mirror of https://github.com/rust-lang/rust
81 lines
2.0 KiB
Rust
81 lines
2.0 KiB
Rust
//@ run-pass
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trait Foo<const N: usize> {
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fn myfun(&self) -> usize;
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}
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trait Bar<const N: usize> : Foo<N> {}
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trait Baz: Foo<3> {} //~ WARN trait `Baz` is never used
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struct FooType<const N: usize>;
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struct BarType<const N: usize>;
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struct BazType;
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impl<const N: usize> Foo<N> for FooType<N> {
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fn myfun(&self) -> usize { N }
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}
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impl<const N: usize> Foo<N> for BarType<N> {
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fn myfun(&self) -> usize { N + 1 }
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}
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impl<const N: usize> Bar<N> for BarType<N> {}
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impl Foo<3> for BazType {
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fn myfun(&self) -> usize { 999 }
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}
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impl Baz for BazType {}
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trait Foz {}
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trait Boz: Foo<3> + Foz {} //~ WARN trait `Boz` is never used
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trait Bok<const N: usize>: Foo<N> + Foz {}
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struct FozType; //~ WARN struct `FozType` is never constructed
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struct BozType;
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struct BokType<const N: usize>;
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impl Foz for FozType {}
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impl Foz for BozType {}
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impl Foo<3> for BozType {
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fn myfun(&self) -> usize { 9999 }
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}
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impl Boz for BozType {}
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impl<const N: usize> Foz for BokType<N> {}
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impl<const N: usize> Foo<N> for BokType<N> {
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fn myfun(&self) -> usize { N + 2 }
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}
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impl<const N: usize> Bok<N> for BokType<N> {}
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fn a<const N: usize>(x: &dyn Foo<N>) -> usize { x.myfun() }
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fn b(x: &dyn Foo<3>) -> usize { x.myfun() }
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fn c<T: Bok<N>, const N: usize>(x: T) -> usize { a::<N>(&x) }
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fn d<T: ?Sized + Foo<3>>(x: &T) -> usize { x.myfun() }
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fn e(x: &dyn Bar<3>) -> usize { d(x) }
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fn main() {
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let foo = FooType::<3> {};
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assert!(a(&foo) == 3);
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assert!(b(&foo) == 3);
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assert!(d(&foo) == 3);
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let bar = BarType::<3> {};
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assert!(a(&bar) == 4);
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assert!(b(&bar) == 4);
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assert!(d(&bar) == 4);
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assert!(e(&bar) == 4);
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let baz = BazType {};
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assert!(a(&baz) == 999);
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assert!(b(&baz) == 999);
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assert!(d(&baz) == 999);
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let boz = BozType {};
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assert!(a(&boz) == 9999);
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assert!(b(&boz) == 9999);
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assert!(d(&boz) == 9999);
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let bok = BokType::<3> {};
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assert!(a(&bok) == 5);
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assert!(b(&bok) == 5);
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assert!(d(&bok) == 5);
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assert!(c(BokType::<3> {}) == 5);
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}
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