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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:19:03 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:19:03 +0000 |
commit | 64d98f8ee037282c35007b64c2649055c56af1db (patch) | |
tree | 5492bcf97fce41ee1c0b1cc2add283f3e66cdab0 /tests/ui/type-alias-impl-trait/issue-84660-unsoundness.rs | |
parent | Adding debian version 1.67.1+dfsg1-1. (diff) | |
download | rustc-64d98f8ee037282c35007b64c2649055c56af1db.tar.xz rustc-64d98f8ee037282c35007b64c2649055c56af1db.zip |
Merging upstream version 1.68.2+dfsg1.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'tests/ui/type-alias-impl-trait/issue-84660-unsoundness.rs')
-rw-r--r-- | tests/ui/type-alias-impl-trait/issue-84660-unsoundness.rs | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/tests/ui/type-alias-impl-trait/issue-84660-unsoundness.rs b/tests/ui/type-alias-impl-trait/issue-84660-unsoundness.rs new file mode 100644 index 000000000..48d4b0c96 --- /dev/null +++ b/tests/ui/type-alias-impl-trait/issue-84660-unsoundness.rs @@ -0,0 +1,41 @@ +// Another example from issue #84660, this time weaponized as a safe transmute: an opaque type in an +// impl header being accepted was used to create unsoundness. + +#![feature(type_alias_impl_trait)] + +trait Foo {} +impl Foo for () {} +type Bar = impl Foo; +fn _defining_use() -> Bar {} + +trait Trait<T, In> { + type Out; + fn convert(i: In) -> Self::Out; +} + +impl<In, Out> Trait<Bar, In> for Out { + type Out = Out; + fn convert(_i: In) -> Self::Out { + unreachable!(); + } +} + +impl<In, Out> Trait<(), In> for Out { //~ ERROR conflicting implementations of trait `Trait<Bar, _>` + type Out = In; + fn convert(i: In) -> Self::Out { + i + } +} + +fn transmute<In, Out>(i: In) -> Out { + <Out as Trait<Bar, In>>::convert(i) +} + +fn main() { + let d; + { + let x = "Hello World".to_string(); + d = transmute::<&String, &String>(&x); + } + println!("{}", d); +} |