{"ast_node_type":"variable","tokens":[{"end":67,"kind":"keyword","start":0,"text":"let"}]}
            let source_file = &all_source_files[source_file_index];
        for (on_disk_index, &source_file_index) in required_source_files.iter().enumerate() {
            // Don't serialize imported `SourceFile`s, unless we're in a proc-macro crate.