1 files changed, 25 insertions, 0 deletions
diff --git a/tests/ui/traits/next-solver/coherence/trait_ref_is_knowable-normalization-2.rs b/tests/ui/traits/next-solver/coherence/trait_ref_is_knowable-normalization-2.rs
new file mode 100644
index 000000000..d16f9d22c
--- /dev/null
+++ b/tests/ui/traits/next-solver/coherence/trait_ref_is_knowable-normalization-2.rs
@@ -0,0 +1,25 @@
+// compile-flags: -Znext-solver
+// check-pass
+
+use std::future::{Future, IntoFuture};
+use std::pin::Pin;
+
+// We check that this does not overlap with the following impl from std:
+//     impl<P> Future for Pin<P> where P: DerefMut, <P as Deref>::Target: Future { .. }
+// This should fail because we know ` <&mut Value as Deref>::Target: Future` not to hold.
+// For this to work we have to normalize in the `trait_ref_is_knowable` check as we
+// otherwise add an ambiguous candidate here.
+//
+// See https://github.com/rust-lang/trait-system-refactor-initiative/issues/51
+// for more details.
+struct Value;
+impl<'a> IntoFuture for Pin<&'a mut Value> {
+    type Output = ();
+    type IntoFuture = Pin<Box<dyn Future<Output = ()> + Send>>;
+
+    fn into_future(self) -> Self::IntoFuture {
+        todo!()
+    }
+}
+
+fn main() {}