Macro count_args

macro_rules! count_args {
    (@one $($t:tt)*) => { ... };
    ($(($($x:tt)*)),*$(,)?) => { ... };
}

Macro created by t0mstone You can check the original source at https://github.com/T0mstone/tlibs/blob/master/some_macros/src/lib.rs#L23-L29