src/test/ui/associated-type-bounds/trait-alias-impl-trait.rs

   1 // run-pass
   2
   3 #![feature(associated_type_bounds)]
   4 // revisions: min_tait full_tait
   5 #![feature(min_type_alias_impl_trait)]
   6 #![cfg_attr(full_tait, feature(type_alias_impl_trait))]
   7 //[full_tait]~^ WARN incomplete
   8
   9 use std::ops::Add;
  10
  11 trait Tr1 { type As1; fn mk(self) -> Self::As1; }
  12 trait Tr2<'a> { fn tr2(self) -> &'a Self; }
  13
  14 fn assert_copy<T: Copy>(x: T) { let _x = x; let _x = x; }
  15 fn assert_static<T: 'static>(_: T) {}
  16 fn assert_forall_tr2<T: for<'a> Tr2<'a>>(_: T) {}
  17
  18 struct S1;
  19 #[derive(Copy, Clone)]
  20 struct S2;
  21 impl Tr1 for S1 { type As1 = S2; fn mk(self) -> Self::As1 { S2 } }
  22
  23 type Et1 = impl Tr1<As1: Copy>;
  24 fn def_et1() -> Et1 { S1 }
  25 pub fn use_et1() { assert_copy(def_et1().mk()); }
  26
  27 type Et2 = impl Tr1<As1: 'static>;
  28 fn def_et2() -> Et2 { S1 }
  29 pub fn use_et2() { assert_static(def_et2().mk()); }
  30
  31 type Et3 = impl Tr1<As1: Clone + Iterator<Item: Add<u8, Output: Into<u8>>>>;
  32 fn def_et3() -> Et3 {
  33     struct A;
  34     impl Tr1 for A {
  35         type As1 = core::ops::Range<u8>;
  36         fn mk(self) -> Self::As1 { 0..10 }
  37     }
  38     A
  39 }
  40 pub fn use_et3() {
  41     let _0 = def_et3().mk().clone();
  42     let mut s = 0u8;
  43     for _1 in _0 {
  44         let _2 = _1 + 1u8;
  45         s += _2.into();
  46     }
  47     assert_eq!(s, (0..10).map(|x| x + 1).sum());
  48 }
  49
  50 type Et4 = impl Tr1<As1: for<'a> Tr2<'a>>;
  51 fn def_et4() -> Et4 {
  52     #[derive(Copy, Clone)]
  53     struct A;
  54     impl Tr1 for A {
  55         type As1 = A;
  56         fn mk(self) -> A { A }
  57     }
  58     impl<'a> Tr2<'a> for A {
  59         fn tr2(self) -> &'a Self { &A }
  60     }
  61     A
  62 }
  63 pub fn use_et4() { assert_forall_tr2(def_et4().mk()); }
  64
  65 fn main() {
  66     let _ = use_et1();
  67     let _ = use_et2();
  68     let _ = use_et3();
  69     let _ = use_et4();
  70 }