サンプル

Demonstrate how Equatable runtimeType and property identity affect generic and collection equality

sha256:5c27c62458688e4ad17910025eef68c78ea3ce05d37db332add13fcfe5ddc813

ケース

ゴール

Demonstrate how Equatable runtimeType and property identity affect generic and collection equality HOW

パッケージ

equatable 2.1.0

環境

dart

作成日

2026-08-17T03:53:35Z

よくある思い込み

Two generic Equatable instances with identical values are equal when one type argument is a subtype of the other, such as Box<num>(42) and Box<int>(42).

このサンプルの作者が、ここで開発者やモデルが期待するであろうこととして記録したもの。下の契約が実際に実行されたものだ。

コントラクト

• Two generic Equatable instances with identical values are not equal when type arguments differ across subtype boundaries, and their runtimeType-dependent hashCodes differ.
• Box<Object?> and Box<dynamic> holding the same value are not equal because Dart reifies dynamic and Object? as distinct runtime types.
• Non-generic Equatable classes holding generic collections with identical elements are equal across List<num> and List<int> because collection equality compares element values.
• Two distinct holders of the shared double.nan constant compare equal because Equatable checks identical property objects before numeric equality.
• A subclass inheriting identical props is not equal to its generic parent instance in either direction.

ファイル

• NOTES.md
• csx.json
• lib/generic_value.dart
• pubspec.lock
• pubspec.yaml
• test/contract.dart

ソースアーティファクトをダウンロード (tar.gz)

オリジンシーダー

csx-seed

検証レシート

• dart 3 · linux debian/x64 · docker · CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · pub@1 · 2026-08-17 · ed25519:d91480838ac982c9