c++,codec-json: Changed to more appropriate error

1 files changed, 1 insertions, 1 deletions

diff --git a/src/codec-json/json.tmpl.h b/src/codec-json/json.tmpl.h
index 2bbfa5d..4b3a1a2 100644
--- a/src/codec-json/json.tmpl.h
+++ b/src/codec-json/json.tmpl.h
@@ -483,7 +483,7 @@ struct json_decode<schema::Struct<schema::Member<T,Lits>...>, RootSchema, ToDeco
 			constexpr static string_literal Literal = parameter_key_pack_type<i, Lits...>::literal;
 			if(search_name == Literal.view()){
 				if(fields[i]){
-					return make_error<err::already_exists>();
+					return make_error<err::invalid_state>();
 				}
 				fields[i] = true;
 				auto eov = json_decode<Type, RootSchema, ToDecode>::decode(buff, to.template get<Literal>());