The following test fails with a CCE:

public class MethodReferenceTestPrivateTypeConversion {

    interface ISi { int m(Short a); }
    
    public static void main(String[] args) {
      (new MethodReferenceTestPrivateTypeConversion()).testUnboxObjectToNumberWiden();
    }

    public void testUnboxObjectToNumberWiden() {
        ISi q = (new E<Short>())::xI;
        q.m((short)77);
    }
    
    class E<T> {
        private T xI(T t) { return t; }
    }
}

The <Short> info is lost and the type of the result (before conversion to the functional interface type) is needed.

Maurizio suggests that something like preserving the type computed by Attr into the JCMemberReference tree should be done.

This problem exists before and after the change from reference bridging to reference to lambda conversion for 8037404 et. al.