From 56dbeeb5ac05d8e34983db20453d72bdeb222cbe Mon Sep 17 00:00:00 2001
From: Michael Goulet <michael@errs.io>
Date: Sun, 31 Mar 2024 21:03:59 -0400
Subject: [PATCH] Add regression tests for 123303

---
 .../traits/stack-error-order-dependence-2.rs  | 24 +++++++++++++++++++
 .../ui/traits/stack-error-order-dependence.rs | 19 +++++++++++++++
 2 files changed, 43 insertions(+)
 create mode 100644 tests/ui/traits/stack-error-order-dependence-2.rs
 create mode 100644 tests/ui/traits/stack-error-order-dependence.rs

diff --git a/tests/ui/traits/stack-error-order-dependence-2.rs b/tests/ui/traits/stack-error-order-dependence-2.rs
new file mode 100644
index 000000000000..323685aa15bb
--- /dev/null
+++ b/tests/ui/traits/stack-error-order-dependence-2.rs
@@ -0,0 +1,24 @@
+//@ check-pass
+// Regression test for <https://github.com/rust-lang/rust/issues/123303>.
+// This time EXCEPT without `dyn` builtin bounds :^)
+
+pub trait Trait: Supertrait {}
+
+trait Impossible {}
+impl<F: ?Sized + Impossible> Trait for F {}
+
+pub trait Supertrait {}
+
+impl<T: ?Sized + Trait + Impossible> Supertrait for T {}
+
+fn needs_supertrait<T: ?Sized + Supertrait>() {}
+fn needs_trait<T: ?Sized + Trait>() {}
+
+struct A;
+impl Trait for A where A: Supertrait {}
+impl Supertrait for A {}
+
+fn main() {
+    needs_supertrait::<A>();
+    needs_trait::<A>();
+}
diff --git a/tests/ui/traits/stack-error-order-dependence.rs b/tests/ui/traits/stack-error-order-dependence.rs
new file mode 100644
index 000000000000..037c292a542d
--- /dev/null
+++ b/tests/ui/traits/stack-error-order-dependence.rs
@@ -0,0 +1,19 @@
+//@ check-pass
+// Regression test for <https://github.com/rust-lang/rust/issues/123303>.
+
+pub trait Trait: Supertrait {}
+
+trait Impossible {}
+impl<F: ?Sized + Impossible> Trait for F {}
+
+pub trait Supertrait {}
+
+impl<T: ?Sized + Trait + Impossible> Supertrait for T {}
+
+fn needs_supertrait<T: ?Sized + Supertrait>() {}
+fn needs_trait<T: ?Sized + Trait>() {}
+
+fn main() {
+    needs_supertrait::<dyn Trait>();
+    needs_trait::<dyn Trait>();
+}