1 files changed, 479 insertions, 0 deletions
diff --git a/library/core/tests/cell.rs b/library/core/tests/cell.rs
new file mode 100644
index 000000000..7b77b2134
--- /dev/null
+++ b/library/core/tests/cell.rs
@@ -0,0 +1,479 @@
+use core::cell::*;
+use core::default::Default;
+use std::mem::drop;
+
+#[test]
+fn smoketest_unsafe_cell() {
+    let mut x = UnsafeCell::new(10);
+    let ref_mut = &mut x;
+    unsafe {
+        // The asserts are repeated in order to ensure that `get()`
+        // is non-mutating.
+        assert_eq!(*ref_mut.get(), 10);
+        assert_eq!(*ref_mut.get(), 10);
+        *ref_mut.get_mut() += 5;
+        assert_eq!(*ref_mut.get(), 15);
+        assert_eq!(*ref_mut.get(), 15);
+        assert_eq!(x.into_inner(), 15);
+    }
+}
+
+#[test]
+fn unsafe_cell_raw_get() {
+    let x = UnsafeCell::new(10);
+    let ptr = &x as *const UnsafeCell<i32>;
+    unsafe {
+        // The asserts are repeated in order to ensure that `raw_get()`
+        // is non-mutating.
+        assert_eq!(*UnsafeCell::raw_get(ptr), 10);
+        assert_eq!(*UnsafeCell::raw_get(ptr), 10);
+        *UnsafeCell::raw_get(ptr) += 5;
+        assert_eq!(*UnsafeCell::raw_get(ptr), 15);
+        assert_eq!(*UnsafeCell::raw_get(ptr), 15);
+        assert_eq!(x.into_inner(), 15);
+    }
+}
+
+#[test]
+fn smoketest_cell() {
+    let x = Cell::new(10);
+    assert_eq!(x, Cell::new(10));
+    assert_eq!(x.get(), 10);
+    x.set(20);
+    assert_eq!(x, Cell::new(20));
+    assert_eq!(x.get(), 20);
+
+    let y = Cell::new((30, 40));
+    assert_eq!(y, Cell::new((30, 40)));
+    assert_eq!(y.get(), (30, 40));
+}
+
+#[test]
+fn cell_update() {
+    let x = Cell::new(10);
+
+    assert_eq!(x.update(|x| x + 5), 15);
+    assert_eq!(x.get(), 15);
+
+    assert_eq!(x.update(|x| x / 3), 5);
+    assert_eq!(x.get(), 5);
+}
+
+#[test]
+fn cell_has_sensible_show() {
+    let x = Cell::new("foo bar");
+    assert!(format!("{x:?}").contains(x.get()));
+
+    x.set("baz qux");
+    assert!(format!("{x:?}").contains(x.get()));
+}
+
+#[test]
+fn ref_and_refmut_have_sensible_show() {
+    let refcell = RefCell::new("foo");
+
+    let refcell_refmut = refcell.borrow_mut();
+    assert_eq!(format!("{refcell_refmut}"), "foo"); // Display
+    assert!(format!("{refcell_refmut:?}").contains("foo")); // Debug
+    drop(refcell_refmut);
+
+    let refcell_ref = refcell.borrow();
+    assert_eq!(format!("{refcell_ref}"), "foo"); // Display
+    assert!(format!("{refcell_ref:?}").contains("foo")); // Debug
+    drop(refcell_ref);
+}
+
+#[test]
+fn double_imm_borrow() {
+    let x = RefCell::new(0);
+    let _b1 = x.borrow();
+    x.borrow();
+}
+
+#[test]
+fn no_mut_then_imm_borrow() {
+    let x = RefCell::new(0);
+    let _b1 = x.borrow_mut();
+    assert!(x.try_borrow().is_err());
+}
+
+#[test]
+fn no_imm_then_borrow_mut() {
+    let x = RefCell::new(0);
+    let _b1 = x.borrow();
+    assert!(x.try_borrow_mut().is_err());
+}
+
+#[test]
+fn no_double_borrow_mut() {
+    let x = RefCell::new(0);
+    assert!(x.try_borrow().is_ok());
+    let _b1 = x.borrow_mut();
+    assert!(x.try_borrow().is_err());
+}
+
+#[test]
+fn imm_release_borrow_mut() {
+    let x = RefCell::new(0);
+    {
+        let _b1 = x.borrow();
+    }
+    x.borrow_mut();
+}
+
+#[test]
+fn mut_release_borrow_mut() {
+    let x = RefCell::new(0);
+    {
+        let _b1 = x.borrow_mut();
+    }
+    x.borrow();
+}
+
+#[test]
+fn double_borrow_single_release_no_borrow_mut() {
+    let x = RefCell::new(0);
+    let _b1 = x.borrow();
+    {
+        let _b2 = x.borrow();
+    }
+    assert!(x.try_borrow().is_ok());
+    assert!(x.try_borrow_mut().is_err());
+}
+
+#[test]
+#[should_panic]
+fn discard_doesnt_unborrow() {
+    let x = RefCell::new(0);
+    let _b = x.borrow();
+    let _ = _b;
+    let _b = x.borrow_mut();
+}
+
+#[test]
+fn ref_clone_updates_flag() {
+    let x = RefCell::new(0);
+    {
+        let b1 = x.borrow();
+        assert!(x.try_borrow().is_ok());
+        assert!(x.try_borrow_mut().is_err());
+        {
+            let _b2 = Ref::clone(&b1);
+            assert!(x.try_borrow().is_ok());
+            assert!(x.try_borrow_mut().is_err());
+        }
+        assert!(x.try_borrow().is_ok());
+        assert!(x.try_borrow_mut().is_err());
+    }
+    assert!(x.try_borrow().is_ok());
+    assert!(x.try_borrow_mut().is_ok());
+}
+
+#[test]
+fn ref_map_does_not_update_flag() {
+    let x = RefCell::new(Some(5));
+    {
+        let b1: Ref<'_, Option<u32>> = x.borrow();
+        assert!(x.try_borrow().is_ok());
+        assert!(x.try_borrow_mut().is_err());
+        {
+            let b2: Ref<'_, u32> = Ref::map(b1, |o| o.as_ref().unwrap());
+            assert_eq!(*b2, 5);
+            assert!(x.try_borrow().is_ok());
+            assert!(x.try_borrow_mut().is_err());
+        }
+        assert!(x.try_borrow().is_ok());
+        assert!(x.try_borrow_mut().is_ok());
+    }
+    assert!(x.try_borrow().is_ok());
+    assert!(x.try_borrow_mut().is_ok());
+}
+
+#[test]
+fn ref_map_split_updates_flag() {
+    let x = RefCell::new([1, 2]);
+    {
+        let b1 = x.borrow();
+        assert!(x.try_borrow().is_ok());
+        assert!(x.try_borrow_mut().is_err());
+        {
+            let (_b2, _b3) = Ref::map_split(b1, |slc| slc.split_at(1));
+            assert!(x.try_borrow().is_ok());
+            assert!(x.try_borrow_mut().is_err());
+        }
+        assert!(x.try_borrow().is_ok());
+        assert!(x.try_borrow_mut().is_ok());
+    }
+    assert!(x.try_borrow().is_ok());
+    assert!(x.try_borrow_mut().is_ok());
+
+    {
+        let b1 = x.borrow_mut();
+        assert!(x.try_borrow().is_err());
+        assert!(x.try_borrow_mut().is_err());
+        {
+            let (_b2, _b3) = RefMut::map_split(b1, |slc| slc.split_at_mut(1));
+            assert!(x.try_borrow().is_err());
+            assert!(x.try_borrow_mut().is_err());
+            drop(_b2);
+            assert!(x.try_borrow().is_err());
+            assert!(x.try_borrow_mut().is_err());
+        }
+        assert!(x.try_borrow().is_ok());
+        assert!(x.try_borrow_mut().is_ok());
+    }
+    assert!(x.try_borrow().is_ok());
+    assert!(x.try_borrow_mut().is_ok());
+}
+
+#[test]
+fn ref_map_split() {
+    let x = RefCell::new([1, 2]);
+    let (b1, b2) = Ref::map_split(x.borrow(), |slc| slc.split_at(1));
+    assert_eq!(*b1, [1]);
+    assert_eq!(*b2, [2]);
+}
+
+#[test]
+fn ref_mut_map_split() {
+    let x = RefCell::new([1, 2]);
+    {
+        let (mut b1, mut b2) = RefMut::map_split(x.borrow_mut(), |slc| slc.split_at_mut(1));
+        assert_eq!(*b1, [1]);
+        assert_eq!(*b2, [2]);
+        b1[0] = 2;
+        b2[0] = 1;
+    }
+    assert_eq!(*x.borrow(), [2, 1]);
+}
+
+#[test]
+fn ref_map_accessor() {
+    struct X(RefCell<(u32, char)>);
+    impl X {
+        fn accessor(&self) -> Ref<'_, u32> {
+            Ref::map(self.0.borrow(), |tuple| &tuple.0)
+        }
+    }
+    let x = X(RefCell::new((7, 'z')));
+    let d: Ref<'_, u32> = x.accessor();
+    assert_eq!(*d, 7);
+}
+
+#[test]
+fn ref_mut_map_accessor() {
+    struct X(RefCell<(u32, char)>);
+    impl X {
+        fn accessor(&self) -> RefMut<'_, u32> {
+            RefMut::map(self.0.borrow_mut(), |tuple| &mut tuple.0)
+        }
+    }
+    let x = X(RefCell::new((7, 'z')));
+    {
+        let mut d: RefMut<'_, u32> = x.accessor();
+        assert_eq!(*d, 7);
+        *d += 1;
+    }
+    assert_eq!(*x.0.borrow(), (8, 'z'));
+}
+
+#[test]
+fn as_ptr() {
+    let c1: Cell<usize> = Cell::new(0);
+    c1.set(1);
+    assert_eq!(1, unsafe { *c1.as_ptr() });
+
+    let c2: Cell<usize> = Cell::new(0);
+    unsafe {
+        *c2.as_ptr() = 1;
+    }
+    assert_eq!(1, c2.get());
+
+    let r1: RefCell<usize> = RefCell::new(0);
+    *r1.borrow_mut() = 1;
+    assert_eq!(1, unsafe { *r1.as_ptr() });
+
+    let r2: RefCell<usize> = RefCell::new(0);
+    unsafe {
+        *r2.as_ptr() = 1;
+    }
+    assert_eq!(1, *r2.borrow());
+}
+
+#[test]
+fn cell_default() {
+    let cell: Cell<u32> = Default::default();
+    assert_eq!(0, cell.get());
+}
+
+#[test]
+fn cell_set() {
+    let cell = Cell::new(10);
+    cell.set(20);
+    assert_eq!(20, cell.get());
+
+    let cell = Cell::new("Hello".to_owned());
+    cell.set("World".to_owned());
+    assert_eq!("World".to_owned(), cell.into_inner());
+}
+
+#[test]
+fn cell_replace() {
+    let cell = Cell::new(10);
+    assert_eq!(10, cell.replace(20));
+    assert_eq!(20, cell.get());
+
+    let cell = Cell::new("Hello".to_owned());
+    assert_eq!("Hello".to_owned(), cell.replace("World".to_owned()));
+    assert_eq!("World".to_owned(), cell.into_inner());
+}
+
+#[test]
+fn cell_into_inner() {
+    let cell = Cell::new(10);
+    assert_eq!(10, cell.into_inner());
+
+    let cell = Cell::new("Hello world".to_owned());
+    assert_eq!("Hello world".to_owned(), cell.into_inner());
+}
+
+#[test]
+fn cell_exterior() {
+    #[derive(Copy, Clone)]
+    #[allow(dead_code)]
+    struct Point {
+        x: isize,
+        y: isize,
+        z: isize,
+    }
+
+    fn f(p: &Cell<Point>) {
+        assert_eq!(p.get().z, 12);
+        p.set(Point { x: 10, y: 11, z: 13 });
+        assert_eq!(p.get().z, 13);
+    }
+
+    let a = Point { x: 10, y: 11, z: 12 };
+    let b = &Cell::new(a);
+    assert_eq!(b.get().z, 12);
+    f(b);
+    assert_eq!(a.z, 12);
+    assert_eq!(b.get().z, 13);
+}
+
+#[test]
+fn cell_does_not_clone() {
+    #[derive(Copy)]
+    #[allow(dead_code)]
+    struct Foo {
+        x: isize,
+    }
+
+    impl Clone for Foo {
+        fn clone(&self) -> Foo {
+            // Using Cell in any way should never cause clone() to be
+            // invoked -- after all, that would permit evil user code to
+            // abuse `Cell` and trigger crashes.
+
+            panic!();
+        }
+    }
+
+    let x = Cell::new(Foo { x: 22 });
+    let _y = x.get();
+    let _z = x.clone();
+}
+
+#[test]
+fn refcell_default() {
+    let cell: RefCell<u64> = Default::default();
+    assert_eq!(0, *cell.borrow());
+}
+
+#[test]
+fn unsafe_cell_unsized() {
+    let cell: &UnsafeCell<[i32]> = &UnsafeCell::new([1, 2, 3]);
+    {
+        let val: &mut [i32] = unsafe { &mut *cell.get() };
+        val[0] = 4;
+        val[2] = 5;
+    }
+    let comp: &mut [i32] = &mut [4, 2, 5];
+    assert_eq!(unsafe { &mut *cell.get() }, comp);
+}
+
+#[test]
+fn refcell_unsized() {
+    let cell: &RefCell<[i32]> = &RefCell::new([1, 2, 3]);
+    {
+        let b = &mut *cell.borrow_mut();
+        b[0] = 4;
+        b[2] = 5;
+    }
+    let comp: &mut [i32] = &mut [4, 2, 5];
+    assert_eq!(&*cell.borrow(), comp);
+}
+
+#[test]
+fn refcell_ref_coercion() {
+    let cell: RefCell<[i32; 3]> = RefCell::new([1, 2, 3]);
+    {
+        let mut cellref: RefMut<'_, [i32; 3]> = cell.borrow_mut();
+        cellref[0] = 4;
+        let mut coerced: RefMut<'_, [i32]> = cellref;
+        coerced[2] = 5;
+    }
+    {
+        let comp: &mut [i32] = &mut [4, 2, 5];
+        let cellref: Ref<'_, [i32; 3]> = cell.borrow();
+        assert_eq!(&*cellref, comp);
+        let coerced: Ref<'_, [i32]> = cellref;
+        assert_eq!(&*coerced, comp);
+    }
+}
+
+#[test]
+#[should_panic]
+fn refcell_swap_borrows() {
+    let x = RefCell::new(0);
+    let _b = x.borrow();
+    let y = RefCell::new(1);
+    x.swap(&y);
+}
+
+#[test]
+#[should_panic]
+fn refcell_replace_borrows() {
+    let x = RefCell::new(0);
+    let _b = x.borrow();
+    x.replace(1);
+}
+
+#[test]
+fn refcell_format() {
+    let name = RefCell::new("rust");
+    let what = RefCell::new("rocks");
+    let msg = format!("{name} {}", &*what.borrow(), name = &*name.borrow());
+    assert_eq!(msg, "rust rocks".to_string());
+}
+
+#[allow(dead_code)]
+fn const_cells() {
+    const UNSAFE_CELL: UnsafeCell<i32> = UnsafeCell::new(3);
+    const _: i32 = UNSAFE_CELL.into_inner();
+
+    const REF_CELL: RefCell<i32> = RefCell::new(3);
+    const _: i32 = REF_CELL.into_inner();
+
+    const CELL: Cell<i32> = Cell::new(3);
+    const _: i32 = CELL.into_inner();
+
+    const UNSAFE_CELL_FROM: UnsafeCell<i32> = UnsafeCell::from(3);
+    const _: i32 = UNSAFE_CELL.into_inner();
+
+    const REF_CELL_FROM: RefCell<i32> = RefCell::from(3);
+    const _: i32 = REF_CELL.into_inner();
+
+    const CELL_FROM: Cell<i32> = Cell::from(3);
+    const _: i32 = CELL.into_inner();
+}