1use proc_macro::TokenStream;
 2use quote::quote;
 3use syn::{DeriveInput, parse_macro_input};
 4
 5pub fn derive_register_component(input: TokenStream) -> TokenStream {
 6    let input = parse_macro_input!(input as DeriveInput);
 7
 8    let name = input.ident;
 9    let register_fn_name = syn::Ident::new(
10        &format!("__component_registry_internal_register_{}", name),
11        name.span(),
12    );
13    let expanded = quote! {
14        const _: () = {
15            struct AssertComponent<T: component::Component>(::std::marker::PhantomData<T>);
16            let _ = AssertComponent::<#name>(::std::marker::PhantomData);
17        };
18
19        #[allow(non_snake_case)]
20        fn #register_fn_name() {
21            component::register_component::<#name>();
22        }
23
24        component::__private::inventory::submit! {
25            component::ComponentFn::new(#register_fn_name)
26        }
27    };
28    expanded.into()
29}