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CA2013: Do not use ReferenceEquals with value types

  • Article
Property Value
Rule ID CA2013
Title Do not use ReferenceEquals with value types
Category Reliability
Fix is breaking or non-breaking Non-breaking
Enabled by default in .NET 9 As warning

Cause

Using System.Object.ReferenceEquals method to test one or more value types for equality.

Rule description

When comparing values using ReferenceEquals, if objA and objB are value types, they are boxed before they are passed to the ReferenceEquals method. This means that even if both objA and objB represent the same instance of a value type, the ReferenceEquals method nevertheless returns false, as the following example shows.

How to fix violations

To fix the violation, replace it with a more appropriate equality check such as ==.


    int int1 = 1, int2 = 1;

    // Violation occurs, returns false.
    Console.WriteLine(Object.ReferenceEquals(int1, int2));  // false

    // Use appropriate equality operator or method instead
    Console.WriteLine(int1 == int2);                        // true
    Console.WriteLine(object.Equals(int1, int2));           // true

When to suppress warnings

It is not safe to suppress a warning from this rule. We recommend using the more appropriate equality operator, such as ==.

See also