GenApi shouldn't add _dummy and _dummyObject if there are public value and ref fields.

[pakrym]

For example in the following struct object _dummy is not required because RenderTreeFrame has public ref fields which should be sufficient for compiler checks.

    [System.Runtime.InteropServices.StructLayoutAttribute(System.Runtime.InteropServices.LayoutKind.Explicit)]
    public readonly partial struct RenderTreeFrame
    {
        private readonly object _dummy;
        [System.Runtime.InteropServices.FieldOffsetAttribute(8)]
        public readonly int AttributeEventHandlerId;
        [System.Runtime.InteropServices.FieldOffsetAttribute(16)]
        public readonly string AttributeName;
        [System.Runtime.InteropServices.FieldOffsetAttribute(24)]
        public readonly object AttributeValue;
        [System.Runtime.InteropServices.FieldOffsetAttribute(12)]
        public readonly int ComponentId;
        [System.Runtime.InteropServices.FieldOffsetAttribute(16)]
        public readonly System.Action<object> ComponentReferenceCaptureAction;
        [System.Runtime.InteropServices.FieldOffsetAttribute(8)]
        public readonly int ComponentReferenceCaptureParentFrameIndex;
}

cc @jaredpar am I correct in this assumption?

[rynowak]

Updoot for this. Having to maintain a manual ref-assembly type just resulted in an ask mode bug for us in 3.0 - https://github.com/aspnet/AspNetCore/pull/13522/files

This is risky business for us because once you go manual with a ref-assembly type, you lose all validation.

[dougbu]

Fixed in d6dd7a0