fun <R> f0(f: KFunction0<R>): MetaFeature<R>
Creates a MetaFeature for the given function f without arguments.
Notice for assertion function writers: you should use ExpectImpl.feature and pass a
class reference instead of using this convenience function (e.g. ExpectImpl.feature(MyClass::fun)).
This way we are always able to report the function name, even if the subject is not defined which occurs if a
previous transformation of the subject could not be carried out.