Vendor dependencies

Let's see how I like this workflow.

vendor/pin-project-lite/tests/ui/pinned_drop/conditional-drop-impl.rs

@@ -0,0 +1,26 @@
+use pin_project_lite::pin_project;
+
+// In `Drop` impl, the implementor must specify the same requirement as type definition.
+
+struct DropImpl<T> {
+    f: T,
+}
+
+impl<T: Unpin> Drop for DropImpl<T> {
+    //~^ ERROR E0367
+    fn drop(&mut self) {}
+}
+
+pin_project! {
+    //~^ ERROR E0367
+    struct PinnedDropImpl<T> {
+        #[pin]
+        f: T,
+    }
+
+    impl<T: Unpin> PinnedDrop for PinnedDropImpl<T> {
+        fn drop(_this: Pin<&mut Self>) {}
+    }
+}
+
+fn main() {}