summaryrefslogtreecommitdiffstats
path: root/src/tools/clippy/tests/ui/redundant_clone.fixed
blob: da52c0acf93b0fd463f70b4af1f448ece365acfb (plain)
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
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
// run-rustfix
// rustfix-only-machine-applicable

#![feature(lint_reasons)]
#![allow(clippy::implicit_clone, clippy::drop_non_drop)]
use std::ffi::OsString;
use std::path::Path;

fn main() {
    let _s = ["lorem", "ipsum"].join(" ");

    let s = String::from("foo");
    let _s = s;

    let s = String::from("foo");
    let _s = s;

    let s = String::from("foo");
    let _s = s;

    let _s = Path::new("/a/b/").join("c");

    let _s = Path::new("/a/b/").join("c");

    let _s = OsString::new();

    let _s = OsString::new();

    // Check that lint level works
    #[allow(clippy::redundant_clone)]
    let _s = String::new().to_string();

    // Check that lint level works
    #[expect(clippy::redundant_clone)]
    let _s = String::new().to_string();

    let tup = (String::from("foo"),);
    let _t = tup.0;

    let tup_ref = &(String::from("foo"),);
    let _s = tup_ref.0.clone(); // this `.clone()` cannot be removed

    {
        let x = String::new();
        let y = &x;

        let _x = x.clone(); // ok; `x` is borrowed by `y`

        let _ = y.len();
    }

    let x = (String::new(),);
    let _ = Some(String::new()).unwrap_or_else(|| x.0.clone()); // ok; closure borrows `x`

    with_branch(Alpha, true);
    cannot_double_move(Alpha);
    cannot_move_from_type_with_drop();
    borrower_propagation();
    not_consumed();
    issue_5405();
    manually_drop();
    clone_then_move_cloned();
    hashmap_neg();
    false_negative_5707();
}

#[derive(Clone)]
struct Alpha;
fn with_branch(a: Alpha, b: bool) -> (Alpha, Alpha) {
    if b { (a.clone(), a) } else { (Alpha, a) }
}

fn cannot_double_move(a: Alpha) -> (Alpha, Alpha) {
    (a.clone(), a)
}

struct TypeWithDrop {
    x: String,
}

impl Drop for TypeWithDrop {
    fn drop(&mut self) {}
}

fn cannot_move_from_type_with_drop() -> String {
    let s = TypeWithDrop { x: String::new() };
    s.x.clone() // removing this `clone()` summons E0509
}

fn borrower_propagation() {
    let s = String::new();
    let t = String::new();

    {
        fn b() -> bool {
            unimplemented!()
        }
        let _u = if b() { &s } else { &t };

        // ok; `s` and `t` are possibly borrowed
        let _s = s.clone();
        let _t = t.clone();
    }

    {
        let _u = || s.len();
        let _v = [&t; 32];
        let _s = s.clone(); // ok
        let _t = t.clone(); // ok
    }

    {
        let _u = {
            let u = Some(&s);
            let _ = s.clone(); // ok
            u
        };
        let _s = s.clone(); // ok
    }

    {
        use std::convert::identity as id;
        let _u = id(id(&s));
        let _s = s.clone(); // ok, `u` borrows `s`
    }

    let _s = s;
    let _t = t;

    #[derive(Clone)]
    struct Foo {
        x: usize,
    }

    {
        let f = Foo { x: 123 };
        let _x = Some(f.x);
        let _f = f;
    }

    {
        let f = Foo { x: 123 };
        let _x = &f.x;
        let _f = f.clone(); // ok
    }
}

fn not_consumed() {
    let x = std::path::PathBuf::from("home");
    let y = x.join("matthias");
    // join() creates a new owned PathBuf, does not take a &mut to x variable, thus the .clone() is
    // redundant. (It also does not consume the PathBuf)

    println!("x: {:?}, y: {:?}", x, y);

    let mut s = String::new();
    s.clone().push_str("foo"); // OK, removing this `clone()` will change the behavior.
    s.push_str("bar");
    assert_eq!(s, "bar");

    let t = Some(s);
    // OK
    if let Some(x) = t.clone() {
        println!("{}", x);
    }
    if let Some(x) = t {
        println!("{}", x);
    }
}

#[allow(clippy::clone_on_copy)]
fn issue_5405() {
    let a: [String; 1] = [String::from("foo")];
    let _b: String = a[0].clone();

    let c: [usize; 2] = [2, 3];
    let _d: usize = c[1].clone();
}

fn manually_drop() {
    use std::mem::ManuallyDrop;
    use std::sync::Arc;

    let a = ManuallyDrop::new(Arc::new("Hello!".to_owned()));
    let _ = a.clone(); // OK

    let p: *const String = Arc::into_raw(ManuallyDrop::into_inner(a));
    unsafe {
        Arc::from_raw(p);
        Arc::from_raw(p);
    }
}

fn clone_then_move_cloned() {
    // issue #5973
    let x = Some(String::new());
    // ok, x is moved while the clone is in use.
    assert_eq!(x.clone(), None, "not equal {}", x.unwrap());

    // issue #5595
    fn foo<F: Fn()>(_: &Alpha, _: F) {}
    let x = Alpha;
    // ok, data is moved while the clone is in use.
    foo(&x, move || {
        let _ = x;
    });

    // issue #6998
    struct S(String);
    impl S {
        fn m(&mut self) {}
    }
    let mut x = S(String::new());
    x.0.clone().chars().for_each(|_| x.m());
}

fn hashmap_neg() {
    // issue 5707
    use std::collections::HashMap;
    use std::path::PathBuf;

    let p = PathBuf::from("/");

    let mut h: HashMap<&str, &str> = HashMap::new();
    h.insert("orig-p", p.to_str().unwrap());

    let mut q = p.clone();
    q.push("foo");

    println!("{:?} {}", h, q.display());
}

fn false_negative_5707() {
    fn foo(_x: &Alpha, _y: &mut Alpha) {}

    let x = Alpha;
    let mut y = Alpha;
    foo(&x, &mut y);
    let _z = x.clone(); // pr 7346 can't lint on `x`
    drop(y);
}