public static void Test()
{
int i = 0;
DInvariant <int> dInt = () => i;
DVariant <int> dVariantInt = () => i;
// All of the following statements generate a compiler error
// because type variance in generic parameters is not supported
// for value types, even if generic type parameters are declared variant.
// DInvariant<Object> dObject = dInt;
// DInvariant<long> dLong = dInt;
// DVariant<Object> dVariantObject = dVariantInt;
// DVariant<long> dVariantLong = dVariantInt;
}
public void TestVariance()
{
DInvariant <string> dinString = () => "";
//DInvariant<object> dinObject = dinString;
DCovariant <string> dcoString = () => " ";
DCovariant <object> dcoObject = dcoString;
DContravariant <object> dcontraObject = (a) => Console.WriteLine(a);
DContravariant <string> dcontraString = dcontraObject;
DVariant <object, string> dObjectString = (a) => $"{a} ";
DVariant <object, object> dObjectObject = dObjectString;
DVariant <string, string> dStringString = dObjectString;
DVariant <string, object> dStringObject = dObjectString;
}
