IComparer interface is to Comparison delegate as IEqualityComparer is to what?

.net, c#

Solution

There is no equivalent because there can't be one. `IComparer<T>` defines only a single member, so you can "distill" it into a delegate.

In contrast, `IEqualityComparer<T>` must provide both `Equals` and `GetHashCode` implementations in order to be universally useful. You can't fit both of these into a delegate, hence no equivalent to `Comparison<T>`.

That said, the signature of a delegate that directly compares two instances of a type `T` for equality would be the one given for `EqualityComparer<T>.Equals` -- i.e. `Func<T, T, bool>`.

Problem

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