namespace System.Diagnostics.CodeAnalysis { [AttributeUsage(AttributeTargets.Property | AttributeTargets.Parameter | AttributeTargets.ReturnValue, AllowMultiple = true, Inherited = false)] internal sealed class NotNullIfNotNullAttribute : Attribute { public string ParameterName { get; } public NotNullIfNotNullAttribute(string parameterName) { ParameterName = parameterName; } } }