1 files changed, 26 insertions, 0 deletions
diff --git a/tests/rustdoc-ui/normalize-cycle.rs b/tests/rustdoc-ui/normalize-cycle.rs
new file mode 100644
index 00000000000..1ed9ac6bc34
--- /dev/null
+++ b/tests/rustdoc-ui/normalize-cycle.rs
@@ -0,0 +1,26 @@
+// check-pass
+// compile-flags: -Znormalize-docs
+// Regression test for <https://github.com/rust-lang/rust/issues/79459>.
+pub trait Query {}
+
+pub trait AsQuery {
+    type Query;
+}
+
+impl<T: Query> AsQuery for T {
+    type Query = T;
+}
+
+pub trait SelectDsl<Selection> {
+    type Output;
+}
+
+impl<T, Selection> SelectDsl<Selection> for T
+where
+    T: AsQuery,
+    T::Query: SelectDsl<Selection>,
+{
+    type Output = <T::Query as SelectDsl<Selection>>::Output;
+}
+
+pub type Select<Source, Selection> = <Source as SelectDsl<Selection>>::Output;