Vendor dependencies

Let's see how I like this workflow.

vendor/pin-project-lite/tests/ui/pin_project/conflict-drop.rs

@@ -0,0 +1,15 @@
+use pin_project_lite::pin_project;
+
+pin_project! { //~ ERROR E0119
+    struct Foo<T, U> {
+        #[pin]
+        future: T,
+        field: U,
+    }
+}
+
+impl<T, U> Drop for Foo<T, U> {
+    fn drop(&mut self) {}
+}
+
+fn main() {}