diff options
Diffstat (limited to 'src/test/ui/coherence/coherence-impl-trait-for-marker-trait-positive.rs')
-rw-r--r-- | src/test/ui/coherence/coherence-impl-trait-for-marker-trait-positive.rs | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/src/test/ui/coherence/coherence-impl-trait-for-marker-trait-positive.rs b/src/test/ui/coherence/coherence-impl-trait-for-marker-trait-positive.rs new file mode 100644 index 000000000..faac6d983 --- /dev/null +++ b/src/test/ui/coherence/coherence-impl-trait-for-marker-trait-positive.rs @@ -0,0 +1,30 @@ +#![feature(auto_traits)] +#![feature(negative_impls)] + +// Test for issue #56934 - that it is impossible to redundantly +// implement an auto-trait for a trait object type that contains it. + +// Positive impl variant. + +auto trait Marker1 {} +auto trait Marker2 {} + +trait Object: Marker1 {} + +// A supertrait marker is illegal... +impl Marker1 for dyn Object + Marker2 { } //~ ERROR E0371 +// ...and also a direct component. +impl Marker2 for dyn Object + Marker2 { } //~ ERROR E0371 + +// But implementing a marker if it is not present is OK. +impl Marker2 for dyn Object {} // OK + +// A non-principal trait-object type is orphan even in its crate. +unsafe impl Send for dyn Marker2 {} //~ ERROR E0117 + +// And impl'ing a remote marker for a local trait object is forbidden +// by one of these special orphan-like rules. +unsafe impl Send for dyn Object {} //~ ERROR E0321 +unsafe impl Send for dyn Object + Marker2 {} //~ ERROR E0321 + +fn main() { } |