Macro dbg_cond 

macro_rules! dbg_cond {
    ($val:expr) => { ... };
}

this macro under introspect feature can be used to debug how derive proc macros (crate::InteractiveClap, crate::ToCliArgs) work

# interactive-clap-derive folder
cargo test test_doc_comments_propagate --features introspect -- --nocapture
# from repo root
cargo run --example struct_with_subargs --features interactive-clap-derive/introspect