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https://github.com/rust-lang/rust
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27 lines
752 B
Rust
27 lines
752 B
Rust
#![feature(type_alias_impl_trait)]
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#[derive(Clone)]
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struct CopyIfEq<T, U>(T, U);
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impl<T: Copy> Copy for CopyIfEq<T, T> {}
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type E<'a, 'b> = impl Sized;
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fn foo<'a: 'b, 'b, 'c>(x: &'static i32, mut y: &'a i32) -> E<'b, 'c> {
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let v = CopyIfEq::<*mut _, *mut _>(&mut { x }, &mut y);
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// This assignment requires that `x` and `y` have the same type due to the
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// `Copy` impl. The reason why we are using a copy to create a constraint
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// is that only borrow checking (not regionck in type checking) enforces
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// this bound.
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let u = v;
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let _: *mut &'a i32 = u.1;
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unsafe {
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let _: &'b i32 = *u.0;
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}
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u.0
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//~^ ERROR hidden type for `E<'b, 'c>` captures lifetime that does not appear in bounds
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}
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fn main() {}
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