Merge pull request #1376 from zeenix/fix-serialize-dict-empty-struct

🚑️ zd: Fix use of empty structs with SerializeDict

Author: zeenix

zvariant/tests/dict_value.rs

@@ -231,4 +231,8 @@ fn dict_value() {
         let decoded = encoded.deserialize::<TestDenyUnknown>();
         assert!(decoded.is_err());
     }
+
+    #[derive(Default, Debug, SerializeDict, DeserializeDict, Type)]
+    #[zvariant(signature = "dict")]
+    struct TestEmpty {}
 }

zvariant_derive/src/dict.rs

@@ -69,10 +69,13 @@ pub fn expand_serialize_derive(input: DeriveInput) -> Result<TokenStream, Error>
                 #[derive(Serialize)]
                 #[serde(rename_all = #rename_all_str)]
                 struct #helper<'a> {
+                    #[serde(skip)]
+                    phantom: ::std::marker::PhantomData<&'a ()>,
                     #(#field_defs,)*
                 }
 
                 let helper = #helper {
+                    phantom: ::std::marker::PhantomData,
                     #(#field_inits,)*
                 };