1 files changed, 30 insertions, 0 deletions
diff --git a/src/test/ui/coherence/coherence-impl-trait-for-marker-trait-negative.rs b/src/test/ui/coherence/coherence-impl-trait-for-marker-trait-negative.rs
new file mode 100644
index 000000000..50d9a480a
--- /dev/null
+++ b/src/test/ui/coherence/coherence-impl-trait-for-marker-trait-negative.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.
+
+// Negative 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.
+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.
+impl !Send for dyn Object {} //~ ERROR E0321
+impl !Send for dyn Object + Marker2 {} //~ ERROR E0321
+
+fn main() { }