[java] Resolve #468

- This is still not perfect. There are plenty of scenarios where this
could fail (ie: multidimensional arrays), but is closer to what we want
without a full rewrite.
 - On the future we need to review this rule once again.

pmd-java/src/main/java/net/sourceforge/pmd/lang/java/rule/sunsecure/ArrayIsStoredDirectlyRule.java

@@ -131,7 +131,7 @@ public class ArrayIsStoredDirectlyRule extends AbstractSunSecureRule {
                     if (val == null) {
                         continue;
                     }
-                    ASTPrimarySuffix foo = se.getFirstDescendantOfType(ASTPrimarySuffix.class);
+                    ASTPrimarySuffix foo = e.getFirstDescendantOfType(ASTPrimarySuffix.class);
                     if (foo != null && foo.isArrayDereference()) {
                         continue;
                     }

pmd-java/src/test/resources/net/sourceforge/pmd/lang/java/rule/sunsecure/xml/ArrayIsStoredDirectly.xml

@@ -175,6 +175,23 @@ public class NotificationPacket {
             this.message = new String(rawTypeData, StandardCharsets.UTF_8);
         }
     }
+}
+        ]]></code>
+    </test-code>
+    
+    <test-code>
+        <description>#468 False positive when qualifying with this</description>
+        <expected-problems>0</expected-problems>
+        <code><![CDATA[
+public class Foo {
+    private final int[] a;
+
+    public Foo(int[] b) {
+        this.a = new int[b.length];
+        for (int i = 0; i < b.length; i++) {
+            this.a[i] = b[i];
+        }
+    }
 }
         ]]></code>
     </test-code>