Top "Contravariance" questions

Within the type system of a programming language, covariance and contravariance refers to the ordering of types from narrower to wider and their interchangeability or equivalence in certain situations (such as parameters, generics, and return types)

T must be contravariantly valid

What is wrong with this? interface IRepository<out T> where T : IBusinessEntity { IQueryable<T> GetAll(); void …

c# .net generics covariance contravariance
Simple examples of co and contravariance

Could someone provide me simple C# examples of convariance, contravariance, invariance and contra-invariance (if such thing exists). All samples I've …

c# .net covariance contravariance invariants
Why does ReSharper suggest that I make type parameter T contravariant?

ReSharper suggests me to make type parameter T contravariant by changing this: interface IBusinessValidator<T> where T: IEntity { …

c# resharper contravariance
Why covariance and contravariance do not support value type

IEnumerable<T> is co-variant but it does not support value type, just only reference type. The below simple …

c# .net c#-4.0 covariance contravariance
Difference between Covariance and Contra-variance in programming languages

Can anyone explain the concept of covariance and contravariance in programming language theory?

java c# programming-languages covariance contravariance