Nullability of type of parameter 'obj' doesn't match overridden member (possibly because of nullability attributes).

Cannot convert null literal to non-nullable reference type.

Converting null literal or possible null value to non-nullable type.

Converting null literal or possible null value to non-nullable type.

Converting null literal or possible null value to non-nullable type.

Possible null reference return.

Converting null literal or possible null value to non-nullable type.

Converting null literal or possible null value to non-nullable type.

Possible null reference argument for parameter 'fileName' in 'CascFoundFile.CascFoundFile(string fileName, nint plainName, byte[] encodingKey, CascLocales locales, long fileSize, CascStorageContext ownerContext)'.