Vendor dependencies

Let's see how I like this workflow.

vendor/pin-project-lite/tests/ui/pin_project/invalid.rs

@@ -0,0 +1,25 @@
+use pin_project_lite::pin_project;
+
+pin_project! {
+    struct A<T> {
+        #[pin()] //~ ERROR no rules expected the token `(`
+        pinned: T,
+    }
+}
+
+pin_project! {
+    #[pin] //~ ERROR cannot find attribute `pin` in this scope
+    struct B<T> {
+        pinned: T,
+    }
+}
+
+pin_project! {
+    struct C<T> {
+        #[pin]
+        #[pin] //~ ERROR no rules expected the token `#`
+        pinned: T,
+    }
+}
+
+fn main() {}