NullabilityInfoContext does not properly respect CodeAnalysis attribute on indexer property

[madelson]

Description

In most cases code analysis attributes like AllowNull are respected, but this is not true for indexer properties.

Reproduction Steps

public void Main()
{
        var context = new NullabilityInfoContext();
        var indexerInfo = context.Create(typeof(HasIndexer).GetProperty("Item")!);
       Console.WriteLine(indexerInfo.WriteState); // NotNull (should be Nullable)
}

    public class HasIndexer
    {
        [AllowNull] public string this[string? s]
        {
            get => default!;
            set { }
        }
    }

Expected behavior

The write state should be nullable because the following compiles without warnings:

new HasIndexer()["a"] = null;

Actual behavior

Write state is not null as if the attribute were not present.

Regression?

No response

Known Workarounds

No response

Configuration

VS 17.0.2, .NET 6, Windows 10 x64.

I don't have any reason to believe this is configuration specific.

Other information

CC @Shane32

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Issue Details

---

Description

In most cases code analysis attributes like AllowNull are respected, but this is not true for indexer properties.

Reproduction Steps

public void Main()
{
        var context = new NullabilityInfoContext();
        var indexerInfo = context.Create(typeof(HasIndexer).GetProperty("Item")!);
       Console.WriteLine(indexerInfo.WriteState); // NotNull (should be Nullable)
}

    public class HasIndexer
    {
        [AllowNull] public string this[string? s]
        {
            get => default!;
            set { }
        }
    }

Expected behavior

The write state should be nullable because the following compiles without warnings:

new HasIndexer()["a"] = null;

Actual behavior

Write state is not null as if the attribute were not present.

Regression?

No response

Known Workarounds

No response

Configuration

VS 17.0.2, .NET 6, Windows 10 x64.

I don't have any reason to believe this is configuration specific.

Other information

CC @Shane32

Author:	madelson
Assignees:	-
Labels:	area-System.Reflection
Milestone:	-

[danmoseley]

Thanks for opening these nullable annotation bugs @madelson . Are you interested in offering a PR for any of them?

[madelson]

@danmoseley yes I'm working on fixes for some of them with the idea of sending a PR.