Extension methods and API evolution

[Stefan Schulz]

Peter Levart wrote:
> A no-language-change alternative of that might be standardizing an annotation in the JDK
> platform that every IDE would add support for. For example:
>
> package java.util;
>
> @UtilityMethods({
>      "java.util.Collections#binarySearch",
>      "java.util.Collections#checkedList",
>      "java.util.Collections#fill",
>      "java.util.Collections#indexOfSubList",
>      "java.util.Collections#lastIndexOfSubList",
>      "java.util.Collections#replaceAll",
>      "java.util.Collections#reverse",
>      "java.util.Collections#rotate",
>      "java.util.Collections#shuffle",
>      "java.util.Collections#sort",
>      "java.util.Collections#swap",
>      "java.util.Collections#synchronizedList",
>      "java.util.Collections#unmodifiableList"
> })
> public interface List<E>  extends Collection<E>  {
> ...

While this is on declaration-site extension methods, I could think of 
this working for use-site extension methods as well. As IDEs need to 
scan and index classes anyway, this would help in finding matching 
use-site extensions a lot. Even better, as no String-matching is needed. 
For example:

package java.util;

public class Collections {

     @ExtensionMethod(List.class)
     public static <T extends Comparable<? super T>>
         void sort(List<T> list) {...}
...
}

Stefan