Summary

InstanceOfTree.getType() returns null in some cases, but its documentation does not say it does. The proposal herein is to document the existing behavior.

Problem

InstanceOfTree.getType() returns null in some cases, but its documentation does not say it does.

Solution

Enhance the InstanceOfTree.getType() documentation to specify when the method returns null. The existing behavior is not changed. The method returns null if the instanceof uses a pattern, and the pattern is not a type test (binding) pattern.

Alternatively, the method could attempt to return a non-null value for patterns, but the semantics is unclear for complex patterns.

Specification

This is the proposed change:

diff --git a/src/jdk.compiler/share/classes/com/sun/source/tree/InstanceOfTree.java b/src/jdk.compiler/share/classes/com/sun/source/tree/InstanceOfTree.java
index f752f7f31913f..dfbf20f0640fb 100644
--- a/src/jdk.compiler/share/classes/com/sun/source/tree/InstanceOfTree.java
+++ b/src/jdk.compiler/share/classes/com/sun/source/tree/InstanceOfTree.java
@@ -48,8 +48,11 @@ public interface InstanceOfTree extends ExpressionTree {
     ExpressionTree getExpression();

     /**
-     * Returns the type for which to check.
-     * @return the type
+     * Returns the type for which to check, or {@code null} if this instanceof
+     * uses a pattern other the {@link BindingPatternTree}.
+     *
+     * @return the type or {@code null} if this instanceof uses a pattern other than
+     *         the {@linkplain BindingPatternTree}
      * @see #getPattern()
      */
     Tree getType();