mirror of https://github.com/rust-lang/rust
63 lines
1.4 KiB
Rust
63 lines
1.4 KiB
Rust
//@ run-pass
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use std::ops::Add;
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trait Tr1 { type As1; fn mk(self) -> Self::As1; }
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trait Tr2<'a> { fn tr2(self) -> &'a Self; } //~ WARN method `tr2` is never used
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fn assert_copy<T: Copy>(x: T) { let _x = x; let _x = x; }
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fn assert_static<T: 'static>(_: T) {}
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fn assert_forall_tr2<T: for<'a> Tr2<'a>>(_: T) {}
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struct S1;
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#[derive(Copy, Clone)]
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struct S2;
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impl Tr1 for S1 { type As1 = S2; fn mk(self) -> Self::As1 { S2 } }
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fn def_et1() -> impl Tr1<As1: Copy> { S1 }
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pub fn use_et1() { assert_copy(def_et1().mk()); }
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fn def_et2() -> impl Tr1<As1: 'static> { S1 }
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pub fn use_et2() { assert_static(def_et2().mk()); }
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fn def_et3() -> impl Tr1<As1: Clone + Iterator<Item: Add<u8, Output: Into<u8>>>> {
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struct A;
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impl Tr1 for A {
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type As1 = core::ops::Range<u8>;
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fn mk(self) -> Self::As1 { 0..10 }
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}
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A
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}
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pub fn use_et3() {
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let _0 = def_et3().mk().clone();
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let mut s = 0u8;
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for _1 in _0 {
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let _2 = _1 + 1u8;
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s += _2.into();
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}
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assert_eq!(s, (0..10).map(|x| x + 1).sum());
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}
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fn def_et4() -> impl Tr1<As1: for<'a> Tr2<'a>> {
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#[derive(Copy, Clone)]
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struct A;
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impl Tr1 for A {
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type As1 = A;
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fn mk(self) -> A { A }
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}
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impl<'a> Tr2<'a> for A {
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fn tr2(self) -> &'a Self { &A }
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}
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A
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}
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pub fn use_et4() { assert_forall_tr2(def_et4().mk()); }
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fn main() {
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use_et1();
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use_et2();
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use_et3();
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use_et4();
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}
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