Macro userror::flm

macro_rules! flm {
    () => { ... };
    ($message:expr) => { ... };
    ($format:expr, $( $val:expr ),+) => { ... };
}

Prepend file and line info into a given message.

This is useful for internal errors to avoid messy uses of file! and line!.

The first argument to this macro must always be a string literal. If a single argument is given then a &'static str will be returned. If multiple arguments are given the the first argument is used as a format string for format!.