Merge branch '4.0'

* 4.0:
  fixed wrong merge
  Tweak message to be Flex friendly
  [Routing] fixed tests
  Fixing wrong class_exists on interface
  Preserve percent-encoding in URLs when performing redirects in the UrlMatcher
  removed FIXME
  [Console] Fix a bug when passing a letter that could be an alias
  add missing validation options to XSD file
  Take advantage of AnnotationRegistry::registerUniqueLoader
  [DI] Optimize Container::get() for perf
  fix merge
  Fix tests
  Refactoring tests.

Author: fabpot

Tests/OptionsResolverTest.php

@@ -1504,12 +1504,12 @@ public function testArrayAccess()
         });
 
         $this->resolver->setDefault('lazy2', function (Options $options) {
-            Assert::assertTrue(isset($options['default1']));
-            Assert::assertTrue(isset($options['default2']));
-            Assert::assertTrue(isset($options['required']));
-            Assert::assertTrue(isset($options['lazy1']));
-            Assert::assertTrue(isset($options['lazy2']));
-            Assert::assertFalse(isset($options['defined']));
+            Assert::assertArrayHasKey('default1', $options);
+            Assert::assertArrayHasKey('default2', $options);
+            Assert::assertArrayHasKey('required', $options);
+            Assert::assertArrayHasKey('lazy1', $options);
+            Assert::assertArrayHasKey('lazy2', $options);
+            Assert::assertArrayNotHasKey('defined', $options);
 
             Assert::assertSame(0, $options['default1']);
             Assert::assertSame(42, $options['default2']);