Incompatibility with IReadOnlyList<> and C# 12 Syntax

[Schaeri]

We have identified an issue with Blazored/FluentValidation following the migration to .NET 8.0 and C# 12. Since we work with Fluxor, all our data is immutable. Moreover, we use the IReadOnlyList<> interface for lists throughout.

With the new C# 12 syntax for list initialization, a "standard" list/array is no longer created; instead, a type named "<>z__ReadOnlyArray" is generated. This new type neither possesses an Item property nor can it be converted into an object array. The code in the ToFieldIdentifier method within the EditContextFluentValidationExtensions class throws an exception as a result.

The following example demonstrates the problem (Note: the code must be compiled with C# 12, and we have tested with Visual Studio 17.9.0):

List<string> list = ["1", "2"];
IReadOnlyList<string> readonlyList = ["1", "2"];

var listHasItemProperty = list.GetType().GetProperties().Any(x => x.Name == "Item");
var readOnlyListHasItemProperty = readonlyList.GetType().GetProperties().Any(x => x.Name == "Item");

Console.WriteLine(listHasItemProperty); // True
Console.WriteLine(readOnlyListHasItemProperty); // False

var objects = readonlyList as object[];
Console.WriteLine(objects != null); // False

The following PR resolves the issue #214

[Schaeri]

Thank you very much for accepting the pull request. When will the package be released on NuGet?