Merge branch '4.0'

* 4.0: (42 commits)
  fix merge
  Remove some unused variables and properties
  [appveyor] disable memory limit on composer up
  [HttpFoundation] don't prefix cookies with "Set-Cookie:"
  Remove some unused variables and properties
  [HttpFoundation] Fixed default user-agent (3.X -> 4.X)
  Fix debug:form definition
  Remove some unused variables, properties and methods
  fix some edge cases with indented blocks
  [ExpressionLanguage] Fix parse error on 5.3
  [HttpKernel] remove noisy frame in controller stack traces
  [DI] Force root-namespace for function calls in the dumper container
  [DI] Fix circular-aliases message
  register system cache clearer only if it's used
  doc : Namespace prefix must end with a "\"
  [ExpressionLanguage] throw an SyntaxError instead of letting a undefined index notice
  Prevent a loop in aliases within the `findDefinition` method
  [HttpKernel] Disable inlining on PHP 5
  Ensure that inlined services with parameterized class name can be dumped
  [DI] Fix non-string class handling in PhpDumper
  ...

Author: nicolas-grekas

Parser/TokenStream.php

@@ -31,11 +31,6 @@ class TokenStream
      */
     private $tokens = array();
 
-    /**
-     * @var bool
-     */
-    private $frozen = false;
-
     /**
      * @var Token[]
      */
@@ -49,7 +44,7 @@ class TokenStream
     /**
      * @var Token|null
      */
-    private $peeked = null;
+    private $peeked;
 
     /**
      * @var bool
@@ -75,8 +70,6 @@ public function push(Token $token)
      */
     public function freeze()
     {
-        $this->frozen = true;
-
         return $this;
     }