diff --git a/src/Symfony/Component/DependencyInjection/Loader/XmlFileLoader.php b/src/Symfony/Component/DependencyInjection/Loader/XmlFileLoader.php
index 6b1381b012..91bb2d071d 100644
--- a/src/Symfony/Component/DependencyInjection/Loader/XmlFileLoader.php
+++ b/src/Symfony/Component/DependencyInjection/Loader/XmlFileLoader.php
@@ -505,13 +505,13 @@ EOF
     {
         foreach ($alias->attributes as $name => $node) {
             if (!in_array($name, array('alias', 'id', 'public'))) {
-                @trigger_error(sprintf('Using the attribute "%s" is deprecated for alias definition "%s" in "%s". Allowed attributes are "alias", "id" and "public". The XmlFileLoader will raise an exception in Symfony 4.0, instead of silently ignoring unsupported attributes.', $name, $alias->getAttribute('id'), $file), E_USER_DEPRECATED);
+                @trigger_error(sprintf('Using the attribute "%s" is deprecated for the service "%s" which is defined as an alias in "%s". Allowed attributes for service aliases are "alias", "id" and "public". The XmlFileLoader will raise an exception in Symfony 4.0, instead of silently ignoring unsupported attributes.', $name, $alias->getAttribute('id'), $file), E_USER_DEPRECATED);
             }
         }
 
         foreach ($alias->childNodes as $child) {
             if ($child instanceof \DOMElement && $child->namespaceURI === self::NS) {
-                @trigger_error(sprintf('Using the element "%s" is deprecated for alias definition "%s" in "%s". The XmlFileLoader will raise an exception in Symfony 4.0, instead of silently ignoring unsupported elements.', $child->localName, $alias->getAttribute('id'), $file), E_USER_DEPRECATED);
+                @trigger_error(sprintf('Using the element "%s" is deprecated for the service "%s" which is defined as an alias in "%s". The XmlFileLoader will raise an exception in Symfony 4.0, instead of silently ignoring unsupported elements.', $child->localName, $alias->getAttribute('id'), $file), E_USER_DEPRECATED);
             }
         }
     }
diff --git a/src/Symfony/Component/DependencyInjection/Loader/YamlFileLoader.php b/src/Symfony/Component/DependencyInjection/Loader/YamlFileLoader.php
index 82bbf90182..569c8f4e02 100644
--- a/src/Symfony/Component/DependencyInjection/Loader/YamlFileLoader.php
+++ b/src/Symfony/Component/DependencyInjection/Loader/YamlFileLoader.php
@@ -180,7 +180,7 @@ class YamlFileLoader extends FileLoader
 
             foreach ($service as $key => $value) {
                 if (!in_array($key, array('alias', 'public'))) {
-                    @trigger_error(sprintf('The configuration key "%s" is unsupported for alias definition "%s" in "%s". Allowed configuration keys are "alias" and "public". The YamlFileLoader will raise an exception in Symfony 4.0, instead of silently ignoring unsupported attributes.', $key, $id, $file), E_USER_DEPRECATED);
+                    @trigger_error(sprintf('The configuration key "%s" is unsupported for the service "%s" which is defined as an alias in "%s". Allowed configuration keys for service aliases are "alias" and "public". The YamlFileLoader will raise an exception in Symfony 4.0, instead of silently ignoring unsupported attributes.', $key, $id, $file), E_USER_DEPRECATED);
                 }
             }
 
diff --git a/src/Symfony/Component/DependencyInjection/Tests/Loader/XmlFileLoaderTest.php b/src/Symfony/Component/DependencyInjection/Tests/Loader/XmlFileLoaderTest.php
index a351c62ebc..04fad8b581 100644
--- a/src/Symfony/Component/DependencyInjection/Tests/Loader/XmlFileLoaderTest.php
+++ b/src/Symfony/Component/DependencyInjection/Tests/Loader/XmlFileLoaderTest.php
@@ -563,9 +563,9 @@ class XmlFileLoaderTest extends \PHPUnit_Framework_TestCase
     public function testAliasDefinitionContainsUnsupportedElements()
     {
         $deprecations = array(
-            'Using the attribute "class" is deprecated for alias definition "bar"',
-            'Using the element "tag" is deprecated for alias definition "bar"',
-            'Using the element "factory" is deprecated for alias definition "bar"',
+            'Using the attribute "class" is deprecated for the service "bar" which is defined as an alias',
+            'Using the element "tag" is deprecated for the service "bar" which is defined as an alias',
+            'Using the element "factory" is deprecated for the service "bar" which is defined as an alias',
         );
 
         ErrorAssert::assertDeprecationsAreTriggered($deprecations, function () {