#nullable enable

​

using System;

using System.Runtime.CompilerServices;

​

try

{

    string? a = null;

    a.ThrowIfNull();

}

catch (InvalidOperationException e)

{

    Console.WriteLine(e.Message);

}

​

try

{

    int? b = null;

    int? c = 5;

    (b + c).ThrowIfNull();

}

catch (InvalidOperationException e)

{

    Console.WriteLine(e.Message);

}

​

​

public static class NullableExtensions

{

    public static T ThrowIfNull<T>(

        this T? input, [CallerArgumentExpression("input")] string? description = null)

        where T : struct =>

        input ?? ThrowMustNotBeNull<T>(description);

​

    public static T ThrowIfNull<T>(

        this T? input, [CallerArgumentExpression("input")] string? description = null)

        where T : class =>

        input ?? ThrowMustNotBeNull<T>(description);

​

    private static T ThrowMustNotBeNull<T>(string? description) =>

        throw new InvalidOperationException($"{description} must not be null");

}

​

​