summaryrefslogtreecommitdiffstats
path: root/src/tools/clippy/tests/ui/redundant_pattern_matching_result.rs
blob: 39eb10df8789ed5f0fbe613282e42b531cb37fc2 (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
//@run-rustfix
#![warn(clippy::all)]
#![warn(clippy::redundant_pattern_matching)]
#![allow(deprecated, unused_must_use)]
#![allow(
    clippy::if_same_then_else,
    clippy::match_like_matches_macro,
    clippy::needless_bool,
    clippy::uninlined_format_args,
    clippy::unnecessary_wraps
)]

fn main() {
    let result: Result<usize, usize> = Err(5);
    if let Ok(_) = &result {}

    if let Ok(_) = Ok::<i32, i32>(42) {}

    if let Err(_) = Err::<i32, i32>(42) {}

    while let Ok(_) = Ok::<i32, i32>(10) {}

    while let Err(_) = Ok::<i32, i32>(10) {}

    if Ok::<i32, i32>(42).is_ok() {}

    if Err::<i32, i32>(42).is_err() {}

    if let Ok(x) = Ok::<i32, i32>(42) {
        println!("{}", x);
    }

    match Ok::<i32, i32>(42) {
        Ok(_) => true,
        Err(_) => false,
    };

    match Ok::<i32, i32>(42) {
        Ok(_) => false,
        Err(_) => true,
    };

    match Err::<i32, i32>(42) {
        Ok(_) => false,
        Err(_) => true,
    };

    match Err::<i32, i32>(42) {
        Ok(_) => true,
        Err(_) => false,
    };

    let _ = if let Ok(_) = Ok::<usize, ()>(4) { true } else { false };

    issue5504();
    issue6067();
    issue6065();
    issue10726();

    let _ = if let Ok(_) = gen_res() {
        1
    } else if let Err(_) = gen_res() {
        2
    } else {
        3
    };
}

fn gen_res() -> Result<(), ()> {
    Ok(())
}

macro_rules! m {
    () => {
        Some(42u32)
    };
}

fn issue5504() {
    fn result_opt() -> Result<Option<i32>, i32> {
        Err(42)
    }

    fn try_result_opt() -> Result<i32, i32> {
        while let Some(_) = r#try!(result_opt()) {}
        if let Some(_) = r#try!(result_opt()) {}
        Ok(42)
    }

    try_result_opt();

    if let Some(_) = m!() {}
    while let Some(_) = m!() {}
}

fn issue6065() {
    macro_rules! if_let_in_macro {
        ($pat:pat, $x:expr) => {
            if let Some($pat) = $x {}
        };
    }

    // shouldn't be linted
    if_let_in_macro!(_, Some(42));
}

// Methods that are unstable const should not be suggested within a const context, see issue #5697.
// However, in Rust 1.48.0 the methods `is_ok` and `is_err` of `Result` were stabilized as const,
// so the following should be linted.
const fn issue6067() {
    if let Ok(_) = Ok::<i32, i32>(42) {}

    if let Err(_) = Err::<i32, i32>(42) {}

    while let Ok(_) = Ok::<i32, i32>(10) {}

    while let Err(_) = Ok::<i32, i32>(10) {}

    match Ok::<i32, i32>(42) {
        Ok(_) => true,
        Err(_) => false,
    };

    match Err::<i32, i32>(42) {
        Ok(_) => false,
        Err(_) => true,
    };
}

fn issue10726() {
    // This is optional, but it makes the examples easier
    let x: Result<i32, i32> = Ok(42);

    match x {
        Ok(_) => true,
        _ => false,
    };

    match x {
        Ok(_) => false,
        _ => true,
    };

    match x {
        Err(_) => true,
        _ => false,
    };

    match x {
        Err(_) => false,
        _ => true,
    };

    // Don't lint
    match x {
        Err(16) => false,
        _ => true,
    };

    // Don't lint
    match x {
        Ok(16) => false,
        _ => true,
    };
}