1 files changed, 18 insertions, 0 deletions
diff --git a/tests/ui/traits/trait-upcasting/migrate-lint-deny-regions.rs b/tests/ui/traits/trait-upcasting/migrate-lint-deny-regions.rs
new file mode 100644
index 000000000..da1a9cc27
--- /dev/null
+++ b/tests/ui/traits/trait-upcasting/migrate-lint-deny-regions.rs
@@ -0,0 +1,18 @@
+#![deny(deref_into_dyn_supertrait)]
+
+use std::ops::Deref;
+
+trait Bar<'a> {}
+trait Foo<'a>: Bar<'a> {}
+
+impl<'a> Deref for dyn Foo<'a> {
+    //~^ ERROR this `Deref` implementation is covered by an implicit supertrait coercion
+    //~| WARN this will change its meaning in a future release!
+    type Target = dyn Bar<'a>;
+
+    fn deref(&self) -> &Self::Target {
+        todo!()
+    }
+}
+
+fn main() {}