contravariance

X++ no longer allows contravariance, parameter covariance, parameter contravariance, and visibility contravariance.

Site Home mfp 2011

Generic co- and contravariance is checked at compile-time.

B# .NET Technical Community Homepage bart 2010

That's the whole point of type safety guarantees provided by co- and contravariance on generic types in C# 4.0.

B# .NET Technical Community Homepage bart 2010

Loaded with my knowledge of generic co- and contravariance, I was surprised to see the following code compile fine.

B# .NET Technical Community Homepage bart 2010

Loaded with my knowledge of generic co- and contravariance, I was surprised to see the following code compile fine.

B# .NET Technical Community Homepage bart 2010

Understand how generic covariance and contravariance affect your designs (see Item 29)

ebookshare 2010

Several generic interfaces and delegates now support covariance and contravariance.

Tweakers.net Mixed RSS Feed Japke Rosink 2010

That's where the real protection lies, hence the phrase "declaration site" in the real name of the feature: declaration site co- and contravariance for generic interface and delegate types.

B# .NET Technical Community Homepage bart 2010

We've added support for interoperability with dynamic languages and legacy object models, named and optional parameters, the ability to "link" against interfaces from a Primary Interop Assembly, and my favourite feature, covariance and contravariance of interface and delegate types.

MSDN Blogs Eric Lippert 2010

The reuse of keywords out and in as modifiers on generic type parameters is what's referred to as the new C# 4.0 feature called definition-site generic co- and contravariance for interface and delegate types

B# .NET Technical Community Homepage bart 2010