Do not use Optional on ref or out. parameters

Metadata

ID: csharp-best-practices/optional-ref-out

Language: C#

Severity: Info

Category: Best Practices

The modifier Optional should not be used on ref or out parameters because it’s semantically incorrect:

an out parameter is used as a value to return from the function and, therefore, is not optional
a ref parameter is passed back to the caller

class MyClass {

    public static void routine([Optional] out i)
    {
    }
}

class MyClass {
    public static void routine([Optional] ref int i)
    {
    }

}

1
2
rulesets:
  - csharp-best-practices     # Rules to enforce C# best practices.

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