V3115. It is not recommended to throw exceptions from 'Equals(object obj)' method.

V3115. It is not recommended to throw exceptions from 'Equals(object obj)' method.


The analyzer detected that overridden method 'Equals(object obj)' might throw an exception.

Consider the following example:

public override bool Equals(object obj)
{
  return obj.GetType() == this.GetType();
} 

If the 'obj' argument is null, a 'NullReferenceException' will be thrown. The programmer must have forgotten about this scenario when implementing the method. Use a null check to make this code work properly:

public override bool Equals(object obj)
{
  if (obj == null)
    return false;

  return obj.GetType() == this.GetType();
} 

Another poor practice when implementing the 'Equals(object obj)' method is to explicitly throw an exception from it. For example:

public override bool Equals(object obj)
{
    if (obj == null)
        throw new InvalidOperationException("Invalid argument.");

    return obj == this;
}

This method is very likely to be called in such a block of code where exception throwing and handling are not expected.

If one of the objects does not meet the conditions, return 'false':

public override bool Equals(object obj)
{
    if (obj == null)
        return false;

    return obj == this;
}

According to Common Weakness Enumeration, potential errors found by using this diagnostic are classified as CWE-684.

You can look at examples of errors detected by the V3115 diagnostic.


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