From 81dd5ed8153c43b2f57e10df8ccf1cbc63e8c009 Mon Sep 17 00:00:00 2001
From: Daniel Ehrenberg <littledan@chromium.org>
Date: Wed, 28 Jun 2017 15:03:15 +0200
Subject: [PATCH] Normative: Disallow nested destructuring assignment with rest
 properties

Follow-up for #43
---
 Spec.html | 19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/Spec.html b/Spec.html
index 86652d4..88cf69a 100644
--- a/Spec.html
+++ b/Spec.html
@@ -125,6 +125,15 @@ <h1>Runtime Semantics: DestructuringAssignmentEvaluation</h1>
   </emu-clause>
 
   <ins class="block">
+    <emu-clause id="nested-rest-prohibition">
+      <h1>Static Semantics: Early Errors</h1>
+      <emu-grammar>
+        AssignmentRestProperty[Yield, Await] :
+          `...` DestructuringAssignmentTarget[Yield, Await]
+      </emu-grammar>
+      <ul><li>It is a Syntax Error if |DestructuringAssignmentTarget| is an |ArrayLiteral| or an |ObjectLiteral|.</li></ul>
+    </emu-clause>
+
     <emu-clause id="Rest-RuntimeSemantics-PropertyDestructuringAssignmentEvaluation">
       <h1>Runtime Semantics: PropertyDestructuringAssignmentEvaluation</h1>
       <p>With parameters _value_.</p>
@@ -174,16 +183,12 @@ <h1>Runtime Semantics: RestDestructuringAssignmentEvaluation</h1>
 
       <emu-grammar>AssignmentRestProperty[Yield, Await] : `...` DestructuringAssignmentTarget</emu-grammar>
       <emu-alg>
-        1. If |DestructuringAssignmentTarget| is neither an |ObjectLiteral| nor an |ArrayLiteral|, then
-          1. Let _lref_ be the result of evaluating |DestructuringAssignmentTarget|.
-          1. ReturnIfAbrupt(_lref_).
+        1. Let _lref_ be the result of evaluating |DestructuringAssignmentTarget|.
+        1. ReturnIfAbrupt(_lref_).
         1. Let _restObj_ be ObjectCreate(%ObjectPrototype%).
         1. Let _assignStatus_ be CopyDataProperties(_restObj_, _value_, _excludedNames_).
         1. ReturnIfAbrupt(_assignStatus_).
-        1. If |DestructuringAssignmentTarget| is neither an |ObjectLiteral| nor an |ArrayLiteral|, then
-          1. Return PutValue(_lref_, _restObj_).
-        1. Let _nestedAssignmentPattern_ be the parse of the source text corresponding to |DestructuringAssignmentTarget| using either |AssignmentPattern[?Yield, ?Await]| as the goal symbol, adopting the parameter values from |AssignmentRestProperty|.
-        1. Return the result of performing DestructuringAssignmentEvaluation of _nestedAssignmentPattern_ with _restObj_ as the argument.
+        1. Return PutValue(_lref_, _restObj_).
       </emu-alg>
     </emu-clause>
   </ins>