From 58e9d8d871d0f047539870bd3eee2b860ad2ba82 Mon Sep 17 00:00:00 2001
From: Jordan Harband <ljharb@gmail.com>
Date: Mon, 28 Jun 2021 19:35:28 -0700
Subject: [PATCH] Normative: add `#x in obj` syntax (#2290)

See https://github.com/tc39/proposal-private-fields-in-in/issues/7
---
 spec.html | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/spec.html b/spec.html
index 80a449af80..9db84c545b 100644
--- a/spec.html
+++ b/spec.html
@@ -7708,6 +7708,7 @@ <h1>Static Semantics: IsFunctionDefinition</h1>
           RelationalExpression `&gt;=` ShiftExpression
           RelationalExpression `instanceof` ShiftExpression
           RelationalExpression `in` ShiftExpression
+          PrivateIdentifier `in` ShiftExpression
 
         EqualityExpression :
           EqualityExpression `==` RelationalExpression
@@ -8456,6 +8457,7 @@ <h1>Static Semantics: AssignmentTargetType</h1>
           RelationalExpression `&gt;=` ShiftExpression
           RelationalExpression `instanceof` ShiftExpression
           RelationalExpression `in` ShiftExpression
+          PrivateIdentifier `in` ShiftExpression
 
         EqualityExpression :
           EqualityExpression `==` RelationalExpression
@@ -17124,6 +17126,7 @@ <h2>Syntax</h2>
         RelationalExpression[?In, ?Yield, ?Await] `&gt;=` ShiftExpression[?Yield, ?Await]
         RelationalExpression[?In, ?Yield, ?Await] `instanceof` ShiftExpression[?Yield, ?Await]
         [+In] RelationalExpression[+In, ?Yield, ?Await] `in` ShiftExpression[?Yield, ?Await]
+        [+In] PrivateIdentifier `in` ShiftExpression[?Yield, ?Await]
     </emu-grammar>
     <emu-note>
       <p>The <sub>[In]</sub> grammar parameter is needed to avoid confusing the `in` operator in a relational expression with the `in` operator in a `for` statement.</p>
@@ -17184,6 +17187,17 @@ <h1>Runtime Semantics: Evaluation</h1>
         1. If Type(_rval_) is not Object, throw a *TypeError* exception.
         1. Return ? HasProperty(_rval_, ? ToPropertyKey(_lval_)).
       </emu-alg>
+      <emu-grammar>RelationalExpression : PrivateIdentifier `in` ShiftExpression</emu-grammar>
+      <emu-alg>
+        1. Let _privateIdentifier_ be the StringValue of |PrivateIdentifier|.
+        1. Let _rref_ be the result of evaluating |ShiftExpression|.
+        1. Let _rval_ be ? GetValue(_rref_).
+        1. If Type(_rval_) is not Object, throw a *TypeError* exception.
+        1. Let _privateEnv_ be the running execution context's PrivateEnvironment.
+        1. Let _privateName_ be ! ResolvePrivateIdentifier(_privateEnv_, _privateIdentifier_).
+        1. If ! PrivateElementFind(_privateName_, _rval_) is not ~empty~, return *true*.
+        1. Return *false*.
+      </emu-alg>
     </emu-clause>
 
     <emu-clause id="sec-instanceofoperator" aoid="InstanceofOperator">
@@ -21226,6 +21240,13 @@ <h1>Static Semantics: AllPrivateIdentifiersValid</h1>
         1. Let _newNames_ be the list-concatenation of _names_ and PrivateBoundIdentifiers of |ClassBody|.
         1. Return AllPrivateIdentifiersValid of |ClassElementList| with argument _newNames_.
       </emu-alg>
+
+      <emu-grammar>RelationalExpression : PrivateIdentifier `in` ShiftExpression</emu-grammar>
+      <emu-alg>
+        1. If _names_ contains the StringValue of |PrivateIdentifier|, then
+          1. Return AllPrivateIdentifiersValid of |ShiftExpression| with argument _names_.
+        1. Return *false*.
+      </emu-alg>
     </emu-clause>
 
     <emu-clause id="sec-static-semantics-privateboundidentifiers" type="sdo" aoid="PrivateBoundIdentifiers">
@@ -22088,6 +22109,7 @@ <h1>Expression Rules</h1>
             RelationalExpression `&gt;=` ShiftExpression
             RelationalExpression `instanceof` ShiftExpression
             RelationalExpression `in` ShiftExpression
+            PrivateIdentifier `in` ShiftExpression
 
           ShiftExpression :
             ShiftExpression `&lt;&lt;` AdditiveExpression