code: public function process(Tokens $tokens, Token $token, $index)
      {
          if (!$token->equalsAny([
              [T_CLASS, 'class'],
              [T_STRING, 'class'],
          ], false)) {
              return;
          }
  
          $prevIndex = $tokens->getPrevMeaningfulToken($index);
          $prevToken = $tokens[$prevIndex];
  
          if ($prevToken->isGivenKind(T_DOUBLE_COLON)) {
              $tokens[$index] = new Token([CT::T_CLASS_CONSTANT, $token->getContent()]);
          }
      }
docs: {@inheritdoc}