The use of == to compare two objects is expected to do a reference comparison. That is, it is expected to return true if
and only if they are the same object instance. Overloading the operator to do anything else will inevitably lead to the introduction of bugs by
callers.
public static bool operator ==(MyType x, MyType y) // Noncompliant: confusing for the caller
{
// custom implementation
}
On the other hand, overloading it to do exactly that is pointless; that’s what == does by default.
public static bool operator ==(MyType x, MyType y) // Noncompliant: redundant
{
if (x == null)
{
return y == null;
}
return object.ReferenceEquals(x,y);
}
Exceptions
- Classes with overloaded
operator + or operator - are ignored.
- Classes that implement
IComparable<T> or IEquatable<T> most probably behave as value-type objects and are
ignored.
