{"ast_node_type":"function","tokens":[{"end":84,"kind":"keyword","start":0,"text":"pub(crate)"}]}
    pub(crate) fn duplicate_key(&self, span: Span, key: Symbol) -> ErrorGuaranteed {
    /// emit an error that a `name = value` pair was found where that name was already seen.
        self.emit_err(AttributeParseError {