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

   1 // edition:2018
   2 // FIXME: run-rustfix waiting on multi-span suggestions
   3
   4 #![warn(clippy::ref_binding_to_reference)]
   5 #![allow(clippy::needless_borrowed_reference)]
   6
   7 fn f1(_: &str) {}
   8 macro_rules! m2 {
   9     ($e:expr) => {
  10         f1(*$e)
  11     };
  12 }
  13 macro_rules! m3 {
  14     ($i:ident) => {
  15         Some(ref $i)
  16     };
  17 }
  18
  19 #[allow(dead_code)]
  20 fn main() {
  21     let x = String::new();
  22
  23     // Ok, the pattern is from a macro
  24     let _: &&String = match Some(&x) {
  25         m3!(x) => x,
  26         None => return,
  27     };
  28
  29     // Err, reference to a &String
  30     let _: &&String = match Some(&x) {
  31         Some(ref x) => x,
  32         None => return,
  33     };
  34
  35     // Err, reference to a &String
  36     let _: &&String = match Some(&x) {
  37         Some(ref x) => {
  38             f1(x);
  39             f1(*x);
  40             x
  41         },
  42         None => return,
  43     };
  44
  45     // Err, reference to a &String
  46     match Some(&x) {
  47         Some(ref x) => m2!(x),
  48         None => return,
  49     }
  50
  51     // Err, reference to a &String
  52     let _ = |&ref x: &&String| {
  53         let _: &&String = x;
  54     };
  55 }
  56
  57 // Err, reference to a &String
  58 fn f2<'a>(&ref x: &&'a String) -> &'a String {
  59     let _: &&String = x;
  60     *x
  61 }
  62
  63 trait T1 {
  64     // Err, reference to a &String
  65     fn f(&ref x: &&String) {
  66         let _: &&String = x;
  67     }
  68 }
  69
  70 struct S;
  71 impl T1 for S {
  72     // Err, reference to a &String
  73     fn f(&ref x: &&String) {
  74         let _: &&String = x;
  75     }
  76 }