suprising for a naive Java or C++ developer

type_surprise.go

package main

// see https://gist.github.com/1324737  for a java version of the same issue, which does work
type fruit interface  {
	foo() int
}

type apple interface {
	fruit
	bar() int
}

func needFruit(f fruit) {
}

func needManyFruits(f []fruit) {
}

func f() {
	var f fruit
	var a apple

	needFruit(f)
	needFruit(a)  //duck typing plus the "borrowing" of interface fruit into apple works like inheritance
	
	var fs []fruit
	var as []apple
	
	needManyFruits(fs)
	needManyFruits(as)  //this doesn't work! a naive C++ or java developer is surprised!

	//there is a hint of an explanation here: http://golang.org/doc/go_faq.html#convert_slice_of_interface
	
}