33 lines
835 B
Rust
33 lines
835 B
Rust
// run-pass
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// To work around #46855
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// compile-flags: -Z mir-opt-level=0
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// Regression test for the inhabitedness of unions with uninhabited variants, issue #46845
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use std::mem;
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#[derive(Copy, Clone)]
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enum Never { }
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// A single uninhabited variant shouldn't make the whole union uninhabited.
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union Foo {
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a: u64,
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_b: Never
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}
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// If all the variants are uninhabited, however, the union should be uninhabited.
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// NOTE(#49298) the union being uninhabited shouldn't change its size.
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union Bar {
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_a: (Never, u64),
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_b: (u64, Never)
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}
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fn main() {
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assert_eq!(mem::size_of::<Foo>(), 8);
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// See the note on `Bar`'s definition for why this isn't `0`.
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assert_eq!(mem::size_of::<Bar>(), 8);
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let f = [Foo { a: 42 }, Foo { a: 10 }];
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println!("{}", unsafe { f[0].a });
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assert_eq!(unsafe { f[1].a }, 10);
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}
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