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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/traits/wf-object/no-duplicates.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/traits/wf-object/no-duplicates.rs')
-rw-r--r-- | src/test/ui/traits/wf-object/no-duplicates.rs | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/src/test/ui/traits/wf-object/no-duplicates.rs b/src/test/ui/traits/wf-object/no-duplicates.rs new file mode 100644 index 000000000..678ede582 --- /dev/null +++ b/src/test/ui/traits/wf-object/no-duplicates.rs @@ -0,0 +1,33 @@ +// The purpose of this test is to demonstrate that duplicating object safe traits +// that are not auto-traits is rejected even though one could reasonably accept this. + +// Some arbitrary object-safe trait: +trait Obj {} + +// Demonstrate that recursive expansion of trait aliases doesn't affect stable behavior: +type _0 = dyn Obj + Obj; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +// Some variations: + +type _1 = dyn Send + Obj + Obj; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _2 = dyn Obj + Send + Obj; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _3 = dyn Obj + Send + Send; // But it is OK to duplicate auto traits. + +// Take higher ranked types into account. + +// Note that `'a` and `'b` are intentionally different to make sure we consider +// them semantically the same. +trait ObjL<'l> {} +type _4 = dyn for<'a> ObjL<'a> + for<'b> ObjL<'b>; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +trait ObjT<T> {} +type _5 = dyn ObjT<for<'a> fn(&'a u8)> + ObjT<for<'b> fn(&'b u8)>; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +fn main() {} |