presto-main/src/main/java/io/prestosql/sql/planner/EqualityInference.java/EqualityInference/EqualityInference
class EqualityInference:    private EqualityInference(Multimap<Expression, Expression> equalitySets, Map<Expression, Expression> canonicalMap, Set<Expression> derivedExpressions)
    {
        this.equalitySets = equalitySets;
        this.canonicalMap = canonicalMap;
        this.derivedExpressions = derivedExpressions;
    }