src/tools/clippy/tests/ui/needless_question_mark.rs

   1 // run-rustfix
   2
   3 #![warn(clippy::needless_question_mark)]
   4 #![allow(
   5     clippy::needless_return,
   6     clippy::unnecessary_unwrap,
   7     clippy::upper_case_acronyms,
   8     dead_code,
   9     unused_must_use
  10 )]
  11 #![feature(custom_inner_attributes)]
  12
  13 struct TO {
  14     magic: Option<usize>,
  15 }
  16
  17 struct TR {
  18     magic: Result<usize, bool>,
  19 }
  20
  21 fn simple_option_bad1(to: TO) -> Option<usize> {
  22     // return as a statement
  23     return Some(to.magic?);
  24 }
  25
  26 // formatting will add a semi-colon, which would make
  27 // this identical to the test case above
  28 #[rustfmt::skip]
  29 fn simple_option_bad2(to: TO) -> Option<usize> {
  30     // return as an expression
  31     return Some(to.magic?)
  32 }
  33
  34 fn simple_option_bad3(to: TO) -> Option<usize> {
  35     // block value "return"
  36     Some(to.magic?)
  37 }
  38
  39 fn simple_option_bad4(to: Option<TO>) -> Option<usize> {
  40     // single line closure
  41     to.and_then(|t| Some(t.magic?))
  42 }
  43
  44 // formatting this will remove the block brackets, making
  45 // this test identical to the one above
  46 #[rustfmt::skip]
  47 fn simple_option_bad5(to: Option<TO>) -> Option<usize> {
  48     // closure with body
  49     to.and_then(|t| {
  50         Some(t.magic?)
  51     })
  52 }
  53
  54 fn simple_result_bad1(tr: TR) -> Result<usize, bool> {
  55     return Ok(tr.magic?);
  56 }
  57
  58 // formatting will add a semi-colon, which would make
  59 // this identical to the test case above
  60 #[rustfmt::skip]
  61 fn simple_result_bad2(tr: TR) -> Result<usize, bool> {
  62     return Ok(tr.magic?)
  63 }
  64
  65 fn simple_result_bad3(tr: TR) -> Result<usize, bool> {
  66     Ok(tr.magic?)
  67 }
  68
  69 fn simple_result_bad4(tr: Result<TR, bool>) -> Result<usize, bool> {
  70     tr.and_then(|t| Ok(t.magic?))
  71 }
  72
  73 // formatting this will remove the block brackets, making
  74 // this test identical to the one above
  75 #[rustfmt::skip]
  76 fn simple_result_bad5(tr: Result<TR, bool>) -> Result<usize, bool> {
  77     tr.and_then(|t| {
  78         Ok(t.magic?)
  79     })
  80 }
  81
  82 fn also_bad(tr: Result<TR, bool>) -> Result<usize, bool> {
  83     if tr.is_ok() {
  84         let t = tr.unwrap();
  85         return Ok(t.magic?);
  86     }
  87     Err(false)
  88 }
  89
  90 fn false_positive_test<U, T>(x: Result<(), U>) -> Result<(), T>
  91 where
  92     T: From<U>,
  93 {
  94     Ok(x?)
  95 }
  96
  97 fn main() {}
  98
  99 // #6921 if a macro wraps an expr in Some(  ) and the ? is in the macro use,
 100 // the suggestion fails to apply; do not lint
 101 macro_rules! some_in_macro {
 102     ($expr:expr) => {
 103         || -> _ { Some($expr) }()
 104     };
 105 }
 106
 107 pub fn test1() {
 108     let x = Some(3);
 109     let _x = some_in_macro!(x?);
 110 }
 111
 112 // this one is ok because both the ? and the Some are both inside the macro def
 113 macro_rules! some_and_qmark_in_macro {
 114     ($expr:expr) => {
 115         || -> Option<_> { Some(Some($expr)?) }()
 116     };
 117 }
 118
 119 pub fn test2() {
 120     let x = Some(3);
 121     let _x = some_and_qmark_in_macro!(x?);
 122 }