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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/coherence/coherence-fn-inputs.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/coherence/coherence-fn-inputs.rs')
-rw-r--r-- | tests/ui/coherence/coherence-fn-inputs.rs | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/tests/ui/coherence/coherence-fn-inputs.rs b/tests/ui/coherence/coherence-fn-inputs.rs new file mode 100644 index 000000000..3afec5c54 --- /dev/null +++ b/tests/ui/coherence/coherence-fn-inputs.rs @@ -0,0 +1,25 @@ +// Test that we consider these two types completely equal: +// +// * `for<'a, 'b> fn(&'a u32, &'b u32)` +// * `for<'c> fn(&'c u32, &'c u32)` +// +// For a long time we considered these to be distinct types. But in fact they +// are equivalent, if you work through the implications of subtyping -- this is +// because: +// +// * `'c` can be the intersection of `'a` and `'b` (and there is always an intersection) +// * `'a` and `'b` can both be equal to `'c` + +trait Trait {} +impl Trait for for<'a, 'b> fn(&'a u32, &'b u32) {} +impl Trait for for<'c> fn(&'c u32, &'c u32) { + //~^ ERROR conflicting implementations + // + // Note in particular that we do NOT get a future-compatibility warning + // here. This is because the new leak-check proposed in [MCP 295] does not + // "error" when these two types are equated. + // + // [MCP 295]: https://github.com/rust-lang/compiler-team/issues/295 +} + +fn main() {} |