Macro bail_no_function 

macro_rules! bail_no_function {
    () => { ... };
    (@ candidates = $candidates:expr, $($fmt_arg:tt)*) => { ... };
    (candidates = $candidates:expr, $($fmt_arg:tt)*) => { ... };
    ($($fmt_arg:tt)*) => { ... };
}

Constructs a NoFunction and bails out.