From 67cf388bd72dcaea1b10c8e7b35f254f9eee00c2 Mon Sep 17 00:00:00 2001
From: Ms2ger <Ms2ger@gmail.com>
Date: Mon, 15 Apr 2019 16:20:18 +0200
Subject: [PATCH] Limit the special case in the [[Set]] algorithm to
 [OverrideBuiltins] interfaces

This is the case where it makes most sense, since the prototype chain can't
shadow any properties.

This change does not affect normal usage; it is only detectable by messing with
the prototype of the object.

The majority of implementations (Gecko and Chrome) already follow the proposed
change; WebKit follows the existing spec.

Fixes #630.
---
 index.bs | 1 +
 1 file changed, 1 insertion(+)

diff --git a/index.bs b/index.bs
index 5aba1f92..47fb07ef 100644
--- a/index.bs
+++ b/index.bs
@@ -12534,6 +12534,7 @@ Additionally, [=legacy platform objects=] have internal methods as defined in:
             1.  [=Invoke the indexed property setter=] with |P| and |V|.
             1.  Return <emu-val>true</emu-val>.
         1.  If |O| [=implements=] an interface with a [=named property setter=]
+            and the [{{OverrideBuiltins}}] [=extended attribute=],
             and <a abstract-op>Type</a>(|P|) is String, then:
             1.  [=Invoke the named property setter=] with |P| and |V|.
             1.  Return <emu-val>true</emu-val>.