From db3a0e5769a5340b9e9a5c7a6817af335cbe6b67 Mon Sep 17 00:00:00 2001
From: Lucas Sunsi Abreu <lsunsi@proton.me>
Date: Fri, 11 Sep 2026 11:10:35 -0300
Subject: [PATCH] Add regression test for matching associated types on new
 solver

---
 .../associated-types-match-despite-generic.rs | 21 +++++++++++++++++++
 1 file changed, 21 insertions(+)
 create mode 100644 tests/ui/associated-types/associated-types-match-despite-generic.rs

diff --git a/tests/ui/associated-types/associated-types-match-despite-generic.rs b/tests/ui/associated-types/associated-types-match-despite-generic.rs
new file mode 100644
index 0000000000000..04fc374e59a0c
--- /dev/null
+++ b/tests/ui/associated-types/associated-types-match-despite-generic.rs
@@ -0,0 +1,21 @@
+//! Regression test for <https://github.com/rust-lang/trait-system-refactor-initiative/issues/216>.
+//@compile-flags: -Znext-solver=globally
+//@ check-pass
+
+struct Outer;
+struct Inner;
+trait Id<T> {
+    type This;
+}
+impl<T, U> Id<U> for T {
+    type This = T;
+}
+
+fn free<T>(x: T) -> <T as Id<Inner>>::This
+where
+    <T as Id<Outer>>::This: Id<Inner, This = <T as Id<Inner>>::This>,
+{
+    x
+}
+
+fn main() {}