Add Java 23 constants for AST

Backports AST Java 23 constants and helper methods of
eclipse-jdt@3e78c6e
to master.

org.eclipse.jdt.core/dom/org/eclipse/jdt/core/dom/AST.java

@@ -469,6 +469,22 @@ public final class AST {
 	 * @since 3.38
 	 */
 	public static final int JLS22 = 22;
+	/**
+	 * Constant for indicating the AST API that handles JLS23.
+	 * <p>
+	 * This API is capable of handling all constructs in the
+	 * Java language as described in the Java Language
+	 * Specification, Java SE 23 Edition (JLS23).
+	 * JLS23 is a superset of all earlier versions of the
+	 * Java language, and the JLS23 API can be used to manipulate
+	 * programs written in all versions of the Java language
+	 * up to and including Java SE 23(aka JDK 23).
+	 * </p>
+	 *
+	 * @noreference This field is not intended to be referenced by clients. Java 23 support is WIP.
+	 * @since 3.38
+	 */
+	public static final int JLS23 = 23;
 	/**
 	 * Internal synonym for {@link #JLS15}. Use to alleviate
 	 * deprecation warnings once JLS15 is deprecated
@@ -506,9 +522,14 @@ public final class AST {
 	static final int JLS21_INTERNAL = JLS21;
 	/**
 	 * Internal synonym for {@link #JLS22}. Use to alleviate
-	 * deprecation warnings once JLS21 is deprecated
+	 * deprecation warnings once JLS22 is deprecated
 	 */
 	static final int JLS22_INTERNAL = JLS22;
+	/**
+	 * Internal synonym for {@link #JLS23}. Use to alleviate
+	 * deprecation warnings once JLS23 is deprecated
+	 */
+	static final int JLS23_INTERNAL = JLS23;
 	/**
 	 * Internal property for latest supported JLS level
 	 * This provides the latest JLS level.
@@ -1260,6 +1281,7 @@ private static Map<String, Long> getLevelMapTable() {
         t.put(JavaCore.VERSION_20, ClassFileConstants.JDK20);
         t.put(JavaCore.VERSION_21, ClassFileConstants.JDK21);
         t.put(JavaCore.VERSION_22, ClassFileConstants.JDK22);
+        t.put(JavaCore.VERSION_23, ClassFileConstants.JDK23);
         return Collections.unmodifiableMap(t);
 	}
 	private static Map<String, Integer> getApiLevelMapTable() {
@@ -1286,6 +1308,7 @@ private static Map<String, Integer> getApiLevelMapTable() {
         t.put(JavaCore.VERSION_20, JLS20_INTERNAL);
         t.put(JavaCore.VERSION_21, JLS21_INTERNAL);
         t.put(JavaCore.VERSION_22, JLS22_INTERNAL);
+        t.put(JavaCore.VERSION_23, JLS23_INTERNAL);
         return Collections.unmodifiableMap(t);
 	}
 	/**

org.eclipse.jdt.core/dom/org/eclipse/jdt/core/dom/ASTNode.java

@@ -2613,6 +2613,21 @@ final void supportedOnlyIn22() {
 		}
 	}
 	/**
+ 	 * Checks that this AST operation is only used when
+     * building JLS23 level ASTs.
+     * <p>
+     * Use this method to prevent access to new properties available only in JLS23.
+     * </p>
+     *
+	 * @exception UnsupportedOperationException if this operation is not used in JLS23
+	 * @since 3.38
+	 */
+	final void supportedOnlyIn23() {
+		if (this.ast.apiLevel < AST.JLS23_INTERNAL) {
+			throw new UnsupportedOperationException("Operation only supported in JLS23 AST"); //$NON-NLS-1$
+		}
+	}
+	/**
      * Checks that this AST operation is not used when
      * building JLS20 level ASTs.
      * <p>