Operators should have symmetrical overloads

There are no circumstances where either equality or inequality is applicable to instances of a type, and the opposite operator is undefined. Types typically implement the inequality operator by returning the negated value of the equality operator.

The C# compiler issues an error for violations of this rule.

A type implements the equality or inequality operator and does not implement the opposite operator.

By default, this rule only looks at externally visible types, but this is configurable.

To fix a violation of this rule, implement both the equality and inequality operators, or remove the one that's present.

Do not suppress a warning from this rule. If you do, your type will not work in a manner that's consistent with .NET.