/// <summary>
/// Tries to convert the specified <paramref name="comparer"/> to a strongly typed <see cref="SetEqualityComparer{T}"/>.
/// </summary>
/// <param name="comparer">The comparer to convert to a <see cref="SetEqualityComparer{T}"/>, if possible.</param>
/// <param name="equalityComparer">The result <see cref="SetEqualityComparer{T}"/> of the conversion.</param>
/// <returns><c>true</c> if the conversion was successful; otherwise, <c>false</c>.</returns>
public static bool TryGetSetEqualityComparer(IEqualityComparer comparer, out SetEqualityComparer <T> equalityComparer)
{
// StructuralEqualityComparer is too "dumb" to resolve generic collections.
// This is done on purpose for performance reasons. Sets
// must convert the comparison mode to the resolved SetEqualityComparer<T>
// to prevent StructuralEqualityComparer from needing to use reflection to do it.
if (comparer is StructuralEqualityComparer seComparer)
{
if (seComparer.Equals(StructuralEqualityComparer.Default))
{
equalityComparer = Default;
}
else
{
equalityComparer = Aggressive;
}
return(true);
}
else if (comparer is SetEqualityComparer <T> setComparer)
{
equalityComparer = setComparer;
return(true);
}
equalityComparer = null;
return(false);
}
public virtual int GetHashCode(IEqualityComparer comparer) => SetEqualityComparer <T> .GetHashCode(this, comparer);
public virtual bool Equals(object?other, IEqualityComparer comparer) => SetEqualityComparer <T> .Equals(this, other, comparer);