diff --git a/packages/babel-helper-create-class-features-plugin/package.json b/packages/babel-helper-create-class-features-plugin/package.json
index 9ab516a97a..0f4c7a651f 100644
--- a/packages/babel-helper-create-class-features-plugin/package.json
+++ b/packages/babel-helper-create-class-features-plugin/package.json
@@ -18,6 +18,7 @@
     "babel-plugin"
   ],
   "dependencies": {
+    "@babel/helper-annotate-as-pure": "workspace:^7.12.13",
     "@babel/helper-function-name": "workspace:^7.12.13",
     "@babel/helper-member-expression-to-functions": "workspace:^7.13.0",
     "@babel/helper-optimise-call-expression": "workspace:^7.12.13",
diff --git a/packages/babel-helper-create-class-features-plugin/src/fields.js b/packages/babel-helper-create-class-features-plugin/src/fields.js
index 185da71b5b..699792f6db 100644
--- a/packages/babel-helper-create-class-features-plugin/src/fields.js
+++ b/packages/babel-helper-create-class-features-plugin/src/fields.js
@@ -4,6 +4,7 @@ import ReplaceSupers, {
 } from "@babel/helper-replace-supers";
 import memberExpressionToFunctions from "@babel/helper-member-expression-to-functions";
 import optimiseCall from "@babel/helper-optimise-call-expression";
+import annotateAsPure from "@babel/helper-annotate-as-pure";
 
 import * as ts from "./typescript";
 
@@ -53,20 +54,23 @@ export function buildPrivateNamesNodes(
     const { static: isStatic, method: isMethod, getId, setId } = value;
     const isAccessor = getId || setId;
     const id = t.cloneNode(value.id);
+
+    let init;
+
     if (privateFieldsAsProperties) {
-      initNodes.push(
-        template.statement.ast`
-          var ${id} = ${state.addHelper("classPrivateFieldLooseKey")}("${name}")
-        `,
-      );
-    } else if (isMethod && !isStatic) {
-      if (isAccessor) {
-        initNodes.push(template.statement.ast`var ${id} = new WeakMap();`);
-      } else {
-        initNodes.push(template.statement.ast`var ${id} = new WeakSet();`);
-      }
+      init = t.callExpression(state.addHelper("classPrivateFieldLooseKey"), [
+        t.stringLiteral(name),
+      ]);
     } else if (!isStatic) {
-      initNodes.push(template.statement.ast`var ${id} = new WeakMap();`);
+      init = t.newExpression(
+        t.identifier(!isMethod || isAccessor ? "WeakMap" : "WeakSet"),
+        [],
+      );
+    }
+
+    if (init) {
+      annotateAsPure(init);
+      initNodes.push(template.statement.ast`var ${id} = ${init}`);
     }
   }
 
diff --git a/packages/babel-helper-create-class-features-plugin/test/fixtures/plugin-proposal-private-methods/loose-false/output.js b/packages/babel-helper-create-class-features-plugin/test/fixtures/plugin-proposal-private-methods/loose-false/output.js
index c137eb6f8e..6e921bc9e0 100644
--- a/packages/babel-helper-create-class-features-plugin/test/fixtures/plugin-proposal-private-methods/loose-false/output.js
+++ b/packages/babel-helper-create-class-features-plugin/test/fixtures/plugin-proposal-private-methods/loose-false/output.js
@@ -1,4 +1,4 @@
-var _privateMethod = new WeakSet();
+var _privateMethod = /*#__PURE__*/new WeakSet();
 
 class X {
   constructor() {
diff --git a/packages/babel-helper-create-class-features-plugin/test/fixtures/plugin-proposal-private-methods/loose-true/output.js b/packages/babel-helper-create-class-features-plugin/test/fixtures/plugin-proposal-private-methods/loose-true/output.js
index e4a5f492a1..032386d672 100644
--- a/packages/babel-helper-create-class-features-plugin/test/fixtures/plugin-proposal-private-methods/loose-true/output.js
+++ b/packages/babel-helper-create-class-features-plugin/test/fixtures/plugin-proposal-private-methods/loose-true/output.js
@@ -1,4 +1,4 @@
-var _privateMethod = babelHelpers.classPrivateFieldLooseKey("privateMethod");
+var _privateMethod = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateMethod");
 
 class X {
   constructor() {
diff --git a/packages/babel-helper-create-class-features-plugin/test/fixtures/replace-supers/method/output.js b/packages/babel-helper-create-class-features-plugin/test/fixtures/replace-supers/method/output.js
index 2c03af5e9a..af58f2d3c9 100644
--- a/packages/babel-helper-create-class-features-plugin/test/fixtures/replace-supers/method/output.js
+++ b/packages/babel-helper-create-class-features-plugin/test/fixtures/replace-supers/method/output.js
@@ -1,4 +1,4 @@
-var _foo = new WeakSet();
+var _foo = /*#__PURE__*/new WeakSet();
 
 class A extends B {
   constructor(...args) {
diff --git a/packages/babel-plugin-bugfix-v8-spread-parameters-in-optional-chaining/test/fixtures/basic/class-private-integration-optional-chaining/output.mjs b/packages/babel-plugin-bugfix-v8-spread-parameters-in-optional-chaining/test/fixtures/basic/class-private-integration-optional-chaining/output.mjs
index c3d3c2a6c0..b9c029038b 100644
--- a/packages/babel-plugin-bugfix-v8-spread-parameters-in-optional-chaining/test/fixtures/basic/class-private-integration-optional-chaining/output.mjs
+++ b/packages/babel-plugin-bugfix-v8-spread-parameters-in-optional-chaining/test/fixtures/basic/class-private-integration-optional-chaining/output.mjs
@@ -1,4 +1,4 @@
-var _m = new WeakMap();
+var _m = /*#__PURE__*/new WeakMap();
 
 class C {
   constructor() {
diff --git a/packages/babel-plugin-bugfix-v8-spread-parameters-in-optional-chaining/test/fixtures/basic/class-private-integration/output.mjs b/packages/babel-plugin-bugfix-v8-spread-parameters-in-optional-chaining/test/fixtures/basic/class-private-integration/output.mjs
index c3d3c2a6c0..b9c029038b 100644
--- a/packages/babel-plugin-bugfix-v8-spread-parameters-in-optional-chaining/test/fixtures/basic/class-private-integration/output.mjs
+++ b/packages/babel-plugin-bugfix-v8-spread-parameters-in-optional-chaining/test/fixtures/basic/class-private-integration/output.mjs
@@ -1,4 +1,4 @@
-var _m = new WeakMap();
+var _m = /*#__PURE__*/new WeakMap();
 
 class C {
   constructor() {
diff --git a/packages/babel-plugin-proposal-async-generator-functions/test/fixtures/async-generators/class-private-method/output.js b/packages/babel-plugin-proposal-async-generator-functions/test/fixtures/async-generators/class-private-method/output.js
index 49eb3ac98d..edaf639ec2 100644
--- a/packages/babel-plugin-proposal-async-generator-functions/test/fixtures/async-generators/class-private-method/output.js
+++ b/packages/babel-plugin-proposal-async-generator-functions/test/fixtures/async-generators/class-private-method/output.js
@@ -1,4 +1,4 @@
-var _g = new WeakSet();
+var _g = /*#__PURE__*/new WeakSet();
 
 class C {
   constructor() {
diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/assignment/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/assignment/output.js
index 01d86ae43b..0afbe45140 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/assignment/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/assignment/output.js
@@ -1,4 +1,4 @@
-var _foo = babelHelpers.classPrivateFieldLooseKey("foo");
+var _foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
 var Foo = /*#__PURE__*/function () {
   "use strict";
diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/call/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/call/output.js
index 8dd76aa398..c988a3d123 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/call/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/call/output.js
@@ -1,4 +1,4 @@
-var _foo = babelHelpers.classPrivateFieldLooseKey("foo");
+var _foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
 var Foo = /*#__PURE__*/function () {
   "use strict";
diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/canonical/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/canonical/output.js
index 6fd5a88e8f..e5b8cc06a5 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/canonical/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/canonical/output.js
@@ -1,6 +1,6 @@
-var _x = babelHelpers.classPrivateFieldLooseKey("x");
+var _x = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("x");
 
-var _y = babelHelpers.classPrivateFieldLooseKey("y");
+var _y = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("y");
 
 var Point = /*#__PURE__*/function () {
   "use strict";
diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/constructor-collision/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/constructor-collision/output.js
index be36bc5ade..7fdec04530 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/constructor-collision/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/constructor-collision/output.js
@@ -1,6 +1,6 @@
 var foo = "bar";
 
-var _bar = babelHelpers.classPrivateFieldLooseKey("bar");
+var _bar = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("bar");
 
 var Foo = function Foo() {
   "use strict";
diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/declaration-order/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/declaration-order/output.js
index 5ac4a570a2..bf7542de2e 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/declaration-order/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/declaration-order/output.js
@@ -1,4 +1,4 @@
-var _x = babelHelpers.classPrivateFieldLooseKey("x");
+var _x = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("x");
 
 var C = function C() {
   "use strict";
diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/derived-multiple-supers/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/derived-multiple-supers/output.js
index 1a333b7beb..7dfa0b162c 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/derived-multiple-supers/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/derived-multiple-supers/output.js
@@ -1,4 +1,4 @@
-var _bar = babelHelpers.classPrivateFieldLooseKey("bar");
+var _bar = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("bar");
 
 var Foo = /*#__PURE__*/function (_Bar) {
   "use strict";
diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/derived/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/derived/output.js
index 2c17edf9f6..aac5de4471 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/derived/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/derived/output.js
@@ -1,4 +1,4 @@
-var _prop = babelHelpers.classPrivateFieldLooseKey("prop");
+var _prop = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("prop");
 
 var Foo = function Foo() {
   "use strict";
@@ -10,7 +10,7 @@ var Foo = function Foo() {
   });
 };
 
-var _prop2 = babelHelpers.classPrivateFieldLooseKey("prop");
+var _prop2 = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("prop");
 
 var Bar = /*#__PURE__*/function (_Foo) {
   "use strict";
diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-array-pattern-1/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-array-pattern-1/output.js
index aca9a6ffbd..8e81d30d9c 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-array-pattern-1/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-array-pattern-1/output.js
@@ -1,4 +1,4 @@
-var _client = babelHelpers.classPrivateFieldLooseKey("client");
+var _client = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("client");
 
 var Foo = function Foo(props) {
   "use strict";
diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-array-pattern-2/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-array-pattern-2/output.js
index 0ad3e87f84..1d82a347b4 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-array-pattern-2/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-array-pattern-2/output.js
@@ -1,4 +1,4 @@
-var _client = babelHelpers.classPrivateFieldLooseKey("client");
+var _client = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("client");
 
 var Foo = function Foo(props) {
   "use strict";
diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-array-pattern-3/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-array-pattern-3/output.js
index 5125b8751c..b5b722313f 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-array-pattern-3/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-array-pattern-3/output.js
@@ -1,4 +1,4 @@
-var _client = babelHelpers.classPrivateFieldLooseKey("client");
+var _client = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("client");
 
 var Foo = function Foo(props) {
   "use strict";
diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-array-pattern-static/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-array-pattern-static/output.js
index 8c39a0a1e3..323252f978 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-array-pattern-static/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-array-pattern-static/output.js
@@ -1,4 +1,4 @@
-var _client = babelHelpers.classPrivateFieldLooseKey("client");
+var _client = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("client");
 
 var Foo = function Foo(props) {
   "use strict";
diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-array-pattern/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-array-pattern/output.js
index 77a5dd147e..f92b0bc0c0 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-array-pattern/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-array-pattern/output.js
@@ -1,4 +1,4 @@
-var _client = babelHelpers.classPrivateFieldLooseKey("client");
+var _client = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("client");
 
 var Foo = function Foo(props) {
   "use strict";
diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-object-pattern-1/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-object-pattern-1/output.js
index 548562c808..3248b2a8ec 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-object-pattern-1/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-object-pattern-1/output.js
@@ -1,4 +1,4 @@
-var _client = babelHelpers.classPrivateFieldLooseKey("client");
+var _client = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("client");
 
 var Foo = function Foo(props) {
   "use strict";
diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-object-pattern-2/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-object-pattern-2/output.js
index 50cc270663..ee114c2e39 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-object-pattern-2/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-object-pattern-2/output.js
@@ -1,4 +1,4 @@
-var _client = babelHelpers.classPrivateFieldLooseKey("client");
+var _client = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("client");
 
 var Foo = function Foo(props) {
   "use strict";
diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-object-pattern-3/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-object-pattern-3/output.js
index 8c5d47987b..59eec86629 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-object-pattern-3/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-object-pattern-3/output.js
@@ -1,4 +1,4 @@
-var _client = babelHelpers.classPrivateFieldLooseKey("client");
+var _client = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("client");
 
 var Foo = function Foo(props) {
   "use strict";
diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-object-pattern-static/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-object-pattern-static/output.js
index 35dea60861..4438d26ca7 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-object-pattern-static/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-object-pattern-static/output.js
@@ -1,4 +1,4 @@
-var _client = babelHelpers.classPrivateFieldLooseKey("client");
+var _client = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("client");
 
 var Foo = function Foo(props) {
   "use strict";
diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-object-pattern/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-object-pattern/output.js
index c9d88717a7..547af9f98d 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-object-pattern/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-object-pattern/output.js
@@ -1,4 +1,4 @@
-var _client = babelHelpers.classPrivateFieldLooseKey("client");
+var _client = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("client");
 
 var Foo = function Foo(props) {
   "use strict";
diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/extracted-this/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/extracted-this/output.js
index 3f4ec2bf29..4c84f25b28 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/extracted-this/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/extracted-this/output.js
@@ -1,8 +1,8 @@
 var foo = "bar";
 
-var _bar = babelHelpers.classPrivateFieldLooseKey("bar");
+var _bar = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("bar");
 
-var _baz = babelHelpers.classPrivateFieldLooseKey("baz");
+var _baz = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("baz");
 
 var Foo = function Foo(_foo) {
   "use strict";
diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/foobar/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/foobar/output.js
index c49e0efc1c..c02e9d7904 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/foobar/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/foobar/output.js
@@ -1,4 +1,4 @@
-var _scopedFunctionWithThis = babelHelpers.classPrivateFieldLooseKey("scopedFunctionWithThis");
+var _scopedFunctionWithThis = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("scopedFunctionWithThis");
 
 var Child = /*#__PURE__*/function (_Parent) {
   "use strict";
diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/instance-undefined/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/instance-undefined/output.js
index 53d2b25da9..85082254dd 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/instance-undefined/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/instance-undefined/output.js
@@ -1,4 +1,4 @@
-var _bar = babelHelpers.classPrivateFieldLooseKey("bar");
+var _bar = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("bar");
 
 var Foo = function Foo() {
   "use strict";
diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/instance/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/instance/output.js
index 2b489c2e4f..bd3da3a3fc 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/instance/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/instance/output.js
@@ -1,4 +1,4 @@
-var _bar = babelHelpers.classPrivateFieldLooseKey("bar");
+var _bar = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("bar");
 
 var Foo = function Foo() {
   "use strict";
diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/logical-assignment/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/logical-assignment/output.js
index af8f46e40d..3038c5cc94 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/logical-assignment/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/logical-assignment/output.js
@@ -1,8 +1,8 @@
-var _nullish = babelHelpers.classPrivateFieldLooseKey("nullish");
+var _nullish = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("nullish");
 
-var _and = babelHelpers.classPrivateFieldLooseKey("and");
+var _and = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("and");
 
-var _or = babelHelpers.classPrivateFieldLooseKey("or");
+var _or = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("or");
 
 class Foo {
   constructor() {
diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/multiple/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/multiple/output.js
index 0cbc19abca..e8655e3e84 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/multiple/output.js
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@@ -1,6 +1,6 @@
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 var Foo = function Foo() {
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/native-classes/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/native-classes/output.js
index ab122fa219..ca834cc12b 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/native-classes/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/native-classes/output.js
@@ -1,6 +1,6 @@
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-var _bar = babelHelpers.classPrivateFieldLooseKey("bar");
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 class Foo {
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/nested-class-computed-redeclared/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/nested-class-computed-redeclared/output.js
index de5558a031..f3dbcb3ae3 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/nested-class-computed-redeclared/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/nested-class-computed-redeclared/output.js
@@ -1,4 +1,4 @@
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 var Foo = /*#__PURE__*/function () {
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-      var _foo2 = babelHelpers.classPrivateFieldLooseKey("foo");
+      var _foo2 = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
       _babelHelpers$classPr = babelHelpers.classPrivateFieldLooseBase(this, _foo2)[_foo2];
 
diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/nested-class-computed/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/nested-class-computed/output.js
index 547c20ddd4..0b8c486d9d 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/nested-class-computed/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/nested-class-computed/output.js
@@ -1,4 +1,4 @@
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 var Foo = /*#__PURE__*/function () {
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/nested-class-extends-computed-redeclared/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/nested-class-extends-computed-redeclared/output.js
index 1e1dcda7c6..9e67bb674e 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/nested-class-extends-computed-redeclared/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/nested-class-extends-computed-redeclared/output.js
@@ -1,4 +1,4 @@
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+var _foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
 var Foo = /*#__PURE__*/function () {
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@@ -18,7 +18,7 @@ var Foo = /*#__PURE__*/function () {
 
       var _babelHelpers$classPr;
 
-      var _foo2 = babelHelpers.classPrivateFieldLooseKey("foo");
+      var _foo2 = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
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@@ -38,7 +38,7 @@ var Foo = /*#__PURE__*/function () {
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-      }((_foo3 = babelHelpers.classPrivateFieldLooseKey("foo"), _babelHelpers$classPr = babelHelpers.classPrivateFieldLooseBase(this, _foo3)[_foo3], /*#__PURE__*/function () {
+      }((_foo3 = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo"), _babelHelpers$classPr = babelHelpers.classPrivateFieldLooseBase(this, _foo3)[_foo3], /*#__PURE__*/function () {
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           Object.defineProperty(this, _foo3, {
diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/nested-class-extends-computed/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/nested-class-extends-computed/output.js
index d9117e0e11..15f96529a5 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/nested-class-extends-computed/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/nested-class-extends-computed/output.js
@@ -1,4 +1,4 @@
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 var Foo = /*#__PURE__*/function () {
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@@ -16,7 +16,7 @@ var Foo = /*#__PURE__*/function () {
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-      var _foo2 = babelHelpers.classPrivateFieldLooseKey("foo");
+      var _foo2 = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
       var Nested = /*#__PURE__*/function (_ref) {
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/nested-class-other-redeclared/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/nested-class-other-redeclared/output.js
index 30185d756a..678915fa80 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/nested-class-other-redeclared/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/nested-class-other-redeclared/output.js
@@ -1,6 +1,6 @@
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 var Foo = /*#__PURE__*/function () {
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@@ -20,7 +20,7 @@ var Foo = /*#__PURE__*/function () {
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-      var _bar2 = babelHelpers.classPrivateFieldLooseKey("bar");
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       var Nested = /*#__PURE__*/function () {
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/nested-class-redeclared/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/nested-class-redeclared/output.js
index e1b562b69e..0a130fae3e 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/nested-class-redeclared/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/nested-class-redeclared/output.js
@@ -1,4 +1,4 @@
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       var Nested = /*#__PURE__*/function () {
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/nested-class/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/nested-class/output.js
index b0c3fc7b6e..ba57fe8a23 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/nested-class/output.js
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@@ -1,4 +1,4 @@
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 var Foo = /*#__PURE__*/function () {
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/non-block-arrow-func/output.mjs b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/non-block-arrow-func/output.mjs
index 94a870cdea..ff72789344 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/non-block-arrow-func/output.mjs
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@@ -1,7 +1,7 @@
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-  return _temp = (_props = babelHelpers.classPrivateFieldLooseKey("props"), _class = class App {
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/optional-chain-before-member-call-with-transform/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/optional-chain-before-member-call-with-transform/output.js
index ab0dd5413c..f6d823932f 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/optional-chain-before-member-call-with-transform/output.js
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@@ -1,8 +1,8 @@
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 class Foo {
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/optional-chain-before-member-call/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/optional-chain-before-member-call/output.js
index 1f631a119a..5d938f1259 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/optional-chain-before-member-call/output.js
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@@ -1,8 +1,8 @@
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 class Foo {
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/optional-chain-before-property-with-transform/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/optional-chain-before-property-with-transform/output.js
index facdbb24d3..80241bfd16 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/optional-chain-before-property-with-transform/output.js
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@@ -1,6 +1,6 @@
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 class Foo {
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/optional-chain-before-property/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/optional-chain-before-property/output.js
index 237a49a8c3..e1eb90a908 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/optional-chain-before-property/output.js
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 class Foo {
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/optional-chain-cast-to-boolean/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/optional-chain-cast-to-boolean/output.js
index f5aaf8eabf..8825c68dbf 100644
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 class C {
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/optional-chain-delete-property-with-transform/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/optional-chain-delete-property-with-transform/output.js
index a81b1844ef..a32b7a8f55 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/optional-chain-delete-property-with-transform/output.js
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@@ -1,6 +1,6 @@
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 class Foo {
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/optional-chain-delete-property/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/optional-chain-delete-property/output.js
index b79081a2a2..49e8e6df8f 100644
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/optional-chain-in-function-param-with-transform/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/optional-chain-in-function-param-with-transform/output.js
index e25db066a6..310c81d80e 100644
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/optional-chain-in-function-param/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/optional-chain-in-function-param/output.js
index b02c5c4909..aa59673e2a 100644
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 class Foo {
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/optional-chain-member-optional-call-spread-arguments/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/optional-chain-member-optional-call-spread-arguments/output.js
index 2747157820..eab422186c 100644
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/optional-chain-member-optional-call-with-transform/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/optional-chain-member-optional-call-with-transform/output.js
index e18cf8da52..710223ea4a 100644
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/optional-chain-member-optional-call/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/optional-chain-member-optional-call/output.js
index 39df9809c9..f1e06e120e 100644
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/optional-chain-optional-member-call-with-transform/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/optional-chain-optional-member-call-with-transform/output.js
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@@ -1,8 +1,8 @@
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 class Foo {
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/optional-chain-optional-member-call/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/optional-chain-optional-member-call/output.js
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 class Foo {
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/optional-chain-optional-property-with-transform/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/optional-chain-optional-property-with-transform/output.js
index 08c3400263..3a0b3a81ca 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/optional-chain-optional-property-with-transform/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/optional-chain-optional-property-with-transform/output.js
@@ -1,6 +1,6 @@
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+var _self = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("self");
 
 class Foo {
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/optional-chain-optional-property/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/optional-chain-optional-property/output.js
index 0f0af5abe7..eeb342ebda 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/optional-chain-optional-property/output.js
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@@ -1,6 +1,6 @@
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+var _self = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("self");
 
 class Foo {
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/parenthesized-optional-member-call-with-transform/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/parenthesized-optional-member-call-with-transform/output.js
index 7b39559261..c6820738d0 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/parenthesized-optional-member-call-with-transform/output.js
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@@ -1,6 +1,6 @@
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+var _m = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("m");
 
 class Foo {
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/private-in-derived/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/private-in-derived/output.js
index e639dae81d..1e2c32a6e4 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/private-in-derived/output.js
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/reevaluated/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/reevaluated/output.js
index e94af3d102..bdfa8dc953 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/reevaluated/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/reevaluated/output.js
@@ -1,7 +1,7 @@
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-  return _temp = (_foo = babelHelpers.classPrivateFieldLooseKey("foo"), _bar = babelHelpers.classPrivateFieldLooseKey("bar"), _class = class Foo {
+  return _temp = (_foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo"), _bar = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("bar"), _class = class Foo {
     constructor() {
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/reference-in-other-property/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/reference-in-other-property/output.js
index 5f3ccaed8b..729fd372d5 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/reference-in-other-property/output.js
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 var Foo = function Foo() {
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/static-call/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/static-call/output.js
index 463a51028b..3924a0fbef 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/static-call/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/static-call/output.js
@@ -1,4 +1,4 @@
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 var Foo = /*#__PURE__*/function () {
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/static-export/output.mjs b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/static-export/output.mjs
index e821a22235..81aab1c608 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/static-export/output.mjs
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 export default class MyClass2 {}
 Object.defineProperty(MyClass2, _property2, {
diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/static-infer-name/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/static-infer-name/output.js
index 675806cbd1..9f9239b680 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/static-infer-name/output.js
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@@ -1,6 +1,6 @@
 var _class, _num, _temp;
 
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 }), _temp);
diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/static-inherited/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/static-inherited/output.js
index 4d5a4ffd89..086eb4637e 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/static-inherited/output.js
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 });
 
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 class Sub1 extends Base {
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/static-this/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/static-this/output.js
index 85b9da1e55..2c8b5ead09 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/static-this/output.js
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index 19efa1d1ea..b314748e4d 100644
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@@ -1,4 +1,4 @@
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/static/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/static/output.js
index c60a6e95fa..60326066de 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/static/output.js
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/super-expression/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/super-expression/output.js
index 285bd459ce..72e5778094 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/super-expression/output.js
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 var Foo = /*#__PURE__*/function (_Bar) {
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/super-statement/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/super-statement/output.js
index 5a2c2cf37e..ee1dcdef93 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/super-statement/output.js
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@@ -1,4 +1,4 @@
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 var Foo = /*#__PURE__*/function (_Bar) {
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/update/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/update/output.js
index 090f88475c..10f5127c28 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/update/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/update/output.js
@@ -1,4 +1,4 @@
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 var Foo = /*#__PURE__*/function () {
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/1-helpermemberexpressionfunction/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/1-helpermemberexpressionfunction/output.js
index c956f5663c..89ad20142e 100644
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+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/1-helpermemberexpressionfunction/output.js
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index d26bb1888d..a7817db0ff 100644
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index 684c861734..27947d1df6 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/call/output.js
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--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/canonical/output.js
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/constructor-collision/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/constructor-collision/output.js
index feb87b54c3..05d01f4911 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/constructor-collision/output.js
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index 88dbfb0a0c..b2c777ecc3 100644
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@@ -1,4 +1,4 @@
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/destructuring-object-pattern/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/destructuring-object-pattern/output.js
index bced4d04ad..7459b76bc9 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/destructuring-object-pattern/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/destructuring-object-pattern/output.js
@@ -1,4 +1,4 @@
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/extracted-this/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/extracted-this/output.js
index 406853af0d..1fb7de2ab4 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/extracted-this/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/extracted-this/output.js
@@ -1,8 +1,8 @@
 var foo = "bar";
 
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+var _bar = /*#__PURE__*/new WeakMap();
 
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 var Foo = function Foo(_foo) {
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/foobar/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/foobar/output.js
index bda5c48f85..2ae9b573b3 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/foobar/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/foobar/output.js
@@ -1,4 +1,4 @@
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/instance-undefined/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/instance-undefined/output.js
index 7a63144830..8c8ba57dec 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/instance-undefined/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/instance-undefined/output.js
@@ -1,4 +1,4 @@
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 var Foo = function Foo() {
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/instance/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/instance/output.js
index 1ca01a02e6..c7208f4d74 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/instance/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/instance/output.js
@@ -1,4 +1,4 @@
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 var Foo = function Foo() {
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/logical-assignment/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/logical-assignment/output.js
index 973697c962..e61da807ce 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/logical-assignment/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/logical-assignment/output.js
@@ -1,8 +1,8 @@
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 class Foo {
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/multiple/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/multiple/output.js
index 166ae183db..fd609d4458 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/multiple/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/multiple/output.js
@@ -1,6 +1,6 @@
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+var _x = /*#__PURE__*/new WeakMap();
 
-var _y = new WeakMap();
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 var Foo = function Foo() {
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/native-classes/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/native-classes/output.js
index 7f35537d1e..98f4973499 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/native-classes/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/native-classes/output.js
@@ -1,4 +1,4 @@
-var _bar = new WeakMap();
+var _bar = /*#__PURE__*/new WeakMap();
 
 class Foo {
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/nested-class-computed-redeclared/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/nested-class-computed-redeclared/output.js
index c1bc2d924d..085b255c26 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/nested-class-computed-redeclared/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/nested-class-computed-redeclared/output.js
@@ -1,4 +1,4 @@
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@@ -17,7 +17,7 @@ var Foo = /*#__PURE__*/function () {
     value: function test() {
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-      var _foo2 = new WeakMap();
+      var _foo2 = /*#__PURE__*/new WeakMap();
 
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/nested-class-computed/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/nested-class-computed/output.js
index 74e8c4a1fa..102e922394 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/nested-class-computed/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/nested-class-computed/output.js
@@ -1,4 +1,4 @@
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+var _foo = /*#__PURE__*/new WeakMap();
 
 var Foo = /*#__PURE__*/function () {
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/nested-class-extends-computed-redeclared/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/nested-class-extends-computed-redeclared/output.js
index 42fd4e9547..816f80cbeb 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/nested-class-extends-computed-redeclared/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/nested-class-extends-computed-redeclared/output.js
@@ -1,4 +1,4 @@
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 var Foo = /*#__PURE__*/function () {
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@@ -19,7 +19,7 @@ var Foo = /*#__PURE__*/function () {
 
       var _babelHelpers$classPr;
 
-      var _foo2 = new WeakMap();
+      var _foo2 = /*#__PURE__*/new WeakMap();
 
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@@ -41,7 +41,7 @@ var Foo = /*#__PURE__*/function () {
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         return Nested;
-      }((_foo3 = new WeakMap(), _babelHelpers$classPr = babelHelpers.classPrivateFieldGet(this, _foo3), /*#__PURE__*/function () {
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/nested-class-extends-computed/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/nested-class-extends-computed/output.js
index 32e75135ea..dddde36ed4 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/nested-class-extends-computed/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/nested-class-extends-computed/output.js
@@ -1,4 +1,4 @@
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+var _foo = /*#__PURE__*/new WeakMap();
 
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@@ -17,7 +17,7 @@ var Foo = /*#__PURE__*/function () {
     value: function test() {
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-      var _foo2 = new WeakMap();
+      var _foo2 = /*#__PURE__*/new WeakMap();
 
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/nested-class-other-redeclared/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/nested-class-other-redeclared/output.js
index 75298ceab6..080795751a 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/nested-class-other-redeclared/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/nested-class-other-redeclared/output.js
@@ -1,6 +1,6 @@
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+var _foo = /*#__PURE__*/new WeakMap();
 
-var _bar = new WeakMap();
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 var Foo = /*#__PURE__*/function () {
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@@ -22,7 +22,7 @@ var Foo = /*#__PURE__*/function () {
   babelHelpers.createClass(Foo, [{
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     value: function test() {
-      var _bar2 = new WeakMap();
+      var _bar2 = /*#__PURE__*/new WeakMap();
 
       var Nested = /*#__PURE__*/function () {
         function Nested() {
diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/nested-class-redeclared/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/nested-class-redeclared/output.js
index 9c42a9cb9a..1030037c7a 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/nested-class-redeclared/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/nested-class-redeclared/output.js
@@ -1,4 +1,4 @@
-var _foo = new WeakMap();
+var _foo = /*#__PURE__*/new WeakMap();
 
 var Foo = /*#__PURE__*/function () {
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@@ -15,7 +15,7 @@ var Foo = /*#__PURE__*/function () {
   babelHelpers.createClass(Foo, [{
     key: "test",
     value: function test() {
-      var _foo2 = new WeakMap();
+      var _foo2 = /*#__PURE__*/new WeakMap();
 
       var Nested = /*#__PURE__*/function () {
         function Nested() {
diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/nested-class/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/nested-class/output.js
index f54285d07f..69123eded4 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/nested-class/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/nested-class/output.js
@@ -1,4 +1,4 @@
-var _foo = new WeakMap();
+var _foo = /*#__PURE__*/new WeakMap();
 
 var Foo = /*#__PURE__*/function () {
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/optional-chain-delete-property-with-transform/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/optional-chain-delete-property-with-transform/output.js
index a81b1844ef..a32b7a8f55 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/optional-chain-delete-property-with-transform/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/optional-chain-delete-property-with-transform/output.js
@@ -1,6 +1,6 @@
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+var _x = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("x");
 
-var _self = babelHelpers.classPrivateFieldLooseKey("self");
+var _self = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("self");
 
 class Foo {
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/optional-chain-member-optional-call-spread-arguments/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/optional-chain-member-optional-call-spread-arguments/output.js
index f9d16a2b45..593a5772ca 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/optional-chain-member-optional-call-spread-arguments/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/optional-chain-member-optional-call-spread-arguments/output.js
@@ -1,4 +1,4 @@
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+var _m = /*#__PURE__*/new WeakMap();
 
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/private-in-derived/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/private-in-derived/output.js
index f53f26e4e7..1e57996600 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/private-in-derived/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/private-in-derived/output.js
@@ -1,4 +1,4 @@
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/reevaluated/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/reevaluated/output.js
index d5e34a53b7..8c6a955412 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/reevaluated/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/reevaluated/output.js
@@ -1,7 +1,7 @@
 function classFactory() {
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-  return _temp = (_foo = new WeakMap(), _class = class Foo {
+  return _temp = (_foo = /*#__PURE__*/new WeakMap(), _class = class Foo {
     constructor() {
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/reference-in-other-property/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/reference-in-other-property/output.js
index 8c08e58342..0b7476ce49 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/reference-in-other-property/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/reference-in-other-property/output.js
@@ -1,8 +1,8 @@
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+var _four = /*#__PURE__*/new WeakMap();
 
 var Foo = function Foo() {
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/regression-T7364/output.mjs b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/regression-T7364/output.mjs
index 1d150f3f70..ae07dabb78 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/regression-T7364/output.mjs
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/regression-T7364/output.mjs
@@ -1,4 +1,4 @@
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 class MyClass {
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@@ -20,7 +20,7 @@ class MyClass {
 
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 (class MyClass2 {
   constructor() {
@@ -42,7 +42,7 @@ var _myAsyncMethod2 = new WeakMap();
 
 });
 
-var _myAsyncMethod3 = new WeakMap();
+var _myAsyncMethod3 = /*#__PURE__*/new WeakMap();
 
 export default class MyClass3 {
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/super-call/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/super-call/output.js
index bd230ab4b6..78bcdf3764 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/super-call/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/super-call/output.js
@@ -14,7 +14,7 @@ var A = /*#__PURE__*/function () {
   return A;
 }();
 
-var _foo = new WeakMap();
+var _foo = /*#__PURE__*/new WeakMap();
 
 var B = /*#__PURE__*/function (_A) {
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/super-expression/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/super-expression/output.js
index d33ffd9deb..1f17e973a2 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/super-expression/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/super-expression/output.js
@@ -1,4 +1,4 @@
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 var Foo = /*#__PURE__*/function (_Bar) {
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/super-statement/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/super-statement/output.js
index 9fe307cf4c..e652b376af 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/super-statement/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/super-statement/output.js
@@ -1,4 +1,4 @@
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+var _bar = /*#__PURE__*/new WeakMap();
 
 var Foo = /*#__PURE__*/function (_Bar) {
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/update/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/update/output.js
index e00b6447f8..59d092de2d 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/private/update/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/private/update/output.js
@@ -1,4 +1,4 @@
-var _foo = new WeakMap();
+var _foo = /*#__PURE__*/new WeakMap();
 
 var Foo = /*#__PURE__*/function () {
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diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/regression/8882/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/regression/8882/output.js
index 33bb89ed9e..f41cc8189c 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/regression/8882/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/regression/8882/output.js
@@ -5,7 +5,7 @@ for (let i = 0; i <= 10; ++i) {
 
   let _i;
 
-  classes.push((_temp = (_bar = new WeakMap(), _i = i, _class = class A {
+  classes.push((_temp = (_bar = /*#__PURE__*/new WeakMap(), _i = i, _class = class A {
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diff --git a/packages/babel-plugin-proposal-class-static-block/test/fixtures/integration-loose/class-binding/output.js b/packages/babel-plugin-proposal-class-static-block/test/fixtures/integration-loose/class-binding/output.js
index 1c8b0fc717..8b78293ec5 100644
--- a/packages/babel-plugin-proposal-class-static-block/test/fixtures/integration-loose/class-binding/output.js
+++ b/packages/babel-plugin-proposal-class-static-block/test/fixtures/integration-loose/class-binding/output.js
@@ -1,4 +1,4 @@
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+var _ = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("_");
 
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diff --git a/packages/babel-plugin-proposal-class-static-block/test/fixtures/integration-loose/class-declaration/output.js b/packages/babel-plugin-proposal-class-static-block/test/fixtures/integration-loose/class-declaration/output.js
index 1c8b0fc717..8b78293ec5 100644
--- a/packages/babel-plugin-proposal-class-static-block/test/fixtures/integration-loose/class-declaration/output.js
+++ b/packages/babel-plugin-proposal-class-static-block/test/fixtures/integration-loose/class-declaration/output.js
@@ -1,4 +1,4 @@
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diff --git a/packages/babel-plugin-proposal-class-static-block/test/fixtures/integration-loose/in-class-heritage/output.js b/packages/babel-plugin-proposal-class-static-block/test/fixtures/integration-loose/in-class-heritage/output.js
index 790f057648..799e4784c2 100644
--- a/packages/babel-plugin-proposal-class-static-block/test/fixtures/integration-loose/in-class-heritage/output.js
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@@ -1,8 +1,8 @@
 var _class, _2, _temp, _class2, _3, _temp2;
 
-var _ = babelHelpers.classPrivateFieldLooseKey("_");
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-class Foo extends (_temp = (_2 = babelHelpers.classPrivateFieldLooseKey("_"), _class = class extends (_temp2 = (_3 = babelHelpers.classPrivateFieldLooseKey("_"), _class2 = class Base {}), Object.defineProperty(_class2, _3, {
+class Foo extends (_temp = (_2 = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("_"), _class = class extends (_temp2 = (_3 = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("_"), _class2 = class Base {}), Object.defineProperty(_class2, _3, {
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diff --git a/packages/babel-plugin-proposal-class-static-block/test/fixtures/integration-loose/multiple-static-initializers/output.js b/packages/babel-plugin-proposal-class-static-block/test/fixtures/integration-loose/multiple-static-initializers/output.js
index 3d22e82383..2e8b3339a1 100644
--- a/packages/babel-plugin-proposal-class-static-block/test/fixtures/integration-loose/multiple-static-initializers/output.js
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-var _bar = babelHelpers.classPrivateFieldLooseKey("bar");
+var _bar = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("bar");
 
-var _ = babelHelpers.classPrivateFieldLooseKey("_");
+var _ = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("_");
 
-var _2 = babelHelpers.classPrivateFieldLooseKey("_2");
+var _2 = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("_2");
 
 class Foo {}
 
diff --git a/packages/babel-plugin-proposal-class-static-block/test/fixtures/integration-loose/name-conflict/output.js b/packages/babel-plugin-proposal-class-static-block/test/fixtures/integration-loose/name-conflict/output.js
index 9782eba3fa..ee0d0c1efc 100644
--- a/packages/babel-plugin-proposal-class-static-block/test/fixtures/integration-loose/name-conflict/output.js
+++ b/packages/babel-plugin-proposal-class-static-block/test/fixtures/integration-loose/name-conflict/output.js
@@ -1,6 +1,6 @@
-var _ = babelHelpers.classPrivateFieldLooseKey("_");
+var _ = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("_");
 
-var _2 = babelHelpers.classPrivateFieldLooseKey("_2");
+var _2 = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("_2");
 
 class Foo {}
 
diff --git a/packages/babel-plugin-proposal-class-static-block/test/fixtures/integration-loose/super-static-block/output.js b/packages/babel-plugin-proposal-class-static-block/test/fixtures/integration-loose/super-static-block/output.js
index 384a75d00d..a2df83a020 100644
--- a/packages/babel-plugin-proposal-class-static-block/test/fixtures/integration-loose/super-static-block/output.js
+++ b/packages/babel-plugin-proposal-class-static-block/test/fixtures/integration-loose/super-static-block/output.js
@@ -1,8 +1,8 @@
 var _class, _2, _temp;
 
-var _ = babelHelpers.classPrivateFieldLooseKey("_");
+var _ = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("_");
 
-class Foo extends (_temp = (_2 = babelHelpers.classPrivateFieldLooseKey("_"), _class = class {}), Object.defineProperty(_class, _2, {
+class Foo extends (_temp = (_2 = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("_"), _class = class {}), Object.defineProperty(_class, _2, {
   writable: true,
   value: (() => {
     _class.bar = 42;
@@ -15,7 +15,7 @@ Object.defineProperty(Foo, _, {
   value: (() => {
     var _class2, _3, _temp2;
 
-    Foo.foo = (_temp2 = (_3 = babelHelpers.classPrivateFieldLooseKey("_"), _class2 = class {}), Object.defineProperty(_class2, _3, {
+    Foo.foo = (_temp2 = (_3 = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("_"), _class2 = class {}), Object.defineProperty(_class2, _3, {
       writable: true,
       value: (() => {
         _class2.bar = 42;
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors-loose/basic/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors-loose/basic/output.js
index 77463ece9e..0bc82c7b2b 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors-loose/basic/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors-loose/basic/output.js
@@ -1,6 +1,6 @@
-var _privateField = babelHelpers.classPrivateFieldLooseKey("privateField");
+var _privateField = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateField");
 
-var _privateFieldValue = babelHelpers.classPrivateFieldLooseKey("privateFieldValue");
+var _privateFieldValue = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateFieldValue");
 
 class Cl {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors-loose/get-only-setter/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors-loose/get-only-setter/output.js
index c98b43005c..eb7d64bc21 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors-loose/get-only-setter/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors-loose/get-only-setter/output.js
@@ -1,6 +1,6 @@
-var _privateField = babelHelpers.classPrivateFieldLooseKey("privateField");
+var _privateField = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateField");
 
-var _privateFieldValue = babelHelpers.classPrivateFieldLooseKey("privateFieldValue");
+var _privateFieldValue = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateFieldValue");
 
 class Cl {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors-loose/reassignment/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors-loose/reassignment/output.js
index 4d4038b1c5..8572a992d1 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors-loose/reassignment/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors-loose/reassignment/output.js
@@ -1,6 +1,6 @@
 var counter = 0;
 
-var _privateFieldValue = babelHelpers.classPrivateFieldLooseKey("privateFieldValue");
+var _privateFieldValue = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateFieldValue");
 
 class Foo {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors-loose/set-only-getter/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors-loose/set-only-getter/output.js
index 932304f692..afe4ff5ae8 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors-loose/set-only-getter/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors-loose/set-only-getter/output.js
@@ -1,6 +1,6 @@
-var _privateField = babelHelpers.classPrivateFieldLooseKey("privateField");
+var _privateField = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateField");
 
-var _privateFieldValue = babelHelpers.classPrivateFieldLooseKey("privateFieldValue");
+var _privateFieldValue = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateFieldValue");
 
 class Cl {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors-loose/updates/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors-loose/updates/output.js
index c28fd1253d..71d566f4fc 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors-loose/updates/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors-loose/updates/output.js
@@ -1,6 +1,6 @@
-var _privateField = babelHelpers.classPrivateFieldLooseKey("privateField");
+var _privateField = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateField");
 
-var _privateFieldValue = babelHelpers.classPrivateFieldLooseKey("privateFieldValue");
+var _privateFieldValue = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateFieldValue");
 
 class Cl {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors-privateFieldsAsProperties/basic/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors-privateFieldsAsProperties/basic/output.js
index 77463ece9e..0bc82c7b2b 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors-privateFieldsAsProperties/basic/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors-privateFieldsAsProperties/basic/output.js
@@ -1,6 +1,6 @@
-var _privateField = babelHelpers.classPrivateFieldLooseKey("privateField");
+var _privateField = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateField");
 
-var _privateFieldValue = babelHelpers.classPrivateFieldLooseKey("privateFieldValue");
+var _privateFieldValue = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateFieldValue");
 
 class Cl {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors-privateFieldsAsProperties/get-only-setter/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors-privateFieldsAsProperties/get-only-setter/output.js
index c98b43005c..eb7d64bc21 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors-privateFieldsAsProperties/get-only-setter/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors-privateFieldsAsProperties/get-only-setter/output.js
@@ -1,6 +1,6 @@
-var _privateField = babelHelpers.classPrivateFieldLooseKey("privateField");
+var _privateField = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateField");
 
-var _privateFieldValue = babelHelpers.classPrivateFieldLooseKey("privateFieldValue");
+var _privateFieldValue = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateFieldValue");
 
 class Cl {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors-privateFieldsAsProperties/set-only-getter/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors-privateFieldsAsProperties/set-only-getter/output.js
index 932304f692..afe4ff5ae8 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors-privateFieldsAsProperties/set-only-getter/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors-privateFieldsAsProperties/set-only-getter/output.js
@@ -1,6 +1,6 @@
-var _privateField = babelHelpers.classPrivateFieldLooseKey("privateField");
+var _privateField = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateField");
 
-var _privateFieldValue = babelHelpers.classPrivateFieldLooseKey("privateFieldValue");
+var _privateFieldValue = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateFieldValue");
 
 class Cl {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors-privateFieldsAsProperties/updates/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors-privateFieldsAsProperties/updates/output.js
index c28fd1253d..71d566f4fc 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors-privateFieldsAsProperties/updates/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors-privateFieldsAsProperties/updates/output.js
@@ -1,6 +1,6 @@
-var _privateField = babelHelpers.classPrivateFieldLooseKey("privateField");
+var _privateField = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateField");
 
-var _privateFieldValue = babelHelpers.classPrivateFieldLooseKey("privateFieldValue");
+var _privateFieldValue = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateFieldValue");
 
 class Cl {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors/basic/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors/basic/output.js
index 97c18b66fc..658554a063 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors/basic/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors/basic/output.js
@@ -1,6 +1,6 @@
-var _privateField = new WeakMap();
+var _privateField = /*#__PURE__*/new WeakMap();
 
-var _privateFieldValue = new WeakMap();
+var _privateFieldValue = /*#__PURE__*/new WeakMap();
 
 class Cl {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors/get-only-setter/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors/get-only-setter/output.js
index 44182ac5e6..2a0691beef 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors/get-only-setter/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors/get-only-setter/output.js
@@ -1,6 +1,6 @@
-var _privateField = new WeakMap();
+var _privateField = /*#__PURE__*/new WeakMap();
 
-var _privateFieldValue = new WeakMap();
+var _privateFieldValue = /*#__PURE__*/new WeakMap();
 
 class Cl {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors/reassignment/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors/reassignment/output.js
index 19fc2b357a..4ee6f05ac8 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors/reassignment/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors/reassignment/output.js
@@ -1,6 +1,6 @@
 var results = [];
 
-var _privateFieldValue = new WeakMap();
+var _privateFieldValue = /*#__PURE__*/new WeakMap();
 
 class Foo {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors/set-only-getter/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors/set-only-getter/output.js
index 998614b922..52a97f6ec2 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors/set-only-getter/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors/set-only-getter/output.js
@@ -1,6 +1,6 @@
-var _privateField = new WeakMap();
+var _privateField = /*#__PURE__*/new WeakMap();
 
-var _privateFieldValue = new WeakMap();
+var _privateFieldValue = /*#__PURE__*/new WeakMap();
 
 class Cl {
   get self() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors/updates/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors/updates/output.js
index 54afa98088..0da9a9fc07 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors/updates/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/accessors/updates/output.js
@@ -1,6 +1,6 @@
-var _privateField = new WeakMap();
+var _privateField = /*#__PURE__*/new WeakMap();
 
-var _privateFieldValue = new WeakMap();
+var _privateFieldValue = /*#__PURE__*/new WeakMap();
 
 class Cl {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/assumption-constantSuper/private-method-super/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/assumption-constantSuper/private-method-super/output.js
index b27add84eb..74762cfc04 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/assumption-constantSuper/private-method-super/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/assumption-constantSuper/private-method-super/output.js
@@ -5,7 +5,7 @@ class Base {
 
 }
 
-var _privateMethod = new WeakSet();
+var _privateMethod = /*#__PURE__*/new WeakSet();
 
 class Sub extends Base {
   constructor(...args) {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/duplicated-names/get-set/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/duplicated-names/get-set/output.js
index 5836631255..995151f762 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/duplicated-names/get-set/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/duplicated-names/get-set/output.js
@@ -1,6 +1,6 @@
-var _privateField = new WeakMap();
+var _privateField = /*#__PURE__*/new WeakMap();
 
-var _getSet = new WeakMap();
+var _getSet = /*#__PURE__*/new WeakMap();
 
 class Cl {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/duplicated-names/set-get/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/duplicated-names/set-get/output.js
index cac35a8db3..3c26592e76 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/duplicated-names/set-get/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/duplicated-names/set-get/output.js
@@ -1,6 +1,6 @@
-var _privateField = new WeakMap();
+var _privateField = /*#__PURE__*/new WeakMap();
 
-var _getSet = new WeakMap();
+var _getSet = /*#__PURE__*/new WeakMap();
 
 class Cl {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-loose/assignment/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-loose/assignment/output.js
index 897f052cd4..57a10bab4f 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-loose/assignment/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-loose/assignment/output.js
@@ -1,4 +1,4 @@
-var _privateMethod = babelHelpers.classPrivateFieldLooseKey("privateMethod");
+var _privateMethod = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateMethod");
 
 class Foo {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-loose/async/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-loose/async/output.js
index 1ae55ce6cb..531077f32e 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-loose/async/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-loose/async/output.js
@@ -1,4 +1,4 @@
-var _foo = babelHelpers.classPrivateFieldLooseKey("foo");
+var _foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
 class Cl {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-loose/before-fields/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-loose/before-fields/output.js
index 8c43d19a9a..a5266e6369 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-loose/before-fields/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-loose/before-fields/output.js
@@ -1,6 +1,6 @@
-var _priv = babelHelpers.classPrivateFieldLooseKey("priv");
+var _priv = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("priv");
 
-var _method = babelHelpers.classPrivateFieldLooseKey("method");
+var _method = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("method");
 
 class Cl {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-loose/class-expression/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-loose/class-expression/output.js
index ff898d7d6e..422497beac 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-loose/class-expression/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-loose/class-expression/output.js
@@ -1,6 +1,6 @@
 var _foo;
 
-console.log((_foo = babelHelpers.classPrivateFieldLooseKey("foo"), class A {
+console.log((_foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo"), class A {
   constructor() {
     Object.defineProperty(this, _foo, {
       value: _foo2
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-loose/context/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-loose/context/output.js
index 2960e45fa6..d867181077 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-loose/context/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-loose/context/output.js
@@ -1,4 +1,4 @@
-var _getStatus = babelHelpers.classPrivateFieldLooseKey("getStatus");
+var _getStatus = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("getStatus");
 
 class Foo {
   constructor(status) {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-loose/exfiltrated/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-loose/exfiltrated/output.js
index ff76ee756f..6201734b50 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-loose/exfiltrated/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-loose/exfiltrated/output.js
@@ -1,6 +1,6 @@
 var exfiltrated;
 
-var _privateMethod = babelHelpers.classPrivateFieldLooseKey("privateMethod");
+var _privateMethod = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateMethod");
 
 class Foo {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-loose/generator/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-loose/generator/output.js
index 4f1bca35bf..0c7e6d237e 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-loose/generator/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-loose/generator/output.js
@@ -1,4 +1,4 @@
-var _foo = babelHelpers.classPrivateFieldLooseKey("foo");
+var _foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
 class Cl {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-loose/reassignment/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-loose/reassignment/output.js
index 319626f6ff..b9d7349277 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-loose/reassignment/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-loose/reassignment/output.js
@@ -1,6 +1,6 @@
 var counter = 0;
 
-var _privateMethod = babelHelpers.classPrivateFieldLooseKey("privateMethod");
+var _privateMethod = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateMethod");
 
 class Foo {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-loose/super/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-loose/super/output.js
index 7f8aa27309..c2a0b85b7c 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-loose/super/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-loose/super/output.js
@@ -5,7 +5,7 @@ class Base {
 
 }
 
-var _privateMethod = babelHelpers.classPrivateFieldLooseKey("privateMethod");
+var _privateMethod = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateMethod");
 
 class Sub extends Base {
   constructor(...args) {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-privateFieldsAsProperties/assignment/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-privateFieldsAsProperties/assignment/output.js
index 897f052cd4..57a10bab4f 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-privateFieldsAsProperties/assignment/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-privateFieldsAsProperties/assignment/output.js
@@ -1,4 +1,4 @@
-var _privateMethod = babelHelpers.classPrivateFieldLooseKey("privateMethod");
+var _privateMethod = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateMethod");
 
 class Foo {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-privateFieldsAsProperties/async/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-privateFieldsAsProperties/async/output.js
index 1ae55ce6cb..531077f32e 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-privateFieldsAsProperties/async/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-privateFieldsAsProperties/async/output.js
@@ -1,4 +1,4 @@
-var _foo = babelHelpers.classPrivateFieldLooseKey("foo");
+var _foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
 class Cl {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-privateFieldsAsProperties/before-fields/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-privateFieldsAsProperties/before-fields/output.js
index f3ac631a5a..496c84319d 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-privateFieldsAsProperties/before-fields/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-privateFieldsAsProperties/before-fields/output.js
@@ -1,6 +1,6 @@
-var _priv = babelHelpers.classPrivateFieldLooseKey("priv");
+var _priv = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("priv");
 
-var _method = babelHelpers.classPrivateFieldLooseKey("method");
+var _method = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("method");
 
 class Cl {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-privateFieldsAsProperties/class-expression/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-privateFieldsAsProperties/class-expression/output.js
index ff898d7d6e..422497beac 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-privateFieldsAsProperties/class-expression/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-privateFieldsAsProperties/class-expression/output.js
@@ -1,6 +1,6 @@
 var _foo;
 
-console.log((_foo = babelHelpers.classPrivateFieldLooseKey("foo"), class A {
+console.log((_foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo"), class A {
   constructor() {
     Object.defineProperty(this, _foo, {
       value: _foo2
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-privateFieldsAsProperties/context/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-privateFieldsAsProperties/context/output.js
index 9e744365c3..fa507dc6c9 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-privateFieldsAsProperties/context/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-privateFieldsAsProperties/context/output.js
@@ -1,4 +1,4 @@
-var _getStatus = babelHelpers.classPrivateFieldLooseKey("getStatus");
+var _getStatus = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("getStatus");
 
 class Foo {
   constructor(status) {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-privateFieldsAsProperties/exfiltrated/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-privateFieldsAsProperties/exfiltrated/output.js
index 20aabf9d90..e122babf3c 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-privateFieldsAsProperties/exfiltrated/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-privateFieldsAsProperties/exfiltrated/output.js
@@ -1,6 +1,6 @@
 let exfiltrated;
 
-var _privateMethod = babelHelpers.classPrivateFieldLooseKey("privateMethod");
+var _privateMethod = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateMethod");
 
 class Foo {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-privateFieldsAsProperties/generator/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-privateFieldsAsProperties/generator/output.js
index 4f1bca35bf..0c7e6d237e 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-privateFieldsAsProperties/generator/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-privateFieldsAsProperties/generator/output.js
@@ -1,4 +1,4 @@
-var _foo = babelHelpers.classPrivateFieldLooseKey("foo");
+var _foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
 class Cl {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-privateFieldsAsProperties/super/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-privateFieldsAsProperties/super/output.js
index 135e85a475..773a093db0 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-privateFieldsAsProperties/super/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-privateFieldsAsProperties/super/output.js
@@ -5,7 +5,7 @@ class Base {
 
 }
 
-var _privateMethod = babelHelpers.classPrivateFieldLooseKey("privateMethod");
+var _privateMethod = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateMethod");
 
 class Sub extends Base {
   constructor(...args) {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method/assignment/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method/assignment/output.js
index 287035cd1b..0c4c7958ab 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method/assignment/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method/assignment/output.js
@@ -1,4 +1,4 @@
-var _privateMethod = new WeakSet();
+var _privateMethod = /*#__PURE__*/new WeakSet();
 
 class Foo {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method/async/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method/async/output.js
index 18681ae3c9..256f7fe629 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method/async/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method/async/output.js
@@ -1,4 +1,4 @@
-var _foo = new WeakSet();
+var _foo = /*#__PURE__*/new WeakSet();
 
 class Cl {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method/before-fields/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method/before-fields/output.js
index 9efe6b690e..447aba2a50 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method/before-fields/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method/before-fields/output.js
@@ -1,6 +1,6 @@
-var _priv = new WeakMap();
+var _priv = /*#__PURE__*/new WeakMap();
 
-var _method = new WeakSet();
+var _method = /*#__PURE__*/new WeakSet();
 
 class Cl {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method/class-expression/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method/class-expression/output.js
index 2c128cc199..f0c034edfe 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method/class-expression/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method/class-expression/output.js
@@ -1,6 +1,6 @@
 var _foo;
 
-console.log((_foo = new WeakSet(), class A {
+console.log((_foo = /*#__PURE__*/new WeakSet(), class A {
   constructor() {
     _foo.add(this);
   }
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method/context/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method/context/output.js
index a771a166fa..0be6a465b0 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method/context/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method/context/output.js
@@ -1,4 +1,4 @@
-var _getStatus = new WeakSet();
+var _getStatus = /*#__PURE__*/new WeakSet();
 
 class Foo {
   constructor(status) {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method/exfiltrated/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method/exfiltrated/output.js
index 6501d6da34..88d1606b8f 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method/exfiltrated/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method/exfiltrated/output.js
@@ -1,6 +1,6 @@
 var exfiltrated;
 
-var _privateMethod = new WeakSet();
+var _privateMethod = /*#__PURE__*/new WeakSet();
 
 class Foo {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method/generator/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method/generator/output.js
index aceb5e4475..2d3984fd5d 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method/generator/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method/generator/output.js
@@ -1,4 +1,4 @@
-var _foo = new WeakSet();
+var _foo = /*#__PURE__*/new WeakSet();
 
 class Cl {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method/read-only/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method/read-only/output.js
index b45320ca4a..9b9b5db279 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method/read-only/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method/read-only/output.js
@@ -1,4 +1,4 @@
-var _method = new WeakSet();
+var _method = /*#__PURE__*/new WeakSet();
 
 class A {
   self() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method/reassignment/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method/reassignment/output.js
index d0dbda0511..d06ddb53ec 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method/reassignment/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method/reassignment/output.js
@@ -1,6 +1,6 @@
 var results = [];
 
-var _privateFieldValue = new WeakSet();
+var _privateFieldValue = /*#__PURE__*/new WeakSet();
 
 class Foo {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method/super/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method/super/output.js
index 7bcd4ac7ef..475654149f 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method/super/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-method/super/output.js
@@ -5,7 +5,7 @@ class Base {
 
 }
 
-var _privateMethod = new WeakSet();
+var _privateMethod = /*#__PURE__*/new WeakSet();
 
 class Sub extends Base {
   constructor(...args) {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-loose/basic/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-loose/basic/output.js
index 8b6f957e0b..3710640c43 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-loose/basic/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-loose/basic/output.js
@@ -1,4 +1,4 @@
-var _privateStaticMethod = babelHelpers.classPrivateFieldLooseKey("privateStaticMethod");
+var _privateStaticMethod = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateStaticMethod");
 
 class Cl {
   static staticMethod2() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-loose/class-check/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-loose/class-check/output.js
index 8ff4aacd7a..f7a56b73e9 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-loose/class-check/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-loose/class-check/output.js
@@ -1,4 +1,4 @@
-var _privateStaticMethod = babelHelpers.classPrivateFieldLooseKey("privateStaticMethod");
+var _privateStaticMethod = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateStaticMethod");
 
 class Cl {
   publicMethod(checked) {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-loose/class-expression/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-loose/class-expression/output.js
index cfff4ef1bc..171fe93641 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-loose/class-expression/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-loose/class-expression/output.js
@@ -1,6 +1,6 @@
 var _class, _foo, _temp;
 
-console.log((_temp = (_foo = babelHelpers.classPrivateFieldLooseKey("foo"), _class = class A {
+console.log((_temp = (_foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo"), _class = class A {
   method() {
     babelHelpers.classPrivateFieldLooseBase(this, _foo)[_foo]();
   }
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-loose/exfiltrated/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-loose/exfiltrated/output.js
index f8cc8e9d65..c1de78501a 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-loose/exfiltrated/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-loose/exfiltrated/output.js
@@ -1,6 +1,6 @@
 var exfiltrated;
 
-var _privateStaticMethod = babelHelpers.classPrivateFieldLooseKey("privateStaticMethod");
+var _privateStaticMethod = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateStaticMethod");
 
 class Cl {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-loose/generator/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-loose/generator/output.js
index 095f86b0ef..90aea89ae8 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-loose/generator/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-loose/generator/output.js
@@ -1,4 +1,4 @@
-var _foo = babelHelpers.classPrivateFieldLooseKey("foo");
+var _foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
 class Cl {
   test() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-loose/reassignment/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-loose/reassignment/output.js
index 7ba99ec7c2..346a9a014e 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-loose/reassignment/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-loose/reassignment/output.js
@@ -1,4 +1,4 @@
-var _privateStaticMethod = babelHelpers.classPrivateFieldLooseKey("privateStaticMethod");
+var _privateStaticMethod = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateStaticMethod");
 
 class Cl {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-loose/super/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-loose/super/output.js
index 9232666b00..0c809ab47a 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-loose/super/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-loose/super/output.js
@@ -5,7 +5,7 @@ class Base {
 
 }
 
-var _subStaticPrivateMethod = babelHelpers.classPrivateFieldLooseKey("subStaticPrivateMethod");
+var _subStaticPrivateMethod = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("subStaticPrivateMethod");
 
 class Sub extends Base {
   static basePublicStaticMethod() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-loose/this/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-loose/this/output.js
index ed8fac6d2b..4da1dd1aa9 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-loose/this/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-loose/this/output.js
@@ -5,9 +5,9 @@ class A {
 
 }
 
-var _getA = babelHelpers.classPrivateFieldLooseKey("getA");
+var _getA = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("getA");
 
-var _getB = babelHelpers.classPrivateFieldLooseKey("getB");
+var _getB = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("getB");
 
 class B extends A {
   static get b() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-privateFieldsAsProperties/async/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-privateFieldsAsProperties/async/output.js
index 8910dd1b8e..e27e1b7a8e 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-privateFieldsAsProperties/async/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-privateFieldsAsProperties/async/output.js
@@ -1,4 +1,4 @@
-var _privateStaticMethod = babelHelpers.classPrivateFieldLooseKey("privateStaticMethod");
+var _privateStaticMethod = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateStaticMethod");
 
 class Cl {
   test() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-privateFieldsAsProperties/basic/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-privateFieldsAsProperties/basic/output.js
index 8b6f957e0b..3710640c43 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-privateFieldsAsProperties/basic/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-privateFieldsAsProperties/basic/output.js
@@ -1,4 +1,4 @@
-var _privateStaticMethod = babelHelpers.classPrivateFieldLooseKey("privateStaticMethod");
+var _privateStaticMethod = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateStaticMethod");
 
 class Cl {
   static staticMethod2() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-privateFieldsAsProperties/class-check/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-privateFieldsAsProperties/class-check/output.js
index 8ff4aacd7a..f7a56b73e9 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-privateFieldsAsProperties/class-check/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-privateFieldsAsProperties/class-check/output.js
@@ -1,4 +1,4 @@
-var _privateStaticMethod = babelHelpers.classPrivateFieldLooseKey("privateStaticMethod");
+var _privateStaticMethod = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateStaticMethod");
 
 class Cl {
   publicMethod(checked) {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-privateFieldsAsProperties/class-expression/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-privateFieldsAsProperties/class-expression/output.js
index cfff4ef1bc..171fe93641 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-privateFieldsAsProperties/class-expression/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-privateFieldsAsProperties/class-expression/output.js
@@ -1,6 +1,6 @@
 var _class, _foo, _temp;
 
-console.log((_temp = (_foo = babelHelpers.classPrivateFieldLooseKey("foo"), _class = class A {
+console.log((_temp = (_foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo"), _class = class A {
   method() {
     babelHelpers.classPrivateFieldLooseBase(this, _foo)[_foo]();
   }
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-privateFieldsAsProperties/exfiltrated/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-privateFieldsAsProperties/exfiltrated/output.js
index 55fb8eed2b..b948c339bd 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-privateFieldsAsProperties/exfiltrated/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-privateFieldsAsProperties/exfiltrated/output.js
@@ -1,6 +1,6 @@
 let exfiltrated;
 
-var _privateStaticMethod = babelHelpers.classPrivateFieldLooseKey("privateStaticMethod");
+var _privateStaticMethod = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateStaticMethod");
 
 class Cl {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-privateFieldsAsProperties/generator/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-privateFieldsAsProperties/generator/output.js
index 095f86b0ef..90aea89ae8 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-privateFieldsAsProperties/generator/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-privateFieldsAsProperties/generator/output.js
@@ -1,4 +1,4 @@
-var _foo = babelHelpers.classPrivateFieldLooseKey("foo");
+var _foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
 class Cl {
   test() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-privateFieldsAsProperties/reassignment/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-privateFieldsAsProperties/reassignment/output.js
index 7ba99ec7c2..346a9a014e 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-privateFieldsAsProperties/reassignment/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-privateFieldsAsProperties/reassignment/output.js
@@ -1,4 +1,4 @@
-var _privateStaticMethod = babelHelpers.classPrivateFieldLooseKey("privateStaticMethod");
+var _privateStaticMethod = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateStaticMethod");
 
 class Cl {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-privateFieldsAsProperties/super/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-privateFieldsAsProperties/super/output.js
index 3a734d066f..4e40259673 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-privateFieldsAsProperties/super/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-privateFieldsAsProperties/super/output.js
@@ -5,7 +5,7 @@ class Base {
 
 }
 
-var _subStaticPrivateMethod = babelHelpers.classPrivateFieldLooseKey("subStaticPrivateMethod");
+var _subStaticPrivateMethod = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("subStaticPrivateMethod");
 
 class Sub extends Base {
   static basePublicStaticMethod() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-privateFieldsAsProperties/this/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-privateFieldsAsProperties/this/output.js
index c73cb416d5..4e26f53c8a 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-privateFieldsAsProperties/this/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method-privateFieldsAsProperties/this/output.js
@@ -5,9 +5,9 @@ class A {
 
 }
 
-var _getA = babelHelpers.classPrivateFieldLooseKey("getA");
+var _getA = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("getA");
 
-var _getB = babelHelpers.classPrivateFieldLooseKey("getB");
+var _getB = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("getB");
 
 class B extends A {
   static get b() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/static-accessors-loose/basic/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/static-accessors-loose/basic/output.js
index 105cdd7da0..e54575ca76 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/static-accessors-loose/basic/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/static-accessors-loose/basic/output.js
@@ -1,6 +1,6 @@
-var _PRIVATE_STATIC_FIELD = babelHelpers.classPrivateFieldLooseKey("PRIVATE_STATIC_FIELD");
+var _PRIVATE_STATIC_FIELD = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("PRIVATE_STATIC_FIELD");
 
-var _privateStaticFieldValue = babelHelpers.classPrivateFieldLooseKey("privateStaticFieldValue");
+var _privateStaticFieldValue = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateStaticFieldValue");
 
 class Cl {
   static getValue() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/static-accessors-loose/destructure-set/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/static-accessors-loose/destructure-set/output.js
index 4b48880d23..d6e0386575 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/static-accessors-loose/destructure-set/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/static-accessors-loose/destructure-set/output.js
@@ -1,6 +1,6 @@
-var _p = babelHelpers.classPrivateFieldLooseKey("p");
+var _p = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("p");
 
-var _q = babelHelpers.classPrivateFieldLooseKey("q");
+var _q = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("q");
 
 class C {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/static-accessors-loose/get-only-setter/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/static-accessors-loose/get-only-setter/output.js
index 6ec9998a56..78f810f55f 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/static-accessors-loose/get-only-setter/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/static-accessors-loose/get-only-setter/output.js
@@ -1,6 +1,6 @@
-var _PRIVATE_STATIC_FIELD = babelHelpers.classPrivateFieldLooseKey("PRIVATE_STATIC_FIELD");
+var _PRIVATE_STATIC_FIELD = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("PRIVATE_STATIC_FIELD");
 
-var _privateStaticFieldValue = babelHelpers.classPrivateFieldLooseKey("privateStaticFieldValue");
+var _privateStaticFieldValue = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateStaticFieldValue");
 
 class Cl {
   static getPrivateStaticFieldValue() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/static-accessors-loose/set-only-getter/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/static-accessors-loose/set-only-getter/output.js
index 66d4f85877..ef1d00c2e8 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/static-accessors-loose/set-only-getter/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/static-accessors-loose/set-only-getter/output.js
@@ -1,6 +1,6 @@
-var _privateField = babelHelpers.classPrivateFieldLooseKey("privateField");
+var _privateField = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateField");
 
-var _privateFieldValue = babelHelpers.classPrivateFieldLooseKey("privateFieldValue");
+var _privateFieldValue = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateFieldValue");
 
 class Cl {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/static-accessors-loose/updates/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/static-accessors-loose/updates/output.js
index 9cc25d1c8c..219cd3910f 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/static-accessors-loose/updates/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/static-accessors-loose/updates/output.js
@@ -1,6 +1,6 @@
-var _privateField = babelHelpers.classPrivateFieldLooseKey("privateField");
+var _privateField = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateField");
 
-var _privateFieldValue = babelHelpers.classPrivateFieldLooseKey("privateFieldValue");
+var _privateFieldValue = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateFieldValue");
 
 class Cl {
   static publicGetPrivateField() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/static-accessors-privateFieldsAsProperties/basic/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/static-accessors-privateFieldsAsProperties/basic/output.js
index 105cdd7da0..e54575ca76 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/static-accessors-privateFieldsAsProperties/basic/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/static-accessors-privateFieldsAsProperties/basic/output.js
@@ -1,6 +1,6 @@
-var _PRIVATE_STATIC_FIELD = babelHelpers.classPrivateFieldLooseKey("PRIVATE_STATIC_FIELD");
+var _PRIVATE_STATIC_FIELD = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("PRIVATE_STATIC_FIELD");
 
-var _privateStaticFieldValue = babelHelpers.classPrivateFieldLooseKey("privateStaticFieldValue");
+var _privateStaticFieldValue = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateStaticFieldValue");
 
 class Cl {
   static getValue() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/static-accessors-privateFieldsAsProperties/destructure-set/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/static-accessors-privateFieldsAsProperties/destructure-set/output.js
index 4b48880d23..d6e0386575 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/static-accessors-privateFieldsAsProperties/destructure-set/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/static-accessors-privateFieldsAsProperties/destructure-set/output.js
@@ -1,6 +1,6 @@
-var _p = babelHelpers.classPrivateFieldLooseKey("p");
+var _p = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("p");
 
-var _q = babelHelpers.classPrivateFieldLooseKey("q");
+var _q = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("q");
 
 class C {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/static-accessors-privateFieldsAsProperties/get-only-setter/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/static-accessors-privateFieldsAsProperties/get-only-setter/output.js
index 6ec9998a56..78f810f55f 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/static-accessors-privateFieldsAsProperties/get-only-setter/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/static-accessors-privateFieldsAsProperties/get-only-setter/output.js
@@ -1,6 +1,6 @@
-var _PRIVATE_STATIC_FIELD = babelHelpers.classPrivateFieldLooseKey("PRIVATE_STATIC_FIELD");
+var _PRIVATE_STATIC_FIELD = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("PRIVATE_STATIC_FIELD");
 
-var _privateStaticFieldValue = babelHelpers.classPrivateFieldLooseKey("privateStaticFieldValue");
+var _privateStaticFieldValue = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateStaticFieldValue");
 
 class Cl {
   static getPrivateStaticFieldValue() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/static-accessors-privateFieldsAsProperties/set-only-getter/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/static-accessors-privateFieldsAsProperties/set-only-getter/output.js
index 62e5992370..5a91fb3747 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/static-accessors-privateFieldsAsProperties/set-only-getter/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/static-accessors-privateFieldsAsProperties/set-only-getter/output.js
@@ -1,6 +1,6 @@
-var _privateField = babelHelpers.classPrivateFieldLooseKey("privateField");
+var _privateField = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateField");
 
-var _privateFieldValue = babelHelpers.classPrivateFieldLooseKey("privateFieldValue");
+var _privateFieldValue = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateFieldValue");
 
 class Cl {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-methods/test/fixtures/static-accessors-privateFieldsAsProperties/updates/output.js b/packages/babel-plugin-proposal-private-methods/test/fixtures/static-accessors-privateFieldsAsProperties/updates/output.js
index 3d9711b788..91b64e57ef 100644
--- a/packages/babel-plugin-proposal-private-methods/test/fixtures/static-accessors-privateFieldsAsProperties/updates/output.js
+++ b/packages/babel-plugin-proposal-private-methods/test/fixtures/static-accessors-privateFieldsAsProperties/updates/output.js
@@ -1,6 +1,6 @@
-var _privateField = babelHelpers.classPrivateFieldLooseKey("privateField");
+var _privateField = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateField");
 
-var _privateFieldValue = babelHelpers.classPrivateFieldLooseKey("privateFieldValue");
+var _privateFieldValue = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateFieldValue");
 
 class Cl {
   static publicGetPrivateField() {
diff --git a/packages/babel-plugin-proposal-private-property-in-object/package.json b/packages/babel-plugin-proposal-private-property-in-object/package.json
index 464b0c2762..2200348fa6 100644
--- a/packages/babel-plugin-proposal-private-property-in-object/package.json
+++ b/packages/babel-plugin-proposal-private-property-in-object/package.json
@@ -17,7 +17,7 @@
     "babel-plugin"
   ],
   "dependencies": {
-    "@babel/helper-compilation-targets": "workspace:^7.12.17",
+    "@babel/helper-annotate-as-pure": "workspace:^7.12.13",
     "@babel/helper-create-class-features-plugin": "workspace:^7.13.0",
     "@babel/helper-plugin-utils": "workspace:^7.13.0",
     "@babel/plugin-syntax-private-property-in-object": "workspace:^7.13.0"
diff --git a/packages/babel-plugin-proposal-private-property-in-object/src/index.js b/packages/babel-plugin-proposal-private-property-in-object/src/index.js
index 2beb98dae6..9d7d31a294 100644
--- a/packages/babel-plugin-proposal-private-property-in-object/src/index.js
+++ b/packages/babel-plugin-proposal-private-property-in-object/src/index.js
@@ -5,6 +5,7 @@ import {
   FEATURES,
   injectInitialization as injectConstructorInit,
 } from "@babel/helper-create-class-features-plugin";
+import annotateAsPure from "@babel/helper-annotate-as-pure";
 
 export default declare(({ assertVersion, types: t, template }, { loose }) => {
   assertVersion(7);
@@ -72,7 +73,10 @@ export default declare(({ assertVersion, types: t, template }, { loose }) => {
 
       inject(reference, template.expression.ast`${t.cloneNode(id)}.add(this)`);
 
-      outerClass.insertBefore(template.ast`var ${id} = new WeakSet()`);
+      const newExpr = t.newExpression(t.identifier("WeakSet"), []);
+      annotateAsPure(newExpr);
+
+      outerClass.insertBefore(template.ast`var ${id} = ${newExpr}`);
     }
 
     return t.cloneNode(id);
diff --git a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/assumption-privateFieldsAsProperties/accessor/output.js b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/assumption-privateFieldsAsProperties/accessor/output.js
index 40db38108d..ca993c31ef 100644
--- a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/assumption-privateFieldsAsProperties/accessor/output.js
+++ b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/assumption-privateFieldsAsProperties/accessor/output.js
@@ -1,4 +1,4 @@
-var _foo = babelHelpers.classPrivateFieldLooseKey("foo");
+var _foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
 class Foo {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/assumption-privateFieldsAsProperties/compiled-classes/output.js b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/assumption-privateFieldsAsProperties/compiled-classes/output.js
index 1889def268..eea2454f62 100644
--- a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/assumption-privateFieldsAsProperties/compiled-classes/output.js
+++ b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/assumption-privateFieldsAsProperties/compiled-classes/output.js
@@ -1,6 +1,6 @@
-var _foo = babelHelpers.classPrivateFieldLooseKey("foo");
+var _foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
-var _bar = babelHelpers.classPrivateFieldLooseKey("bar");
+var _bar = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("bar");
 
 let Foo = /*#__PURE__*/function () {
   "use strict";
diff --git a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/assumption-privateFieldsAsProperties/field/output.js b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/assumption-privateFieldsAsProperties/field/output.js
index df6a89c95c..81bf64307a 100644
--- a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/assumption-privateFieldsAsProperties/field/output.js
+++ b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/assumption-privateFieldsAsProperties/field/output.js
@@ -1,4 +1,4 @@
-var _foo = babelHelpers.classPrivateFieldLooseKey("foo");
+var _foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
 class Foo {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/assumption-privateFieldsAsProperties/method/output.js b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/assumption-privateFieldsAsProperties/method/output.js
index 6bde632989..4957a58ecc 100644
--- a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/assumption-privateFieldsAsProperties/method/output.js
+++ b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/assumption-privateFieldsAsProperties/method/output.js
@@ -1,4 +1,4 @@
-var _foo = babelHelpers.classPrivateFieldLooseKey("foo");
+var _foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
 class Foo {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/assumption-privateFieldsAsProperties/nested-class-other-redeclared/output.js b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/assumption-privateFieldsAsProperties/nested-class-other-redeclared/output.js
index 42541d4512..f07ced4f8b 100644
--- a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/assumption-privateFieldsAsProperties/nested-class-other-redeclared/output.js
+++ b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/assumption-privateFieldsAsProperties/nested-class-other-redeclared/output.js
@@ -1,6 +1,6 @@
-var _foo = babelHelpers.classPrivateFieldLooseKey("foo");
+var _foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
-var _bar = babelHelpers.classPrivateFieldLooseKey("bar");
+var _bar = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("bar");
 
 class Foo {
   constructor() {
@@ -15,7 +15,7 @@ class Foo {
   }
 
   test() {
-    var _bar2 = babelHelpers.classPrivateFieldLooseKey("bar");
+    var _bar2 = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("bar");
 
     class Nested {
       constructor() {
diff --git a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/assumption-privateFieldsAsProperties/nested-class-redeclared/output.js b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/assumption-privateFieldsAsProperties/nested-class-redeclared/output.js
index e20e475ad9..99d94eec79 100644
--- a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/assumption-privateFieldsAsProperties/nested-class-redeclared/output.js
+++ b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/assumption-privateFieldsAsProperties/nested-class-redeclared/output.js
@@ -1,4 +1,4 @@
-var _foo = babelHelpers.classPrivateFieldLooseKey("foo");
+var _foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
 class Foo {
   constructor() {
@@ -9,7 +9,7 @@ class Foo {
   }
 
   test() {
-    var _foo2 = babelHelpers.classPrivateFieldLooseKey("foo");
+    var _foo2 = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
     class Nested {
       constructor() {
diff --git a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/assumption-privateFieldsAsProperties/nested-class/output.js b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/assumption-privateFieldsAsProperties/nested-class/output.js
index b87aa82053..972e8075cc 100644
--- a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/assumption-privateFieldsAsProperties/nested-class/output.js
+++ b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/assumption-privateFieldsAsProperties/nested-class/output.js
@@ -1,4 +1,4 @@
-var _foo = babelHelpers.classPrivateFieldLooseKey("foo");
+var _foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
 class Foo {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/assumption-privateFieldsAsProperties/static-accessor/output.js b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/assumption-privateFieldsAsProperties/static-accessor/output.js
index 0f063078b1..045270ad39 100644
--- a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/assumption-privateFieldsAsProperties/static-accessor/output.js
+++ b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/assumption-privateFieldsAsProperties/static-accessor/output.js
@@ -1,4 +1,4 @@
-var _foo = babelHelpers.classPrivateFieldLooseKey("foo");
+var _foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
 class Foo {
   test(other) {
diff --git a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/assumption-privateFieldsAsProperties/static-field/output.js b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/assumption-privateFieldsAsProperties/static-field/output.js
index b69ce320b7..8a13e9186c 100644
--- a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/assumption-privateFieldsAsProperties/static-field/output.js
+++ b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/assumption-privateFieldsAsProperties/static-field/output.js
@@ -1,4 +1,4 @@
-var _foo = babelHelpers.classPrivateFieldLooseKey("foo");
+var _foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
 class Foo {
   test(other) {
diff --git a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/assumption-privateFieldsAsProperties/static-method/output.js b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/assumption-privateFieldsAsProperties/static-method/output.js
index 09ee6ad805..83bab303a4 100644
--- a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/assumption-privateFieldsAsProperties/static-method/output.js
+++ b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/assumption-privateFieldsAsProperties/static-method/output.js
@@ -1,4 +1,4 @@
-var _foo = babelHelpers.classPrivateFieldLooseKey("foo");
+var _foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
 class Foo {
   test(other) {
diff --git a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private-loose/accessor/output.js b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private-loose/accessor/output.js
index a3d6297345..9984179820 100644
--- a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private-loose/accessor/output.js
+++ b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private-loose/accessor/output.js
@@ -1,4 +1,4 @@
-var _foo = babelHelpers.classPrivateFieldLooseKey("foo");
+var _foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
 let Foo = /*#__PURE__*/function () {
   "use strict";
diff --git a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private-loose/field/output.js b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private-loose/field/output.js
index ef83b46205..89fcd20b3d 100644
--- a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private-loose/field/output.js
+++ b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private-loose/field/output.js
@@ -1,4 +1,4 @@
-var _foo = babelHelpers.classPrivateFieldLooseKey("foo");
+var _foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
 let Foo = /*#__PURE__*/function () {
   "use strict";
diff --git a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private-loose/method/output.js b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private-loose/method/output.js
index 45362fb301..9b5a35fa23 100644
--- a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private-loose/method/output.js
+++ b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private-loose/method/output.js
@@ -1,4 +1,4 @@
-var _foo = babelHelpers.classPrivateFieldLooseKey("foo");
+var _foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
 let Foo = /*#__PURE__*/function () {
   "use strict";
diff --git a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private-loose/native-classes/output.js b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private-loose/native-classes/output.js
index f40acdaefc..13ebbe4210 100644
--- a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private-loose/native-classes/output.js
+++ b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private-loose/native-classes/output.js
@@ -1,4 +1,4 @@
-var _bar = new WeakMap();
+var _bar = /*#__PURE__*/new WeakMap();
 
 class Foo {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private-loose/nested-class-other-redeclared/output.js b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private-loose/nested-class-other-redeclared/output.js
index c87d10c075..3710347256 100644
--- a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private-loose/nested-class-other-redeclared/output.js
+++ b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private-loose/nested-class-other-redeclared/output.js
@@ -1,6 +1,6 @@
-var _foo = babelHelpers.classPrivateFieldLooseKey("foo");
+var _foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
-var _bar = babelHelpers.classPrivateFieldLooseKey("bar");
+var _bar = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("bar");
 
 let Foo = /*#__PURE__*/function () {
   "use strict";
@@ -20,7 +20,7 @@ let Foo = /*#__PURE__*/function () {
   babelHelpers.createClass(Foo, [{
     key: "test",
     value: function test() {
-      var _bar2 = babelHelpers.classPrivateFieldLooseKey("bar");
+      var _bar2 = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("bar");
 
       let Nested = /*#__PURE__*/function () {
         function Nested() {
diff --git a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private-loose/nested-class-redeclared/output.js b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private-loose/nested-class-redeclared/output.js
index b37a080dbe..1f548b814c 100644
--- a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private-loose/nested-class-redeclared/output.js
+++ b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private-loose/nested-class-redeclared/output.js
@@ -1,4 +1,4 @@
-var _foo = babelHelpers.classPrivateFieldLooseKey("foo");
+var _foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
 let Foo = /*#__PURE__*/function () {
   "use strict";
@@ -14,7 +14,7 @@ let Foo = /*#__PURE__*/function () {
   babelHelpers.createClass(Foo, [{
     key: "test",
     value: function test() {
-      var _foo2 = babelHelpers.classPrivateFieldLooseKey("foo");
+      var _foo2 = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
       let Nested = /*#__PURE__*/function () {
         function Nested() {
diff --git a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private-loose/nested-class/output.js b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private-loose/nested-class/output.js
index 89011bdd32..75838559d3 100644
--- a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private-loose/nested-class/output.js
+++ b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private-loose/nested-class/output.js
@@ -1,4 +1,4 @@
-var _foo = babelHelpers.classPrivateFieldLooseKey("foo");
+var _foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
 let Foo = /*#__PURE__*/function () {
   "use strict";
diff --git a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private-loose/static-accessor/output.js b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private-loose/static-accessor/output.js
index 0e511d0f4e..84c86bb30c 100644
--- a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private-loose/static-accessor/output.js
+++ b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private-loose/static-accessor/output.js
@@ -1,4 +1,4 @@
-var _foo = babelHelpers.classPrivateFieldLooseKey("foo");
+var _foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
 let Foo = /*#__PURE__*/function () {
   "use strict";
diff --git a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private-loose/static-field/output.js b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private-loose/static-field/output.js
index b943d85937..273eadf31b 100644
--- a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private-loose/static-field/output.js
+++ b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private-loose/static-field/output.js
@@ -1,4 +1,4 @@
-var _foo = babelHelpers.classPrivateFieldLooseKey("foo");
+var _foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
 let Foo = /*#__PURE__*/function () {
   "use strict";
diff --git a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private-loose/static-method/output.js b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private-loose/static-method/output.js
index 2eacb6470e..646174ed7d 100644
--- a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private-loose/static-method/output.js
+++ b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private-loose/static-method/output.js
@@ -1,4 +1,4 @@
-var _foo = babelHelpers.classPrivateFieldLooseKey("foo");
+var _foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
 let Foo = /*#__PURE__*/function () {
   "use strict";
diff --git a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private/accessor/output.js b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private/accessor/output.js
index 5154c49e47..75a7587782 100644
--- a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private/accessor/output.js
+++ b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private/accessor/output.js
@@ -1,4 +1,4 @@
-var _foo = new WeakMap();
+var _foo = /*#__PURE__*/new WeakMap();
 
 let Foo = /*#__PURE__*/function () {
   "use strict";
diff --git a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private/field/output.js b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private/field/output.js
index db3727f36e..c83e48bcd8 100644
--- a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private/field/output.js
+++ b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private/field/output.js
@@ -1,4 +1,4 @@
-var _foo = new WeakMap();
+var _foo = /*#__PURE__*/new WeakMap();
 
 let Foo = /*#__PURE__*/function () {
   "use strict";
diff --git a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private/method/output.js b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private/method/output.js
index 6e418ceb51..ac675cbf7d 100644
--- a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private/method/output.js
+++ b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private/method/output.js
@@ -1,4 +1,4 @@
-var _foo = new WeakSet();
+var _foo = /*#__PURE__*/new WeakSet();
 
 let Foo = /*#__PURE__*/function () {
   "use strict";
diff --git a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private/native-classes/output.js b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private/native-classes/output.js
index f40acdaefc..13ebbe4210 100644
--- a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private/native-classes/output.js
+++ b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private/native-classes/output.js
@@ -1,4 +1,4 @@
-var _bar = new WeakMap();
+var _bar = /*#__PURE__*/new WeakMap();
 
 class Foo {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private/nested-class-other-redeclared/output.js b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private/nested-class-other-redeclared/output.js
index c4b80a1a23..a54b7a6691 100644
--- a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private/nested-class-other-redeclared/output.js
+++ b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private/nested-class-other-redeclared/output.js
@@ -1,6 +1,6 @@
-var _foo = new WeakMap();
+var _foo = /*#__PURE__*/new WeakMap();
 
-var _bar = new WeakMap();
+var _bar = /*#__PURE__*/new WeakMap();
 
 let Foo = /*#__PURE__*/function () {
   "use strict";
@@ -22,7 +22,7 @@ let Foo = /*#__PURE__*/function () {
   babelHelpers.createClass(Foo, [{
     key: "test",
     value: function test() {
-      var _bar2 = new WeakMap();
+      var _bar2 = /*#__PURE__*/new WeakMap();
 
       let Nested = /*#__PURE__*/function () {
         function Nested() {
diff --git a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private/nested-class-redeclared/output.js b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private/nested-class-redeclared/output.js
index 882976816e..20a7183234 100644
--- a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private/nested-class-redeclared/output.js
+++ b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private/nested-class-redeclared/output.js
@@ -1,4 +1,4 @@
-var _foo = new WeakMap();
+var _foo = /*#__PURE__*/new WeakMap();
 
 let Foo = /*#__PURE__*/function () {
   "use strict";
@@ -15,7 +15,7 @@ let Foo = /*#__PURE__*/function () {
   babelHelpers.createClass(Foo, [{
     key: "test",
     value: function test() {
-      var _foo2 = new WeakMap();
+      var _foo2 = /*#__PURE__*/new WeakMap();
 
       let Nested = /*#__PURE__*/function () {
         function Nested() {
diff --git a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private/nested-class/output.js b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private/nested-class/output.js
index e85b24741d..2c52c716a1 100644
--- a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private/nested-class/output.js
+++ b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/private/nested-class/output.js
@@ -1,4 +1,4 @@
-var _foo = new WeakMap();
+var _foo = /*#__PURE__*/new WeakMap();
 
 let Foo = /*#__PURE__*/function () {
   "use strict";
diff --git a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/accessor/output.js b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/accessor/output.js
index 7a64679f5a..f7a2a1df36 100644
--- a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/accessor/output.js
+++ b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/accessor/output.js
@@ -1,4 +1,4 @@
-var _FooBrandCheck = new WeakSet();
+var _FooBrandCheck = /*#__PURE__*/new WeakSet();
 
 class Foo {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/class-expression-in-default-param/output.js b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/class-expression-in-default-param/output.js
index 5289f0c5e8..79443544a1 100644
--- a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/class-expression-in-default-param/output.js
+++ b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/class-expression-in-default-param/output.js
@@ -1,7 +1,7 @@
 (x = (() => {
   var _fooBrandCheck;
 
-  return _fooBrandCheck = new WeakSet(), class {
+  return _fooBrandCheck = /*#__PURE__*/new WeakSet(), class {
     #foo = void _fooBrandCheck.add(this);
 
     test(other) {
diff --git a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/class-expression-instance/output.js b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/class-expression-instance/output.js
index 495153fae0..1641170870 100644
--- a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/class-expression-instance/output.js
+++ b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/class-expression-instance/output.js
@@ -1,7 +1,7 @@
 function fn() {
   var _privBrandCheck;
 
-  return new (_privBrandCheck = new WeakSet(), class {
+  return new (_privBrandCheck = /*#__PURE__*/new WeakSet(), class {
     #priv = void _privBrandCheck.add(this);
 
     method(obj) {
diff --git a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/class-expression-static/output.js b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/class-expression-static/output.js
index 39716aed53..ff0e5b1a65 100644
--- a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/class-expression-static/output.js
+++ b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/class-expression-static/output.js
@@ -1,7 +1,7 @@
 function fn() {
   var _privBrandCheck;
 
-  return new (_privBrandCheck = new WeakSet(), class {
+  return new (_privBrandCheck = /*#__PURE__*/new WeakSet(), class {
     static #priv = void _privBrandCheck.add(this);
 
     method(obj) {
diff --git a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/field/output.js b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/field/output.js
index 7ff1de3959..c0ea2596a7 100644
--- a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/field/output.js
+++ b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/field/output.js
@@ -1,6 +1,6 @@
 var _temp;
 
-var _fooBrandCheck = new WeakSet();
+var _fooBrandCheck = /*#__PURE__*/new WeakSet();
 
 class Foo {
   #foo = (_temp = 1, _fooBrandCheck.add(this), _temp);
diff --git a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/half-constructed-instance/output.js b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/half-constructed-instance/output.js
index 4d8bbd2a8b..6a6068c69d 100644
--- a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/half-constructed-instance/output.js
+++ b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/half-constructed-instance/output.js
@@ -1,10 +1,10 @@
 var _temp, _temp2;
 
-var _FBrandCheck = new WeakSet();
+var _FBrandCheck = /*#__PURE__*/new WeakSet();
 
-var _xBrandCheck = new WeakSet();
+var _xBrandCheck = /*#__PURE__*/new WeakSet();
 
-var _yBrandCheck = new WeakSet();
+var _yBrandCheck = /*#__PURE__*/new WeakSet();
 
 class F {
   m() {
diff --git a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/half-constructed-static/output.js b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/half-constructed-static/output.js
index e0ebbc3e27..5a318b5822 100644
--- a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/half-constructed-static/output.js
+++ b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/half-constructed-static/output.js
@@ -1,8 +1,8 @@
 var _temp, _temp2;
 
-var _xBrandCheck = new WeakSet();
+var _xBrandCheck = /*#__PURE__*/new WeakSet();
 
-var _yBrandCheck = new WeakSet();
+var _yBrandCheck = /*#__PURE__*/new WeakSet();
 
 class F {
   static m() {
diff --git a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/method/output.js b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/method/output.js
index 59a6fb1062..71e16edbe9 100644
--- a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/method/output.js
+++ b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/method/output.js
@@ -1,4 +1,4 @@
-var _FooBrandCheck = new WeakSet();
+var _FooBrandCheck = /*#__PURE__*/new WeakSet();
 
 class Foo {
   constructor() {
diff --git a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/multiple-checks/output.js b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/multiple-checks/output.js
index 98dc5cd7d8..da055a4bc1 100644
--- a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/multiple-checks/output.js
+++ b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/multiple-checks/output.js
@@ -1,6 +1,6 @@
-var _xBrandCheck = new WeakSet();
+var _xBrandCheck = /*#__PURE__*/new WeakSet();
 
-var _ABrandCheck = new WeakSet();
+var _ABrandCheck = /*#__PURE__*/new WeakSet();
 
 class A {
   #x = (_ABrandCheck.add(this), void _xBrandCheck.add(this));
diff --git a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/nested-class-other-redeclared/output.js b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/nested-class-other-redeclared/output.js
index 2f11e248f1..9048d00014 100644
--- a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/nested-class-other-redeclared/output.js
+++ b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/nested-class-other-redeclared/output.js
@@ -1,8 +1,8 @@
 var _temp, _temp3;
 
-var _fooBrandCheck = new WeakSet();
+var _fooBrandCheck = /*#__PURE__*/new WeakSet();
 
-var _barBrandCheck2 = new WeakSet();
+var _barBrandCheck2 = /*#__PURE__*/new WeakSet();
 
 class Foo {
   #foo = (_temp = 1, _fooBrandCheck.add(this), _temp);
@@ -11,7 +11,7 @@ class Foo {
   test() {
     var _temp2;
 
-    var _barBrandCheck = new WeakSet();
+    var _barBrandCheck = /*#__PURE__*/new WeakSet();
 
     class Nested {
       #bar = (_temp2 = 2, _barBrandCheck.add(this), _temp2);
diff --git a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/nested-class-redeclared/output.js b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/nested-class-redeclared/output.js
index 87094388d2..279f759f6f 100644
--- a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/nested-class-redeclared/output.js
+++ b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/nested-class-redeclared/output.js
@@ -1,6 +1,6 @@
 var _temp2;
 
-var _fooBrandCheck2 = new WeakSet();
+var _fooBrandCheck2 = /*#__PURE__*/new WeakSet();
 
 class Foo {
   #foo = (_temp2 = 1, _fooBrandCheck2.add(this), _temp2);
@@ -8,7 +8,7 @@ class Foo {
   test() {
     var _temp;
 
-    var _fooBrandCheck = new WeakSet();
+    var _fooBrandCheck = /*#__PURE__*/new WeakSet();
 
     class Nested {
       #foo = (_temp = 2, _fooBrandCheck.add(this), _temp);
diff --git a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/nested-class/output.js b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/nested-class/output.js
index c897b8d6c8..ff28dc7902 100644
--- a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/nested-class/output.js
+++ b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/nested-class/output.js
@@ -1,6 +1,6 @@
 var _temp;
 
-var _fooBrandCheck = new WeakSet();
+var _fooBrandCheck = /*#__PURE__*/new WeakSet();
 
 class Foo {
   #foo = (_temp = 1, _fooBrandCheck.add(this), _temp);
diff --git a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/static-field/output.js b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/static-field/output.js
index ceadc64ac4..588b3ad0b3 100644
--- a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/static-field/output.js
+++ b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/static-field/output.js
@@ -1,6 +1,6 @@
 var _temp;
 
-var _fooBrandCheck = new WeakSet();
+var _fooBrandCheck = /*#__PURE__*/new WeakSet();
 
 class Foo {
   static #foo = (_temp = 1, _fooBrandCheck.add(this), _temp);
diff --git a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/static-shadowed-binding/output.js b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/static-shadowed-binding/output.js
index b89f6ea5a3..9b87e5b5b4 100644
--- a/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/static-shadowed-binding/output.js
+++ b/packages/babel-plugin-proposal-private-property-in-object/test/fixtures/to-native-fields/static-shadowed-binding/output.js
@@ -1,4 +1,4 @@
-var _fooBrandCheck = new WeakSet();
+var _fooBrandCheck = /*#__PURE__*/new WeakSet();
 
 class A {
   static #foo = void _fooBrandCheck.add(this);
diff --git a/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/methods-loose-preset-not-loose/output.js b/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/methods-loose-preset-not-loose/output.js
index 2b545a555f..17ecd43528 100644
--- a/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/methods-loose-preset-not-loose/output.js
+++ b/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/methods-loose-preset-not-loose/output.js
@@ -1,4 +1,4 @@
-var _foo = babelHelpers.classPrivateFieldLooseKey("foo");
+var _foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
 class A {
   constructor() {
diff --git a/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/preset-loose-no-plugins/output.js b/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/preset-loose-no-plugins/output.js
index 2b545a555f..17ecd43528 100644
--- a/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/preset-loose-no-plugins/output.js
+++ b/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/preset-loose-no-plugins/output.js
@@ -1,4 +1,4 @@
-var _foo = babelHelpers.classPrivateFieldLooseKey("foo");
+var _foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
 class A {
   constructor() {
diff --git a/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/preset-not-loose-no-plugins/output.js b/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/preset-not-loose-no-plugins/output.js
index 80ef2f6606..f3de7b04fc 100644
--- a/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/preset-not-loose-no-plugins/output.js
+++ b/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/preset-not-loose-no-plugins/output.js
@@ -1,4 +1,4 @@
-var _foo = new WeakSet();
+var _foo = /*#__PURE__*/new WeakSet();
 
 class A {
   constructor() {
diff --git a/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/properties-and-methods-loose-preset-not-loose/output.js b/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/properties-and-methods-loose-preset-not-loose/output.js
index 2b545a555f..17ecd43528 100644
--- a/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/properties-and-methods-loose-preset-not-loose/output.js
+++ b/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/properties-and-methods-loose-preset-not-loose/output.js
@@ -1,4 +1,4 @@
-var _foo = babelHelpers.classPrivateFieldLooseKey("foo");
+var _foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
 class A {
   constructor() {
diff --git a/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/properties-and-methods-not-loose-preset-loose/output.js b/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/properties-and-methods-not-loose-preset-loose/output.js
index 80ef2f6606..f3de7b04fc 100644
--- a/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/properties-and-methods-not-loose-preset-loose/output.js
+++ b/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/properties-and-methods-not-loose-preset-loose/output.js
@@ -1,4 +1,4 @@
-var _foo = new WeakSet();
+var _foo = /*#__PURE__*/new WeakSet();
 
 class A {
   constructor() {
diff --git a/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/properties-loose-preset-loose/output.js b/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/properties-loose-preset-loose/output.js
index 2b545a555f..17ecd43528 100644
--- a/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/properties-loose-preset-loose/output.js
+++ b/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/properties-loose-preset-loose/output.js
@@ -1,4 +1,4 @@
-var _foo = babelHelpers.classPrivateFieldLooseKey("foo");
+var _foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
 class A {
   constructor() {
diff --git a/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/properties-loose-preset-not-loose/output.js b/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/properties-loose-preset-not-loose/output.js
index 2b545a555f..17ecd43528 100644
--- a/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/properties-loose-preset-not-loose/output.js
+++ b/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/properties-loose-preset-not-loose/output.js
@@ -1,4 +1,4 @@
-var _foo = babelHelpers.classPrivateFieldLooseKey("foo");
+var _foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
 class A {
   constructor() {
diff --git a/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/properties-not-loose-preset-loose/output.js b/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/properties-not-loose-preset-loose/output.js
index 80ef2f6606..f3de7b04fc 100644
--- a/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/properties-not-loose-preset-loose/output.js
+++ b/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/properties-not-loose-preset-loose/output.js
@@ -1,4 +1,4 @@
-var _foo = new WeakSet();
+var _foo = /*#__PURE__*/new WeakSet();
 
 class A {
   constructor() {
diff --git a/packages/babel-preset-env/test/fixtures/shipped-proposals/new-class-features-chrome-90/output.js b/packages/babel-preset-env/test/fixtures/shipped-proposals/new-class-features-chrome-90/output.js
index ce3182dcfd..cb0872d195 100644
--- a/packages/babel-preset-env/test/fixtures/shipped-proposals/new-class-features-chrome-90/output.js
+++ b/packages/babel-preset-env/test/fixtures/shipped-proposals/new-class-features-chrome-90/output.js
@@ -1,4 +1,4 @@
-var _fooBrandCheck = new WeakSet();
+var _fooBrandCheck = /*#__PURE__*/new WeakSet();
 
 class A {
   #foo = void _fooBrandCheck.add(this);
diff --git a/packages/babel-preset-env/test/fixtures/shipped-proposals/new-class-features-firefox-70/output.js b/packages/babel-preset-env/test/fixtures/shipped-proposals/new-class-features-firefox-70/output.js
index c953ed1420..9de4928f8a 100644
--- a/packages/babel-preset-env/test/fixtures/shipped-proposals/new-class-features-firefox-70/output.js
+++ b/packages/babel-preset-env/test/fixtures/shipped-proposals/new-class-features-firefox-70/output.js
@@ -1,4 +1,4 @@
-var _foo = new WeakMap();
+var _foo = /*#__PURE__*/new WeakMap();
 
 class A {
   constructor() {
diff --git a/yarn.lock b/yarn.lock
index 620a5b0ca1..e08ed1afd7 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -393,7 +393,7 @@ __metadata:
   languageName: node
   linkType: hard
 
-"@babel/helper-compilation-targets@workspace:^7.12.17, @babel/helper-compilation-targets@workspace:^7.13.13, @babel/helper-compilation-targets@workspace:^7.13.16, @babel/helper-compilation-targets@workspace:^7.13.8, @babel/helper-compilation-targets@workspace:packages/babel-helper-compilation-targets":
+"@babel/helper-compilation-targets@workspace:^7.13.13, @babel/helper-compilation-targets@workspace:^7.13.16, @babel/helper-compilation-targets@workspace:^7.13.8, @babel/helper-compilation-targets@workspace:packages/babel-helper-compilation-targets":
   version: 0.0.0-use.local
   resolution: "@babel/helper-compilation-targets@workspace:packages/babel-helper-compilation-targets"
   dependencies:
@@ -427,6 +427,7 @@ __metadata:
   resolution: "@babel/helper-create-class-features-plugin@workspace:packages/babel-helper-create-class-features-plugin"
   dependencies:
     "@babel/core": "workspace:*"
+    "@babel/helper-annotate-as-pure": "workspace:^7.12.13"
     "@babel/helper-function-name": "workspace:^7.12.13"
     "@babel/helper-member-expression-to-functions": "workspace:^7.13.0"
     "@babel/helper-optimise-call-expression": "workspace:^7.12.13"
@@ -1448,7 +1449,7 @@ __metadata:
   resolution: "@babel/plugin-proposal-private-property-in-object@workspace:packages/babel-plugin-proposal-private-property-in-object"
   dependencies:
     "@babel/core": "workspace:*"
-    "@babel/helper-compilation-targets": "workspace:^7.12.17"
+    "@babel/helper-annotate-as-pure": "workspace:^7.12.13"
     "@babel/helper-create-class-features-plugin": "workspace:^7.13.0"
     "@babel/helper-plugin-test-runner": "workspace:*"
     "@babel/helper-plugin-utils": "workspace:^7.13.0"