GenericHell

GenHell.java

import java.util.Collection;
import java.util.Collections;

public class GenHell {

    class Model {}

    class BillingReserve<T extends Model> {

        BillingReserve(Collection<Long> ids) {
            
        }
    }

    <T extends Model> void makeHell(Collection<T> col) {
        Collection<Long> one = Collections.singleton(1L);

        new BillingReserve(col); //compile WTF

        new BillingReserve<>(col); //non-compile
        new BillingReserve<>(one); //compile

        new BillingReserve<Model>(col); //non-compile
        new BillingReserve<Model>(one); //compile model not needed

        new BillingReserve<T>(col); //non-compile
        new BillingReserve<T>(one); //compile
    }
}