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
|
#![allow(dead_code)]
fn main() {
let _ = (0..4).filter_map(|x| if x > 1 { Some(x) } else { None });
let _ = (0..4).filter_map(|x| {
if x > 1 {
return Some(x);
};
None
});
let _ = (0..4).filter_map(|x| match x {
0 | 1 => None,
_ => Some(x),
});
let _ = (0..4).filter_map(|x| Some(x + 1));
let _ = (0..4).filter_map(i32::checked_abs);
}
fn filter_map_none_changes_item_type() -> impl Iterator<Item = bool> {
"".chars().filter_map(|_| None)
}
// https://github.com/rust-lang/rust-clippy/issues/4433#issue-483920107
mod comment_483920107 {
enum Severity {
Warning,
Other,
}
struct ServerError;
impl ServerError {
fn severity(&self) -> Severity {
Severity::Warning
}
}
struct S {
warnings: Vec<ServerError>,
}
impl S {
fn foo(&mut self, server_errors: Vec<ServerError>) {
#[allow(unused_variables)]
let errors: Vec<ServerError> = server_errors
.into_iter()
.filter_map(|se| match se.severity() {
Severity::Warning => {
self.warnings.push(se);
None
},
_ => Some(se),
})
.collect();
}
}
}
// https://github.com/rust-lang/rust-clippy/issues/4433#issuecomment-611006622
mod comment_611006622 {
struct PendingRequest {
reply_to: u8,
token: u8,
expires: u8,
group_id: u8,
}
enum Value {
Null,
}
struct Node;
impl Node {
fn send_response(&self, _reply_to: u8, _token: u8, _value: Value) -> &Self {
self
}
fn on_error_warn(&self) -> &Self {
self
}
}
struct S {
pending_requests: Vec<PendingRequest>,
}
impl S {
fn foo(&mut self, node: Node, now: u8, group_id: u8) {
// "drain_filter"
self.pending_requests = self
.pending_requests
.drain(..)
.filter_map(|pending| {
if pending.expires <= now {
return None; // Expired, remove
}
if pending.group_id == group_id {
// Matched - reuse strings and remove
node.send_response(pending.reply_to, pending.token, Value::Null)
.on_error_warn();
None
} else {
// Keep waiting
Some(pending)
}
})
.collect();
}
}
}
// https://github.com/rust-lang/rust-clippy/issues/4433#issuecomment-621925270
// This extrapolation doesn't reproduce the false positive. Additional context seems necessary.
mod comment_621925270 {
struct Signature(u8);
fn foo(sig_packets: impl Iterator<Item = Result<Signature, ()>>) -> impl Iterator<Item = u8> {
sig_packets.filter_map(|res| match res {
Ok(Signature(sig_packet)) => Some(sig_packet),
_ => None,
})
}
}
// https://github.com/rust-lang/rust-clippy/issues/4433#issuecomment-1052978898
mod comment_1052978898 {
#![allow(clippy::redundant_closure)]
pub struct S(u8);
impl S {
pub fn consume(self) {
println!("yum");
}
}
pub fn filter_owned() -> impl Iterator<Item = S> {
(0..10).map(|i| S(i)).filter_map(|s| {
if s.0 & 1 == 0 {
s.consume();
None
} else {
Some(s)
}
})
}
}
|
