Add private brand checks to shippedProposals (#13176)

packages/babel-compat-data/data/plugins.json

@@ -2,6 +2,9 @@
   "proposal-class-static-block": {
     "chrome": "91"
   },
+  "proposal-private-property-in-object": {
+    "chrome": "91"
+  },
   "proposal-class-properties": {
     "chrome": "74",
     "opera": "62",

packages/babel-compat-data/scripts/data/plugin-features.js

@@ -136,6 +136,8 @@ const es2021 = {
 
 const shippedProposal = {
   "proposal-class-static-block": "Class static initialization blocks",
+  "proposal-private-property-in-object":
+    "Ergonomic brand checks for private fields",
   "proposal-class-properties": {
     features: [
       "static class fields",

packages/babel-compat-data/scripts/download-compat-table.sh

@@ -1,7 +1,7 @@
 #!/bin/bash
 set -e
 
-COMPAT_TABLE_COMMIT=ca2d70e305bc3295ade6b06a1c33a929db1ccacf
+COMPAT_TABLE_COMMIT=bcf74805f08ef13371ebe3aa36030bed4cd9a902
 GIT_HEAD=build/compat-table/.git/HEAD
 
 if [ -d "build/compat-table" ]; then

packages/babel-preset-env/data/shipped-proposals.js

@@ -6,6 +6,7 @@ const proposalPlugins = new Set([
   "proposal-class-properties",
   "proposal-private-methods",
   "proposal-class-static-block",
+  "proposal-private-property-in-object",
 ]);
 
 // use intermediary object to enforce alphabetical key order
@@ -21,6 +22,7 @@ const pluginSyntaxObject = {
   "proposal-optional-chaining": "syntax-optional-chaining",
   // note: we don't have syntax-private-methods
   "proposal-private-methods": "syntax-class-properties",
+  "proposal-private-property-in-object": "syntax-private-property-in-object",
   "proposal-unicode-property-regex": null,
 };
 

packages/babel-preset-env/package.json

@@ -34,6 +34,7 @@
     "@babel/plugin-proposal-optional-catch-binding": "workspace:^7.13.8",
     "@babel/plugin-proposal-optional-chaining": "workspace:^7.13.12",
     "@babel/plugin-proposal-private-methods": "workspace:^7.13.0",
+    "@babel/plugin-proposal-private-property-in-object": "workspace:^7.13.0",
     "@babel/plugin-proposal-unicode-property-regex": "workspace:^7.12.13",
     "@babel/plugin-syntax-async-generators": "^7.8.4",
     "@babel/plugin-syntax-class-properties": "workspace:^7.12.13",
@@ -47,6 +48,7 @@
     "@babel/plugin-syntax-object-rest-spread": "^7.8.3",
     "@babel/plugin-syntax-optional-catch-binding": "^7.8.3",
     "@babel/plugin-syntax-optional-chaining": "^7.8.3",
+    "@babel/plugin-syntax-private-property-in-object": "workspace:^7.13.0",
     "@babel/plugin-syntax-top-level-await": "workspace:^7.12.13",
     "@babel/plugin-transform-arrow-functions": "workspace:^7.13.0",
     "@babel/plugin-transform-async-to-generator": "workspace:^7.13.0",

packages/babel-preset-env/src/available-plugins.js

@@ -13,6 +13,7 @@ import syntaxNumericSeparator from "@babel/plugin-syntax-numeric-separator";
 import syntaxObjectRestSpread from "@babel/plugin-syntax-object-rest-spread";
 import syntaxOptionalCatchBinding from "@babel/plugin-syntax-optional-catch-binding";
 import syntaxOptionalChaining from "@babel/plugin-syntax-optional-chaining";
+import syntaxPrivatePropertyInObject from "@babel/plugin-syntax-private-property-in-object";
 import syntaxTopLevelAwait from "@babel/plugin-syntax-top-level-await";
 import proposalAsyncGeneratorFunctions from "@babel/plugin-proposal-async-generator-functions";
 import proposalClassProperties from "@babel/plugin-proposal-class-properties";
@@ -27,6 +28,7 @@ import proposalObjectRestSpread from "@babel/plugin-proposal-object-rest-spread"
 import proposalOptionalCatchBinding from "@babel/plugin-proposal-optional-catch-binding";
 import proposalOptionalChaining from "@babel/plugin-proposal-optional-chaining";
 import proposalPrivateMethods from "@babel/plugin-proposal-private-methods";
+import proposalPrivatePropertyInObject from "@babel/plugin-proposal-private-property-in-object";
 import proposalUnicodePropertyRegex from "@babel/plugin-proposal-unicode-property-regex";
 import transformAsyncToGenerator from "@babel/plugin-transform-async-to-generator";
 import transformArrowFunctions from "@babel/plugin-transform-arrow-functions";
@@ -93,6 +95,7 @@ export default {
   "proposal-optional-catch-binding": () => proposalOptionalCatchBinding,
   "proposal-optional-chaining": () => proposalOptionalChaining,
   "proposal-private-methods": () => proposalPrivateMethods,
+  "proposal-private-property-in-object": () => proposalPrivatePropertyInObject,
   "proposal-unicode-property-regex": () => proposalUnicodePropertyRegex,
   "syntax-async-generators": () => syntaxAsyncGenerators,
   "syntax-class-properties": () => syntaxClassProperties,
@@ -106,6 +109,7 @@ export default {
   "syntax-object-rest-spread": () => syntaxObjectRestSpread,
   "syntax-optional-catch-binding": () => syntaxOptionalCatchBinding,
   "syntax-optional-chaining": () => syntaxOptionalChaining,
+  "syntax-private-property-in-object": () => syntaxPrivatePropertyInObject,
   "syntax-top-level-await": () => syntaxTopLevelAwait,
   "transform-arrow-functions": () => transformArrowFunctions,
   "transform-async-to-generator": () => transformAsyncToGenerator,
@@ -145,4 +149,5 @@ export default {
 
 export const minVersions = {
   "proposal-class-static-block": "7.12.0",
+  "proposal-private-property-in-object": "7.10.0",
 };

packages/babel-preset-env/src/index.js

@@ -394,8 +394,6 @@ option \`forceAllTransforms: true\` instead.
       if (
         pluginName === "proposal-class-properties" ||
         pluginName === "proposal-private-methods" ||
-        // This is not included in preset-env yet, but let's keep it here so we
-        // don't forget about it in the future.
         pluginName === "proposal-private-property-in-object"
       ) {
         return [

packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs2-shippedProposals-chrome-71/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   proposal-class-properties { chrome < 84 }
   proposal-private-methods { chrome < 84 }
   proposal-numeric-separator { chrome < 75 }

packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs2-shippedProposals/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { ie }
+  proposal-private-property-in-object { ie }
   proposal-class-properties { ie }
   proposal-private-methods { ie }
   proposal-numeric-separator { ie }

packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-all-chrome-71/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   proposal-class-properties { chrome < 84 }
   proposal-private-methods { chrome < 84 }
   proposal-numeric-separator { chrome < 75 }

packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-all/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { ie }
+  proposal-private-property-in-object { ie }
   proposal-class-properties { ie }
   proposal-private-methods { ie }
   proposal-numeric-separator { ie }

packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-babel-polyfill/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { ie }
+  proposal-private-property-in-object { ie }
   proposal-class-properties { ie }
   proposal-private-methods { ie }
   proposal-numeric-separator { ie }

packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-es-chrome-71/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   proposal-class-properties { chrome < 84 }
   proposal-private-methods { chrome < 84 }
   proposal-numeric-separator { chrome < 75 }

packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-es-proposals-chrome-71/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   proposal-class-properties { chrome < 84 }
   proposal-private-methods { chrome < 84 }
   proposal-numeric-separator { chrome < 75 }

packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-es-proposals/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { ie }
+  proposal-private-property-in-object { ie }
   proposal-class-properties { ie }
   proposal-private-methods { ie }
   proposal-numeric-separator { ie }

packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-es/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { ie }
+  proposal-private-property-in-object { ie }
   proposal-class-properties { ie }
   proposal-private-methods { ie }
   proposal-numeric-separator { ie }

packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-runtime-only-chrome-71/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   proposal-class-properties { chrome < 84 }
   proposal-private-methods { chrome < 84 }
   proposal-numeric-separator { chrome < 75 }

packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-runtime-only/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   proposal-class-properties { chrome < 84 }
   proposal-private-methods { chrome < 84 }
   proposal-numeric-separator { chrome < 75 }

packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-specific-entries-chrome-71/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   proposal-class-properties { chrome < 84 }
   proposal-private-methods { chrome < 84 }
   proposal-numeric-separator { chrome < 75 }

packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-specific-entries/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { ie }
+  proposal-private-property-in-object { ie }
   proposal-class-properties { ie }
   proposal-private-methods { ie }
   proposal-numeric-separator { ie }

packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-stable-chrome-71/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   proposal-class-properties { chrome < 84 }
   proposal-private-methods { chrome < 84 }
   proposal-numeric-separator { chrome < 75 }

packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-stable-samsung-8.2/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { samsung }
+  proposal-private-property-in-object { samsung }
   proposal-class-properties { samsung }
   proposal-private-methods { samsung }
   proposal-numeric-separator { samsung < 11 }

packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-stable/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { ie }
+  proposal-private-property-in-object { ie }
   proposal-class-properties { ie }
   proposal-private-methods { ie }
   proposal-numeric-separator { ie }

packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-stage-chrome-71/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   proposal-class-properties { chrome < 84 }
   proposal-private-methods { chrome < 84 }
   proposal-numeric-separator { chrome < 75 }

packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-stage/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { ie }
+  proposal-private-property-in-object { ie }
   proposal-class-properties { ie }
   proposal-private-methods { ie }
   proposal-numeric-separator { ie }

packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-web-chrome-71/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   proposal-class-properties { chrome < 84 }
   proposal-private-methods { chrome < 84 }
   proposal-numeric-separator { chrome < 75 }

packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-web/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { ie }
+  proposal-private-property-in-object { ie }
   proposal-class-properties { ie }
   proposal-private-methods { ie }
   proposal-numeric-separator { ie }

packages/babel-preset-env/test/fixtures/debug-babel-7/entry-no-corejs-shippedProposals/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { ie }
+  proposal-private-property-in-object { ie }
   proposal-class-properties { ie }
   proposal-private-methods { ie }
   proposal-numeric-separator { ie }

packages/babel-preset-env/test/fixtures/debug-babel-7/shippedProposals-chrome-80/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   proposal-class-properties { chrome < 84 }
   proposal-private-methods { chrome < 84 }
   syntax-numeric-separator

packages/babel-preset-env/test/fixtures/debug-babel-7/shippedProposals-chrome-84/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   syntax-class-properties
   syntax-numeric-separator
   proposal-logical-assignment-operators { chrome < 85 }

packages/babel-preset-env/test/fixtures/debug-babel-7/usage-corejs2-shippedProposals-1/stdout.txt

@@ -11,6 +11,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91, firefox, ie }
+  proposal-private-property-in-object { chrome < 91, firefox, ie }
   proposal-class-properties { chrome < 84, firefox, ie }
   proposal-private-methods { chrome < 84, firefox, ie }
   proposal-numeric-separator { chrome < 75, firefox < 70, ie }

packages/babel-preset-env/test/fixtures/debug-babel-7/usage-corejs2-shippedProposals-2/stdout.txt

@@ -11,6 +11,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91, firefox, ie }
+  proposal-private-property-in-object { chrome < 91, firefox, ie }
   proposal-class-properties { chrome < 84, firefox, ie }
   proposal-private-methods { chrome < 84, firefox, ie }
   proposal-numeric-separator { chrome < 75, firefox < 70, ie }

packages/babel-preset-env/test/fixtures/debug-babel-7/usage-corejs3-shippedProposals-1/stdout.txt

@@ -11,6 +11,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91, firefox, ie }
+  proposal-private-property-in-object { chrome < 91, firefox, ie }
   proposal-class-properties { chrome < 84, firefox, ie }
   proposal-private-methods { chrome < 84, firefox, ie }
   proposal-numeric-separator { chrome < 75, firefox < 70, ie }

packages/babel-preset-env/test/fixtures/debug-babel-7/usage-corejs3-shippedProposals-2/stdout.txt

@@ -11,6 +11,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91, firefox, ie }
+  proposal-private-property-in-object { chrome < 91, firefox, ie }
   proposal-class-properties { chrome < 84, firefox, ie }
   proposal-private-methods { chrome < 84, firefox, ie }
   proposal-numeric-separator { chrome < 75, firefox < 70, ie }

packages/babel-preset-env/test/fixtures/debug/entry-corejs2-shippedProposals-chrome-71/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   proposal-class-properties { chrome < 84 }
   proposal-private-methods { chrome < 84 }
   proposal-numeric-separator { chrome < 75 }

packages/babel-preset-env/test/fixtures/debug/entry-corejs2-shippedProposals/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { ie }
+  proposal-private-property-in-object { ie }
   proposal-class-properties { ie }
   proposal-private-methods { ie }
   proposal-numeric-separator { ie }

packages/babel-preset-env/test/fixtures/debug/entry-corejs3-all-chrome-71/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   proposal-class-properties { chrome < 84 }
   proposal-private-methods { chrome < 84 }
   proposal-numeric-separator { chrome < 75 }

packages/babel-preset-env/test/fixtures/debug/entry-corejs3-all/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { ie }
+  proposal-private-property-in-object { ie }
   proposal-class-properties { ie }
   proposal-private-methods { ie }
   proposal-numeric-separator { ie }

packages/babel-preset-env/test/fixtures/debug/entry-corejs3-babel-polyfill/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { ie }
+  proposal-private-property-in-object { ie }
   proposal-class-properties { ie }
   proposal-private-methods { ie }
   proposal-numeric-separator { ie }

packages/babel-preset-env/test/fixtures/debug/entry-corejs3-es-chrome-71/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   proposal-class-properties { chrome < 84 }
   proposal-private-methods { chrome < 84 }
   proposal-numeric-separator { chrome < 75 }

packages/babel-preset-env/test/fixtures/debug/entry-corejs3-es-proposals-chrome-71/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   proposal-class-properties { chrome < 84 }
   proposal-private-methods { chrome < 84 }
   proposal-numeric-separator { chrome < 75 }

packages/babel-preset-env/test/fixtures/debug/entry-corejs3-es-proposals/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { ie }
+  proposal-private-property-in-object { ie }
   proposal-class-properties { ie }
   proposal-private-methods { ie }
   proposal-numeric-separator { ie }

packages/babel-preset-env/test/fixtures/debug/entry-corejs3-es/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { ie }
+  proposal-private-property-in-object { ie }
   proposal-class-properties { ie }
   proposal-private-methods { ie }
   proposal-numeric-separator { ie }

packages/babel-preset-env/test/fixtures/debug/entry-corejs3-runtime-only-chrome-71/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   proposal-class-properties { chrome < 84 }
   proposal-private-methods { chrome < 84 }
   proposal-numeric-separator { chrome < 75 }

packages/babel-preset-env/test/fixtures/debug/entry-corejs3-runtime-only/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   proposal-class-properties { chrome < 84 }
   proposal-private-methods { chrome < 84 }
   proposal-numeric-separator { chrome < 75 }

packages/babel-preset-env/test/fixtures/debug/entry-corejs3-specific-entries-chrome-71/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   proposal-class-properties { chrome < 84 }
   proposal-private-methods { chrome < 84 }
   proposal-numeric-separator { chrome < 75 }

packages/babel-preset-env/test/fixtures/debug/entry-corejs3-specific-entries/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { ie }
+  proposal-private-property-in-object { ie }
   proposal-class-properties { ie }
   proposal-private-methods { ie }
   proposal-numeric-separator { ie }

packages/babel-preset-env/test/fixtures/debug/entry-corejs3-stable-chrome-71/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   proposal-class-properties { chrome < 84 }
   proposal-private-methods { chrome < 84 }
   proposal-numeric-separator { chrome < 75 }

packages/babel-preset-env/test/fixtures/debug/entry-corejs3-stable-samsung-8.2/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { samsung }
+  proposal-private-property-in-object { samsung }
   proposal-class-properties { samsung }
   proposal-private-methods { samsung }
   proposal-numeric-separator { samsung < 11 }

packages/babel-preset-env/test/fixtures/debug/entry-corejs3-stable/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { ie }
+  proposal-private-property-in-object { ie }
   proposal-class-properties { ie }
   proposal-private-methods { ie }
   proposal-numeric-separator { ie }

packages/babel-preset-env/test/fixtures/debug/entry-corejs3-stage-chrome-71/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   proposal-class-properties { chrome < 84 }
   proposal-private-methods { chrome < 84 }
   proposal-numeric-separator { chrome < 75 }

packages/babel-preset-env/test/fixtures/debug/entry-corejs3-stage/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { ie }
+  proposal-private-property-in-object { ie }
   proposal-class-properties { ie }
   proposal-private-methods { ie }
   proposal-numeric-separator { ie }

packages/babel-preset-env/test/fixtures/debug/entry-corejs3-web-chrome-71/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   proposal-class-properties { chrome < 84 }
   proposal-private-methods { chrome < 84 }
   proposal-numeric-separator { chrome < 75 }

packages/babel-preset-env/test/fixtures/debug/entry-corejs3-web/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { ie }
+  proposal-private-property-in-object { ie }
   proposal-class-properties { ie }
   proposal-private-methods { ie }
   proposal-numeric-separator { ie }

packages/babel-preset-env/test/fixtures/debug/entry-no-corejs-shippedProposals/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { ie }
+  proposal-private-property-in-object { ie }
   proposal-class-properties { ie }
   proposal-private-methods { ie }
   proposal-numeric-separator { ie }

packages/babel-preset-env/test/fixtures/debug/shippedProposals-chrome-80/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   proposal-class-properties { chrome < 84 }
   proposal-private-methods { chrome < 84 }
   syntax-numeric-separator

packages/babel-preset-env/test/fixtures/debug/shippedProposals-chrome-84/stdout.txt

@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   syntax-class-properties
   syntax-numeric-separator
   proposal-logical-assignment-operators { chrome < 85 }

packages/babel-preset-env/test/fixtures/debug/usage-corejs2-shippedProposals-1/stdout.txt

@@ -11,6 +11,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91, firefox, ie }
+  proposal-private-property-in-object { chrome < 91, firefox, ie }
   proposal-class-properties { chrome < 84, firefox, ie }
   proposal-private-methods { chrome < 84, firefox, ie }
   proposal-numeric-separator { chrome < 75, firefox < 70, ie }

packages/babel-preset-env/test/fixtures/debug/usage-corejs2-shippedProposals-2/stdout.txt

@@ -11,6 +11,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91, firefox, ie }
+  proposal-private-property-in-object { chrome < 91, firefox, ie }
   proposal-class-properties { chrome < 84, firefox, ie }
   proposal-private-methods { chrome < 84, firefox, ie }
   proposal-numeric-separator { chrome < 75, firefox < 70, ie }

packages/babel-preset-env/test/fixtures/debug/usage-corejs3-shippedProposals-1/stdout.txt

@@ -11,6 +11,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91, firefox, ie }
+  proposal-private-property-in-object { chrome < 91, firefox, ie }
   proposal-class-properties { chrome < 84, firefox, ie }
   proposal-private-methods { chrome < 84, firefox, ie }
   proposal-numeric-separator { chrome < 75, firefox < 70, ie }

packages/babel-preset-env/test/fixtures/debug/usage-corejs3-shippedProposals-2/stdout.txt

@@ -11,6 +11,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91, firefox, ie }
+  proposal-private-property-in-object { chrome < 91, firefox, ie }
   proposal-class-properties { chrome < 84, firefox, ie }
   proposal-private-methods { chrome < 84, firefox, ie }
   proposal-numeric-separator { chrome < 75, firefox < 70, ie }

packages/babel-preset-env/test/fixtures/loose-class-features-precedence/methods-loose-preset-not-loose/stderr.txt

@@ -1,4 +1,8 @@
-Though the "loose" option was set to "false" in your @babel/preset-env config, it will not be used for @babel/plugin-proposal-class-properties since the "loose" mode option was set to "true" for @babel/plugin-proposal-private-methods.
+Though the "loose" option was set to "false" in your @babel/preset-env config, it will not be used for @babel/plugin-proposal-private-private-property-in-object since the "loose" mode option was set to "true" for @babel/plugin-proposal-private-methods.
+The "loose" option must be the same for @babel/plugin-proposal-class-properties, @babel/plugin-proposal-private-methods and @babel/plugin-proposal-private-property-in-object (when they are enabled): you can silence this warning by explicitly adding
+	["@babel/plugin-proposal-private-private-property-in-object", { "loose": true }]
+to the "plugins" section of your Babel config.
+Though the "loose" option was set to "false" in your @babel/preset-env config, it will not be used for @babel/plugin-proposal-class-properties since the "loose" mode option was set to "true" for @babel/plugin-proposal-private-private-property-in-object.
 The "loose" option must be the same for @babel/plugin-proposal-class-properties, @babel/plugin-proposal-private-methods and @babel/plugin-proposal-private-property-in-object (when they are enabled): you can silence this warning by explicitly adding
 	["@babel/plugin-proposal-class-properties", { "loose": true }]
 to the "plugins" section of your Babel config.

packages/babel-preset-env/test/fixtures/loose-class-features-precedence/properties-and-methods-loose-preset-not-loose/stderr.txt

@@ -0,0 +1,4 @@
+Though the "loose" option was set to "false" in your @babel/preset-env config, it will not be used for @babel/plugin-proposal-private-private-property-in-object since the "loose" mode option was set to "true" for @babel/plugin-proposal-private-methods.
+The "loose" option must be the same for @babel/plugin-proposal-class-properties, @babel/plugin-proposal-private-methods and @babel/plugin-proposal-private-property-in-object (when they are enabled): you can silence this warning by explicitly adding
+	["@babel/plugin-proposal-private-private-property-in-object", { "loose": true }]
+to the "plugins" section of your Babel config.

packages/babel-preset-env/test/fixtures/loose-class-features-precedence/properties-and-methods-not-loose-preset-loose/stderr.txt

@@ -0,0 +1,4 @@
+Though the "loose" option was set to "true" in your @babel/preset-env config, it will not be used for @babel/plugin-proposal-private-private-property-in-object since the "loose" mode option was set to "false" for @babel/plugin-proposal-private-methods.
+The "loose" option must be the same for @babel/plugin-proposal-class-properties, @babel/plugin-proposal-private-methods and @babel/plugin-proposal-private-property-in-object (when they are enabled): you can silence this warning by explicitly adding
+	["@babel/plugin-proposal-private-private-property-in-object", { "loose": false }]
+to the "plugins" section of your Babel config.

packages/babel-preset-env/test/fixtures/loose-class-features-precedence/properties-loose-preset-not-loose/stderr.txt

@@ -1,4 +1,8 @@
-Though the "loose" option was set to "false" in your @babel/preset-env config, it will not be used for @babel/plugin-proposal-private-methods since the "loose" mode option was set to "true" for @babel/plugin-proposal-class-properties.
+Though the "loose" option was set to "false" in your @babel/preset-env config, it will not be used for @babel/plugin-proposal-private-private-property-in-object since the "loose" mode option was set to "true" for @babel/plugin-proposal-class-properties.
+The "loose" option must be the same for @babel/plugin-proposal-class-properties, @babel/plugin-proposal-private-methods and @babel/plugin-proposal-private-property-in-object (when they are enabled): you can silence this warning by explicitly adding
+	["@babel/plugin-proposal-private-private-property-in-object", { "loose": true }]
+to the "plugins" section of your Babel config.
+Though the "loose" option was set to "false" in your @babel/preset-env config, it will not be used for @babel/plugin-proposal-private-methods since the "loose" mode option was set to "true" for @babel/plugin-proposal-private-private-property-in-object.
 The "loose" option must be the same for @babel/plugin-proposal-class-properties, @babel/plugin-proposal-private-methods and @babel/plugin-proposal-private-property-in-object (when they are enabled): you can silence this warning by explicitly adding
 	["@babel/plugin-proposal-private-methods", { "loose": true }]
 to the "plugins" section of your Babel config.

packages/babel-preset-env/test/fixtures/loose-class-features-precedence/properties-not-loose-preset-loose/stderr.txt

@@ -1,4 +1,8 @@
-Though the "loose" option was set to "true" in your @babel/preset-env config, it will not be used for @babel/plugin-proposal-private-methods since the "loose" mode option was set to "false" for @babel/plugin-proposal-class-properties.
+Though the "loose" option was set to "true" in your @babel/preset-env config, it will not be used for @babel/plugin-proposal-private-private-property-in-object since the "loose" mode option was set to "false" for @babel/plugin-proposal-class-properties.
+The "loose" option must be the same for @babel/plugin-proposal-class-properties, @babel/plugin-proposal-private-methods and @babel/plugin-proposal-private-property-in-object (when they are enabled): you can silence this warning by explicitly adding
+	["@babel/plugin-proposal-private-private-property-in-object", { "loose": false }]
+to the "plugins" section of your Babel config.
+Though the "loose" option was set to "true" in your @babel/preset-env config, it will not be used for @babel/plugin-proposal-private-methods since the "loose" mode option was set to "false" for @babel/plugin-proposal-private-private-property-in-object.
 The "loose" option must be the same for @babel/plugin-proposal-class-properties, @babel/plugin-proposal-private-methods and @babel/plugin-proposal-private-property-in-object (when they are enabled): you can silence this warning by explicitly adding
 	["@babel/plugin-proposal-private-methods", { "loose": false }]
 to the "plugins" section of your Babel config.

packages/babel-preset-env/test/fixtures/shipped-proposals/class-static-block-chrome-90/input.js

@@ -1,5 +0,0 @@
-class A {
-  static {
-    register(A);
-  }
-}

packages/babel-preset-env/test/fixtures/shipped-proposals/class-static-block-chrome-90/output.js

@@ -1,5 +0,0 @@
-class A {
-  static #_ = (() => {
-    register(A);
-  })();
-}

packages/babel-preset-env/test/fixtures/shipped-proposals/class-static-block-chrome-91/input.js

@@ -1,5 +0,0 @@
-class A {
-  static {
-    register(A);
-  }
-}

packages/babel-preset-env/test/fixtures/shipped-proposals/class-static-block-chrome-91/output.js

@@ -1,5 +0,0 @@
-class A {
-  static {
-    register(A);
-  }
-}

packages/babel-preset-env/test/fixtures/shipped-proposals/class-static-block-firefox-70/input.js

@@ -1,5 +0,0 @@
-class A {
-  static {
-    register(A);
-  }
-}

packages/babel-preset-env/test/fixtures/shipped-proposals/class-static-block-firefox-70/output.js

@@ -1,8 +0,0 @@
-class A {}
-
-var _ = {
-  writable: true,
-  value: (() => {
-    register(A);
-  })()
-};

packages/babel-preset-env/test/fixtures/shipped-proposals/new-class-features-chrome-90/input.js

@@ -0,0 +1,7 @@
+class A {
+  #foo;
+
+  static {
+    register(A, #foo in A);
+  }
+}

packages/babel-preset-env/test/fixtures/shipped-proposals/new-class-features-chrome-90/output.js

@@ -0,0 +1,8 @@
+var _fooBrandCheck = new WeakSet();
+
+class A {
+  #foo = void _fooBrandCheck.add(this);
+  static #_ = (() => {
+    register(A, _fooBrandCheck.has(A));
+  })();
+}

packages/babel-preset-env/test/fixtures/shipped-proposals/new-class-features-chrome-91/input.js

@@ -0,0 +1,7 @@
+class A {
+  #foo;
+
+  static {
+    register(A, #foo in A);
+  }
+}

packages/babel-preset-env/test/fixtures/shipped-proposals/new-class-features-chrome-91/output.js

@@ -0,0 +1,6 @@
+class A {
+  #foo;
+  static {
+    register(A, #foo in A);
+  }
+}

packages/babel-preset-env/test/fixtures/shipped-proposals/new-class-features-firefox-70/input.js

@@ -0,0 +1,7 @@
+class A {
+  #foo;
+
+  static {
+    register(A, #foo in A);
+  }
+}

packages/babel-preset-env/test/fixtures/shipped-proposals/new-class-features-firefox-70/output.js

@@ -0,0 +1,18 @@
+var _foo = new WeakMap();
+
+class A {
+  constructor() {
+    _foo.set(this, {
+      writable: true,
+      value: void 0
+    });
+  }
+
+}
+
+var _ = {
+  writable: true,
+  value: (() => {
+    register(A, _foo.has(A));
+  })()
+};

yarn.lock

@@ -1443,7 +1443,7 @@ __metadata:
   languageName: unknown
   linkType: soft
 
-"@babel/plugin-proposal-private-property-in-object@workspace:*, @babel/plugin-proposal-private-property-in-object@workspace:packages/babel-plugin-proposal-private-property-in-object":
+"@babel/plugin-proposal-private-property-in-object@workspace:*, @babel/plugin-proposal-private-property-in-object@workspace:^7.13.0, @babel/plugin-proposal-private-property-in-object@workspace:packages/babel-plugin-proposal-private-property-in-object":
   version: 0.0.0-use.local
   resolution: "@babel/plugin-proposal-private-property-in-object@workspace:packages/babel-plugin-proposal-private-property-in-object"
   dependencies:
@@ -3111,6 +3111,7 @@ __metadata:
     "@babel/plugin-proposal-optional-catch-binding": "workspace:^7.13.8"
     "@babel/plugin-proposal-optional-chaining": "workspace:^7.13.12"
     "@babel/plugin-proposal-private-methods": "workspace:^7.13.0"
+    "@babel/plugin-proposal-private-property-in-object": "workspace:^7.13.0"
     "@babel/plugin-proposal-unicode-property-regex": "workspace:^7.12.13"
     "@babel/plugin-syntax-async-generators": ^7.8.4
     "@babel/plugin-syntax-class-properties": "workspace:^7.12.13"
@@ -3124,6 +3125,7 @@ __metadata:
     "@babel/plugin-syntax-object-rest-spread": ^7.8.3
     "@babel/plugin-syntax-optional-catch-binding": ^7.8.3
     "@babel/plugin-syntax-optional-chaining": ^7.8.3
+    "@babel/plugin-syntax-private-property-in-object": "workspace:^7.13.0"
     "@babel/plugin-syntax-top-level-await": "workspace:^7.12.13"
     "@babel/plugin-transform-arrow-functions": "workspace:^7.13.0"
     "@babel/plugin-transform-async-to-generator": "workspace:^7.13.0"