src/jdk.compiler/share/classes/com/sun/tools/javac/code/Source.java

*** 236,10 ***
--- 236,12 ---
          PATTERN_SWITCH(JDK21, Fragments.FeaturePatternSwitch, DiagKind.PLURAL),
          REDUNDANT_STRICTFP(JDK17),
          UNCONDITIONAL_PATTERN_IN_INSTANCEOF(JDK21, Fragments.FeatureUnconditionalPatternsInInstanceof, DiagKind.PLURAL),
          RECORD_PATTERNS(JDK21, Fragments.FeatureDeconstructionPatterns, DiagKind.PLURAL),
          STRING_TEMPLATES(JDK21, Fragments.FeatureStringTemplates, DiagKind.PLURAL),
+         PRIMITIVE_CLASSES(JDK21, Fragments.FeaturePrimitiveClasses, DiagKind.PLURAL),
+         VALUE_CLASSES(JDK21, Fragments.FeatureValueClasses, DiagKind.PLURAL),
          WARN_ON_ILLEGAL_UTF8(MIN, JDK21),
          UNNAMED_VARIABLES(JDK21, Fragments.FeatureUnnamedVariables, DiagKind.PLURAL),
          ;
  
          enum DiagKind {

*** 293,10 ***
--- 295,13 ---
                      Fragments.FeatureNotSupportedInSourcePlural(optFragment, sourceName, minLevel.name);
          }
  
          public Error error(String sourceName) {
              Assert.checkNonNull(optFragment);
+             if (this == PRIMITIVE_CLASSES) {
+                 return Errors.PrimitiveClassesNotSupported(minLevel.name);
+             }
              return optKind == DiagKind.NORMAL ?
                      Errors.FeatureNotSupportedInSource(optFragment, sourceName, minLevel.name) :
                      Errors.FeatureNotSupportedInSourcePlural(optFragment, sourceName, minLevel.name);
          }
      }