pub(crate) fn parse_as_enum_or_struct_inner<I, C>(
    first_arg: TokenTree,
    rest_of_stream: &mut I,
    type_name: &str,
    rti: &ReflectedTypeInfo,
    ctx: &mut C
) -> Result<Option<String>, String> where
    C: TestDeserializeContext,
    I: Iterator<Item = TokenTree>,