Auto merge of #2033 - RalfJung:arbitrary-self-dyn, r=RalfJung

test arbitrary-self dyn receivers

Requires rust-lang/rust#95071

rust-version

@@ -1 +1 @@
-c7ce69faf2a7ea16c15d922985ca27ba70da30ee
+9bd53718e2537d95d8c092609618c2dcd6f05127

tests/run-pass/dyn-arbitrary-self.rs

@@ -0,0 +1,134 @@
+#![feature(arbitrary_self_types, unsize, coerce_unsized, dispatch_from_dyn)]
+#![feature(rustc_attrs)]
+
+fn pin_box_dyn() {
+    use std::pin::Pin;
+
+    trait Foo {
+        fn bar(self: Pin<&mut Self>) -> bool;
+    }
+
+    impl Foo for &'static str {
+        fn bar(self: Pin<&mut Self>) -> bool {
+            true
+        }
+    }
+
+    let mut test: Pin<Box<dyn Foo>> = Box::pin("foo");
+    test.as_mut().bar();
+}
+
+fn stdlib_pointers() {
+    use std::{
+        rc::Rc,
+        sync::Arc,
+        pin::Pin,
+    };
+
+    trait Trait {
+        fn by_rc(self: Rc<Self>) -> i64;
+        fn by_arc(self: Arc<Self>) -> i64;
+        fn by_pin_mut(self: Pin<&mut Self>) -> i64;
+        fn by_pin_box(self: Pin<Box<Self>>) -> i64;
+    }
+
+    impl Trait for i64 {
+        fn by_rc(self: Rc<Self>) -> i64 {
+            *self
+        }
+        fn by_arc(self: Arc<Self>) -> i64 {
+            *self
+        }
+        fn by_pin_mut(self: Pin<&mut Self>) -> i64 {
+            *self
+        }
+        fn by_pin_box(self: Pin<Box<Self>>) -> i64 {
+            *self
+        }
+    }
+
+    let rc = Rc::new(1i64) as Rc<dyn Trait>;
+    assert_eq!(1, rc.by_rc());
+
+    let arc = Arc::new(2i64) as Arc<dyn Trait>;
+    assert_eq!(2, arc.by_arc());
+
+    let mut value = 3i64;
+    let pin_mut = Pin::new(&mut value) as Pin<&mut dyn Trait>;
+    assert_eq!(3, pin_mut.by_pin_mut());
+
+    let pin_box = Into::<Pin<Box<i64>>>::into(Box::new(4i64)) as Pin<Box<dyn Trait>>;
+    assert_eq!(4, pin_box.by_pin_box());
+}
+
+fn pointers_and_wrappers() {
+    use std::{
+        ops::{Deref, CoerceUnsized, DispatchFromDyn},
+        marker::Unsize,
+    };
+
+    struct Ptr<T: ?Sized>(Box<T>);
+
+    impl<T: ?Sized> Deref for Ptr<T> {
+        type Target = T;
+
+        fn deref(&self) -> &T {
+            &*self.0
+        }
+    }
+
+    impl<T: Unsize<U> + ?Sized, U: ?Sized> CoerceUnsized<Ptr<U>> for Ptr<T> {}
+    impl<T: Unsize<U> + ?Sized, U: ?Sized> DispatchFromDyn<Ptr<U>> for Ptr<T> {}
+
+    struct Wrapper<T: ?Sized>(T);
+
+    impl<T: ?Sized> Deref for Wrapper<T> {
+        type Target = T;
+
+        fn deref(&self) -> &T {
+            &self.0
+        }
+    }
+
+    impl<T: CoerceUnsized<U>, U> CoerceUnsized<Wrapper<U>> for Wrapper<T> {}
+    impl<T: DispatchFromDyn<U>, U> DispatchFromDyn<Wrapper<U>> for Wrapper<T> {}
+
+
+    trait Trait {
+        // This method isn't object-safe yet. Unsized by-value `self` is object-safe (but not callable
+        // without unsized_locals), but wrappers arond `Self` currently are not.
+        // FIXME (mikeyhew) uncomment this when unsized rvalues object-safety is implemented
+        // fn wrapper(self: Wrapper<Self>) -> i32;
+        fn ptr_wrapper(self: Ptr<Wrapper<Self>>) -> i32;
+        fn wrapper_ptr(self: Wrapper<Ptr<Self>>) -> i32;
+        fn wrapper_ptr_wrapper(self: Wrapper<Ptr<Wrapper<Self>>>) -> i32;
+    }
+
+    impl Trait for i32 {
+        fn ptr_wrapper(self: Ptr<Wrapper<Self>>) -> i32 {
+            **self
+        }
+        fn wrapper_ptr(self: Wrapper<Ptr<Self>>) -> i32 {
+            **self
+        }
+        fn wrapper_ptr_wrapper(self: Wrapper<Ptr<Wrapper<Self>>>) -> i32 {
+            ***self
+        }
+    }
+
+    let pw = Ptr(Box::new(Wrapper(5))) as Ptr<Wrapper<dyn Trait>>;
+    assert_eq!(pw.ptr_wrapper(), 5);
+
+    let wp = Wrapper(Ptr(Box::new(6))) as Wrapper<Ptr<dyn Trait>>;
+    assert_eq!(wp.wrapper_ptr(), 6);
+
+    let wpw = Wrapper(Ptr(Box::new(Wrapper(7)))) as Wrapper<Ptr<Wrapper<dyn Trait>>>;
+    assert_eq!(wpw.wrapper_ptr_wrapper(), 7);
+}
+
+
+fn main() {
+    pin_box_dyn();
+    stdlib_pointers();
+    pointers_and_wrappers();
+}