1 files changed, 29 insertions, 0 deletions
diff --git a/tests/ui/rfc-1445-restrict-constants-in-patterns/cant-hide-behind-doubly-indirect-param.rs b/tests/ui/rfc-1445-restrict-constants-in-patterns/cant-hide-behind-doubly-indirect-param.rs
new file mode 100644
index 000000000..1699dae46
--- /dev/null
+++ b/tests/ui/rfc-1445-restrict-constants-in-patterns/cant-hide-behind-doubly-indirect-param.rs
@@ -0,0 +1,29 @@
+// This is part of a set of tests exploring the different ways a
+// structural-match ADT might try to hold a
+// non-structural-match in hidden manner that lets matches
+// through that we had intended to reject.
+//
+// See discussion on rust-lang/rust#62307 and rust-lang/rust#62339
+#![warn(indirect_structural_match)]
+// run-pass
+
+struct NoDerive(#[allow(unused_tuple_struct_fields)] i32);
+
+// This impl makes NoDerive irreflexive.
+impl PartialEq for NoDerive { fn eq(&self, _: &Self) -> bool { false } }
+
+impl Eq for NoDerive { }
+
+#[derive(PartialEq, Eq)]
+struct WrapParam<'a, T>(&'a &'a T);
+
+const WRAP_DOUBLY_INDIRECT_PARAM: & &WrapParam<NoDerive> = & &WrapParam(& & NoDerive(0));
+
+fn main() {
+    match WRAP_DOUBLY_INDIRECT_PARAM {
+        WRAP_DOUBLY_INDIRECT_PARAM => { panic!("WRAP_DOUBLY_INDIRECT_PARAM matched itself"); }
+        //~^ WARN must be annotated with `#[derive(PartialEq, Eq)]`
+        //~| WARN this was previously accepted
+        _ => { println!("WRAP_DOUBLY_INDIRECT_PARAM correctly did not match itself"); }
+    }
+}