Dart Modern Features

1. When to use this skill

Use this skill when:

• Writing or reviewing Dart code targeting Dart 3.0 or later.
• Refactoring legacy Dart code to use modern, concise, and zero-cost features such as records, extension types, class modifiers, null-aware collection elements, dot shorthands, and digit separators.
• Looking for idiomatic ways to handle multiple return values or zero-cost domain wrappers.

For pattern matching, switch expressions, and list/map/split destructuring, use [dart-use-pattern-matching]. For converting closed class hierarchies into exhaustive sealed types, use [dart-seal-type-hierarchies].

When NOT to use (Abstention Guardrails)