{"ast_node_type":"other","tokens":[{"end":86,"kind":"keyword","start":0,"text":"Some(\"/home/bors/rust/.rustup/toolchains/nightly/lib/rustlib/src/rust\".into())"}]}
        Some("/home/bors/rust/.rustup/toolchains/nightly/lib/rustlib/src/rust".into())
        real_rust_source_base_dir,
    );