From d2faa6128850b575057f727075256d0b95d5322f Mon Sep 17 00:00:00 2001
From: Dan Ehrenberg <littledan@chromium.org>
Date: Mon, 25 Jul 2016 17:37:38 -0700
Subject: [PATCH] Ban new.target and arguments from initializers

---
 spec/new-productions.htm | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/spec/new-productions.htm b/spec/new-productions.htm
index c9ea6a5..5b9e30e 100644
--- a/spec/new-productions.htm
+++ b/spec/new-productions.htm
@@ -9,6 +9,18 @@ <h1>|PublicFieldDefinition|</h1>
   </emu-grammar>
 </emu-clause>
 
+<emu-clause id="public-field-definition-early-errors">
+  <h1>Static Semantics: Early Errors</h1>
+    PublicFieldDefinition :
+      PropertyName[?Yield] Initializer?
+  <emu-grammar>
+  </emu-grammar>
+  <emu-alg>
+    1. It is a SyntaxError if |Initializer| contains |NewTarget|.
+    1. It is a SyntaxError if |Initializer| contains an |Identifier| with the StringValue `"arguments"`.
+  </emu-alg>
+</emu-clause>
+
 <emu-clause id="static-semantics-class-public-fields">
   <h1>Static Semantics: ClassPublicFields</h1>
 
@@ -101,6 +113,8 @@ <h1>InitializePublicInstanceFields ( _O_, _constructor_ )</h1>
     1. Assert: Assert _constructor_ is an ECMAScript function object.
     1. Let _lex_ be the Lexical Environment of the running execution context.
     1. Let _initializerEnv_ be NewFunctionEnvironment ( _constructor_, *undefined* ).
+    1. Perform ! _envRec_.CreateImmutableBinding(`"arguments"`, ~false~).
+    1. Perform ! _envRec_.InitializeBinding(`"arguments"`, ~undefined~).
     1. Let _initializerEnvRec_ be the value of _initializerEnv_'s EnvironmentRecord.
     1. Perform _initializerER_.BindThisValue ( _O_ ).
     1. Set the running execution context's LexicalEnvironment to _initializerEnv_.