Why is this an issue?
Making a base call in an overriding method is generally a good idea, but not in GetHashCode and Equals for
classes that directly extend object because those methods are based on the object reference. Meaning that no two objects
that use those base methods will ever be equal or have the same hash.
Noncompliant code example
public class Point
{
private readonly int x;
public MyClass(int x)
{
this.x = x;
}
public override int GetHashCode()
{
return x.GetHashCode() ^ base.GetHashCode(); //Noncompliant
}
}
Compliant solution
public class Point
{
private readonly int x;
public MyClass(int x)
{
this.x = x;
}
public override int GetHashCode()
{
return x.GetHashCode();
}
}
Exceptions
This rule doesn’t report on guard conditions checking for reference equality.
public class Point
{
public override bool Equals(object obj)
{
if (base.Equals(obj)) // Compliant, although it could be replaced with object.ReferenceEquals(obj, this), which is clearer
{
return true;
}
...
}
}
