diff --git a/package.json b/package.json
index 1e23237ee..14bdb1368 100644
--- a/package.json
+++ b/package.json
@@ -32,8 +32,8 @@
   "dependencies": {
     "@angular/compiler": "18.1.0",
     "@babel/code-frame": "7.24.7",
-    "@babel/parser": "7.24.7",
-    "@babel/types": "7.24.7",
+    "@babel/parser": "7.24.8",
+    "@babel/types": "7.24.8",
     "@glimmer/syntax": "0.92.0",
     "@iarna/toml": "2.2.5",
     "@prettier/is-es5-identifier-name": "0.2.0",
@@ -105,7 +105,7 @@
     "yaml-unist-parser": "2.0.1"
   },
   "devDependencies": {
-    "@babel/generator": "7.24.7",
+    "@babel/generator": "7.24.8",
     "@eslint/compat": "1.0.3",
     "@eslint/eslintrc": "3.1.0",
     "@eslint/js": "9.5.0",
diff --git a/src/language-js/needs-parens.js b/src/language-js/needs-parens.js
index 4b8c2ac4c..67383e9e8 100644
--- a/src/language-js/needs-parens.js
+++ b/src/language-js/needs-parens.js
@@ -288,6 +288,24 @@ function needsParens(path, options) {
         return true;
       }
       break;
+
+    case "VariableDeclarator":
+      // Legacy syntax
+      // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Errors/Invalid_for-in_initializer
+      // `for (var a = 1 in b);`
+      if (
+        key === "init" &&
+        path.match(
+          undefined,
+          undefined,
+          (node, key) =>
+            key === "declarations" && node.type === "VariableDeclaration",
+          (node, key) => key === "left" && node.type === "ForInStatement",
+        )
+      ) {
+        return true;
+      }
+      break;
   }
 
   switch (node.type) {
diff --git a/src/language-js/parse/babel.js b/src/language-js/parse/babel.js
index 3b707848e..0efd5f0ce 100644
--- a/src/language-js/parse/babel.js
+++ b/src/language-js/parse/babel.js
@@ -174,6 +174,7 @@ const allowedReasonCodes = new Set([
   "StrictEvalArguments",
   "StrictEvalArgumentsBinding",
   "StrictFunction",
+  "ForInOfLoopInitializer",
 
   "EmptyTypeArguments",
   "EmptyTypeParameters",
diff --git a/tests/format/js/for/__snapshots__/format.test.js.snap b/tests/format/js/for/__snapshots__/format.test.js.snap
index 69f2556fe..5112371ac 100644
--- a/tests/format/js/for/__snapshots__/format.test.js.snap
+++ b/tests/format/js/for/__snapshots__/format.test.js.snap
@@ -799,6 +799,71 @@ for (var i = 0; i < 10; ++i) 0;
 ================================================================================
 `;
 
+exports[`for-in-with-initializer.js [flow] format 1`] = `
+"Invalid left-hand side in for-in (3:6)
+  1 | // https://github.com/babel/babel/blob/HEAD/packages/babel-generator/test/fixtures/parentheses/in-inside-for/input.js
+  2 |
+> 3 | for (var a = (b in c) in {});
+    |      ^^^^^^^^^^^^^^^^
+  4 | for (var a = 1 || (b in c) in {});
+  5 | for (var a = 1 + (2 || (b in c)) in {});
+  6 | for (var a = (() => b in c) in {});"
+`;
+
+exports[`for-in-with-initializer.js [typescript] format 1`] = `
+"',' expected. (9:17)
+   7 | for (var a = 1 || (() => b in c) in {});
+   8 | for (var a = (() => { b in c; }) in {});
+>  9 | for (var a = [b in c] in {});
+     |                 ^
+  10 | for (var a = {b: b in c} in {});
+  11 | // Meriyah can't parse
+  12 | // for (var a = (x = b in c) => {} in {});
+Cause: ',' expected."
+`;
+
+exports[`for-in-with-initializer.js format 1`] = `
+====================================options=====================================
+parsers: ["babel", "flow", "typescript"]
+printWidth: 80
+                                                                                | printWidth
+=====================================input======================================
+// https://github.com/babel/babel/blob/HEAD/packages/babel-generator/test/fixtures/parentheses/in-inside-for/input.js
+
+for (var a = (b in c) in {});
+for (var a = 1 || (b in c) in {});
+for (var a = 1 + (2 || (b in c)) in {});
+for (var a = (() => b in c) in {});
+for (var a = 1 || (() => b in c) in {});
+for (var a = (() => { b in c; }) in {});
+for (var a = [b in c] in {});
+for (var a = {b: b in c} in {});
+// Meriyah can't parse
+// for (var a = (x = b in c) => {} in {});
+for (var a = class extends (b in c) {} in {});
+for (var a = function (x = b in c) {} in {});
+
+=====================================output=====================================
+// https://github.com/babel/babel/blob/HEAD/packages/babel-generator/test/fixtures/parentheses/in-inside-for/input.js
+
+for (var a = (b in c) in {});
+for (var a = (1 || b in c) in {});
+for (var a = (1 + (2 || b in c)) in {});
+for (var a = (() => b in c) in {});
+for (var a = (1 || (() => b in c)) in {});
+for (var a = (() => {
+  b in c;
+}) in {});
+for (var a = ([b in c]) in {});
+for (var a = ({ b: b in c }) in {});
+// Meriyah can't parse
+// for (var a = (x = b in c) => {} in {});
+for (var a = (class extends (b in c) {}) in {});
+for (var a = (function (x = b in c) {}) in {});
+
+================================================================================
+`;
+
 exports[`in.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "flow", "typescript"]
@@ -835,6 +900,129 @@ for (a in b) 0;
 ================================================================================
 `;
 
+exports[`parentheses.js [flow] format 1`] = `
+"Unexpected token \`=>\`, expected the token \`;\` (11:27)
+   9 | for (var a = [b in c];;);
+  10 | for (var a = {b: b in c};;);
+> 11 | for (var a = (x = b in c) => {};;);
+     |                           ^^
+  12 | for (var a = class extends (b in c) {};;);
+  13 | for (var a = function (x = b in c) {};;);
+  14 |"
+`;
+
+exports[`parentheses.js [typescript] format 1`] = `
+"',' expected. (9:17)
+   7 | for (var a = 1 || (() => b in c);;);
+   8 | for (var a = (() => { b in c; });;);
+>  9 | for (var a = [b in c];;);
+     |                 ^
+  10 | for (var a = {b: b in c};;);
+  11 | for (var a = (x = b in c) => {};;);
+  12 | for (var a = class extends (b in c) {};;);
+Cause: ',' expected."
+`;
+
+exports[`parentheses.js format 1`] = `
+====================================options=====================================
+parsers: ["babel", "flow", "typescript"]
+printWidth: 80
+                                                                                | printWidth
+=====================================input======================================
+// https://github.com/babel/babel/blob/HEAD/packages/babel-generator/test/fixtures/parentheses/in-inside-for/input.js
+
+for (var a = (b in c);;);
+for (var a = 1 || (b in c);;);
+for (var a = 1 + (2 || (b in c));;);
+for (var a = (() => b in c);;);
+for (var a = 1 || (() => b in c);;);
+for (var a = (() => { b in c; });;);
+for (var a = [b in c];;);
+for (var a = {b: b in c};;);
+for (var a = (x = b in c) => {};;);
+for (var a = class extends (b in c) {};;);
+for (var a = function (x = b in c) {};;);
+
+for (var a in (b in c));
+for (var a in 1 || (b in c));
+for (var a in 1 + (2 || (b in c)));
+for (var a in (() => b in c));
+for (var a in 1 || (() => b in c));
+for (var a in (() => { b in c; }));
+for (var a in [b in c]);
+for (var a in {b: b in c});
+for (var a in (x = b in c) => {});
+for (var a in class extends (b in c) {});
+for (var a in function (x = b in c) {});
+
+for (;a = (b in c););
+for (;a = 1 || (b in c););
+for (;a = 1 + (2 || (b in c)););
+for (;a = (() => b in c););
+for (;a = 1 || (() => b in c););
+for (;a = (() => { b in c; }););
+for (;a = [b in c];);
+for (;a = {b: b in c};);
+for (;a = (x = b in c) => {};);
+for (;a = class extends (b in c) {};);
+for (;a = function (x = b in c) {};);
+
+=====================================output=====================================
+// https://github.com/babel/babel/blob/HEAD/packages/babel-generator/test/fixtures/parentheses/in-inside-for/input.js
+
+for (var a = (b in c); ; );
+for (var a = 1 || (b in c); ; );
+for (var a = 1 + (2 || (b in c)); ; );
+for (var a = () => (b in c); ; );
+for (var a = 1 || (() => (b in c)); ; );
+for (
+  var a = () => {
+    (b in c);
+  };
+  ;
+
+);
+for (var a = [(b in c)]; ; );
+for (var a = { b: (b in c) }; ; );
+for (var a = (x = (b in c)) => {}; ; );
+for (var a = class extends (b in c) {}; ; );
+for (var a = function (x = (b in c)) {}; ; );
+
+for (var a in b in c);
+for (var a in 1 || b in c);
+for (var a in 1 + (2 || b in c));
+for (var a in () => b in c);
+for (var a in 1 || (() => b in c));
+for (var a in () => {
+  b in c;
+});
+for (var a in [b in c]);
+for (var a in { b: b in c });
+for (var a in (x = b in c) => {});
+for (var a in class extends (b in c) {});
+for (var a in function (x = b in c) {});
+
+for (; (a = b in c); );
+for (; (a = 1 || b in c); );
+for (; (a = 1 + (2 || b in c)); );
+for (; (a = () => b in c); );
+for (; (a = 1 || (() => b in c)); );
+for (
+  ;
+  (a = () => {
+    b in c;
+  });
+
+);
+for (; (a = [b in c]); );
+for (; (a = { b: b in c }); );
+for (; (a = (x = b in c) => {}); );
+for (; (a = class extends (b in c) {}); );
+for (; (a = function (x = b in c) {}); );
+
+================================================================================
+`;
+
 exports[`var.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "flow", "typescript"]
diff --git a/tests/format/js/for/for-in-with-initializer.js b/tests/format/js/for/for-in-with-initializer.js
new file mode 100644
index 000000000..616920da7
--- /dev/null
+++ b/tests/format/js/for/for-in-with-initializer.js
@@ -0,0 +1,14 @@
+// https://github.com/babel/babel/blob/HEAD/packages/babel-generator/test/fixtures/parentheses/in-inside-for/input.js
+
+for (var a = (b in c) in {});
+for (var a = 1 || (b in c) in {});
+for (var a = 1 + (2 || (b in c)) in {});
+for (var a = (() => b in c) in {});
+for (var a = 1 || (() => b in c) in {});
+for (var a = (() => { b in c; }) in {});
+for (var a = [b in c] in {});
+for (var a = {b: b in c} in {});
+// Meriyah can't parse
+// for (var a = (x = b in c) => {} in {});
+for (var a = class extends (b in c) {} in {});
+for (var a = function (x = b in c) {} in {});
diff --git a/tests/format/js/for/format.test.js b/tests/format/js/for/format.test.js
index 67c251cce..441b72f6d 100644
--- a/tests/format/js/for/format.test.js
+++ b/tests/format/js/for/format.test.js
@@ -1 +1,6 @@
-runFormatTest(import.meta, ["babel", "flow", "typescript"]);
+runFormatTest(import.meta, ["babel", "flow", "typescript"], {
+  errors: {
+    flow: ["parentheses.js", "for-in-with-initializer.js"],
+    typescript: ["parentheses.js", "for-in-with-initializer.js"],
+  },
+});
diff --git a/tests/format/js/for/parentheses.js b/tests/format/js/for/parentheses.js
new file mode 100644
index 000000000..2a150ba8e
--- /dev/null
+++ b/tests/format/js/for/parentheses.js
@@ -0,0 +1,37 @@
+// https://github.com/babel/babel/blob/HEAD/packages/babel-generator/test/fixtures/parentheses/in-inside-for/input.js
+
+for (var a = (b in c);;);
+for (var a = 1 || (b in c);;);
+for (var a = 1 + (2 || (b in c));;);
+for (var a = (() => b in c);;);
+for (var a = 1 || (() => b in c);;);
+for (var a = (() => { b in c; });;);
+for (var a = [b in c];;);
+for (var a = {b: b in c};;);
+for (var a = (x = b in c) => {};;);
+for (var a = class extends (b in c) {};;);
+for (var a = function (x = b in c) {};;);
+
+for (var a in (b in c));
+for (var a in 1 || (b in c));
+for (var a in 1 + (2 || (b in c)));
+for (var a in (() => b in c));
+for (var a in 1 || (() => b in c));
+for (var a in (() => { b in c; }));
+for (var a in [b in c]);
+for (var a in {b: b in c});
+for (var a in (x = b in c) => {});
+for (var a in class extends (b in c) {});
+for (var a in function (x = b in c) {});
+
+for (;a = (b in c););
+for (;a = 1 || (b in c););
+for (;a = 1 + (2 || (b in c)););
+for (;a = (() => b in c););
+for (;a = 1 || (() => b in c););
+for (;a = (() => { b in c; }););
+for (;a = [b in c];);
+for (;a = {b: b in c};);
+for (;a = (x = b in c) => {};);
+for (;a = class extends (b in c) {};);
+for (;a = function (x = b in c) {};);
diff --git a/tests/format/misc/errors/js/explicit-resource-management/__snapshots__/format.test.js.snap b/tests/format/misc/errors/js/explicit-resource-management/__snapshots__/format.test.js.snap
index 31287efa1..962fe84db 100644
--- a/tests/format/misc/errors/js/explicit-resource-management/__snapshots__/format.test.js.snap
+++ b/tests/format/misc/errors/js/explicit-resource-management/__snapshots__/format.test.js.snap
@@ -80,14 +80,15 @@ exports[`invalid-using-binding-let.js [flow] format 1`] = `
 `;
 
 exports[`invalid-using-binding-pattern.js [babel] format 1`] = `
-"Unexpected token (2:17)
-  1 | {
-> 2 |   using { foo } = f();
-    |                 ^
+"Unexpected token, expected ")" (4:25)
+  2 |   using { foo } = f();
   3 |   using [ bar ] = g();
-  4 |   for (using { qux } of h());
+> 4 |   for (using { qux } of h());
+    |                         ^
   5 |   for (using [ quux ] of i());
-Cause: Unexpected token (2:16)"
+  6 | }
+  7 |
+Cause: Unexpected token, expected ")" (4:24)"
 `;
 
 exports[`invalid-using-binding-pattern.js [flow] format 1`] = `
diff --git a/tests/unit/__snapshots__/visitor-keys.js.snap b/tests/unit/__snapshots__/visitor-keys.js.snap
index f26eae456..fee7bd210 100644
--- a/tests/unit/__snapshots__/visitor-keys.js.snap
+++ b/tests/unit/__snapshots__/visitor-keys.js.snap
@@ -628,9 +628,6 @@ exports[`visitor keys estree 1`] = `
   "ObjectTypeInternalSlot": [
     "id",
     "value",
-    "optional",
-    "static",
-    "method",
   ],
   "ObjectTypeMappedTypeProperty": [
     "keyTparam",
diff --git a/yarn.lock b/yarn.lock
index 84027d36e..b2fe39388 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -78,15 +78,15 @@ __metadata:
   languageName: node
   linkType: hard
 
-"@babel/generator@npm:7.24.7, @babel/generator@npm:^7.24.7, @babel/generator@npm:^7.7.2":
-  version: 7.24.7
-  resolution: "@babel/generator@npm:7.24.7"
+"@babel/generator@npm:7.24.8, @babel/generator@npm:^7.24.7, @babel/generator@npm:^7.7.2":
+  version: 7.24.8
+  resolution: "@babel/generator@npm:7.24.8"
   dependencies:
-    "@babel/types": "npm:^7.24.7"
+    "@babel/types": "npm:^7.24.8"
     "@jridgewell/gen-mapping": "npm:^0.3.5"
     "@jridgewell/trace-mapping": "npm:^0.3.25"
     jsesc: "npm:^2.5.1"
-  checksum: 10/c71d24a4b41b19c10d2f2eb819f27d4cf94220e2322f7c8fed8bfbbb115b2bebbdd6dc1f27dac78a175e90604def58d763af87e0fa81ce4ab1582858162cf768
+  checksum: 10/dc1bd931120f93e7a5b35fdf66c13ca56b966b07ee9ba124f7e24b1905cbcf7d7891cc7c281961876eff9fcff67c46652cce89847665e263bc04d283d4343164
   languageName: node
   linkType: hard
 
@@ -182,10 +182,10 @@ __metadata:
   languageName: node
   linkType: hard
 
-"@babel/helper-string-parser@npm:^7.24.7":
-  version: 7.24.7
-  resolution: "@babel/helper-string-parser@npm:7.24.7"
-  checksum: 10/603d8d962bbe89907aa99a8f19a006759ab7b2464615f20a6a22e3e2e8375af37ddd0e5175c9e622e1c4b2d83607ffb41055a59d0ce34404502af30fde573a5c
+"@babel/helper-string-parser@npm:^7.24.8":
+  version: 7.24.8
+  resolution: "@babel/helper-string-parser@npm:7.24.8"
+  checksum: 10/6d1bf8f27dd725ce02bdc6dffca3c95fb9ab8a06adc2edbd9c1c9d68500274230d1a609025833ed81981eff560045b6b38f7b4c6fb1ab19fc90e5004e3932535
   languageName: node
   linkType: hard
 
@@ -225,12 +225,12 @@ __metadata:
   languageName: node
   linkType: hard
 
-"@babel/parser@npm:7.24.7, @babel/parser@npm:^7.1.0, @babel/parser@npm:^7.14.7, @babel/parser@npm:^7.20.7, @babel/parser@npm:^7.23.9, @babel/parser@npm:^7.24.7":
-  version: 7.24.7
-  resolution: "@babel/parser@npm:7.24.7"
+"@babel/parser@npm:7.24.8, @babel/parser@npm:^7.1.0, @babel/parser@npm:^7.14.7, @babel/parser@npm:^7.20.7, @babel/parser@npm:^7.23.9, @babel/parser@npm:^7.24.7":
+  version: 7.24.8
+  resolution: "@babel/parser@npm:7.24.8"
   bin:
     parser: ./bin/babel-parser.js
-  checksum: 10/ef9ebce60e13db560ccc7af9235d460f6726bb7e23ae2d675098c1fc43d5249067be60d4118889dad33b1d4f85162cf66baf554719e1669f29bb20e71322568e
+  checksum: 10/e44b8327da46e8659bc9fb77f66e2dc4364dd66495fb17d046b96a77bf604f0446f1e9a89cf2f011d78fc3f5cdfbae2e9e0714708e1c985988335683b2e781ef
   languageName: node
   linkType: hard
 
@@ -417,14 +417,14 @@ __metadata:
   languageName: node
   linkType: hard
 
-"@babel/types@npm:7.24.7, @babel/types@npm:^7.0.0, @babel/types@npm:^7.20.7, @babel/types@npm:^7.24.7, @babel/types@npm:^7.3.3, @babel/types@npm:^7.8.3":
-  version: 7.24.7
-  resolution: "@babel/types@npm:7.24.7"
+"@babel/types@npm:7.24.8, @babel/types@npm:^7.0.0, @babel/types@npm:^7.20.7, @babel/types@npm:^7.24.7, @babel/types@npm:^7.24.8, @babel/types@npm:^7.3.3, @babel/types@npm:^7.8.3":
+  version: 7.24.8
+  resolution: "@babel/types@npm:7.24.8"
   dependencies:
-    "@babel/helper-string-parser": "npm:^7.24.7"
+    "@babel/helper-string-parser": "npm:^7.24.8"
     "@babel/helper-validator-identifier": "npm:^7.24.7"
     to-fast-properties: "npm:^2.0.0"
-  checksum: 10/ad3c8c0d6fb4acb0bb74bb5b4bb849b181bf6185677ef9c59c18856c81e43628d0858253cf232f0eca806f02e08eff85a1d3e636a3e94daea737597796b0b430
+  checksum: 10/29b080b2753c22ee5e2455ff767a971443245d945dea4d1b3130e036dcdf0949a89539a581753c68d03d2f2f2325244ee0f91fb83dabee1cbac5db5246838137
   languageName: node
   linkType: hard
 
@@ -7350,9 +7350,9 @@ __metadata:
   dependencies:
     "@angular/compiler": "npm:18.1.0"
     "@babel/code-frame": "npm:7.24.7"
-    "@babel/generator": "npm:7.24.7"
-    "@babel/parser": "npm:7.24.7"
-    "@babel/types": "npm:7.24.7"
+    "@babel/generator": "npm:7.24.8"
+    "@babel/parser": "npm:7.24.8"
+    "@babel/types": "npm:7.24.8"
     "@eslint/compat": "npm:1.0.3"
     "@eslint/eslintrc": "npm:3.1.0"
     "@eslint/js": "npm:9.5.0"