@Override public Boolean visitPatternFieldRef(RexPatternFieldRef fieldRef) {
      return Boolean.FALSE;
    }
A visitor classifying row expressions as simply correlated if they satisfy the conditions
below.
<ul>
<li>all correlated variables have the specified correlation id</li>
<li>all leafs are either correlated variables, dynamic parameters, or literals</li>
<li>intermediate nodes are either calls or field access expressions</li>
</ul>

Examples:
<pre>
+(10, $cor0.DEPTNO) -> TRUE
/(100,+(10, $cor0.DEPTNO)) -> TRUE
CAST(+(10, $cor0.DEPTNO)):INTEGER NOT NULL -> TRUE
+($0, $cor0.DEPTNO) -> FALSE
</pre>
ql/src/java/org/apache/hadoop/hive/ql/optimizer/calcite/rules/CorrelateProjectExtractor.java