models/User.php
public function attemptConfirmation($code)
    {
        /** @var Token $token */
        $token = $this->finder->findToken([
            'user_id' => $this->id,
            'code'    => $code,
            'type'    => Token::TYPE_CONFIRMATION,
        ])->one();

        if ($token === null || $token->isExpired) {
            \Yii::$app->session->setFlash('danger', \Yii::t('user', 'The confirmation link is invalid or expired. Please try requesting a new one.'));
        } else {
            $token->delete();
    
            $this->confirmed_at = time();
    
            \Yii::$app->user->login($this);
    
            \Yii::getLogger()->log('User has been confirmed', Logger::LEVEL_INFO);
    
            if ($this->save(false)) {
                \Yii::$app->session->setFlash('success', \Yii::t('user', 'Thank you, registration is now complete.'));
            } else {
                \Yii::$app->session->setFlash('danger', \Yii::t('user', 'Something went wrong and your account has not been confirmed.'));
            }
        }
    }
public function attemptConfirmation($code)
    {
        /** @var Token $token */
        $token = $this->finder->findToken([
            'user_id' => $this->id,
            'code'    => $code,
            'type'    => Token::TYPE_CONFIRMATION,
        ])->one();

        if ($token === null || $token->isExpired) {
            \Yii::$app->session->setFlash('danger', \Yii::t('user', 'The confirmation link is invalid or expired. Please try requesting a new one.'));
        } else {
            $token->delete();
    
            $this->confirmed_at = time();
    
            \Yii::$app->user->login($this);
    
            \Yii::getLogger()->log('User has been confirmed', Logger::LEVEL_INFO);
    
            if ($this->save(false)) {
                \Yii::$app->session->setFlash('success', \Yii::t('user', 'Thank you, registration is now complete.'));
            } else {
                \Yii::$app->session->setFlash('danger', \Yii::t('user', 'Something went wrong and your account has not been confirmed.'));
            }
        }
    }
This method attempts user confirmation. It uses finder to find token with given code and if it is expired
or does not exist, this method will throw exception.

If confirmation passes it will return true, otherwise it will return false.

@param  string  $code Confirmation code.