immutable top-level constant

Immutable const immutable

Used to annotate a class C. Indicates that C and all subtypes of C must be immutable.

A class is immutable if all of the instance fields of the class, whether defined directly or inherited, are final.

Tools, such as the analyzer, can provide feedback if

• the annotation is associated with anything other than a class, or
• a class that has this annotation or extends, implements or mixes in a class that has this annotation is not immutable.

Implementation

const Immutable immutable = Immutable();