From 98b7dd03ab0eacbe144fca42c199a20662cd3d0a Mon Sep 17 00:00:00 2001
From: fisker Cheung <lionkay@gmail.com>
Date: Thu, 12 Jun 2025 04:52:36 +0800
Subject: [PATCH] Add `checkPrivateFields: false` to acorn parser (#17594)

---
 src/language-js/parse/acorn.js                |  6 +++++
 .../__snapshots__/format.test.js.snap         | 22 +------------------
 .../js/classes-private-fields/format.test.js  |  1 -
 .../__snapshots__/format.test.js.snap         | 12 +---------
 tests/format/js/private-in/format.test.js     |  2 +-
 .../__snapshots__/format.test.js.snap         |  8 +++----
 6 files changed, 13 insertions(+), 38 deletions(-)

diff --git a/src/language-js/parse/acorn.js b/src/language-js/parse/acorn.js
index 6b194e618..abe7dd12c 100644
--- a/src/language-js/parse/acorn.js
+++ b/src/language-js/parse/acorn.js
@@ -16,9 +16,15 @@ import {
 const parseOptions = {
   ecmaVersion: "latest",
   // sourceType: "module",
+  // onInsertedSemicolon: null,
+  // onTrailingComma: null,
+  allowReserved: true,
   allowReturnOutsideFunction: true,
   // allowImportExportEverywhere: true,
+  // allowAwaitOutsideFunction: null,
   allowSuperOutsideMethod: true,
+  // allowHashBang: true,
+  checkPrivateFields: false,
   locations: false,
   ranges: true,
   preserveParens: true,
diff --git a/tests/format/js/classes-private-fields/__snapshots__/format.test.js.snap b/tests/format/js/classes-private-fields/__snapshots__/format.test.js.snap
index 9fc05ae4e..97d8101fd 100644
--- a/tests/format/js/classes-private-fields/__snapshots__/format.test.js.snap
+++ b/tests/format/js/classes-private-fields/__snapshots__/format.test.js.snap
@@ -1,14 +1,4 @@
-// Jest Snapshot v1, https://goo.gl/fbAQLP
-
-exports[`optional-chaining.js [acorn] format 1`] = `
-"Private field '#x' must be declared in an enclosing class (3:13)
-  1 | // https://github.com/babel/babel/pull/11669
-  2 |
-> 3 | delete obj?.#x.a
-    |             ^
-  4 |
-Cause: Private field '#x' must be declared in an enclosing class (3:12)"
-`;
+// Jest Snapshot v1, https://jestjs.io/docs/snapshot-testing
 
 exports[`optional-chaining.js [espree] format 1`] = `
 "Private field '#x' must be declared in an enclosing class (3:13)
@@ -20,16 +10,6 @@ exports[`optional-chaining.js [espree] format 1`] = `
 Cause: Private field '#x' must be declared in an enclosing class"
 `;
 
-exports[`optional-chaining.js - {"semi":false} [acorn] format 1`] = `
-"Private field '#x' must be declared in an enclosing class (3:13)
-  1 | // https://github.com/babel/babel/pull/11669
-  2 |
-> 3 | delete obj?.#x.a
-    |             ^
-  4 |
-Cause: Private field '#x' must be declared in an enclosing class (3:12)"
-`;
-
 exports[`optional-chaining.js - {"semi":false} [espree] format 1`] = `
 "Private field '#x' must be declared in an enclosing class (3:13)
   1 | // https://github.com/babel/babel/pull/11669
diff --git a/tests/format/js/classes-private-fields/format.test.js b/tests/format/js/classes-private-fields/format.test.js
index 6cee9ccd6..8a7838c28 100644
--- a/tests/format/js/classes-private-fields/format.test.js
+++ b/tests/format/js/classes-private-fields/format.test.js
@@ -1,5 +1,4 @@
 const errors = {
-  acorn: ["optional-chaining.js"],
   espree: ["optional-chaining.js"],
 };
 runFormatTest(import.meta, ["babel"], {
diff --git a/tests/format/js/private-in/__snapshots__/format.test.js.snap b/tests/format/js/private-in/__snapshots__/format.test.js.snap
index a0bd23767..7d52da1b5 100644
--- a/tests/format/js/private-in/__snapshots__/format.test.js.snap
+++ b/tests/format/js/private-in/__snapshots__/format.test.js.snap
@@ -1,14 +1,4 @@
-// Jest Snapshot v1, https://goo.gl/fbAQLP
-
-exports[`private-in.js [acorn] format 1`] = `
-"Unexpected token (1:5)
-> 1 | if (#prop in obj) {
-    |     ^
-  2 | }
-  3 |
-  4 | #prop in     obj;
-Cause: Unexpected token (1:4)"
-`;
+// Jest Snapshot v1, https://jestjs.io/docs/snapshot-testing
 
 exports[`private-in.js [espree] format 1`] = `
 "Unexpected token #prop (1:5)
diff --git a/tests/format/js/private-in/format.test.js b/tests/format/js/private-in/format.test.js
index 9f8d910e6..0a93f8d29 100644
--- a/tests/format/js/private-in/format.test.js
+++ b/tests/format/js/private-in/format.test.js
@@ -1,3 +1,3 @@
 runFormatTest(import.meta, ["babel"], {
-  errors: { acorn: true, espree: true },
+  errors: { espree: true },
 });
diff --git a/tests/format/misc/errors/js/async-await/__snapshots__/format.test.js.snap b/tests/format/misc/errors/js/async-await/__snapshots__/format.test.js.snap
index 4e3f738a0..442081ec4 100644
--- a/tests/format/misc/errors/js/async-await/__snapshots__/format.test.js.snap
+++ b/tests/format/misc/errors/js/async-await/__snapshots__/format.test.js.snap
@@ -1,12 +1,12 @@
-// Jest Snapshot v1, https://goo.gl/fbAQLP
+// Jest Snapshot v1, https://jestjs.io/docs/snapshot-testing
 
 exports[`snippet: #0 [acorn] format 1`] = `
-"Cannot use keyword 'await' outside an async function (2:20)
+"Unexpected token (2:26)
   1 | async function foo() {
 > 2 |   function bar(x = await 2) {}
-    |                    ^
+    |                          ^
   3 | }
-Cause: Cannot use keyword 'await' outside an async function (2:19)"
+Cause: Unexpected token (2:25)"
 `;
 
 exports[`snippet: #0 [acorn] format 2`] = `