C#idiomatic C#
ca1510fundamentals/code-analysis/quality-rules

Code analysis

CA1510: Use ArgumentNullException throw helper

Learn about code analysis rule CA1510: Use ArgumentNullException throw helper

CA1510 Maintainability enabled by default in .NET 10: As suggestion
Fix is breaking or non-breaking Non-BreakingApplicable languages C# and Visual Basic

Cause

Code checks whether an argument is null and then conditionally throws an System.ArgumentNullException.

Rule description

Argument checks have a substantial impact on code size and often dominate the code for small functions and property setters. These checks prevent inlining and cause substantial instruction-cache pollution. Throw-helper methods such as System.ArgumentNullException.ThrowIfNull are simpler and more efficient than if blocks that construct a new exception instance.

Example

The following code snippet shows a violation of CA1510:

csharp
void M(string arg)
{
    if (arg is null)
        throw new ArgumentNullException(nameof(arg));
}

The following code snippet shows the fix:

csharp
void M(string arg)
{
    ArgumentNullException.ThrowIfNull(arg);
}

How to fix violations

Replace the if block that throws the exception with a call to System.ArgumentNullException.ThrowIfNull. Or, in Visual Studio, use the lightbulb menu to fix your code automatically.

When to suppress warnings

It's safe to suppress a violation of this rule if you're not concerned about the maintainability of your code. It is also fine to suppress violations that are identified to be false positives.

Suppress a warning

If you just want to suppress a single violation, add preprocessor directives to your source file to disable and then re-enable the rule.

csharp
#pragma warning disable CA1510
// The code that's violating the rule is on this line.
#pragma warning restore CA1510

To disable the rule for a file, folder, or project, set its severity to none in the configuration file.

ini
[*.{cs,vb}]
dotnet_diagnostic.CA1510.severity = none

For more information, see How to suppress code analysis warnings.