Compare two objects by reference when equality operator is overridden

Question

I need to check if two objects of the same type are the same instances and point to the same allocation of memory. The problem is that the type has overloaded equality operator and thus it will use it as comparing the both for equality, but I need to check them for reference. I looked through object.ReferenceEquals() method, but it internally applies equality operator

Answer 1

Operators can't be overridden - they can only be overloaded.

So the == operator in object.ReferenceEquals is still comparing references, or you could do the same thing yourself by casting one or both operands:

string x = "some value";
string y = new string(x.ToCharArray());
Console.WriteLine(x == y);                   // True
Console.WriteLine((object) x == (object) y); // False
Console.WriteLine(ReferenceEquals(x, y));    // False

Answer 2

ReferenceEquals does exactly what you need, unless you're talking about a dictionary. It does not check Equals (it literally just does ldarg.0, ldarg.1, ceq, ret). Alternatively, just cast to object:

bool same = (object)x == (object)y;

If you need dictionary support (so: GetHashCode): System.Runtime.CompilerServices.RuntimeHelpers.GetHashCode(obj) is your friend.