Code Inspection: Join null check with assignment

This inspection supports throw expressions, a new syntax introduced in C# 7.0. A throw expression allows throwing an exception in the middle of another expression, so throwing can now be combined with other tasks such as null-checking. This means that a common operation of checking an argument for null before assigning its value to a variable can now have a more compact look.

In the example below, JetBrains Rider uses a null-coalescing operator to join assignment, checking for null, and throwing an exception into a single statement.

            
public class MyClass
{
    private string myVariable;
    public void SetValue(string newValue)
    {
        if (newValue == null)
        {
            throw new ArgumentNullException(nameof(newValue));
        }
        myVariable = newValue;
    }
}


        

            
public class MyClass
{
    private string myVariable;
    public void SetValue(string newValue)
    {
        myVariable = newValue ?? throw new ArgumentNullException(nameof(newValue));
    }
}


        

Last modified: 08 March 2021