Automatically generate drop for #[metatype]

crates/luaffi_impl/src/lib.rs

@@ -1,3 +1,4 @@
+use darling::{FromMeta, ast::NestedMeta};
 use proc_macro::TokenStream as TokenStream1;
 use quote::ToTokens;
 use syn::parse_macro_input;
@@ -8,7 +9,9 @@ mod utils;
 
 #[proc_macro_attribute]
 pub fn cdef(args: TokenStream1, input: TokenStream1) -> TokenStream1 {
-    cdef::transform(parse_macro_input!(input))
+    NestedMeta::parse_meta_list(args.into())
+        .and_then(|meta| cdef::Args::from_list(&meta).map_err(Into::into))
+        .and_then(|args| cdef::transform(args, syn::parse(input)?))
         .unwrap_or_else(|err| err.into_compile_error().into_token_stream())
         .into()
 }