static @Nullable TypeInfo parseTopLevelClassRefSignatureToTypeInfo(CharIterator signature, TypeInfoProvider mapping) throws ClsFormatException {
    switch (signature.current()) {
      case 'L':
        return parseParameterizedClassRefSignatureToTypeInfo(signature, mapping);
      case 'T':
        return new TypeInfo.RefTypeInfo(parseTypeVariableRefSignature(signature));
      default:
        return null;
    }
  }
static @Nullable TypeInfo parseTopLevelClassRefSignatureToTypeInfo(CharIterator signature, TypeInfoProvider mapping)