src/test/ui/lint/issue-54538-unused-parens-lint.fixed

   1 // run-rustfix
   2
   3 #![feature(box_patterns, stmt_expr_attributes)]
   4 #![feature(or_patterns)]
   5
   6 #![allow(
   7     dead_code,
   8     ellipsis_inclusive_range_patterns,
   9     irrefutable_let_patterns,
  10     unreachable_patterns,
  11     unused_mut,
  12     unused_variables
  13 )]
  14 #![deny(unused_parens)]
  15
  16 fn lint_on_top_level() {
  17     let a = 0; //~ ERROR unnecessary parentheses around pattern
  18     for a in 0..1 {} //~ ERROR unnecessary parentheses around pattern
  19     if let a = 0 {} //~ ERROR unnecessary parentheses around pattern
  20     while let a = 0 {} //~ ERROR unnecessary parentheses around pattern
  21     fn foo(a: u8) {} //~ ERROR unnecessary parentheses around pattern
  22     let _ = |a: u8| 0; //~ ERROR unnecessary parentheses around pattern
  23 }
  24
  25 fn _no_lint_attr() {
  26     let _x = #[allow(dead_code)] (1 + 2);
  27 }
  28
  29 // Don't lint in these cases (#64106).
  30 fn or_patterns_no_lint() {
  31     match Box::new(0) {
  32         box (0 | 1) => {} // Should not lint as `box 0 | 1` binds as `(box 0) | 1`.
  33         _ => {}
  34     }
  35
  36     match 0 {
  37         x @ (0 | 1) => {} // Should not lint as `x @ 0 | 1` binds as `(x @ 0) | 1`.
  38         _ => {}
  39     }
  40
  41     if let &(0 | 1) = &0 {} // Should also not lint.
  42     if let &mut (0 | 1) = &mut 0 {} // Same.
  43
  44     fn foo((Ok(a) | Err(a)): Result<u8, u8>) {} // Doesn't parse if we remove parens for now.
  45
  46     let _ = |(Ok(a) | Err(a)): Result<u8, u8>| 1; // `|Ok(a) | Err(a)| 1` parses as bit-or.
  47 }
  48
  49 fn or_patterns_will_lint() {
  50     if let 0 | 1 = 0 {} //~ ERROR unnecessary parentheses around pattern
  51     if let (0 | 1,) = (0,) {} //~ ERROR unnecessary parentheses around pattern
  52     if let [0 | 1] = [0] {} //~ ERROR unnecessary parentheses around pattern
  53     if let 0 | 1 | 2 = 0 {} //~ ERROR unnecessary parentheses around pattern
  54     struct TS(u8);
  55     if let TS(0 | 1) = TS(0) {} //~ ERROR unnecessary parentheses around pattern
  56     struct NS { f: u8 }
  57     if let NS { f: 0 | 1 } = (NS { f: 0 }) {} //~ ERROR unnecessary parentheses around pattern
  58 }
  59
  60 // Don't lint on `&(mut x)` because `&mut x` means something else (#55342).
  61 fn deref_mut_binding_no_lint() {
  62     let &(mut x) = &0;
  63 }
  64
  65 fn main() {
  66     match 1 {
  67         _ => {} //~ ERROR unnecessary parentheses around pattern
  68         y => {} //~ ERROR unnecessary parentheses around pattern
  69         ref r => {} //~ ERROR unnecessary parentheses around pattern
  70         e @ 1...2 => {} //~ ERROR unnecessary parentheses around pattern
  71         (1...2) => {} // Non ambiguous range pattern should not warn
  72         e @ (3...4) => {} // Non ambiguous range pattern should not warn
  73     }
  74
  75     match &1 {
  76         e @ &(1...2) => {} //~ ERROR unnecessary parentheses around pattern
  77         &_ => {} //~ ERROR unnecessary parentheses around pattern
  78         e @ &(1...2) => {} // Ambiguous range pattern should not warn
  79         &(1...2) => {} // Ambiguous range pattern should not warn
  80     }
  81
  82     match &1 {
  83         e @ &(1...2) | e @ &(3...4) => {} // Complex ambiguous pattern should not warn
  84         &_ => {}
  85     }
  86
  87     match 1 {
  88         _ => {} //~ ERROR unnecessary parentheses around pattern
  89         y => {} //~ ERROR unnecessary parentheses around pattern
  90         ref r => {} //~ ERROR unnecessary parentheses around pattern
  91         e @ 1..=2 => {} //~ ERROR unnecessary parentheses around pattern
  92         (1..=2) => {} // Non ambiguous range pattern should not warn
  93         e @ (3..=4) => {} // Non ambiguous range pattern should not warn
  94     }
  95
  96     match &1 {
  97         e @ &(1..=2) => {} //~ ERROR unnecessary parentheses around pattern
  98         &_ => {} //~ ERROR unnecessary parentheses around pattern
  99         e @ &(1..=2) => {} // Ambiguous range pattern should not warn
 100         &(1..=2) => {} // Ambiguous range pattern should not warn
 101     }
 102
 103     match &1 {
 104         e @ &(1..=2) | e @ &(3..=4) => {} // Complex ambiguous pattern should not warn
 105         &_ => {}
 106     }
 107 }