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use std::any::Any;
use std::cell::RefCell;
use std::cmp::PartialEq;
use std::iter::TrustedLen;
use std::mem;
use std::rc::{Rc, Weak};
#[test]
fn uninhabited() {
enum Void {}
let mut a = Weak::<Void>::new();
a = a.clone();
assert!(a.upgrade().is_none());
let mut a: Weak<dyn Any> = a; // Unsizing
a = a.clone();
assert!(a.upgrade().is_none());
}
#[test]
fn slice() {
let a: Rc<[u32; 3]> = Rc::new([3, 2, 1]);
let a: Rc<[u32]> = a; // Unsizing
let b: Rc<[u32]> = Rc::from(&[3, 2, 1][..]); // Conversion
assert_eq!(a, b);
// Exercise is_dangling() with a DST
let mut a = Rc::downgrade(&a);
a = a.clone();
assert!(a.upgrade().is_some());
}
#[test]
fn trait_object() {
let a: Rc<u32> = Rc::new(4);
let a: Rc<dyn Any> = a; // Unsizing
// Exercise is_dangling() with a DST
let mut a = Rc::downgrade(&a);
a = a.clone();
assert!(a.upgrade().is_some());
let mut b = Weak::<u32>::new();
b = b.clone();
assert!(b.upgrade().is_none());
let mut b: Weak<dyn Any> = b; // Unsizing
b = b.clone();
assert!(b.upgrade().is_none());
}
#[test]
fn float_nan_ne() {
let x = Rc::new(f32::NAN);
assert!(x != x);
assert!(!(x == x));
}
#[test]
fn partial_eq() {
struct TestPEq(RefCell<usize>);
impl PartialEq for TestPEq {
fn eq(&self, other: &TestPEq) -> bool {
*self.0.borrow_mut() += 1;
*other.0.borrow_mut() += 1;
true
}
}
let x = Rc::new(TestPEq(RefCell::new(0)));
assert!(x == x);
assert!(!(x != x));
assert_eq!(*x.0.borrow(), 4);
}
#[test]
fn eq() {
#[derive(Eq)]
struct TestEq(RefCell<usize>);
impl PartialEq for TestEq {
fn eq(&self, other: &TestEq) -> bool {
*self.0.borrow_mut() += 1;
*other.0.borrow_mut() += 1;
true
}
}
let x = Rc::new(TestEq(RefCell::new(0)));
assert!(x == x);
assert!(!(x != x));
assert_eq!(*x.0.borrow(), 0);
}
const SHARED_ITER_MAX: u16 = 100;
fn assert_trusted_len<I: TrustedLen>(_: &I) {}
#[test]
fn shared_from_iter_normal() {
// Exercise the base implementation for non-`TrustedLen` iterators.
{
// `Filter` is never `TrustedLen` since we don't
// know statically how many elements will be kept:
let iter = (0..SHARED_ITER_MAX).filter(|x| x % 2 == 0).map(Box::new);
// Collecting into a `Vec<T>` or `Rc<[T]>` should make no difference:
let vec = iter.clone().collect::<Vec<_>>();
let rc = iter.collect::<Rc<[_]>>();
assert_eq!(&*vec, &*rc);
// Clone a bit and let these get dropped.
{
let _rc_2 = rc.clone();
let _rc_3 = rc.clone();
let _rc_4 = Rc::downgrade(&_rc_3);
}
} // Drop what hasn't been here.
}
#[test]
fn shared_from_iter_trustedlen_normal() {
// Exercise the `TrustedLen` implementation under normal circumstances
// where `size_hint()` matches `(_, Some(exact_len))`.
{
let iter = (0..SHARED_ITER_MAX).map(Box::new);
assert_trusted_len(&iter);
// Collecting into a `Vec<T>` or `Rc<[T]>` should make no difference:
let vec = iter.clone().collect::<Vec<_>>();
let rc = iter.collect::<Rc<[_]>>();
assert_eq!(&*vec, &*rc);
assert_eq!(mem::size_of::<Box<u16>>() * SHARED_ITER_MAX as usize, mem::size_of_val(&*rc));
// Clone a bit and let these get dropped.
{
let _rc_2 = rc.clone();
let _rc_3 = rc.clone();
let _rc_4 = Rc::downgrade(&_rc_3);
}
} // Drop what hasn't been here.
// Try a ZST to make sure it is handled well.
{
let iter = (0..SHARED_ITER_MAX).map(drop);
let vec = iter.clone().collect::<Vec<_>>();
let rc = iter.collect::<Rc<[_]>>();
assert_eq!(&*vec, &*rc);
assert_eq!(0, mem::size_of_val(&*rc));
{
let _rc_2 = rc.clone();
let _rc_3 = rc.clone();
let _rc_4 = Rc::downgrade(&_rc_3);
}
}
}
#[test]
#[should_panic = "I've almost got 99 problems."]
fn shared_from_iter_trustedlen_panic() {
// Exercise the `TrustedLen` implementation when `size_hint()` matches
// `(_, Some(exact_len))` but where `.next()` drops before the last iteration.
let iter = (0..SHARED_ITER_MAX).map(|val| match val {
98 => panic!("I've almost got 99 problems."),
_ => Box::new(val),
});
assert_trusted_len(&iter);
let _ = iter.collect::<Rc<[_]>>();
panic!("I am unreachable.");
}
#[test]
fn shared_from_iter_trustedlen_no_fuse() {
// Exercise the `TrustedLen` implementation when `size_hint()` matches
// `(_, Some(exact_len))` but where the iterator does not behave in a fused manner.
struct Iter(std::vec::IntoIter<Option<Box<u8>>>);
unsafe impl TrustedLen for Iter {}
impl Iterator for Iter {
fn size_hint(&self) -> (usize, Option<usize>) {
(2, Some(2))
}
type Item = Box<u8>;
fn next(&mut self) -> Option<Self::Item> {
self.0.next().flatten()
}
}
let vec = vec![Some(Box::new(42)), Some(Box::new(24)), None, Some(Box::new(12))];
let iter = Iter(vec.into_iter());
assert_trusted_len(&iter);
assert_eq!(&[Box::new(42), Box::new(24)], &*iter.collect::<Rc<[_]>>());
}
#[test]
fn weak_may_dangle() {
fn hmm<'a>(val: &'a mut Weak<&'a str>) -> Weak<&'a str> {
val.clone()
}
// Without #[may_dangle] we get:
let mut val = Weak::new();
hmm(&mut val);
// ~~~~~~~~ borrowed value does not live long enough
//
// `val` dropped here while still borrowed
// borrow might be used here, when `val` is dropped and runs the `Drop` code for type `std::rc::Weak`
}
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