Code Inspection: Auto-property can be made get-only (non-private accessibility)

Starting from C# 6.0, you can define get-only auto-properties, which (similarly to readonly fields) can be only initialized via a constructor or an initializer. JetBrains Rider detects and helps you remove the redundant set accessor on auto-properties that are initialized from the constructor/initializer and have no write usages.

In the example below, an immutable class is intended, and once the value for the Name property is checked for nullability in the constructor, it can be safely used without further null checks. However, the private setter does not guarantee that the property will not be changed later in private members. Therefore, it is a good idea to make this property get-only to prevent any modifications.

public class Person
{
    public string Name { get; set; } // Auto-property can be made get-only

    public Person(string name)
    {
        Name = name ?? throw new ArgumentNullException(nameof(name));
    }

    public override string ToString()
    {
      return $"NAME: {Name.ToUpper()}";
    }
}
    

For the solution-wide inspection to work, you need either or both of the following:

The simplified global usage checking is enabled — Show unused non-private type members when solution-wide analysis is off on the Editor | Inspection Settings page of JetBrains Rider settings Ctrl+Alt+S.
The solution-wide analysis is enabled — Enable solution-wide analysis on the Editor | Inspection Settings page of JetBrains Rider settings Ctrl+Alt+S.

Note that even if a symbol has no direct usages in your solution and JetBrains Rider warns you about it, there could be cases where symbols are used indirectly — for example, via reflection — or they could just be designed as public API. In all those cases you would want to suppress the usage-checking inspection for the symbol, and there are several ways to do so:

The recommended way is to decorate the implicitly used symbols with code annotation attributes. There are two attributes for this purpose: [UsedImplicitly] and [PublicAPI], which are functionally similar, but let you and your teammates understand how the symbol is actually used.
You can also suppress usage-checking inspections with any custom attribute. To do so, mark the definition of that attribute with the [MeansImplicitUse] attribute.
And finally, you can suppress a specific usage-checking inspection as any other code inspection with a suppression comment or a suppression attribute.

Last modified: 08 March 2021