{"ast_node_type":"impl","tokens":[{"end":87,"kind":"keyword","start":0,"text":")"}]}
    ) -> Option<InMacroFile<impl Iterator<Item = (SyntaxToken, SyntaxContext)> + '_>> {
        span: Span,
        let tokens = self.exp_map.ranges_with_span(span).flat_map(move |(range, ctx)| {