Summary

Update javax.land.model API to support component local variables as part of a preview language feature.

Problem

The Derived Record Creation feature contains new language structures to be modeled.

Solution

Use the preview visitors to provide the necessary language model.

Specification

diff --git a/src/java.compiler/share/classes/javax/lang/model/element/ElementKind.java b/src/java.compiler/share/classes/javax/lang/model/element/ElementKind.java
index 4190e2acdab..91382fe6e90 100644
--- a/src/java.compiler/share/classes/javax/lang/model/element/ElementKind.java
+++ b/src/java.compiler/share/classes/javax/lang/model/element/ElementKind.java
@@ -25,6 +25,8 @@

 package javax.lang.model.element;

+import jdk.internal.javac.PreviewFeature;
+
 /**
  * The {@code kind} of an element.
  *
@@ -121,7 +123,14 @@ public enum ElementKind {
      * A binding variable in a pattern.
      * @since 16
      */
-    BINDING_VARIABLE;
+    BINDING_VARIABLE,
+
+    /**
+     * A local component variable in a derived record creation expression.
+     * @since 23
+     */
+    @PreviewFeature(feature=PreviewFeature.Feature.DERIVED_RECORD_CREATION, reflective=true)
+    COMPONENT_LOCAL_VARIABLE;

     // Maintenance note: check if the default implementation of
     // Elements.getOutermostTypeElement needs updating when new kind
@@ -200,7 +209,8 @@ public boolean isInitializer() {
      * Returns {@code true} if this is a kind of variable: including
      * {@code ENUM_CONSTANT}, {@code FIELD}, {@code PARAMETER},
      * {@code LOCAL_VARIABLE}, {@code EXCEPTION_PARAMETER},
-     * {@code RESOURCE_VARIABLE}, and {@code BINDING_VARIABLE}.
+     * {@code RESOURCE_VARIABLE}, {@code BINDING_VARIABLE}, and
+     * {@code COMPONENT_LOCAL_VARIABLE}.
      *
      * @return {@code true} if this is a kind of variable
      * @since 19
@@ -209,7 +219,7 @@ public boolean isVariable() {
         return switch(this) {
         case ENUM_CONSTANT, FIELD, PARAMETER,
              LOCAL_VARIABLE, EXCEPTION_PARAMETER, RESOURCE_VARIABLE,
-             BINDING_VARIABLE -> true;
+             BINDING_VARIABLE, COMPONENT_LOCAL_VARIABLE -> true;
         default -> false;
         };
     }

--- a/src/java.compiler/share/classes/javax/lang/model/util/ElementKindVisitor6.java
+++ b/src/java.compiler/share/classes/javax/lang/model/util/ElementKindVisitor6.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2005, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2005, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -25,6 +25,8 @@

 package javax.lang.model.util;

+import jdk.internal.javac.PreviewFeature;
+
 import javax.lang.model.element.*;
 import javax.annotation.processing.SupportedSourceVersion;
 import javax.lang.model.SourceVersion;
@@ -264,6 +266,9 @@
         case BINDING_VARIABLE:
             return visitVariableAsBindingVariable(e, p);

+        case COMPONENT_LOCAL_VARIABLE:
+            return visitVariableAsComponentLocalVariable(e, p);
+
         default:
             throw new AssertionError("Bad kind " + k + " for VariableElement" + e);
         }
@@ -364,6 +369,22 @@
         return visitUnknown(e, p);
     }

+    /**
+     * Visits a {@code COMPONENT_LOCAL_VARIABLE} variable element.
+     *
+     * @implSpec This implementation calls {@code visitUnknown}.
+     *
+     * @param e the element to visit
+     * @param p a visitor-specified parameter
+     * @return  the result of {@code visitUnknown}
+     *
+     * @since 23
+     */
+    @PreviewFeature(feature=PreviewFeature.Feature.DERIVED_RECORD_CREATION, reflective=true)
+    public R visitVariableAsComponentLocalVariable(VariableElement e, P p) {
+        return visitUnknown(e, p);
+    }
+
     /**
      * {@inheritDoc ElementVisitor}
      *

--- a/src/java.compiler/share/classes/javax/lang/model/util/ElementKindVisitorPreview.java
+++ b/src/java.compiler/share/classes/javax/lang/model/util/ElementKindVisitorPreview.java
@@ -86,4 +86,21 @@ protected ElementKindVisitorPreview() {
     protected ElementKindVisitorPreview(R defaultValue) {
         super(defaultValue);
     }
+
+    /**
+     * {@inheritDoc ElementKindVisitor6}
+     *
+     * @implSpec This implementation calls {@code defaultAction}.
+     *
+     * @param e {@inheritDoc ElementKindVisitor6}
+     * @param p {@inheritDoc ElementKindVisitor6}
+     * @return  the result of {@code defaultAction}
+     *
+     * @since 23
+     */
+    @Override
+    @PreviewFeature(feature=PreviewFeature.Feature.DERIVED_RECORD_CREATION, reflective=true)
+    public R visitVariableAsComponentLocalVariable(VariableElement e, P p) {
+        return defaultAction(e, p);
+     }
 }