.rs
index bad57e7..3c8f536 100644
--- a/src/opaque.rs
+++ b/src/opaque.rs
@@ -1,3 +1,4 @@
+use core::marker::{PhantomData, PhantomPinned};
 use core::mem;
 
 // . size = 0
@@ -5,9 +6,11 @@
 // . ffi-safe
 // . !Send
 // . !Sync
+// . !Unpin
 #[repr(C, packed)]
 pub struct Opaque {
     _private: [*const u8; 0],
+    _pinned: PhantomData<PhantomPinned>,
 }
 
 const_assert_eq!(0, mem::size_of::<Opaque>());

tests/ui/opaque_autotraits.stderr

diff --git a/tests/ui/opaque_autotraits.stderr b/tests/ui/opaque_autotraits.stderr
index 7ce8ae4..61e9179 100644
--- a/tests/ui/opaque_autotraits.stderr
+++ b/tests/ui/opaque_autotraits.stderr
@@ -25,3 +25,16 @@
    = note: required because it appears within the type `[*const u8; 0]`
    = note: required because it appears within the type `cxx::private::Opaque`
    = note: required because it appears within the type `ffi::Opaque`
+
+error[E0277]: `PhantomPinned` cannot be unpinned
+  --> $DIR/opaque_autotraits.rs:17:5
+   |
+12 | fn assert_unpin<T: Unpin>() {}
+   |                    ----- required by this bound in `assert_unpin`
+...
+17 |     assert_unpin::<ffi::Opaque>();
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^ within `ffi::Opaque`, the trait `Unpin` is not implemented for `PhantomPinned`
+   |
+   = note: required because it appears within the type `PhantomData<PhantomPinned>`
+   = note: required because it appears within the type `cxx::private::Opaque`
+   = note: required because it appears within the type `ffi::Opaque`