Macro error 

macro_rules! error {
    ($diagnostic:expr) => { ... };
    ($diagnostic:expr, $fragment:expr) => { ... };
}

Macro to create an Error from a diagnostic function call

Usage:

• error!(diagnostic_function(args)) - Creates an error without fragment
• error!(diagnostic_function(args), fragment) - Creates an error with fragment

Expands to: Error(diagnostic_function(args)) or Error(diagnostic_function(args).with_fragment(fragment))

Examples:

• error!(sequence_exhausted(Type::Uint8))
• error!(sequence_exhausted(Type::Uint8), fragment)