Let's consider following code:

public class Test12 {
    interface Iface<A1 extends A2, A2> {
        String m(A1 t);
    }

    public void run() {
        Iface<? super Integer, Number> i = (Integer a) -> a.toString();
    }
}

It fails with following error:

Error:(7, 44) java: incompatible types: Test12.Iface<java.lang.Integer,java.lang.Integer> cannot be converted to Test12.Iface<? super java.lang.Integer,java.lang.Number>

While it should compile successfully since only A1 should be instantiated as a result of reduction in jls-18.5.3-220-A:
Integer = A1

While A2 should remain unchanged as Number according to jls-18.5.3-220-B.


It looks like resolution takes place along with reduction in jls-18.5.3-210 in javac.