FULL PRODUCT VERSION :
java version "1.8.0_25"
Java(TM) SE Runtime Environment (build 1.8.0_25-b17)
Java HotSpot(TM) 64-Bit Server VM (build 25.25-b02, mixed mode)


ADDITIONAL OS VERSION INFORMATION :
Linux example.com 3.18.1-desktop-3.mga5 #1 SMP Tue Dec 30 22:09:00 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux

A DESCRIPTION OF THE PROBLEM :
Consider the following code:


import java.util.Iterator;
import java.util.LinkedList;

public class Test {
        static class Foo<T> {
                @SafeVarargs
                public Foo(T... args) {
                }
        }

        public static void main(String[] args) {
                Foo<String> foo0 = new Foo<>("0", "1"); // Clear
                Foo<String> foo1 = new Foo<String>("0", "1"); // Clear

                Iterator<String> i = new LinkedList<String>().iterator();

                Foo<Iterator<String>> foo2 = new Foo<>(i, i); // Warning
                Foo<Iterator<String>> foo3 = new Foo<Iterator<String>>(i, i); // Clear
        }
}


ECJ compiles this code with no warnings. When compiled with Oracle JDK or OpenJDK, though, a single warning is issued:

Test.java:19: warning: [unchecked] unchecked generic array creation for varargs parameter of type Iterator<String>[]
                Foo<Iterator<String>> foo2 = new Foo<>(i, i); // Warning
                                             ^
1 warning


There seems to be some relation to the use of the diamond operator. Also, the behavior w.r.t. the warning seems inconsistent when compared with the other three cases, especially with the `... foo0 = ...' case.


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Compile the following code:

import java.util.Iterator;
import java.util.LinkedList;

public class Test {
        static class Foo<T> {
                @SafeVarargs
                public Foo(T... args) {
                }
        }

        public static void main(String[] args) {
                Foo<String> foo0 = new Foo<>("0", "1"); // Clear
                Foo<String> foo1 = new Foo<String>("0", "1"); // Clear

                Iterator<String> i = new LinkedList<String>().iterator();

                Foo<Iterator<String>> foo2 = new Foo<>(i, i); // Warning
                Foo<Iterator<String>> foo3 = new Foo<Iterator<String>>(i, i); // Clear
        }
}


EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
No warnings should be issued by the compiler
ACTUAL -
Test.java:19: warning: [unchecked] unchecked generic array creation for varargs parameter of type Iterator<String>[]
                Foo<Iterator<String>> foo2 = new Foo<>(i, i); // Warning
                                             ^
1 warning


ERROR MESSAGES/STACK TRACES THAT OCCUR :
Test.java:19: warning: [unchecked] unchecked generic array creation for varargs parameter of type Iterator<String>[]
                Foo<Iterator<String>> foo2 = new Foo<>(i, i); // Warning
                                             ^
1 warning


REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import java.util.Iterator;
import java.util.LinkedList;

public class Test {
        static class Foo<T> {
                @SafeVarargs
                public Foo(T... args) {
                }
        }

        public static void main(String[] args) {
                Foo<String> foo0 = new Foo<>("0", "1"); // Clear
                Foo<String> foo1 = new Foo<String>("0", "1"); // Clear

                Iterator<String> i = new LinkedList<String>().iterator();

                Foo<Iterator<String>> foo2 = new Foo<>(i, i); // Warning
                Foo<Iterator<String>> foo3 = new Foo<Iterator<String>>(i, i); // Clear
        }
}

---------- END SOURCE ----------