Let #[autoimpl(Default)] support #[cfg] on fields

Author: dhardy

lib/src/autoimpl/impl_misc.rs

@@ -302,25 +302,37 @@ impl ImplTrait for ImplDefault {
 
     fn struct_items(&self, item: &ItemStruct, _: &ImplArgs) -> Result<(Toks, Toks)> {
         let type_ident = &item.ident;
-        let mut inner;
-        match &item.fields {
+        let inner = match &item.fields {
             Fields::Named(fields) => {
-                inner = quote! {};
+                let mut toks = Toks::new();
                 for field in fields.named.iter() {
+                    for attr in &field.attrs {
+                        if attr.path().get_ident().is_some_and(|path| path == "cfg") {
+                            attr.to_tokens(&mut toks);
+                        }
+                    }
+
                     let ident = field.ident.as_ref().unwrap();
-                    inner.append_all(quote! { #ident: Default::default(), });
+                    toks.append_all(quote! { #ident: Default::default(), });
                 }
-                inner = quote! { #type_ident { #inner } };
+                quote! { #type_ident { #toks } }
             }
             Fields::Unnamed(fields) => {
-                inner = quote! {};
-                for _ in 0..fields.unnamed.len() {
-                    inner.append_all(quote! { Default::default(), });
+                let mut toks = Toks::new();
+                for field in fields.unnamed.iter() {
+                    for attr in &field.attrs {
+                        if attr.path().get_ident().is_some_and(|path| path == "cfg") {
+                            attr.to_tokens(&mut toks);
+                        }
+                    }
+
+                    toks.append_all(quote! { Default::default(), });
                 }
-                inner = quote! { #type_ident(#inner) };
+                quote! { #type_ident(#toks) }
             }
-            Fields::Unit => inner = quote! { #type_ident },
-        }
+            Fields::Unit => quote! { #type_ident },
+        };
+
         let method = quote! {
             fn default() -> Self {
                 #inner

tests/test-cfg/tests/autoimpl.rs

@@ -4,7 +4,7 @@
 
 use impl_tools::autoimpl;
 
-#[autoimpl(Clone, Debug where T: trait)]
+#[autoimpl(Clone, Debug, Default where T: trait)]
 #[derive(PartialEq, Eq)]
 struct S<T> {
     a: T,
@@ -31,6 +31,7 @@ impl<T> S<T> {
 fn test_clone_S() {
     let a = S::new(());
     assert_eq!(a.clone(), a);
+    assert!(a != S::default());
 }
 
 #[test]