comments for macros is lost

[rain2307]

Input C/C++ Header

///this is the comment
#define ABC '1'

Bindgen Invocation

let bindings = bindgen::Builder::default()
    .header(format!("src/test.cpp"))
    .layout_tests(false)
    .clang_arg("-fparse-all-comments")
    .clang_args(&["-E", "-CC"])
    .generate_comments(true)
    .parse_callbacks(Box::new(bindgen::CargoCallbacks))
    .generate()
    .expect("Unable to generate bindings");

The comment line is missing. How can I keep it ?