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 {
36 fn result_map_unit_fn() {
37 let x = HasResult { field: Ok(10) };
39 x.field.map(plus_one);
40 let _: Result<(), usize> = x.field.map(do_nothing);
42 x.field.map(do_nothing);
44 x.field.map(do_nothing);
49 if let Ok(value) = x.field {
50 do_nothing(value + captured)
52 let _: Result<(), usize> = x.field.map(|value| do_nothing(value + captured));
54 x.field.map(|value| x.do_result_nothing(value + captured));
57 x.do_result_plus_one(value + captured);
60 x.field.map(|value| do_nothing(value + captured));
62 x.field.map(|value| do_nothing(value + captured));
65 do_nothing(value + captured);
69 do_nothing(value + captured);
72 x.field.map(|value| diverge(value + captured));
74 x.field.map(|value| diverge(value + captured));
77 diverge(value + captured);
81 diverge(value + captured);
84 x.field.map(|value| plus_one(value + captured));
85 x.field.map(|value| plus_one(value + captured));
87 let y = plus_one(value + captured);
91 plus_one(value + captured);
95 plus_one(value + captured);
98 x.field.map(|ref value| do_nothing(value + captured));
100 x.field.map(|value| {
105 x.field.map(|value| {
112 // Suggestion for the let block should be `{ ... }` as it's too difficult to build a
113 // proper suggestion for these cases
114 x.field.map(|value| {
118 x.field.map(|value| {
123 // The following should suggest `if let Ok(_X) ...` as it's difficult to generate a proper let
124 // variable name for them
125 let res: Result<!, usize> = Ok(42).map(diverge);
126 "12".parse::<i32>().map(diverge);
128 let res: Result<(), usize> = Ok(plus_one(1)).map(do_nothing);
130 // Should suggest `if let Ok(_y) ...` to not override the existing foo variable
131 let y: Result<usize, usize> = Ok(42);