import java.util.concurrent.Callable;

public class ExceptionInference {

    public static void main(String[] args) {
        String s = testInference(new NilToObjE<String, RuntimeException>() {
            @Override
            public String call() {
                return "compiles";
            }
        });
        s = testInference(new NilToObjE<String, RuntimeException>() {
            @Override
            public String call() {
                throw new RuntimeException("compiles");
            }
        });
        s = testInference(() -> "doesn't compile");
        s = testInference(() -> {
            throw new RuntimeException("doesn't compile");
        });
    }

    static <R, E extends Exception> R testInference(NilToObjE<R, E> f) throws E {
        return f.call();
    }

    @FunctionalInterface
    interface NilToObjE<R, E extends Exception> extends Callable<R> {
        @Override
        R call() throws E;
    }
}