src/test/ui/generator/yielding-in-match-guards.rs

   1 // build-pass
   2 // edition:2018
   3
   4 // This test is derived from
   5 // https://github.com/rust-lang/rust/issues/72651#issuecomment-668720468
   6
   7 // This test demonstrates that, in `async fn g()`,
   8 // indeed a temporary borrow `y` from `x` is live
   9 // while `f().await` is being evaluated.
  10 // Thus, `&'_ u8` should be included in type signature
  11 // of the underlying generator.
  12
  13 async fn f() -> u8 { 1 }
  14 async fn foo() -> [bool; 10] { [false; 10] }
  15
  16 pub async fn g(x: u8) {
  17     match x {
  18         y if f().await == y => (),
  19         _ => (),
  20     }
  21 }
  22
  23 // #78366: check the reference to the binding is recorded even if the binding is not autorefed
  24
  25 async fn h(x: usize) {
  26     match x {
  27         y if foo().await[y] => (),
  28         _ => (),
  29     }
  30 }
  31
  32 async fn i(x: u8) {
  33     match x {
  34         y if f().await == y + 1 => (),
  35         _ => (),
  36     }
  37 }
  38
  39 fn main() {
  40     let _ = g(10);
  41     let _ = h(9);
  42     let _ = i(8);
  43 }