Summary

Represent the superclass and superinterfaces in ClassTypeSig with ClassTypeSig and List<ClassTypeSig>.

Problem

In JVMS 4.7.9.1, the superclass and superinterfaces of a class signature is required to be class signatures. Yet Class-File API uses a RefTypeSig, allowing potentially invalid signatures, like using an array class as a superclass.

Solution

Change the superclass and superinterfaces in ClassTypeSig from RefTypeSig and List<RefTypeSig> to ClassTypeSig and List<ClassTypeSig>.

Specification

--- a/src/java.base/share/classes/java/lang/classfile/ClassSignature.java
+++ b/src/java.base/share/classes/java/lang/classfile/ClassSignature.java
@@ -42,10 +42,10 @@ public sealed interface ClassSignature
     List<Signature.TypeParam> typeParameters();

     /** {@return the instantiation of the superclass in this signature} */
-    Signature.RefTypeSig superclassSignature();
+    Signature.ClassTypeSig superclassSignature();

     /** {@return the instantiation of the interfaces in this signature} */
-    List<Signature.RefTypeSig> superinterfaceSignatures();
+    List<Signature.ClassTypeSig> superinterfaceSignatures();

     /** {@return the raw signature string} */
     String signatureString();
@@ -55,8 +55,8 @@ public sealed interface ClassSignature
      * @param superclassSignature the superclass
      * @param superinterfaceSignatures the interfaces
      */
-    public static ClassSignature of(Signature.RefTypeSig superclassSignature,
-                                    Signature.RefTypeSig... superinterfaceSignatures) {
+    public static ClassSignature of(Signature.ClassTypeSig superclassSignature,
+                                    Signature.ClassTypeSig... superinterfaceSignatures) {
         return of(List.of(), superclassSignature, superinterfaceSignatures);
     }

@@ -67,8 +67,8 @@ public static ClassSignature of(Signature.RefTypeSig superclassSignature,
      * @param superinterfaceSignatures the interfaces
      */
     public static ClassSignature of(List<Signature.TypeParam> typeParameters,
-                                    Signature.RefTypeSig superclassSignature,
-                                    Signature.RefTypeSig... superinterfaceSignatures) {
+                                    Signature.ClassTypeSig superclassSignature,
+                                    Signature.ClassTypeSig... superinterfaceSignatures) {
         return new SignaturesImpl.ClassSignatureImpl(
                 requireNonNull(typeParameters),
                 requireNonNull(superclassSignature),