1 files changed, 20 insertions, 0 deletions
diff --git a/src/test/ui/coherence/coherence-subtyping.rs b/src/test/ui/coherence/coherence-subtyping.rs
new file mode 100644
index 000000000..b3ed728a8
--- /dev/null
+++ b/src/test/ui/coherence/coherence-subtyping.rs
@@ -0,0 +1,20 @@
+// Test that two distinct impls which match subtypes of one another
+// yield coherence errors (or not) depending on the variance.
+//
+// Note: This scenario is currently accepted, but as part of the
+// universe transition (#56105) may eventually become an error.
+
+// check-pass
+
+trait TheTrait {
+    fn foo(&self) {}
+}
+
+impl TheTrait for for<'a, 'b> fn(&'a u8, &'b u8) -> &'a u8 {}
+
+impl TheTrait for for<'a> fn(&'a u8, &'a u8) -> &'a u8 {
+    //~^ WARNING conflicting implementation
+    //~^^ WARNING this was previously accepted by the compiler but is being phased out
+}
+
+fn main() {}