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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
commit | 698f8c2f01ea549d77d7dc3338a12e04c11057b9 (patch) | |
tree | 173a775858bd501c378080a10dca74132f05bc50 /src/test/ui/impl-trait/region-escape-via-bound-contravariant.rs | |
parent | Initial commit. (diff) | |
download | rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.tar.xz rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.zip |
Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/test/ui/impl-trait/region-escape-via-bound-contravariant.rs')
-rw-r--r-- | src/test/ui/impl-trait/region-escape-via-bound-contravariant.rs | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/src/test/ui/impl-trait/region-escape-via-bound-contravariant.rs b/src/test/ui/impl-trait/region-escape-via-bound-contravariant.rs new file mode 100644 index 000000000..79319dfe7 --- /dev/null +++ b/src/test/ui/impl-trait/region-escape-via-bound-contravariant.rs @@ -0,0 +1,22 @@ +// In contrast to `region-escape-via-bound-invariant`, in this case we +// *can* return a value of type `&'x u32`, even though `'x` does not +// appear in the bounds. This is because `&` is contravariant, and so +// we are *actually* returning a `&'y u32`. +// +// See https://github.com/rust-lang/rust/issues/46541 for more details. + +// run-pass + +#![allow(dead_code)] + +trait Trait<'a> { } + +impl<'a, 'b> Trait<'b> for &'a u32 { } + +fn foo<'x, 'y>(x: &'x u32) -> impl Trait<'y> +where 'x: 'y +{ + x +} + +fn main() { } |