chore: checkpoint before Python removal

vendor/darling/tests/generics.rs

@@ -0,0 +1,23 @@
+#![allow(dead_code)]
+
+use darling::{FromDeriveInput, FromMeta};
+use syn::parse_quote;
+
+#[derive(Debug, Clone, FromMeta)]
+struct Wrapper<T>(pub T);
+
+#[derive(Debug, FromDeriveInput)]
+#[darling(attributes(hello))]
+struct Foo<T> {
+    lorem: Wrapper<T>,
+}
+
+#[test]
+fn expansion() {
+    let di = parse_quote! {
+        #[hello(lorem = "Hello")]
+        pub struct Foo;
+    };
+
+    Foo::<String>::from_derive_input(&di).unwrap();
+}