diff options
Diffstat (limited to '')
-rw-r--r-- | src/test/ui/issues/issue-46845.rs | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/src/test/ui/issues/issue-46845.rs b/src/test/ui/issues/issue-46845.rs new file mode 100644 index 000000000..fc85b2551 --- /dev/null +++ b/src/test/ui/issues/issue-46845.rs @@ -0,0 +1,32 @@ +// run-pass +// To work around #46855 +// compile-flags: -Z mir-opt-level=0 +// Regression test for the inhabitedness of unions with uninhabited variants, issue #46845 + +use std::mem; + +#[derive(Copy, Clone)] +enum Never { } + +// A single uninhabited variant shouldn't make the whole union uninhabited. +union Foo { + a: u64, + _b: Never +} + +// If all the variants are uninhabited, however, the union should be uninhabited. +// NOTE(#49298) the union being uninhabited shouldn't change its size. +union Bar { + _a: (Never, u64), + _b: (u64, Never) +} + +fn main() { + assert_eq!(mem::size_of::<Foo>(), 8); + // See the note on `Bar`'s definition for why this isn't `0`. + assert_eq!(mem::size_of::<Bar>(), 8); + + let f = [Foo { a: 42 }, Foo { a: 10 }]; + println!("{}", unsafe { f[0].a }); + assert_eq!(unsafe { f[1].a }, 10); +} |