This code:

class ExceptionInferenceBug {

    interface PartialFunction<T, V> {
        V apply(T paramT);
    }

    interface Function<T, V> extends PartialFunction<T, V> {
        V apply(T paramT);
    }

    class O {}

    static <T, V> void run(Function<? super O, V> function) {}
    static <T, V> void run(PartialFunction<? super O, V> function) {}

    public static void main(String[] args) {
        run(t -> t.toString());
    }
}

makes javac generate an assertion error. If the second run method is commented out there is no error.

reported in lambda-dev list: http://mail.openjdk.java.net/pipermail/lambda-dev/2014-February/011910.html