Chaining multiple collection asserts with index

[azygis]

I'm not sure whether it's a bug or not, but consider the following code:

[Test]
public void Dummy()
{
    var items = new SomeStuff[]
    {
        new("Name 1"),
        new("Name 2")
    };

    // OK
    Assert.That(items, Has.Exactly(2).Items);
    Assert.That(items, Has.ItemAt(0).Property(nameof(SomeStuff.Name)).EqualTo("Name 1"));
    Assert.That(items, Has.ItemAt(1).Property(nameof(SomeStuff.Name)).EqualTo("Name 2"));

    // OK
    Assert.That(items, Has.Exactly(2).Items
        .And.One.Property(nameof(SomeStuff.Name)).EqualTo("Name 1")
        .And.One.Property(nameof(SomeStuff.Name)).EqualTo("Name 2"));

    // NOT OK 1
    Assert.That(items, Has.Exactly(2).Items
        .And.ItemAt(0).Property(nameof(SomeStuff.Name)).EqualTo("Name 1")
        .And.ItemAt(1).Property(nameof(SomeStuff.Name)).EqualTo("Name 2"));

    // NOT OK 2
    Assert.That(items, Has.Exactly(2).Items
        .And.One.ItemAt(0).Property(nameof(SomeStuff.Name)).EqualTo("Name 1")
        .And.One.ItemAt(1).Property(nameof(SomeStuff.Name)).EqualTo("Name 2"));
}

public sealed record SomeStuff(string Name);

How would one chain AndConstraint and use the indexer in the same Assert.That call? The NOT OK 1 assert throws:

System.InvalidOperationException : Stack empty.
   at System.Collections.Generic.Stack`1.ThrowForEmptyStack()
   at System.Collections.Generic.Stack`1.Pop()
   at NUnit.Framework.Constraints.ConstraintBuilder.ConstraintStack.Pop()
   at NUnit.Framework.Constraints.BinaryOperator.Reduce(ConstraintStack stack)
   at NUnit.Framework.Constraints.ConstraintBuilder.Resolve()
   at NUnit.Framework.Constraints.Constraint.NUnit.Framework.Constraints.IResolveConstraint.Resolve()
   at NUnit.Framework.Assert.That[TActual](TActual actual, IResolveConstraint expression, String message, Object[] args)
   at NUnit.Framework.Assert.That[TActual](TActual actual, IResolveConstraint expression)
   at SomeTests.Dummy() in /path/TestFile.cs:line 115
   at System.RuntimeMethodHandle.InvokeMethod(Object target, Void** arguments, Signature sig, Boolean isConstructor)
   at System.Reflection.MethodInvoker.Invoke(Object obj, IntPtr* args, BindingFlags invokeAttr)

The NOT OK 2 assert throws:

System.ArgumentException : Default indexer accepting arguments < 0 > was not found on SomeTests+SomeStuff.
   at NUnit.Framework.Constraints.IndexerConstraint.ApplyTo[TActual](TActual actual)
   at NUnit.Framework.Constraints.ExactCountConstraint.ApplyTo[TActual](TActual actual)
   at NUnit.Framework.Constraints.AndConstraint.ApplyTo[TActual](TActual actual)
   at NUnit.Framework.Constraints.AndConstraint.ApplyTo[TActual](TActual actual)
   at NUnit.Framework.Assert.That[TActual](TActual actual, IResolveConstraint expression, String message, Object[] args)
   at NUnit.Framework.Assert.That[TActual](TActual actual, IResolveConstraint expression)
   at SomeTests.Dummy() in /path/TestFile.cs:line 115
   at System.RuntimeMethodHandle.InvokeMethod(Object target, Void** arguments, Signature sig, Boolean isConstructor)
   at System.Reflection.MethodInvoker.Invoke(Object obj, IntPtr* args, BindingFlags invokeAttr)

Namespaces, file paths and test names have been changed to protect the innocent.

[OsirisTerje]

Thanks! This seems to be a bug.
I copied your repro into https://github.com/nunit/nunit.issues/tree/main/Issue4423, split it up and made a couple of more tests there. It looks like it is the ItemAt that give the problem.
It does return two different error message though:

and

The code is:

[azygis]

I think the one that stems from .One.ItemAt is because One is returning the instance from the list to work on. At that point, it tries to use an indexer on an instance that has no indexer.

[OsirisTerje]

Make sense. It should however 1) give a better error message, or not sure if we can, make it a compiler error, and 2) add a nunit.analyzer warnings for this.