Consider this source code:
---
public class Test {

    private static <T> void test(Class<? extends T> clazz, T...
instances) {}

    public static void main(String[] args) {
        Object obj = null;
        test(obj.getClass());
    }

}
---

Compiling this on:
$ javac -fullversion
javac full version "1.9.0-ea-b54"

Leads to:
---
$ javac -source 6 -bootclasspath <path-to-JDK6-rt.jar> Test.java 
warning: [options] source value 1.6 is obsolete and will be removed in a future release
warning: [options] To suppress warnings about obsolete options, use -Xlint:-options.
Test.java:7: error: method test in class Test cannot be applied to given types;
        Test.test(obj.getClass());
            ^
  required: Class<? extends T>,T[]
  found: Class<CAP#1>
  reason: formal varargs element type CAP#1 is not accessible from class Test
  where T is a type-variable:
    T extends Object declared in method <T>test(Class<? extends T>,T...)
  where CAP#1 is a fresh type-variable:
    CAP#1 extends Object from capture of ? extends Object
1 error
2 warnings
---

Workaround is to specify the method's parameter explicitly:
        Test.<Object>test(obj.getClass());

This may be caused by the fix for:

It seems it is caused by the fix for:
https://bugs.openjdk.java.net/browse/JDK-8039214
http://hg.openjdk.java.net/jdk9/dev/langtools/rev/414b82835861