fix: throw expect privateIn when we see tt._in after private name

packages/babel-parser/src/parser/expression.js

@@ -27,6 +27,7 @@ import {
   isReservedWord,
   isStrictReservedWord,
   isStrictBindReservedWord,
+  isIdentifierStart,
 } from "../util/identifier";
 import type { Pos, Position } from "../util/location";
 import * as charCodes from "charcodes";
@@ -1139,10 +1140,12 @@ export default class ExpressionParser extends LValParser {
           return this.finishNode(node, "PipelinePrimaryTopicReference");
         }
 
-        if (this.hasPlugin("privateIn")) {
+        if (isIdentifierStart(this.input.codePointAt(this.state.end))) {
           node = (this.parseMaybePrivateName(true): N.PrivateName);
-          this.classScope.usePrivateName(node.id.name, node.start);
-          if (!this.match(tt._in)) {
+          if (this.match(tt._in)) {
+            this.expectPlugin("privateIn");
+            this.classScope.usePrivateName(node.id.name, node.start);
+          } else {
             this.raise(
               this.state.start,
               Errors.PrivateInExpectedIn,
@@ -1171,11 +1174,7 @@ export default class ExpressionParser extends LValParser {
     const isPrivate = this.match(tt.hash);
 
     if (isPrivate) {
-      this.expectOnePlugin([
-        "classPrivateProperties",
-        "classPrivateMethods",
-        "privateIn",
-      ]);
+      this.expectOnePlugin(["classPrivateProperties", "classPrivateMethods"]);
       if (!isPrivateNameAllowed) {
         this.raise(this.state.pos, Errors.UnexpectedPrivateField);
       }

packages/babel-parser/test/fixtures/experimental/_no-plugin/private-in/input.js

@@ -0,0 +1,7 @@
+class Point {
+  #x = 1;
+  #y = 2;
+  static isPoint(obj) {
+    return #x in obj && #y in obj;
+  }
+}

packages/babel-parser/test/fixtures/experimental/_no-plugin/private-in/options.json

@@ -0,0 +1,6 @@
+{
+  "plugins": [
+    "classPrivateProperties"
+  ],
+  "throws": "This experimental syntax requires enabling the parser plugin: 'privateIn' (5:14)"
+}

packages/babel-parser/test/fixtures/experimental/class-private-methods/asi-failure-generator/options.json

@@ -1,5 +1,5 @@
 {
-  "throws": "Unexpected token (3:3)",
+  "throws": "Unexpected token, expected \";\" (3:9)",
   "plugins": [
     "classProperties",
     "classPrivateMethods"

packages/babel-parser/test/fixtures/experimental/class-private-properties/failure-shorthand/options.json

@@ -1,5 +1,4 @@
 {
-  "throws": "Unexpected token (4:11)",
   "plugins": [
     "classPrivateProperties"
   ]

packages/babel-parser/test/fixtures/experimental/class-private-properties/failure-shorthand/output.json

@@ -0,0 +1,89 @@
+{
+  "type": "File",
+  "start":0,"end":56,"loc":{"start":{"line":1,"column":0},"end":{"line":6,"column":1}},
+  "errors": [
+    "SyntaxError: Private names are only allowed in property accesses (`obj.#x`) or in `in` expressions (`#x in obj`) (4:13)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":56,"loc":{"start":{"line":1,"column":0},"end":{"line":6,"column":1}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ClassDeclaration",
+        "start":0,"end":56,"loc":{"start":{"line":1,"column":0},"end":{"line":6,"column":1}},
+        "id": {
+          "type": "Identifier",
+          "start":6,"end":9,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":9},"identifierName":"Foo"},
+          "name": "Foo"
+        },
+        "superClass": null,
+        "body": {
+          "type": "ClassBody",
+          "start":10,"end":56,"loc":{"start":{"line":1,"column":10},"end":{"line":6,"column":1}},
+          "body": [
+            {
+              "type": "ClassPrivateProperty",
+              "start":14,"end":17,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":5}},
+              "static": false,
+              "key": {
+                "type": "PrivateName",
+                "start":14,"end":16,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":4}},
+                "id": {
+                  "type": "Identifier",
+                  "start":15,"end":16,"loc":{"start":{"line":2,"column":3},"end":{"line":2,"column":4},"identifierName":"x"},
+                  "name": "x"
+                }
+              },
+              "value": null
+            },
+            {
+              "type": "ClassMethod",
+              "start":20,"end":54,"loc":{"start":{"line":3,"column":2},"end":{"line":5,"column":3}},
+              "static": false,
+              "key": {
+                "type": "Identifier",
+                "start":20,"end":31,"loc":{"start":{"line":3,"column":2},"end":{"line":3,"column":13},"identifierName":"constructor"},
+                "name": "constructor"
+              },
+              "computed": false,
+              "kind": "constructor",
+              "id": null,
+              "generator": false,
+              "async": false,
+              "params": [],
+              "body": {
+                "type": "BlockStatement",
+                "start":34,"end":54,"loc":{"start":{"line":3,"column":16},"end":{"line":5,"column":3}},
+                "body": [
+                  {
+                    "type": "ExpressionStatement",
+                    "start":40,"end":50,"loc":{"start":{"line":4,"column":4},"end":{"line":4,"column":14}},
+                    "expression": {
+                      "type": "UnaryExpression",
+                      "start":40,"end":49,"loc":{"start":{"line":4,"column":4},"end":{"line":4,"column":13}},
+                      "operator": "delete",
+                      "prefix": true,
+                      "argument": {
+                        "type": "PrivateName",
+                        "start":47,"end":49,"loc":{"start":{"line":4,"column":11},"end":{"line":4,"column":13}},
+                        "id": {
+                          "type": "Identifier",
+                          "start":48,"end":49,"loc":{"start":{"line":4,"column":12},"end":{"line":4,"column":13},"identifierName":"x"},
+                          "name": "x"
+                        }
+                      }
+                    }
+                  }
+                ],
+                "directives": []
+              }
+            }
+          ]
+        }
+      }
+    ],
+    "directives": []
+  }
+}