.NET-Community-Toolkit/CommunityToolkit.HighPerformance/Attributes/NotNullWhenAttribute.cs

// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

#if !NETSTANDARD2_1_OR_GREATER

namespace System.Diagnostics.CodeAnalysis;

/// <summary>
/// Specifies that when a method returns <see cref="ReturnValue"/>, the parameter
/// will not be null even if the corresponding type allows it.
/// </summary>
/// <remarks>Internal copy of the .NET Standard 2.1 attribute.</remarks>
[AttributeUsage(AttributeTargets.Parameter)]
internal sealed class NotNullWhenAttribute : Attribute
{
    /// <summary>
    /// Initializes a new instance of the <see cref="NotNullWhenAttribute"/> class.
    /// </summary>
    /// <param name="returnValue">
    /// The return value condition. If the method returns this value,
    /// the associated parameter will not be <see langword="null"/>.
    /// </param>
    public NotNullWhenAttribute(bool returnValue)
    {
        ReturnValue = returnValue;
    }

    /// <summary>
    /// Gets a value indicating whether the return value should be <see langword="true"/>.
    /// </summary>
    public bool ReturnValue { get; }
}

#endif