Description jho 2005-08-13 13:15:11 EDT

//suspicious compiler errors on mix of for each and generics
class Node{}
interface Set1<N extends Node> extends Iterable<N>{}
interface Set2 extends Iterable<Node>{}
class SetIterator<N extends Node> implements Iterator<N>{
	public N next(){return null;}
	public boolean hasNext(){return true;}
	public void remove(){}
}
interface Set3<N extends Node> extends Iterable<N>{
	SetIterator<N> iterator();
}
class X{
	void f1(Set1 s){
		Node n_ = s.iterator().next();
		//   ^Type mismatch: cannot convert from Object to Node
		// this was unexpected (s can only contain types derivered 
from Node)
		for (Node n : s){			
			//    ^Type mismatch: cannot convert from Object to 
Node
			// this was unexpected 
		}
	}
	void f2(Set2 s){
		Node n_ = s.iterator().next();
		for (Node n : s){			
		}
	}
	void f3(Set3 s){
		Node n_ = s.iterator().next();
		//  (^ no error here)
		for (Node n : s){			
			//    ^Type mismatch: cannot convert from Object to 
Node
			// this is even stranger as we already know that 
s.iterator().next() have the right type
		}
	}
}