A Practical Intro to Covariance and Contravariance in C#

When defining a generic interface, have you received a hint from Resharper like “The type parameter T could be declared as covariant” (or “contravariant”)? If so, have you then blindly applied the proposed refactoring which decorates your generic parameter with the in or out keyword? Like so: publicinterface ISomeGenericInterface<in T>

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