Java generics extends Cannot infer arguments

Consider the following example:

public class Main {
    public static void main(String[] args) {

        class Parent {
            @Override
            public String toString() {
                return "this is Parent";
            }
        }

        class Child extends Parent {
        }

        class C<T extends Parent> {
            C(T a) {
                System.out.println(a);
            }
        }

        Parent parent = new Parent();
        Child child = new Child();
        C<Child> c = new C<>(child); // Ok
        C<Parent> d = new C<>(parent); // Ok
        C<Parent> e = new C<>(child); // Ok
        C<Child> f = new C<>(parent); // Compile error - Cannot infer arguments
        
    }

The following statement class C<T extends Parent> implies that class C can be generalized with anything that inherits from parent including both Child and Parent.
So, when I generalize it with Child, and try to call constructor with a Parent instance, why won’t it work?

>Solution :

Every Child is a Parent but not every Parent is a Child.