Bug 247788 – Invalid postfix operator and nullish coaleascing inside a block in strict mode

• Component: JavaScriptCore
• Status: RESOLVED CONFIGURATION CHANGED

[Kanguk Lee]

// input.js
"use strict";
function f() {
  x = (``.p++) ?? 0;
  let x;
}

f();
_____________________

Hello,

Executing the input.js using JSC, it throws ReferenceError but TypeError is expected.

Running the input.js with JSC results in:

---
$ jsc input.js
Exception: ReferenceError: Cannot access uninitialized variable.
[e-mail]:3:10
global [e-mail]:7:2
---

while other engines behave like:

---
# V8 (used console.log)
$ node input.js
input.js:3
  x = (``.p++) ?? 0;
           ^

TypeError: Cannot create property 'p' on string ''
...

Node.js v18.11.0

# GraalJS
$ js input.js
TypeError: Cannot assign to read only property 'p' of
	at <js> f(input.js:3:35-42)
	at <js> :program(input.js:7:62-64)
---


WebKit version: 615.1.10

[Radar WebKit Bug Importer]

<rdar://problem/102324685>

[Ross Kirsling]

This is already a TypeError in current JSC; seems like something must have changed since the last Safari TP release.

[Justin Michaud]

Yes, this seems to be fixed. Thanks for reporting!