1 files changed, 18 insertions, 0 deletions
diff --git a/src/test/ui/unsized/issue-75899.rs b/src/test/ui/unsized/issue-75899.rs
new file mode 100644
index 000000000..abff17e11
--- /dev/null
+++ b/src/test/ui/unsized/issue-75899.rs
@@ -0,0 +1,18 @@
+// check-pass
+
+trait Trait {}
+impl<T> Trait for T {}
+
+trait Noop {
+    type Assoc: ?Sized;
+}
+impl<T: ?Sized> Noop for T {
+    type Assoc = T;
+}
+
+struct NoopNewtype<T: ?Sized + Noop>(T::Assoc);
+fn coerce_newtype<T: Trait>(x: &NoopNewtype<T>) -> &NoopNewtype<dyn Trait + '_> {
+    x
+}
+
+fn main() {}