public Frame decorrelateRel(HiveFilter rel) {
    return decorrelateRel((Filter) rel);
  }
Returns whether one type is just a widening of another.

<p>For example:<ul>
<li>{@code VARCHAR(10)} is a widening of {@code VARCHAR(5)}.
<li>{@code VARCHAR(10)} is a widening of {@code VARCHAR(10) NOT NULL}.
</ul>
ql/src/java/org/apache/hadoop/hive/ql/optimizer/calcite/rules/HiveRelDecorrelator.java