1 files changed, 29 insertions, 0 deletions
diff --git a/src/test/ui/traits/pointee-tail-is-generic.rs b/src/test/ui/traits/pointee-tail-is-generic.rs
new file mode 100644
index 000000000..e0da0fc38
--- /dev/null
+++ b/src/test/ui/traits/pointee-tail-is-generic.rs
@@ -0,0 +1,29 @@
+// check-pass
+// edition:2018
+
+#![feature(ptr_metadata)]
+#![feature(type_alias_impl_trait)]
+
+type Opaque = impl std::future::Future;
+
+fn opaque() -> Opaque {
+    async {}
+}
+
+fn a<T>() {
+    // type parameter T is known to be sized
+    is_thin::<T>();
+    // tail of ADT (which is a type param) is known to be sized
+    is_thin::<std::cell::Cell<T>>();
+    // opaque type is known to be sized
+    is_thin::<Opaque>();
+}
+
+fn a2<T: Iterator>() {
+    // associated type is known to be sized
+    is_thin::<T::Item>();
+}
+
+fn is_thin<T: std::ptr::Pointee<Metadata = ()>>() {}
+
+fn main() {}