Merge branch '3.4' into 4.3

* 3.4:
  Fix inconsistent return points.
  [Security/Core] UserInterface::getPassword() can return null
  [Router] Fix TraceableUrlMatcher behaviour with trailing slash

Author: nicolas-grekas

Compiler/CheckArgumentsValidityPass.php

@@ -81,5 +81,7 @@ protected function processValue($value, $isRoot = false)
                 }
             }
         }
+
+        return null;
     }
 }

EnvVarProcessor.php

@@ -120,7 +120,7 @@ public function getEnv($prefix, $name, \Closure $getEnv)
 
         if (false !== $i || 'string' !== $prefix) {
             if (null === $env = $getEnv($name)) {
-                return;
+                return null;
             }
         } elseif (isset($_ENV[$name])) {
             $env = $_ENV[$name];
@@ -132,7 +132,7 @@ public function getEnv($prefix, $name, \Closure $getEnv)
             }
 
             if (null === $env = $this->container->getParameter("env($name)")) {
-                return;
+                return null;
             }
         }
 

LazyProxy/ProxyHelper.php

@@ -50,8 +50,7 @@ public static function getTypeHint(\ReflectionFunctionAbstract $r, \ReflectionPa
         if ('self' === $lcName) {
             return $prefix.$r->getDeclaringClass()->name;
         }
-        if ($parent = $r->getDeclaringClass()->getParentClass()) {
-            return $prefix.$parent->name;
-        }
+
+        return ($parent = $r->getDeclaringClass()->getParentClass()) ? $prefix.$parent->name : null;
     }
 }