1 files changed, 56 insertions, 0 deletions
diff --git a/src/test/ui/inference/type-infer-generalize-ty-var.rs b/src/test/ui/inference/type-infer-generalize-ty-var.rs
new file mode 100644
index 000000000..a3d6916cb
--- /dev/null
+++ b/src/test/ui/inference/type-infer-generalize-ty-var.rs
@@ -0,0 +1,56 @@
+// run-pass
+
+#![allow(non_upper_case_globals)]
+#![allow(dead_code)]
+#![allow(unused_assignments)]
+#![allow(unused_variables)]
+// Test a scenario where we generate a constraint like `?1 <: &?2`.
+// In such a case, it is important that we instantiate `?1` with `&?3`
+// where `?3 <: ?2`, and not with `&?2`. This is a regression test for
+// #18653. The important thing is that we build.
+
+use std::cell::RefCell;
+
+enum Wrap<A> {
+    WrapSome(A),
+    WrapNone
+}
+
+use Wrap::*;
+
+struct T;
+struct U;
+
+trait Get<T: ?Sized> {
+    fn get(&self) -> &T;
+}
+
+impl Get<dyn MyShow + 'static> for Wrap<T> {
+    fn get(&self) -> &(dyn MyShow + 'static) {
+        static x: usize = 42;
+        &x
+    }
+}
+
+impl Get<usize> for Wrap<U> {
+    fn get(&self) -> &usize {
+        static x: usize = 55;
+        &x
+    }
+}
+
+trait MyShow { fn dummy(&self) { } }
+impl<'a> MyShow for &'a (dyn MyShow + 'a) { }
+impl MyShow for usize { }
+fn constrain<'a>(rc: RefCell<&'a (dyn MyShow + 'a)>) { }
+
+fn main() {
+    let mut collection: Wrap<_> = WrapNone;
+
+    {
+        let __arg0 = Get::get(&collection);
+        let __args_cell = RefCell::new(__arg0);
+        constrain(__args_cell);
+    }
+    collection = WrapSome(T);
+}