1 #![feature(never_type)]
2 #![warn(result_map_unit_fn)]
5 fn do_nothing<T>(_: T) {}
7 fn diverge<T>(_: T) -> ! {
11 fn plus_one(value: usize) -> usize {
16 field: Result<usize, usize>,
20 fn do_result_nothing(self: &Self, value: usize) {}
22 fn do_result_plus_one(self: &Self, value: usize) -> usize {
27 fn result_map_unit_fn() {
28 let x = HasResult { field: Ok(10) };
30 x.field.map(plus_one);
31 let _ : Result<(), usize> = x.field.map(do_nothing);
33 x.field.map(do_nothing);
35 x.field.map(do_nothing);
40 if let Ok(value) = x.field { do_nothing(value + captured) };
41 let _ : Result<(), usize> = x.field.map(|value| do_nothing(value + captured));
43 x.field.map(|value| x.do_result_nothing(value + captured));
45 x.field.map(|value| { x.do_result_plus_one(value + captured); });
48 x.field.map(|value| do_nothing(value + captured));
50 x.field.map(|value| { do_nothing(value + captured) });
52 x.field.map(|value| { do_nothing(value + captured); });
54 x.field.map(|value| { { do_nothing(value + captured); } });
57 x.field.map(|value| diverge(value + captured));
59 x.field.map(|value| { diverge(value + captured) });
61 x.field.map(|value| { diverge(value + captured); });
63 x.field.map(|value| { { diverge(value + captured); } });
66 x.field.map(|value| plus_one(value + captured));
67 x.field.map(|value| { plus_one(value + captured) });
68 x.field.map(|value| { let y = plus_one(value + captured); });
70 x.field.map(|value| { plus_one(value + captured); });
72 x.field.map(|value| { { plus_one(value + captured); } });
75 x.field.map(|ref value| { do_nothing(value + captured) });
78 x.field.map(|value| { do_nothing(value); do_nothing(value) });
80 x.field.map(|value| if value > 0 { do_nothing(value); do_nothing(value) });
82 // Suggestion for the let block should be `{ ... }` as it's too difficult to build a
83 // proper suggestion for these cases
88 x.field.map(|value| { do_nothing(value); do_nothing(value); });
90 // The following should suggest `if let Ok(_X) ...` as it's difficult to generate a proper let variable name for them
91 let res: Result<!, usize> = Ok(42).map(diverge);
92 "12".parse::<i32>().map(diverge);
94 let res: Result<(), usize> = Ok(plus_one(1)).map(do_nothing);
96 // Should suggest `if let Ok(_y) ...` to not override the existing foo variable
97 let y: Result<usize, usize> = Ok(42);