1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
|
use std::any::Any;
use std::cell::RefCell;
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`
}
|
