Merging upstream version 1.76.0+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 36 insertions, 0 deletions

diff --git a/tests/ui/traits/next-solver/cycles/inductive-cycle-discarded-coinductive-constraints.rs b/tests/ui/traits/next-solver/cycles/inductive-cycle-discarded-coinductive-constraints.rs
new file mode 100644
index 000000000..a32f7a13a
--- /dev/null
+++ b/tests/ui/traits/next-solver/cycles/inductive-cycle-discarded-coinductive-constraints.rs
@@ -0,0 +1,36 @@
+// check-pass
+// compile-flags: -Znext-solver
+#![feature(rustc_attrs, marker_trait_attr)]
+#[rustc_coinductive]
+trait Trait {}
+
+impl<T, U> Trait for (T, U)
+where
+    (U, T): Trait,
+    (T, U): Inductive,
+    (): ConstrainToU32<T>,
+{}
+
+trait ConstrainToU32<T> {}
+impl ConstrainToU32<u32> for () {}
+
+// We only prefer the candidate without an inductive cycle
+// once the inductive cycle has the same constraints as the
+// other goal.
+#[marker]
+trait Inductive {}
+impl<T, U> Inductive for (T, U)
+where
+    (T, U): Trait,
+{}
+
+impl Inductive for (u32, u32) {}
+
+fn impls_trait<T, U>()
+where
+    (T, U): Trait,
+{}
+
+fn main() {
+    impls_trait::<_, _>();
+}