A DESCRIPTION OF THE PROBLEM :
The following code uses a method parameter with invalid bound, but is accepted by the compiler:

class Parent {}
class Child extends Parent {}
class Container<T extends Child> {}
public class Test {
    public static <T extends Parent> int method(Container<? super T> par) { // Why is this allowed?
           return 0;
    }
    public static void main(String args[]) {
        if (method(new Container<>()) == 0) {
            System.out.println("Zero");
        }
    }
}

We are using the type argument ? super T that has no upper bound and does not satisfy the type parameter declaration on Container<T extends Child> {}.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Just compile the give code with the latest Javac tool.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
The code should be rejected by the compiler.
ACTUAL -
The code is allowed without any error.

---------- BEGIN SOURCE ----------
class Parent {}
class Child extends Parent {}
class Container<T extends Child> {}
public class Test {
    public static <T extends Parent> int method(Container<? super T> par) { // Why is this allowed?
           return 0;
    }
    public static void main(String args[]) {
        if (method(new Container<>()) == 0) {
            System.out.println("Zero");
        }
    }
}
---------- END SOURCE ----------

FREQUENCY : always