Description Markus Keller 2005-08-02 10:57:24 EDT

I20050726-1222

Too many warnings for non-matching types of arguments of varargs call:
- varargs(new Object[] {1, 2}) warns, but shouldn't
- varargs((Serializable) new Serializable[] {3, 4}) warns, but shouldn't

See inlined explanations:

import java.io.Serializable;
import java.util.Arrays;

public class Try {
    static void array(Serializable... items) {
        System.out.println(Arrays.deepToString(items));
    }
    static void varargs(Serializable... items) {
        System.out.println(Arrays.deepToString(items) + " (argument wrapped)");
    }

    public static void main(String[] args) {
        varargs(new Object[] {1, 2}); //warns "Varargs argument Object[]
            //should be cast to Serializable[] ..", but proposed cast to
            //Serializable[] fails at run time (javac does not warn here)
        array(new Serializable[] {3, 4});
        array(new Integer[] {5, 6}); //warns (as javac does)
        array(null); //warns (as javac does)
        
        varargs((Serializable) new Object[] {1, 2});
        varargs((Serializable) new Serializable[] {3, 4}); //warns about
            //unnecessary cast, although cast is necessary (causes varargs call)
        varargs((Serializable) new Integer[] {5, 6});
        varargs((Serializable) null);
        
        array((Serializable[]) new Serializable[] {3, 4}); //warns about
            //unnecessary cast
        array((Serializable[]) new Integer[] {5, 6});
        array((Serializable[]) null);
        array((Serializable[]) new Object[] {1, 2}); // CCE at run time
    }
}