Node.js 20 actions are deprecated. The following actions are running on Node.js 20 and may not work as expected: actions/setup-dotnet@v4. Actions will be forced to run with Node.js 24 by default starting June 2nd, 2026. Node.js 20 will be removed from the runner on September 16th, 2026. Please check if updated versions of these actions are available that support Node.js 24. To opt into Node.js 24 now, set the FORCE_JAVASCRIPT_ACTIONS_TO_NODE24=true environment variable on the runner or in your workflow file. Once Node.js 24 becomes the default, you can temporarily opt out by setting ACTIONS_ALLOW_USE_UNSECURE_NODE_VERSION=true. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/

Nullability of reference types in type of parameter 'value' doesn't match implemented member 'bool IList.Contains(object? value)' (possibly because of nullability attributes).

Nullability of reference types in type of parameter 'value' doesn't match implemented member 'int IList.Add(object? value)' (possibly because of nullability attributes).

Nullability of reference types in type of parameter 'other' of 'bool USinger.Equals(USinger other)' doesn't match implicitly implemented member 'bool IEquatable<USinger>.Equals(USinger? other)' (possibly because of nullability attributes).

Nullability of reference types in type of 'event PropertyChangedEventHandler USinger.PropertyChanged' doesn't match implicitly implemented member 'event PropertyChangedEventHandler? INotifyPropertyChanged.PropertyChanged'.

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.

Cannot convert null literal to non-nullable reference type.

Cannot convert null literal to non-nullable reference type.