third_party/checker_framework_dataflow/java/org/checkerframework/dataflow/analysis/AbstractValue.java

package org.checkerframework.dataflow.analysis;

/**
 * An abstract value used in the org.checkerframework.dataflow analysis.
 *
 * @author Stefan Heule
 */
public interface AbstractValue<V extends AbstractValue<V>> {

    /**
     * Compute the least upper bound of two stores.
     *
     * <p><em>Important</em>: This method must fulfill the following contract:
     *
     * <ul>
     *   <li>Does not change {@code this}.
     *   <li>Does not change {@code other}.
     *   <li>Returns a fresh object which is not aliased yet.
     *   <li>Returns an object of the same (dynamic) type as {@code this}, even if the signature is
     *       more permissive.
     *   <li>Is commutative.
     * </ul>
     */
    V leastUpperBound(V other);
}