1 files changed, 343 insertions, 0 deletions
diff --git a/library/core/tests/mem.rs b/library/core/tests/mem.rs
new file mode 100644
index 000000000..6856d1a1f
--- /dev/null
+++ b/library/core/tests/mem.rs
@@ -0,0 +1,343 @@
+use core::mem::*;
+
+#[cfg(panic = "unwind")]
+use std::rc::Rc;
+
+#[test]
+fn size_of_basic() {
+    assert_eq!(size_of::<u8>(), 1);
+    assert_eq!(size_of::<u16>(), 2);
+    assert_eq!(size_of::<u32>(), 4);
+    assert_eq!(size_of::<u64>(), 8);
+}
+
+#[test]
+#[cfg(target_pointer_width = "16")]
+fn size_of_16() {
+    assert_eq!(size_of::<usize>(), 2);
+    assert_eq!(size_of::<*const usize>(), 2);
+}
+
+#[test]
+#[cfg(target_pointer_width = "32")]
+fn size_of_32() {
+    assert_eq!(size_of::<usize>(), 4);
+    assert_eq!(size_of::<*const usize>(), 4);
+}
+
+#[test]
+#[cfg(target_pointer_width = "64")]
+fn size_of_64() {
+    assert_eq!(size_of::<usize>(), 8);
+    assert_eq!(size_of::<*const usize>(), 8);
+}
+
+#[test]
+fn size_of_val_basic() {
+    assert_eq!(size_of_val(&1u8), 1);
+    assert_eq!(size_of_val(&1u16), 2);
+    assert_eq!(size_of_val(&1u32), 4);
+    assert_eq!(size_of_val(&1u64), 8);
+}
+
+#[test]
+fn align_of_basic() {
+    assert_eq!(align_of::<u8>(), 1);
+    assert_eq!(align_of::<u16>(), 2);
+    assert_eq!(align_of::<u32>(), 4);
+}
+
+#[test]
+#[cfg(target_pointer_width = "16")]
+fn align_of_16() {
+    assert_eq!(align_of::<usize>(), 2);
+    assert_eq!(align_of::<*const usize>(), 2);
+}
+
+#[test]
+#[cfg(target_pointer_width = "32")]
+fn align_of_32() {
+    assert_eq!(align_of::<usize>(), 4);
+    assert_eq!(align_of::<*const usize>(), 4);
+}
+
+#[test]
+#[cfg(target_pointer_width = "64")]
+fn align_of_64() {
+    assert_eq!(align_of::<usize>(), 8);
+    assert_eq!(align_of::<*const usize>(), 8);
+}
+
+#[test]
+fn align_of_val_basic() {
+    assert_eq!(align_of_val(&1u8), 1);
+    assert_eq!(align_of_val(&1u16), 2);
+    assert_eq!(align_of_val(&1u32), 4);
+}
+
+#[test]
+fn test_swap() {
+    let mut x = 31337;
+    let mut y = 42;
+    swap(&mut x, &mut y);
+    assert_eq!(x, 42);
+    assert_eq!(y, 31337);
+}
+
+#[test]
+fn test_replace() {
+    let mut x = Some("test".to_string());
+    let y = replace(&mut x, None);
+    assert!(x.is_none());
+    assert!(y.is_some());
+}
+
+#[test]
+fn test_transmute_copy() {
+    assert_eq!(1, unsafe { transmute_copy(&1) });
+}
+
+#[test]
+fn test_transmute_copy_shrink() {
+    assert_eq!(0_u8, unsafe { transmute_copy(&0_u64) });
+}
+
+#[test]
+fn test_transmute_copy_unaligned() {
+    #[repr(C)]
+    #[derive(Default)]
+    struct Unaligned {
+        a: u8,
+        b: [u8; 8],
+    }
+
+    let u = Unaligned::default();
+    assert_eq!(0_u64, unsafe { transmute_copy(&u.b) });
+}
+
+#[test]
+#[cfg(panic = "unwind")]
+fn test_transmute_copy_grow_panics() {
+    use std::panic;
+
+    let err = panic::catch_unwind(panic::AssertUnwindSafe(|| unsafe {
+        let _unused: u64 = transmute_copy(&1_u8);
+    }));
+
+    match err {
+        Ok(_) => unreachable!(),
+        Err(payload) => {
+            payload
+                .downcast::<&'static str>()
+                .and_then(|s| {
+                    if *s == "cannot transmute_copy if U is larger than T" { Ok(s) } else { Err(s) }
+                })
+                .unwrap_or_else(|p| panic::resume_unwind(p));
+        }
+    }
+}
+
+#[test]
+#[allow(dead_code)]
+fn test_discriminant_send_sync() {
+    enum Regular {
+        A,
+        B(i32),
+    }
+    enum NotSendSync {
+        A(*const i32),
+    }
+
+    fn is_send_sync<T: Send + Sync>() {}
+
+    is_send_sync::<Discriminant<Regular>>();
+    is_send_sync::<Discriminant<NotSendSync>>();
+}
+
+#[test]
+fn assume_init_good() {
+    const TRUE: bool = unsafe { MaybeUninit::<bool>::new(true).assume_init() };
+
+    assert!(TRUE);
+}
+
+#[test]
+fn uninit_array_assume_init() {
+    let mut array: [MaybeUninit<i16>; 5] = MaybeUninit::uninit_array();
+    array[0].write(3);
+    array[1].write(1);
+    array[2].write(4);
+    array[3].write(1);
+    array[4].write(5);
+
+    let array = unsafe { MaybeUninit::array_assume_init(array) };
+
+    assert_eq!(array, [3, 1, 4, 1, 5]);
+
+    let [] = unsafe { MaybeUninit::<!>::array_assume_init([]) };
+}
+
+#[test]
+fn uninit_write_slice() {
+    let mut dst = [MaybeUninit::new(255); 64];
+    let src = [0; 64];
+
+    assert_eq!(MaybeUninit::write_slice(&mut dst, &src), &src);
+}
+
+#[test]
+#[should_panic(expected = "source slice length (32) does not match destination slice length (64)")]
+fn uninit_write_slice_panic_lt() {
+    let mut dst = [MaybeUninit::uninit(); 64];
+    let src = [0; 32];
+
+    MaybeUninit::write_slice(&mut dst, &src);
+}
+
+#[test]
+#[should_panic(expected = "source slice length (128) does not match destination slice length (64)")]
+fn uninit_write_slice_panic_gt() {
+    let mut dst = [MaybeUninit::uninit(); 64];
+    let src = [0; 128];
+
+    MaybeUninit::write_slice(&mut dst, &src);
+}
+
+#[test]
+fn uninit_clone_from_slice() {
+    let mut dst = [MaybeUninit::new(255); 64];
+    let src = [0; 64];
+
+    assert_eq!(MaybeUninit::write_slice_cloned(&mut dst, &src), &src);
+}
+
+#[test]
+#[should_panic(expected = "destination and source slices have different lengths")]
+fn uninit_write_slice_cloned_panic_lt() {
+    let mut dst = [MaybeUninit::uninit(); 64];
+    let src = [0; 32];
+
+    MaybeUninit::write_slice_cloned(&mut dst, &src);
+}
+
+#[test]
+#[should_panic(expected = "destination and source slices have different lengths")]
+fn uninit_write_slice_cloned_panic_gt() {
+    let mut dst = [MaybeUninit::uninit(); 64];
+    let src = [0; 128];
+
+    MaybeUninit::write_slice_cloned(&mut dst, &src);
+}
+
+#[test]
+#[cfg(panic = "unwind")]
+fn uninit_write_slice_cloned_mid_panic() {
+    use std::panic;
+
+    enum IncrementOrPanic {
+        Increment(Rc<()>),
+        ExpectedPanic,
+        UnexpectedPanic,
+    }
+
+    impl Clone for IncrementOrPanic {
+        fn clone(&self) -> Self {
+            match self {
+                Self::Increment(rc) => Self::Increment(rc.clone()),
+                Self::ExpectedPanic => panic!("expected panic on clone"),
+                Self::UnexpectedPanic => panic!("unexpected panic on clone"),
+            }
+        }
+    }
+
+    let rc = Rc::new(());
+
+    let mut dst = [
+        MaybeUninit::uninit(),
+        MaybeUninit::uninit(),
+        MaybeUninit::uninit(),
+        MaybeUninit::uninit(),
+    ];
+
+    let src = [
+        IncrementOrPanic::Increment(rc.clone()),
+        IncrementOrPanic::Increment(rc.clone()),
+        IncrementOrPanic::ExpectedPanic,
+        IncrementOrPanic::UnexpectedPanic,
+    ];
+
+    let err = panic::catch_unwind(panic::AssertUnwindSafe(|| {
+        MaybeUninit::write_slice_cloned(&mut dst, &src);
+    }));
+
+    drop(src);
+
+    match err {
+        Ok(_) => unreachable!(),
+        Err(payload) => {
+            payload
+                .downcast::<&'static str>()
+                .and_then(|s| if *s == "expected panic on clone" { Ok(s) } else { Err(s) })
+                .unwrap_or_else(|p| panic::resume_unwind(p));
+
+            assert_eq!(Rc::strong_count(&rc), 1)
+        }
+    }
+}
+
+#[test]
+fn uninit_write_slice_cloned_no_drop() {
+    #[derive(Clone)]
+    struct Bomb;
+
+    impl Drop for Bomb {
+        fn drop(&mut self) {
+            panic!("dropped a bomb! kaboom")
+        }
+    }
+
+    let mut dst = [MaybeUninit::uninit()];
+    let src = [Bomb];
+
+    MaybeUninit::write_slice_cloned(&mut dst, &src);
+
+    forget(src);
+}
+
+#[test]
+fn uninit_const_assume_init_read() {
+    const FOO: u32 = unsafe { MaybeUninit::new(42).assume_init_read() };
+    assert_eq!(FOO, 42);
+}
+
+#[test]
+fn const_maybe_uninit() {
+    use std::ptr;
+
+    #[derive(Debug, PartialEq)]
+    struct Foo {
+        x: u8,
+        y: u8,
+    }
+
+    const FIELD_BY_FIELD: Foo = unsafe {
+        let mut val = MaybeUninit::uninit();
+        init_y(&mut val); // order shouldn't matter
+        init_x(&mut val);
+        val.assume_init()
+    };
+
+    const fn init_x(foo: &mut MaybeUninit<Foo>) {
+        unsafe {
+            *ptr::addr_of_mut!((*foo.as_mut_ptr()).x) = 1;
+        }
+    }
+
+    const fn init_y(foo: &mut MaybeUninit<Foo>) {
+        unsafe {
+            *ptr::addr_of_mut!((*foo.as_mut_ptr()).y) = 2;
+        }
+    }
+
+    assert_eq!(FIELD_BY_FIELD, Foo { x: 1, y: 2 });
+}