Documentation for EqualityComparer<T> contains wrong remark

[skrysmanski]

The current version of the documentation of EqualityComparer<T> contains this in its "Remarks" section:

We recommend that you derive from the EqualityComparer class instead of implementing the IEqualityComparer interface, because the EqualityComparer class tests for equality using the IEquatable.Equals method instead of the Object.Equals method.

I think this statement is completely wrong. The current (.NET 5) implementation of EqualityComparer<T> is like this (only the relevant parts):

public abstract partial class EqualityComparer<T> : IEqualityComparer, IEqualityComparer<T>
{
    public abstract bool Equals(T? x, T? y);
    public abstract int GetHashCode([DisallowNull] T obj);
}

These two abstract methods are the two methods required by IEqualityComparer<T>. There's no "pre-processing" of x and y.

So I don't see what this remark in the documentation would be referring to.

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[antonfirsov]

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