Merge branch '2.7' into 2.8

* 2.7:
  [HttpKernel] fixed internal subrequests having an if-modified-since-header
  [Validator] Added additional MasterCard range to the CardSchemeValidator
  Make the exception message more clear.
  [Form] fixed bug - name in ButtonBuilder
  [ClassLoader] Fix declared classes being computed when not needed

ClassCollectionLoader.php

@@ -43,12 +43,12 @@ class ClassCollectionLoader
 
         self::$loaded[$name] = true;
 
-        $declared = array_merge(get_declared_classes(), get_declared_interfaces());
-        if (function_exists('get_declared_traits')) {
-            $declared = array_merge($declared, get_declared_traits());
-        }
-
         if ($adaptive) {
+            $declared = array_merge(get_declared_classes(), get_declared_interfaces());
+            if (function_exists('get_declared_traits')) {
+                $declared = array_merge($declared, get_declared_traits());
+            }
+
             // don't include already declared classes
             $classes = array_diff($classes, $declared);
 
@@ -87,11 +87,17 @@ class ClassCollectionLoader
             }
         }
 
-        if (!$reload && is_file($cache)) {
+        if (!$reload && file_exists($cache)) {
             require_once $cache;
 
             return;
         }
+        if (!$adaptive) {
+            $declared = array_merge(get_declared_classes(), get_declared_interfaces());
+            if (function_exists('get_declared_traits')) {
+                $declared = array_merge($declared, get_declared_traits());
+            }
+        }
 
         $files = array();
         $content = '';