src/test/ui/associated-types/associated-types-stream.rs

   1 // run-pass
   2 // Test references to the trait `Stream` in the bounds for associated
   3 // types defined on `Stream`. Issue #20551.
   4 // ignore-compare-mode-chalk
   5
   6
   7 trait Stream {
   8     type Car;
   9     type Cdr: Stream;
  10
  11     fn car(&self) -> Self::Car;
  12     fn cdr(self) -> Self::Cdr;
  13 }
  14
  15 impl Stream for () {
  16     type Car = ();
  17     type Cdr = ();
  18     fn car(&self) -> () { () }
  19     fn cdr(self) -> () { self }
  20 }
  21
  22 impl<T,U> Stream for (T, U)
  23     where T : Clone, U : Stream
  24 {
  25     type Car = T;
  26     type Cdr = U;
  27     fn car(&self) -> T { self.0.clone() }
  28     fn cdr(self) -> U { self.1 }
  29 }
  30
  31 fn main() {
  32     let p = (22, (44, (66, ())));
  33     assert_eq!(p.car(), 22);
  34
  35     let p = p.cdr();
  36     assert_eq!(p.car(), 44);
  37
  38     let p = p.cdr();
  39     assert_eq!(p.car(), 66);
  40 }