mv compiler to compiler/

1 files changed, 707 insertions, 0 deletions

diff --git a/compiler/rustc_data_structures/src/owning_ref/tests.rs b/compiler/rustc_data_structures/src/owning_ref/tests.rs
new file mode 100644
index 00000000000..7b8179e90bd
--- /dev/null
+++ b/compiler/rustc_data_structures/src/owning_ref/tests.rs
@@ -0,0 +1,707 @@
+mod owning_ref {
+    use super::super::OwningRef;
+    use super::super::{BoxRef, Erased, ErasedBoxRef, RcRef};
+    use std::cmp::{Ord, Ordering, PartialEq, PartialOrd};
+    use std::collections::hash_map::DefaultHasher;
+    use std::collections::HashMap;
+    use std::hash::{Hash, Hasher};
+    use std::rc::Rc;
+
+    #[derive(Debug, PartialEq)]
+    struct Example(u32, String, [u8; 3]);
+    fn example() -> Example {
+        Example(42, "hello world".to_string(), [1, 2, 3])
+    }
+
+    #[test]
+    fn new_deref() {
+        let or: OwningRef<Box<()>, ()> = OwningRef::new(Box::new(()));
+        assert_eq!(&*or, &());
+    }
+
+    #[test]
+    fn into() {
+        let or: OwningRef<Box<()>, ()> = Box::new(()).into();
+        assert_eq!(&*or, &());
+    }
+
+    #[test]
+    fn map_offset_ref() {
+        let or: BoxRef<Example> = Box::new(example()).into();
+        let or: BoxRef<_, u32> = or.map(|x| &x.0);
+        assert_eq!(&*or, &42);
+
+        let or: BoxRef<Example> = Box::new(example()).into();
+        let or: BoxRef<_, u8> = or.map(|x| &x.2[1]);
+        assert_eq!(&*or, &2);
+    }
+
+    #[test]
+    fn map_heap_ref() {
+        let or: BoxRef<Example> = Box::new(example()).into();
+        let or: BoxRef<_, str> = or.map(|x| &x.1[..5]);
+        assert_eq!(&*or, "hello");
+    }
+
+    #[test]
+    fn map_static_ref() {
+        let or: BoxRef<()> = Box::new(()).into();
+        let or: BoxRef<_, str> = or.map(|_| "hello");
+        assert_eq!(&*or, "hello");
+    }
+
+    #[test]
+    fn map_chained() {
+        let or: BoxRef<String> = Box::new(example().1).into();
+        let or: BoxRef<_, str> = or.map(|x| &x[1..5]);
+        let or: BoxRef<_, str> = or.map(|x| &x[..2]);
+        assert_eq!(&*or, "el");
+    }
+
+    #[test]
+    fn map_chained_inference() {
+        let or = BoxRef::new(Box::new(example().1)).map(|x| &x[..5]).map(|x| &x[1..3]);
+        assert_eq!(&*or, "el");
+    }
+
+    #[test]
+    fn owner() {
+        let or: BoxRef<String> = Box::new(example().1).into();
+        let or = or.map(|x| &x[..5]);
+        assert_eq!(&*or, "hello");
+        assert_eq!(&**or.owner(), "hello world");
+    }
+
+    #[test]
+    fn into_inner() {
+        let or: BoxRef<String> = Box::new(example().1).into();
+        let or = or.map(|x| &x[..5]);
+        assert_eq!(&*or, "hello");
+        let s = *or.into_inner();
+        assert_eq!(&s, "hello world");
+    }
+
+    #[test]
+    fn fmt_debug() {
+        let or: BoxRef<String> = Box::new(example().1).into();
+        let or = or.map(|x| &x[..5]);
+        let s = format!("{:?}", or);
+        assert_eq!(&s, "OwningRef { owner: \"hello world\", reference: \"hello\" }");
+    }
+
+    #[test]
+    fn erased_owner() {
+        let o1: BoxRef<Example, str> = BoxRef::new(Box::new(example())).map(|x| &x.1[..]);
+
+        let o2: BoxRef<String, str> = BoxRef::new(Box::new(example().1)).map(|x| &x[..]);
+
+        let os: Vec<ErasedBoxRef<str>> = vec![o1.erase_owner(), o2.erase_owner()];
+        assert!(os.iter().all(|e| &e[..] == "hello world"));
+    }
+
+    #[test]
+    fn raii_locks() {
+        use super::super::{MutexGuardRef, RwLockReadGuardRef, RwLockWriteGuardRef};
+        use super::super::{RefMutRef, RefRef};
+        use std::cell::RefCell;
+        use std::sync::{Mutex, RwLock};
+
+        {
+            let a = RefCell::new(1);
+            let a = {
+                let a = RefRef::new(a.borrow());
+                assert_eq!(*a, 1);
+                a
+            };
+            assert_eq!(*a, 1);
+            drop(a);
+        }
+        {
+            let a = RefCell::new(1);
+            let a = {
+                let a = RefMutRef::new(a.borrow_mut());
+                assert_eq!(*a, 1);
+                a
+            };
+            assert_eq!(*a, 1);
+            drop(a);
+        }
+        {
+            let a = Mutex::new(1);
+            let a = {
+                let a = MutexGuardRef::new(a.lock().unwrap());
+                assert_eq!(*a, 1);
+                a
+            };
+            assert_eq!(*a, 1);
+            drop(a);
+        }
+        {
+            let a = RwLock::new(1);
+            let a = {
+                let a = RwLockReadGuardRef::new(a.read().unwrap());
+                assert_eq!(*a, 1);
+                a
+            };
+            assert_eq!(*a, 1);
+            drop(a);
+        }
+        {
+            let a = RwLock::new(1);
+            let a = {
+                let a = RwLockWriteGuardRef::new(a.write().unwrap());
+                assert_eq!(*a, 1);
+                a
+            };
+            assert_eq!(*a, 1);
+            drop(a);
+        }
+    }
+
+    #[test]
+    fn eq() {
+        let or1: BoxRef<[u8]> = BoxRef::new(vec![1, 2, 3].into_boxed_slice());
+        let or2: BoxRef<[u8]> = BoxRef::new(vec![1, 2, 3].into_boxed_slice());
+        assert_eq!(or1.eq(&or2), true);
+    }
+
+    #[test]
+    fn cmp() {
+        let or1: BoxRef<[u8]> = BoxRef::new(vec![1, 2, 3].into_boxed_slice());
+        let or2: BoxRef<[u8]> = BoxRef::new(vec![4, 5, 6].into_boxed_slice());
+        assert_eq!(or1.cmp(&or2), Ordering::Less);
+    }
+
+    #[test]
+    fn partial_cmp() {
+        let or1: BoxRef<[u8]> = BoxRef::new(vec![4, 5, 6].into_boxed_slice());
+        let or2: BoxRef<[u8]> = BoxRef::new(vec![1, 2, 3].into_boxed_slice());
+        assert_eq!(or1.partial_cmp(&or2), Some(Ordering::Greater));
+    }
+
+    #[test]
+    fn hash() {
+        let mut h1 = DefaultHasher::new();
+        let mut h2 = DefaultHasher::new();
+
+        let or1: BoxRef<[u8]> = BoxRef::new(vec![1, 2, 3].into_boxed_slice());
+        let or2: BoxRef<[u8]> = BoxRef::new(vec![1, 2, 3].into_boxed_slice());
+
+        or1.hash(&mut h1);
+        or2.hash(&mut h2);
+
+        assert_eq!(h1.finish(), h2.finish());
+    }
+
+    #[test]
+    fn borrow() {
+        let mut hash = HashMap::new();
+        let key = RcRef::<String>::new(Rc::new("foo-bar".to_string())).map(|s| &s[..]);
+
+        hash.insert(key.clone().map(|s| &s[..3]), 42);
+        hash.insert(key.clone().map(|s| &s[4..]), 23);
+
+        assert_eq!(hash.get("foo"), Some(&42));
+        assert_eq!(hash.get("bar"), Some(&23));
+    }
+
+    #[test]
+    fn total_erase() {
+        let a: OwningRef<Vec<u8>, [u8]> = OwningRef::new(vec![]).map(|x| &x[..]);
+        let b: OwningRef<Box<[u8]>, [u8]> =
+            OwningRef::new(vec![].into_boxed_slice()).map(|x| &x[..]);
+
+        let c: OwningRef<Rc<Vec<u8>>, [u8]> = unsafe { a.map_owner(Rc::new) };
+        let d: OwningRef<Rc<Box<[u8]>>, [u8]> = unsafe { b.map_owner(Rc::new) };
+
+        let e: OwningRef<Rc<dyn Erased>, [u8]> = c.erase_owner();
+        let f: OwningRef<Rc<dyn Erased>, [u8]> = d.erase_owner();
+
+        let _g = e.clone();
+        let _h = f.clone();
+    }
+
+    #[test]
+    fn total_erase_box() {
+        let a: OwningRef<Vec<u8>, [u8]> = OwningRef::new(vec![]).map(|x| &x[..]);
+        let b: OwningRef<Box<[u8]>, [u8]> =
+            OwningRef::new(vec![].into_boxed_slice()).map(|x| &x[..]);
+
+        let c: OwningRef<Box<Vec<u8>>, [u8]> = a.map_owner_box();
+        let d: OwningRef<Box<Box<[u8]>>, [u8]> = b.map_owner_box();
+
+        let _e: OwningRef<Box<dyn Erased>, [u8]> = c.erase_owner();
+        let _f: OwningRef<Box<dyn Erased>, [u8]> = d.erase_owner();
+    }
+
+    #[test]
+    fn try_map1() {
+        use std::any::Any;
+
+        let x = Box::new(123_i32);
+        let y: Box<dyn Any> = x;
+
+        assert!(OwningRef::new(y).try_map(|x| x.downcast_ref::<i32>().ok_or(())).is_ok());
+    }
+
+    #[test]
+    fn try_map2() {
+        use std::any::Any;
+
+        let x = Box::new(123_i32);
+        let y: Box<dyn Any> = x;
+
+        assert!(!OwningRef::new(y).try_map(|x| x.downcast_ref::<i32>().ok_or(())).is_err());
+    }
+}
+
+mod owning_handle {
+    use super::super::OwningHandle;
+    use super::super::RcRef;
+    use std::cell::RefCell;
+    use std::rc::Rc;
+    use std::sync::Arc;
+    use std::sync::RwLock;
+
+    #[test]
+    fn owning_handle() {
+        use std::cell::RefCell;
+        let cell = Rc::new(RefCell::new(2));
+        let cell_ref = RcRef::new(cell);
+        let mut handle =
+            OwningHandle::new_with_fn(cell_ref, |x| unsafe { x.as_ref() }.unwrap().borrow_mut());
+        assert_eq!(*handle, 2);
+        *handle = 3;
+        assert_eq!(*handle, 3);
+    }
+
+    #[test]
+    fn try_owning_handle_ok() {
+        use std::cell::RefCell;
+        let cell = Rc::new(RefCell::new(2));
+        let cell_ref = RcRef::new(cell);
+        let mut handle = OwningHandle::try_new::<_, ()>(cell_ref, |x| {
+            Ok(unsafe { x.as_ref() }.unwrap().borrow_mut())
+        })
+        .unwrap();
+        assert_eq!(*handle, 2);
+        *handle = 3;
+        assert_eq!(*handle, 3);
+    }
+
+    #[test]
+    fn try_owning_handle_err() {
+        use std::cell::RefCell;
+        let cell = Rc::new(RefCell::new(2));
+        let cell_ref = RcRef::new(cell);
+        let handle = OwningHandle::try_new::<_, ()>(cell_ref, |x| {
+            if false {
+                return Ok(unsafe { x.as_ref() }.unwrap().borrow_mut());
+            }
+            Err(())
+        });
+        assert!(handle.is_err());
+    }
+
+    #[test]
+    fn nested() {
+        use std::cell::RefCell;
+        use std::sync::{Arc, RwLock};
+
+        let result = {
+            let complex = Rc::new(RefCell::new(Arc::new(RwLock::new("someString"))));
+            let curr = RcRef::new(complex);
+            let curr =
+                OwningHandle::new_with_fn(curr, |x| unsafe { x.as_ref() }.unwrap().borrow_mut());
+            let mut curr = OwningHandle::new_with_fn(curr, |x| {
+                unsafe { x.as_ref() }.unwrap().try_write().unwrap()
+            });
+            assert_eq!(*curr, "someString");
+            *curr = "someOtherString";
+            curr
+        };
+        assert_eq!(*result, "someOtherString");
+    }
+
+    #[test]
+    fn owning_handle_safe() {
+        use std::cell::RefCell;
+        let cell = Rc::new(RefCell::new(2));
+        let cell_ref = RcRef::new(cell);
+        let handle = OwningHandle::new(cell_ref);
+        assert_eq!(*handle, 2);
+    }
+
+    #[test]
+    fn owning_handle_mut_safe() {
+        use std::cell::RefCell;
+        let cell = Rc::new(RefCell::new(2));
+        let cell_ref = RcRef::new(cell);
+        let mut handle = OwningHandle::new_mut(cell_ref);
+        assert_eq!(*handle, 2);
+        *handle = 3;
+        assert_eq!(*handle, 3);
+    }
+
+    #[test]
+    fn owning_handle_safe_2() {
+        let result = {
+            let complex = Rc::new(RefCell::new(Arc::new(RwLock::new("someString"))));
+            let curr = RcRef::new(complex);
+            let curr =
+                OwningHandle::new_with_fn(curr, |x| unsafe { x.as_ref() }.unwrap().borrow_mut());
+            let mut curr = OwningHandle::new_with_fn(curr, |x| {
+                unsafe { x.as_ref() }.unwrap().try_write().unwrap()
+            });
+            assert_eq!(*curr, "someString");
+            *curr = "someOtherString";
+            curr
+        };
+        assert_eq!(*result, "someOtherString");
+    }
+}
+
+mod owning_ref_mut {
+    use super::super::BoxRef;
+    use super::super::{BoxRefMut, Erased, ErasedBoxRefMut, OwningRefMut};
+    use std::cmp::{Ord, Ordering, PartialEq, PartialOrd};
+    use std::collections::hash_map::DefaultHasher;
+    use std::collections::HashMap;
+    use std::hash::{Hash, Hasher};
+
+    #[derive(Debug, PartialEq)]
+    struct Example(u32, String, [u8; 3]);
+    fn example() -> Example {
+        Example(42, "hello world".to_string(), [1, 2, 3])
+    }
+
+    #[test]
+    fn new_deref() {
+        let or: OwningRefMut<Box<()>, ()> = OwningRefMut::new(Box::new(()));
+        assert_eq!(&*or, &());
+    }
+
+    #[test]
+    fn new_deref_mut() {
+        let mut or: OwningRefMut<Box<()>, ()> = OwningRefMut::new(Box::new(()));
+        assert_eq!(&mut *or, &mut ());
+    }
+
+    #[test]
+    fn mutate() {
+        let mut or: OwningRefMut<Box<usize>, usize> = OwningRefMut::new(Box::new(0));
+        assert_eq!(&*or, &0);
+        *or = 1;
+        assert_eq!(&*or, &1);
+    }
+
+    #[test]
+    fn into() {
+        let or: OwningRefMut<Box<()>, ()> = Box::new(()).into();
+        assert_eq!(&*or, &());
+    }
+
+    #[test]
+    fn map_offset_ref() {
+        let or: BoxRefMut<Example> = Box::new(example()).into();
+        let or: BoxRef<_, u32> = or.map(|x| &mut x.0);
+        assert_eq!(&*or, &42);
+
+        let or: BoxRefMut<Example> = Box::new(example()).into();
+        let or: BoxRef<_, u8> = or.map(|x| &mut x.2[1]);
+        assert_eq!(&*or, &2);
+    }
+
+    #[test]
+    fn map_heap_ref() {
+        let or: BoxRefMut<Example> = Box::new(example()).into();
+        let or: BoxRef<_, str> = or.map(|x| &mut x.1[..5]);
+        assert_eq!(&*or, "hello");
+    }
+
+    #[test]
+    fn map_static_ref() {
+        let or: BoxRefMut<()> = Box::new(()).into();
+        let or: BoxRef<_, str> = or.map(|_| "hello");
+        assert_eq!(&*or, "hello");
+    }
+
+    #[test]
+    fn map_mut_offset_ref() {
+        let or: BoxRefMut<Example> = Box::new(example()).into();
+        let or: BoxRefMut<_, u32> = or.map_mut(|x| &mut x.0);
+        assert_eq!(&*or, &42);
+
+        let or: BoxRefMut<Example> = Box::new(example()).into();
+        let or: BoxRefMut<_, u8> = or.map_mut(|x| &mut x.2[1]);
+        assert_eq!(&*or, &2);
+    }
+
+    #[test]
+    fn map_mut_heap_ref() {
+        let or: BoxRefMut<Example> = Box::new(example()).into();
+        let or: BoxRefMut<_, str> = or.map_mut(|x| &mut x.1[..5]);
+        assert_eq!(&*or, "hello");
+    }
+
+    #[test]
+    fn map_mut_static_ref() {
+        static mut MUT_S: [u8; 5] = *b"hello";
+
+        let mut_s: &'static mut [u8] = unsafe { &mut MUT_S };
+
+        let or: BoxRefMut<()> = Box::new(()).into();
+        let or: BoxRefMut<_, [u8]> = or.map_mut(move |_| mut_s);
+        assert_eq!(&*or, b"hello");
+    }
+
+    #[test]
+    fn map_mut_chained() {
+        let or: BoxRefMut<String> = Box::new(example().1).into();
+        let or: BoxRefMut<_, str> = or.map_mut(|x| &mut x[1..5]);
+        let or: BoxRefMut<_, str> = or.map_mut(|x| &mut x[..2]);
+        assert_eq!(&*or, "el");
+    }
+
+    #[test]
+    fn map_chained_inference() {
+        let or = BoxRefMut::new(Box::new(example().1))
+            .map_mut(|x| &mut x[..5])
+            .map_mut(|x| &mut x[1..3]);
+        assert_eq!(&*or, "el");
+    }
+
+    #[test]
+    fn try_map_mut() {
+        let or: BoxRefMut<String> = Box::new(example().1).into();
+        let or: Result<BoxRefMut<_, str>, ()> = or.try_map_mut(|x| Ok(&mut x[1..5]));
+        assert_eq!(&*or.unwrap(), "ello");
+
+        let or: BoxRefMut<String> = Box::new(example().1).into();
+        let or: Result<BoxRefMut<_, str>, ()> = or.try_map_mut(|_| Err(()));
+        assert!(or.is_err());
+    }
+
+    #[test]
+    fn owner() {
+        let or: BoxRefMut<String> = Box::new(example().1).into();
+        let or = or.map_mut(|x| &mut x[..5]);
+        assert_eq!(&*or, "hello");
+        assert_eq!(&**or.owner(), "hello world");
+    }
+
+    #[test]
+    fn into_inner() {
+        let or: BoxRefMut<String> = Box::new(example().1).into();
+        let or = or.map_mut(|x| &mut x[..5]);
+        assert_eq!(&*or, "hello");
+        let s = *or.into_inner();
+        assert_eq!(&s, "hello world");
+    }
+
+    #[test]
+    fn fmt_debug() {
+        let or: BoxRefMut<String> = Box::new(example().1).into();
+        let or = or.map_mut(|x| &mut x[..5]);
+        let s = format!("{:?}", or);
+        assert_eq!(&s, "OwningRefMut { owner: \"hello world\", reference: \"hello\" }");
+    }
+
+    #[test]
+    fn erased_owner() {
+        let o1: BoxRefMut<Example, str> =
+            BoxRefMut::new(Box::new(example())).map_mut(|x| &mut x.1[..]);
+
+        let o2: BoxRefMut<String, str> =
+            BoxRefMut::new(Box::new(example().1)).map_mut(|x| &mut x[..]);
+
+        let os: Vec<ErasedBoxRefMut<str>> = vec![o1.erase_owner(), o2.erase_owner()];
+        assert!(os.iter().all(|e| &e[..] == "hello world"));
+    }
+
+    #[test]
+    fn raii_locks() {
+        use super::super::RefMutRefMut;
+        use super::super::{MutexGuardRefMut, RwLockWriteGuardRefMut};
+        use std::cell::RefCell;
+        use std::sync::{Mutex, RwLock};
+
+        {
+            let a = RefCell::new(1);
+            let a = {
+                let a = RefMutRefMut::new(a.borrow_mut());
+                assert_eq!(*a, 1);
+                a
+            };
+            assert_eq!(*a, 1);
+            drop(a);
+        }
+        {
+            let a = Mutex::new(1);
+            let a = {
+                let a = MutexGuardRefMut::new(a.lock().unwrap());
+                assert_eq!(*a, 1);
+                a
+            };
+            assert_eq!(*a, 1);
+            drop(a);
+        }
+        {
+            let a = RwLock::new(1);
+            let a = {
+                let a = RwLockWriteGuardRefMut::new(a.write().unwrap());
+                assert_eq!(*a, 1);
+                a
+            };
+            assert_eq!(*a, 1);
+            drop(a);
+        }
+    }
+
+    #[test]
+    fn eq() {
+        let or1: BoxRefMut<[u8]> = BoxRefMut::new(vec![1, 2, 3].into_boxed_slice());
+        let or2: BoxRefMut<[u8]> = BoxRefMut::new(vec![1, 2, 3].into_boxed_slice());
+        assert_eq!(or1.eq(&or2), true);
+    }
+
+    #[test]
+    fn cmp() {
+        let or1: BoxRefMut<[u8]> = BoxRefMut::new(vec![1, 2, 3].into_boxed_slice());
+        let or2: BoxRefMut<[u8]> = BoxRefMut::new(vec![4, 5, 6].into_boxed_slice());
+        assert_eq!(or1.cmp(&or2), Ordering::Less);
+    }
+
+    #[test]
+    fn partial_cmp() {
+        let or1: BoxRefMut<[u8]> = BoxRefMut::new(vec![4, 5, 6].into_boxed_slice());
+        let or2: BoxRefMut<[u8]> = BoxRefMut::new(vec![1, 2, 3].into_boxed_slice());
+        assert_eq!(or1.partial_cmp(&or2), Some(Ordering::Greater));
+    }
+
+    #[test]
+    fn hash() {
+        let mut h1 = DefaultHasher::new();
+        let mut h2 = DefaultHasher::new();
+
+        let or1: BoxRefMut<[u8]> = BoxRefMut::new(vec![1, 2, 3].into_boxed_slice());
+        let or2: BoxRefMut<[u8]> = BoxRefMut::new(vec![1, 2, 3].into_boxed_slice());
+
+        or1.hash(&mut h1);
+        or2.hash(&mut h2);
+
+        assert_eq!(h1.finish(), h2.finish());
+    }
+
+    #[test]
+    fn borrow() {
+        let mut hash = HashMap::new();
+        let key1 = BoxRefMut::<String>::new(Box::new("foo".to_string())).map(|s| &s[..]);
+        let key2 = BoxRefMut::<String>::new(Box::new("bar".to_string())).map(|s| &s[..]);
+
+        hash.insert(key1, 42);
+        hash.insert(key2, 23);
+
+        assert_eq!(hash.get("foo"), Some(&42));
+        assert_eq!(hash.get("bar"), Some(&23));
+    }
+
+    #[test]
+    fn total_erase() {
+        let a: OwningRefMut<Vec<u8>, [u8]> = OwningRefMut::new(vec![]).map_mut(|x| &mut x[..]);
+        let b: OwningRefMut<Box<[u8]>, [u8]> =
+            OwningRefMut::new(vec![].into_boxed_slice()).map_mut(|x| &mut x[..]);
+
+        let c: OwningRefMut<Box<Vec<u8>>, [u8]> = unsafe { a.map_owner(Box::new) };
+        let d: OwningRefMut<Box<Box<[u8]>>, [u8]> = unsafe { b.map_owner(Box::new) };
+
+        let _e: OwningRefMut<Box<dyn Erased>, [u8]> = c.erase_owner();
+        let _f: OwningRefMut<Box<dyn Erased>, [u8]> = d.erase_owner();
+    }
+
+    #[test]
+    fn total_erase_box() {
+        let a: OwningRefMut<Vec<u8>, [u8]> = OwningRefMut::new(vec![]).map_mut(|x| &mut x[..]);
+        let b: OwningRefMut<Box<[u8]>, [u8]> =
+            OwningRefMut::new(vec![].into_boxed_slice()).map_mut(|x| &mut x[..]);
+
+        let c: OwningRefMut<Box<Vec<u8>>, [u8]> = a.map_owner_box();
+        let d: OwningRefMut<Box<Box<[u8]>>, [u8]> = b.map_owner_box();
+
+        let _e: OwningRefMut<Box<dyn Erased>, [u8]> = c.erase_owner();
+        let _f: OwningRefMut<Box<dyn Erased>, [u8]> = d.erase_owner();
+    }
+
+    #[test]
+    fn try_map1() {
+        use std::any::Any;
+
+        let x = Box::new(123_i32);
+        let y: Box<dyn Any> = x;
+
+        assert!(OwningRefMut::new(y).try_map_mut(|x| x.downcast_mut::<i32>().ok_or(())).is_ok());
+    }
+
+    #[test]
+    fn try_map2() {
+        use std::any::Any;
+
+        let x = Box::new(123_i32);
+        let y: Box<dyn Any> = x;
+
+        assert!(!OwningRefMut::new(y).try_map_mut(|x| x.downcast_mut::<i32>().ok_or(())).is_err());
+    }
+
+    #[test]
+    fn try_map3() {
+        use std::any::Any;
+
+        let x = Box::new(123_i32);
+        let y: Box<dyn Any> = x;
+
+        assert!(OwningRefMut::new(y).try_map(|x| x.downcast_ref::<i32>().ok_or(())).is_ok());
+    }
+
+    #[test]
+    fn try_map4() {
+        use std::any::Any;
+
+        let x = Box::new(123_i32);
+        let y: Box<dyn Any> = x;
+
+        assert!(!OwningRefMut::new(y).try_map(|x| x.downcast_ref::<i32>().ok_or(())).is_err());
+    }
+
+    #[test]
+    fn into_owning_ref() {
+        use super::super::BoxRef;
+
+        let or: BoxRefMut<()> = Box::new(()).into();
+        let or: BoxRef<()> = or.into();
+        assert_eq!(&*or, &());
+    }
+
+    struct Foo {
+        u: u32,
+    }
+    struct Bar {
+        f: Foo,
+    }
+
+    #[test]
+    fn ref_mut() {
+        use std::cell::RefCell;
+
+        let a = RefCell::new(Bar { f: Foo { u: 42 } });
+        let mut b = OwningRefMut::new(a.borrow_mut());
+        assert_eq!(b.f.u, 42);
+        b.f.u = 43;
+        let mut c = b.map_mut(|x| &mut x.f);
+        assert_eq!(c.u, 43);
+        c.u = 44;
+        let mut d = c.map_mut(|x| &mut x.u);
+        assert_eq!(*d, 44);
+        *d = 45;
+        assert_eq!(*d, 45);
+    }
+}