Fixed issue magento2-login-as-customer/issues/159

Author: ihorvansach

app/code/Magento/LoginAsCustomerQuote/Plugin/LoginAsCustomerApi/ProcessShoppingCartPlugin.php

@@ -60,7 +60,7 @@ public function __construct(
     }
 
     /**
-     * Remove all items from guest shopping cart
+     * Remove all items from guest shopping cart and mark customer cart as not-guest
      *
      * @param AuthenticateCustomerBySecretInterface $subject
      * @param string $secret
@@ -77,31 +77,9 @@ public function beforeExecute(
             $quote = $this->checkoutSession->getQuote();
             /* Remove items from guest cart */
             $quote->removeAllItems();
+            $quote->setCustomerIsGuest(0);
             $this->quoteRepository->save($quote);
         }
         return null;
     }
-
-    /**
-     * Mark customer cart as not-guest
-     *
-     * @param AuthenticateCustomerBySecretInterface $subject
-     * @param void $result
-     * @param string $secret
-     * @return void
-     * @throws LocalizedException
-     *
-     * @SuppressWarnings(PHPMD.UnusedFormalParameter)
-     */
-    public function afterExecute(
-        AuthenticateCustomerBySecretInterface $subject,
-        $result,
-        string $secret
-    ) {
-        $this->checkoutSession->loadCustomerQuote();
-        $quote = $this->checkoutSession->getQuote();
-
-        $quote->setCustomerIsGuest(0);
-        $this->quoteRepository->save($quote);
-    }
 }