presto-main/src/main/java/io/prestosql/sql/planner/RelationPlanner.java/RelationPlanner/isEqualComparisonExpression
class RelationPlanner:    private static boolean isEqualComparisonExpression(Expression conjunct)
    {
        return conjunct instanceof ComparisonExpression && ((ComparisonExpression) conjunct).getOperator() == ComparisonExpression.Operator.EQUAL;
    }