// Test case for Issue 1628
// https://github.com/typetools/checker-framework/issues/1628

import org.checkerframework.checker.nullness.qual.Nullable;
import org.checkerframework.dataflow.qual.Pure;

class Issue1628<V extends Comparable<? super V>> implements Issue1628R<V> {

    public boolean isEmpty() {
        return false;
    }

    public boolean equals(@Nullable Object o) {
        return (o instanceof Issue1628R) && ((Issue1628R) o).isEmpty();
    }
}

interface Issue1628R<V extends Comparable<? super V>> {
    @Pure
    boolean isEmpty();
}