diff --git a/app/code/Magento/Catalog/etc/di.xml b/app/code/Magento/Catalog/etc/di.xml
index ceaa51b70ecdb..228a9fd59b401 100644
--- a/app/code/Magento/Catalog/etc/di.xml
+++ b/app/code/Magento/Catalog/etc/di.xml
@@ -446,9 +446,9 @@
     <preference for="\Magento\Catalog\Api\CategoryLinkManagementInterface" type="\Magento\Catalog\Model\CategoryLinkManagement" />
     <preference for="Magento\Catalog\Api\Data\ProductWebsiteLinkInterface" type="Magento\Catalog\Model\ProductWebsiteLink" />
     <preference for="Magento\Catalog\Api\ProductWebsiteLinkRepositoryInterface" type="Magento\Catalog\Model\ProductWebsiteLinkRepository" />
-    <preference for="\Magento\Catalog\Api\CategoryLinkRepositoryInterface" type="\Magento\Catalog\Model\CategoryLinkRepository" />
+    <preference for="\Magento\Catalog\Api\CategoryLinkRepositoryInterface" type="Magento\Catalog\Model\CategoryLinkRepository" />
     <preference for="Magento\Catalog\Api\Data\ProductCustomOptionInterface" type="Magento\Catalog\Model\Product\Option" />
-    <preference for="Magento\Catalog\Api\ProductCustomOptionRepositoryInterface" type="\Magento\Catalog\Model\Product\Option\Repository" />
+    <preference for="Magento\Catalog\Api\ProductCustomOptionRepositoryInterface" type="Magento\Catalog\Model\Product\Option\Repository" />
     <preference for="Magento\Catalog\Api\Data\ProductCustomOptionTypeInterface" type="Magento\Catalog\Model\Product\Option\Type" />
     <preference for="Magento\Catalog\Api\ProductTierPriceManagementInterface" type="\Magento\Catalog\Model\Product\TierPriceManagement" />
     <preference for="Magento\Catalog\Api\Data\ProductTierPriceInterface" type="Magento\Catalog\Model\Product\TierPrice" />
diff --git a/app/code/Magento/Downloadable/etc/di.xml b/app/code/Magento/Downloadable/etc/di.xml
index aaf1c18277f20..aaed6ccc079d4 100644
--- a/app/code/Magento/Downloadable/etc/di.xml
+++ b/app/code/Magento/Downloadable/etc/di.xml
@@ -73,8 +73,8 @@
             </argument>
         </arguments>
     </type>
-    <preference for="\Magento\Downloadable\Api\LinkRepositoryInterface" type="\Magento\Downloadable\Model\LinkRepository" />
-    <preference for="\Magento\Downloadable\Api\SampleRepositoryInterface" type="\Magento\Downloadable\Model\SampleRepository" />
+    <preference for="\Magento\Downloadable\Api\LinkRepositoryInterface" type="Magento\Downloadable\Model\LinkRepository" />
+    <preference for="\Magento\Downloadable\Api\SampleRepositoryInterface" type="Magento\Downloadable\Model\SampleRepository" />
     <preference for="\Magento\Downloadable\Api\Data\LinkInterface" type="\Magento\Downloadable\Model\Link" />
     <preference for="\Magento\Downloadable\Api\Data\SampleInterface" type="\Magento\Downloadable\Model\Sample" />
     <preference for="\Magento\Downloadable\Api\Data\File\ContentInterface" type="\Magento\Downloadable\Model\File\Content" />
diff --git a/app/code/Magento/Quote/etc/di.xml b/app/code/Magento/Quote/etc/di.xml
index 2e53f17c127df..4b9d2b8955b6c 100644
--- a/app/code/Magento/Quote/etc/di.xml
+++ b/app/code/Magento/Quote/etc/di.xml
@@ -22,7 +22,7 @@
     <preference for="Magento\Quote\Api\CouponManagementInterface" type="Magento\Quote\Model\CouponManagement" />
     <preference for="Magento\Quote\Api\CartManagementInterface" type="Magento\Quote\Model\QuoteManagement" />
     <preference for="Magento\Authorization\Model\UserContextInterface" type="Magento\Authorization\Model\CompositeUserContext"/>
-    <preference for="Magento\Quote\Api\CartTotalRepositoryInterface" type="\Magento\Quote\Model\Cart\CartTotalRepository" />
+    <preference for="Magento\Quote\Api\CartTotalRepositoryInterface" type="Magento\Quote\Model\Cart\CartTotalRepository" />
     <preference for="Magento\Quote\Api\CartTotalManagementInterface" type="\Magento\Quote\Model\Cart\CartTotalManagement" />
     <preference for="Magento\Quote\Api\Data\TotalsInterface" type="\Magento\Quote\Model\Cart\Totals" />
     <preference for="Magento\Quote\Api\Data\TotalSegmentInterface" type="\Magento\Quote\Model\Cart\TotalSegment" />
diff --git a/setup/src/Magento/Setup/Module/Di/Code/Scanner/RepositoryScanner.php b/setup/src/Magento/Setup/Module/Di/Code/Scanner/RepositoryScanner.php
index b3e4d720ecaf7..1a008850fa25f 100644
--- a/setup/src/Magento/Setup/Module/Di/Code/Scanner/RepositoryScanner.php
+++ b/setup/src/Magento/Setup/Module/Di/Code/Scanner/RepositoryScanner.php
@@ -3,6 +3,7 @@
  * Copyright © 2016 Magento. All rights reserved.
  * See COPYING.txt for license details.
  */
+
 namespace Magento\Setup\Module\Di\Code\Scanner;
 
 use Magento\Framework\Autoload\AutoloaderRegistry;
@@ -37,18 +38,21 @@ public function collectEntities(array $files)
                 if (
                     $forType !== null
                     && $replacementType !== null
-                    && (substr($forType->nodeValue, -19) == 'RepositoryInterface')
+                    && (substr($forType->nodeValue, -19) === 'RepositoryInterface')
                 ) {
-                    if (!class_exists($replacementType->nodeValue, false)
-                        && !AutoloaderRegistry::getAutoloader()->loadClass($replacementType->nodeValue)) {
-                        $persistor = str_replace('\\Repository', 'InterfacePersistor', $replacementType->nodeValue);
-                        $factory = str_replace('\\Repository', 'InterfaceFactory', $replacementType->nodeValue);
-                        $searchResultFactory
-                            = str_replace('\\Repository', 'SearchResultInterfaceFactory', $replacementType->nodeValue);
+                    // backward compatibility workaround for composer below 1.3.0
+                    // (https://github.com/composer/composer/issues/5923)
+                    $nodeValue = ltrim($replacementType->nodeValue, '\\');
+                    if (!class_exists($nodeValue, false)
+                        && !AutoloaderRegistry::getAutoloader()->loadClass($nodeValue)
+                    ) {
+                        $persistor = str_replace('\\Repository', 'InterfacePersistor', $nodeValue);
+                        $factory = str_replace('\\Repository', 'InterfaceFactory', $nodeValue);
+                        $searchResultFactory = str_replace('\\Repository', 'SearchResultInterfaceFactory', $nodeValue);
                         $repositoryClassNames[$persistor] = $persistor;
                         $repositoryClassNames[$factory] = $factory;
                         $repositoryClassNames[$searchResultFactory] = $searchResultFactory;
-                        $repositoryClassNames[$replacementType->nodeValue] = $replacementType->nodeValue;
+                        $repositoryClassNames[$nodeValue] = $nodeValue;
                     }
                 }
             }