Macro std::trace_macros

macro_rules! trace_macros {
    (true) => { ... };
    (false) => { ... };
}

🔬 This is a nightly-only experimental API. (trace_macros #29598)

trace_macros is not stable enough for use and is subject to change

启用或禁用用于调试其他宏的跟踪功能。