Node.js 16 actions are deprecated. Please update the following actions to use Node.js 20: actions/checkout@v3, actions/setup-dotnet@v3. For more information see: https://github.blog/changelog/2023-09-22-github-actions-transitioning-from-node-16-to-node-20/.

Cannot convert null literal to non-nullable reference type.

Cannot convert null literal to non-nullable reference type.

Cannot convert null literal to non-nullable reference type.

Non-nullable field 'left' must contain a non-null value when exiting constructor. Consider declaring the field as nullable.

Non-nullable field 'right' must contain a non-null value when exiting constructor. Consider declaring the field as nullable.

Non-nullable field 'next' must contain a non-null value when exiting constructor. Consider declaring the field as nullable.

Non-nullable field 'children' must contain a non-null value when exiting constructor. Consider declaring the field as nullable.

Non-nullable field 'children' must contain a non-null value when exiting constructor. Consider declaring the field as nullable.

Dereference of a possibly null reference.