1 // Copyright 2014-2018 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution.
4 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
5 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
6 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
7 // option. This file may not be copied, modified, or distributed
8 // except according to those terms.
10 #![feature(never_type)]
11 #![warn(clippy::result_map_unit_fn)]
14 fn do_nothing<T>(_: T) {}
16 fn diverge<T>(_: T) -> ! {
20 fn plus_one(value: usize) -> usize {
25 field: Result<usize, usize>,
29 fn do_result_nothing(self: &Self, value: usize) {}
31 fn do_result_plus_one(self: &Self, value: usize) -> usize {
37 fn result_map_unit_fn() {
38 let x = HasResult { field: Ok(10) };
40 x.field.map(plus_one);
41 let _: Result<(), usize> = x.field.map(do_nothing);
43 x.field.map(do_nothing);
45 x.field.map(do_nothing);
50 if let Ok(value) = x.field { do_nothing(value + captured) };
51 let _: Result<(), usize> = x.field.map(|value| do_nothing(value + captured));
53 x.field.map(|value| x.do_result_nothing(value + captured));
55 x.field.map(|value| { x.do_result_plus_one(value + captured); });
58 x.field.map(|value| do_nothing(value + captured));
60 x.field.map(|value| { do_nothing(value + captured) });
62 x.field.map(|value| { do_nothing(value + captured); });
64 x.field.map(|value| { { do_nothing(value + captured); } });
67 x.field.map(|value| diverge(value + captured));
69 x.field.map(|value| { diverge(value + captured) });
71 x.field.map(|value| { diverge(value + captured); });
73 x.field.map(|value| { { diverge(value + captured); } });
76 x.field.map(|value| plus_one(value + captured));
77 x.field.map(|value| { plus_one(value + captured) });
78 x.field.map(|value| { let y = plus_one(value + captured); });
80 x.field.map(|value| { plus_one(value + captured); });
82 x.field.map(|value| { { plus_one(value + captured); } });
85 x.field.map(|ref value| { do_nothing(value + captured) });
88 x.field.map(|value| { do_nothing(value); do_nothing(value) });
90 x.field.map(|value| if value > 0 { do_nothing(value); do_nothing(value) });
92 // Suggestion for the let block should be `{ ... }` as it's too difficult to build a
93 // proper suggestion for these cases
98 x.field.map(|value| { do_nothing(value); do_nothing(value); });
100 // The following should suggest `if let Ok(_X) ...` as it's difficult to generate a proper let variable name for them
101 let res: Result<!, usize> = Ok(42).map(diverge);
102 "12".parse::<i32>().map(diverge);
104 let res: Result<(), usize> = Ok(plus_one(1)).map(do_nothing);
106 // Should suggest `if let Ok(_y) ...` to not override the existing foo variable
107 let y: Result<usize, usize> = Ok(42);