Implement class features in estree (#12370)

Co-authored-by: Kai Cataldo <kai@kaicataldo.com>

eslint/babel-eslint-parser/src/analyze-scope.js

@@ -166,6 +166,10 @@ class Referencer extends OriginalReferencer {
     this._visitClassProperty(node);
   }
 
+  PropertyDefinition(node) {
+    this._visitClassProperty(node);
+  }
+
   // TODO: Update to visit type annotations when TypeScript/Flow support this syntax.
   ClassPrivateMethod(node) {
     super.MethodDefinition(node);

eslint/babel-eslint-parser/src/visitor-keys.js

@@ -8,11 +8,15 @@ export const newTypes = {
   Literal: ESLINT_VISITOR_KEYS.Literal,
   MethodDefinition: ["decorators"].concat(ESLINT_VISITOR_KEYS.MethodDefinition),
   Property: ["decorators"].concat(ESLINT_VISITOR_KEYS.Property),
+  // todo: remove this when Acorn supports class properties
+  PropertyDefinition: t.VISITOR_KEYS.ClassProperty,
+  // todo: remove this when Acorn supports class properties
+  PrivateIdentifier: [],
 };
 
 // AST Types that shares `"type"` property with Babel but have different shape
 export const conflictTypes = {
-  // todo: remove this when class features are supported
+  // todo: remove this when we drop Babel 7 support
   ClassPrivateMethod: ["decorators"].concat(
     ESLINT_VISITOR_KEYS.MethodDefinition,
   ),

eslint/babel-eslint-plugin/src/rules/no-invalid-this.js

@@ -11,7 +11,10 @@ export default ruleComposer.filterReports(noInvalidThisRule, problem => {
     if (
       node.type === "ClassPrivateMethod" ||
       node.type === "ClassPrivateProperty" ||
-      node.type === "ClassProperty"
+      node.type === "ClassProperty" ||
+      node.type === "PropertyDefinition" ||
+      (node.type === "MethodDefinition" &&
+        node.key.type === "PrivateIdentifier")
     ) {
       inClassMember = true;
       return;

eslint/babel-eslint-plugin/src/rules/semi.js

@@ -79,7 +79,7 @@ function report(context, node, missing) {
 export default ruleComposer.joinReports([
   rule,
   context => ({
-    "ClassProperty, ClassPrivateProperty"(node) {
+    "ClassProperty, ClassPrivateProperty, PropertyDefinition"(node) {
       const options = context.options[1];
       const exceptOneLine = options && options.omitLastInOneLineBlock === true;
       const sourceCode = context.getSourceCode();

eslint/babel-eslint-tests/test/integration/eslint/verify.js

@@ -1734,6 +1734,15 @@ describe("verify", () => {
           { "no-unused-vars": 1 },
         );
       });
+
+      it("type annotations should work", () => {
+        verifyAndAssertMessages(
+          `class C {
+            #p: Array<number>
+          }`,
+          { "no-undef": 1 },
+        );
+      });
     });
 
     describe("private methods", () => {
@@ -1794,6 +1803,31 @@ describe("verify", () => {
           { "no-unreachable": 1 },
         );
       });
+
+      it("should work with func-names", () => {
+        verifyAndAssertMessages(
+          `
+              export class C {
+                #d() {};
+              }
+          `,
+          { "func-names": 1 },
+        );
+      });
+
+      it("should work with space-before-function-paren", () => {
+        verifyAndAssertMessages(
+          `
+              export class C {
+                #d() {};
+              }
+          `,
+          { "space-before-function-paren": 1 },
+          [
+            "2:5 Missing space before function parentheses. space-before-function-paren",
+          ],
+        );
+      });
     });
   });
 

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

@@ -1172,12 +1172,15 @@ export default class ExpressionParser extends LValParser {
           node = (this.parseMaybePrivateName(true): N.PrivateName);
           if (this.match(tt._in)) {
             this.expectPlugin("privateIn");
-            this.classScope.usePrivateName(node.id.name, node.start);
+            this.classScope.usePrivateName(
+              this.getPrivateNameSV(node),
+              node.start,
+            );
           } else if (this.hasPlugin("privateIn")) {
             this.raise(
               this.state.start,
               Errors.PrivateInExpectedIn,
-              node.id.name,
+              this.getPrivateNameSV(node),
             );
           } else {
             throw this.unexpected(start);

packages/babel-parser/src/plugins/estree.js

@@ -194,6 +194,33 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       }
     }
 
+    parseMaybePrivateName(...args: [boolean]): any {
+      const node = super.parseMaybePrivateName(...args);
+      if (node.type === "PrivateName") {
+        return this.convertPrivateNameToPrivateIdentifier(node);
+      }
+      return node;
+    }
+
+    convertPrivateNameToPrivateIdentifier(
+      node: N.PrivateName,
+    ): N.EstreePrivateIdentifier {
+      const name = super.getPrivateNameSV(node);
+      node = (node: any);
+      delete node.id;
+      node.name = name;
+      node.type = "PrivateIdentifier";
+      return node;
+    }
+
+    isPrivateName(node: N.Node): boolean {
+      return node.type === "PrivateIdentifier";
+    }
+
+    getPrivateNameSV(node: N.Node): string {
+      return node.name;
+    }
+
     parseLiteral<T: N.Literal>(
       value: any,
       type: /*T["kind"]*/ string,
@@ -240,11 +267,27 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       delete funcNode.kind;
       // $FlowIgnore
       node.value = funcNode;
-
+      if (type === "ClassPrivateMethod") {
-      type = type === "ClassMethod" ? "MethodDefinition" : type;
+        // $FlowIgnore
+        node.computed = false;
+      }
+      type = "MethodDefinition";
       return this.finishNode(node, type);
     }
 
+    parseClassProperty(...args: [N.ClassProperty]): any {
+      const propertyNode = (super.parseClassProperty(...args): any);
+      propertyNode.type = "PropertyDefinition";
+      return (propertyNode: N.EstreePropertyDefinition);
+    }
+
+    parseClassPrivateProperty(...args: [N.ClassPrivateProperty]): any {
+      const propertyNode = (super.parseClassPrivateProperty(...args): any);
+      propertyNode.type = "PropertyDefinition";
+      propertyNode.computed = false;
+      return (propertyNode: N.EstreePropertyDefinition);
+    }
+
     parseObjectMethod(
       prop: N.ObjectMethod,
       isGenerator: boolean,

packages/babel-parser/src/plugins/flow/index.js

@@ -2181,7 +2181,8 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       if (member.declare) {
         if (
           member.type !== "ClassProperty" &&
-          member.type !== "ClassPrivateProperty"
+          member.type !== "ClassPrivateProperty" &&
+          member.type !== "PropertyDefinition" // Used by estree plugin
         ) {
           this.raise(pos, FlowErrors.DeclareClassElement);
         } else if (member.value) {

packages/babel-parser/src/types.js

@@ -1077,6 +1077,19 @@ export type EstreeImportExpression = NodeBase & {
   source: Expression,
 };
 
+export type EstreePrivateIdentifier = NodeBase & {
+  type: "PrivateIdentifier",
+  name: string,
+};
+
+export type EstreePropertyDefinition = NodeBase & {
+  type: "PropertyDefinition",
+  static: boolean,
+  key: Expression | EstreePrivateIdentifier,
+  computed: boolean,
+  value: Expression,
+};
+
 // === === === ===
 // TypeScript
 // === === === ===

packages/babel-parser/test/fixtures/estree/class-private-method/basic/input.js

@@ -1,3 +1,4 @@
 class A {
   #foo(arg, ...others) {}
+  static #bar(arg, ...others) {}
 }

packages/babel-parser/test/fixtures/estree/class-private-method/basic/output.json

@@ -1,15 +1,15 @@
 {
   "type": "File",
-  "start":0,"end":37,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+  "start":0,"end":70,"loc":{"start":{"line":1,"column":0},"end":{"line":4,"column":1}},
   "program": {
     "type": "Program",
-    "start":0,"end":37,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+    "start":0,"end":70,"loc":{"start":{"line":1,"column":0},"end":{"line":4,"column":1}},
     "sourceType": "script",
     "interpreter": null,
     "body": [
       {
         "type": "ClassDeclaration",
-        "start":0,"end":37,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+        "start":0,"end":70,"loc":{"start":{"line":1,"column":0},"end":{"line":4,"column":1}},
         "id": {
           "type": "Identifier",
           "start":6,"end":7,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":7},"identifierName":"A"},
@@ -18,20 +18,16 @@
         "superClass": null,
         "body": {
           "type": "ClassBody",
-          "start":8,"end":37,"loc":{"start":{"line":1,"column":8},"end":{"line":3,"column":1}},
+          "start":8,"end":70,"loc":{"start":{"line":1,"column":8},"end":{"line":4,"column":1}},
           "body": [
             {
-              "type": "ClassPrivateMethod",
+              "type": "MethodDefinition",
               "start":12,"end":35,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":25}},
               "static": false,
               "key": {
-                "type": "PrivateName",
+                "type": "PrivateIdentifier",
                 "start":12,"end":16,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":6}},
-                "id": {
-                  "type": "Identifier",
-                  "start":13,"end":16,"loc":{"start":{"line":2,"column":3},"end":{"line":2,"column":6},"identifierName":"foo"},
                 "name": "foo"
-                }
               },
               "kind": "method",
               "value": {
@@ -62,8 +58,50 @@
                   "start":33,"end":35,"loc":{"start":{"line":2,"column":23},"end":{"line":2,"column":25}},
                   "body": []
                 }
+              },
+              "computed": false
+            },
+            {
+              "type": "MethodDefinition",
+              "start":38,"end":68,"loc":{"start":{"line":3,"column":2},"end":{"line":3,"column":32}},
+              "static": true,
+              "key": {
+                "type": "PrivateIdentifier",
+                "start":45,"end":49,"loc":{"start":{"line":3,"column":9},"end":{"line":3,"column":13}},
+                "name": "bar"
+              },
+              "kind": "method",
+              "value": {
+                "type": "FunctionExpression",
+                "start":49,"end":68,"loc":{"start":{"line":3,"column":13},"end":{"line":3,"column":32}},
+                "id": null,
+                "generator": false,
+                "async": false,
+                "expression": false,
+                "params": [
+                  {
+                    "type": "Identifier",
+                    "start":50,"end":53,"loc":{"start":{"line":3,"column":14},"end":{"line":3,"column":17},"identifierName":"arg"},
+                    "name": "arg"
+                  },
+                  {
+                    "type": "RestElement",
+                    "start":55,"end":64,"loc":{"start":{"line":3,"column":19},"end":{"line":3,"column":28}},
+                    "argument": {
+                      "type": "Identifier",
+                      "start":58,"end":64,"loc":{"start":{"line":3,"column":22},"end":{"line":3,"column":28},"identifierName":"others"},
+                      "name": "others"
                     }
                   }
+                ],
+                "body": {
+                  "type": "BlockStatement",
+                  "start":66,"end":68,"loc":{"start":{"line":3,"column":30},"end":{"line":3,"column":32}},
+                  "body": []
+                }
+              },
+              "computed": false
+            }
           ]
         }
       }

packages/babel-parser/test/fixtures/estree/class-private-property/basic/input.js

@@ -0,0 +1,4 @@
+class A {
+  #foo = "bar";
+  static #bar = foo;
+}

packages/babel-parser/test/fixtures/estree/class-private-property/basic/options.json

@@ -0,0 +1,3 @@
+{
+  "plugins": ["estree", "classPrivateProperties"]
+}

packages/babel-parser/test/fixtures/estree/class-private-property/basic/output.json

@@ -0,0 +1,61 @@
+{
+  "type": "File",
+  "start":0,"end":48,"loc":{"start":{"line":1,"column":0},"end":{"line":4,"column":1}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":48,"loc":{"start":{"line":1,"column":0},"end":{"line":4,"column":1}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ClassDeclaration",
+        "start":0,"end":48,"loc":{"start":{"line":1,"column":0},"end":{"line":4,"column":1}},
+        "id": {
+          "type": "Identifier",
+          "start":6,"end":7,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":7},"identifierName":"A"},
+          "name": "A"
+        },
+        "superClass": null,
+        "body": {
+          "type": "ClassBody",
+          "start":8,"end":48,"loc":{"start":{"line":1,"column":8},"end":{"line":4,"column":1}},
+          "body": [
+            {
+              "type": "PropertyDefinition",
+              "start":12,"end":25,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":15}},
+              "static": false,
+              "key": {
+                "type": "PrivateIdentifier",
+                "start":12,"end":16,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":6}},
+                "name": "foo"
+              },
+              "value": {
+                "type": "Literal",
+                "start":19,"end":24,"loc":{"start":{"line":2,"column":9},"end":{"line":2,"column":14}},
+                "value": "bar",
+                "raw": "\"bar\""
+              },
+              "computed": false
+            },
+            {
+              "type": "PropertyDefinition",
+              "start":28,"end":46,"loc":{"start":{"line":3,"column":2},"end":{"line":3,"column":20}},
+              "static": true,
+              "key": {
+                "type": "PrivateIdentifier",
+                "start":35,"end":39,"loc":{"start":{"line":3,"column":9},"end":{"line":3,"column":13}},
+                "name": "bar"
+              },
+              "value": {
+                "type": "Identifier",
+                "start":42,"end":45,"loc":{"start":{"line":3,"column":16},"end":{"line":3,"column":19},"identifierName":"foo"},
+                "name": "foo"
+              },
+              "computed": false
+            }
+          ]
+        }
+      }
+    ]
+  }
+}

packages/babel-parser/test/fixtures/estree/class-private-property/flow/input.js

@@ -0,0 +1,5 @@
+class A {
+  #foo = "bar";
+  static #bar = foo;
+  declare #qux: Array<string>;
+}

packages/babel-parser/test/fixtures/estree/class-private-property/flow/options.json

@@ -0,0 +1,3 @@
+{
+  "plugins": ["flow", "estree", "classPrivateProperties"]
+}

packages/babel-parser/test/fixtures/estree/class-private-property/flow/output.json

@@ -0,0 +1,100 @@
+{
+  "type": "File",
+  "start":0,"end":79,"loc":{"start":{"line":1,"column":0},"end":{"line":5,"column":1}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":79,"loc":{"start":{"line":1,"column":0},"end":{"line":5,"column":1}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ClassDeclaration",
+        "start":0,"end":79,"loc":{"start":{"line":1,"column":0},"end":{"line":5,"column":1}},
+        "id": {
+          "type": "Identifier",
+          "start":6,"end":7,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":7},"identifierName":"A"},
+          "name": "A"
+        },
+        "superClass": null,
+        "body": {
+          "type": "ClassBody",
+          "start":8,"end":79,"loc":{"start":{"line":1,"column":8},"end":{"line":5,"column":1}},
+          "body": [
+            {
+              "type": "PropertyDefinition",
+              "start":12,"end":25,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":15}},
+              "static": false,
+              "key": {
+                "type": "PrivateIdentifier",
+                "start":12,"end":16,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":6}},
+                "name": "foo"
+              },
+              "variance": null,
+              "value": {
+                "type": "Literal",
+                "start":19,"end":24,"loc":{"start":{"line":2,"column":9},"end":{"line":2,"column":14}},
+                "value": "bar",
+                "raw": "\"bar\""
+              },
+              "computed": false
+            },
+            {
+              "type": "PropertyDefinition",
+              "start":28,"end":46,"loc":{"start":{"line":3,"column":2},"end":{"line":3,"column":20}},
+              "static": true,
+              "key": {
+                "type": "PrivateIdentifier",
+                "start":35,"end":39,"loc":{"start":{"line":3,"column":9},"end":{"line":3,"column":13}},
+                "name": "bar"
+              },
+              "variance": null,
+              "value": {
+                "type": "Identifier",
+                "start":42,"end":45,"loc":{"start":{"line":3,"column":16},"end":{"line":3,"column":19},"identifierName":"foo"},
+                "name": "foo"
+              },
+              "computed": false
+            },
+            {
+              "type": "PropertyDefinition",
+              "start":49,"end":77,"loc":{"start":{"line":4,"column":2},"end":{"line":4,"column":30}},
+              "declare": true,
+              "static": false,
+              "key": {
+                "type": "PrivateIdentifier",
+                "start":57,"end":61,"loc":{"start":{"line":4,"column":10},"end":{"line":4,"column":14}},
+                "name": "qux"
+              },
+              "variance": null,
+              "typeAnnotation": {
+                "type": "TypeAnnotation",
+                "start":61,"end":76,"loc":{"start":{"line":4,"column":14},"end":{"line":4,"column":29}},
+                "typeAnnotation": {
+                  "type": "GenericTypeAnnotation",
+                  "start":63,"end":76,"loc":{"start":{"line":4,"column":16},"end":{"line":4,"column":29}},
+                  "typeParameters": {
+                    "type": "TypeParameterInstantiation",
+                    "start":68,"end":76,"loc":{"start":{"line":4,"column":21},"end":{"line":4,"column":29}},
+                    "params": [
+                      {
+                        "type": "StringTypeAnnotation",
+                        "start":69,"end":75,"loc":{"start":{"line":4,"column":22},"end":{"line":4,"column":28}}
+                      }
+                    ]
+                  },
+                  "id": {
+                    "type": "Identifier",
+                    "start":63,"end":68,"loc":{"start":{"line":4,"column":16},"end":{"line":4,"column":21},"identifierName":"Array"},
+                    "name": "Array"
+                  }
+                }
+              },
+              "value": null,
+              "computed": false
+            }
+          ]
+        }
+      }
+    ]
+  }
+}

packages/babel-parser/test/fixtures/estree/class-private-property/typescript/input.js

@@ -0,0 +1,5 @@
+class A {
+  #foo = "bar";
+  static #bar = foo;
+  declare #qux: Array<string>;
+}

packages/babel-parser/test/fixtures/estree/class-private-property/typescript/options.json

@@ -0,0 +1,3 @@
+{
+  "plugins": ["typescript", "estree", "classPrivateProperties"]
+}

packages/babel-parser/test/fixtures/estree/class-private-property/typescript/output.json

@@ -0,0 +1,97 @@
+{
+  "type": "File",
+  "start":0,"end":79,"loc":{"start":{"line":1,"column":0},"end":{"line":5,"column":1}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":79,"loc":{"start":{"line":1,"column":0},"end":{"line":5,"column":1}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ClassDeclaration",
+        "start":0,"end":79,"loc":{"start":{"line":1,"column":0},"end":{"line":5,"column":1}},
+        "id": {
+          "type": "Identifier",
+          "start":6,"end":7,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":7},"identifierName":"A"},
+          "name": "A"
+        },
+        "superClass": null,
+        "body": {
+          "type": "ClassBody",
+          "start":8,"end":79,"loc":{"start":{"line":1,"column":8},"end":{"line":5,"column":1}},
+          "body": [
+            {
+              "type": "PropertyDefinition",
+              "start":12,"end":25,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":15}},
+              "static": false,
+              "key": {
+                "type": "PrivateIdentifier",
+                "start":12,"end":16,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":6}},
+                "name": "foo"
+              },
+              "value": {
+                "type": "Literal",
+                "start":19,"end":24,"loc":{"start":{"line":2,"column":9},"end":{"line":2,"column":14}},
+                "value": "bar",
+                "raw": "\"bar\""
+              },
+              "computed": false
+            },
+            {
+              "type": "PropertyDefinition",
+              "start":28,"end":46,"loc":{"start":{"line":3,"column":2},"end":{"line":3,"column":20}},
+              "static": true,
+              "key": {
+                "type": "PrivateIdentifier",
+                "start":35,"end":39,"loc":{"start":{"line":3,"column":9},"end":{"line":3,"column":13}},
+                "name": "bar"
+              },
+              "value": {
+                "type": "Identifier",
+                "start":42,"end":45,"loc":{"start":{"line":3,"column":16},"end":{"line":3,"column":19},"identifierName":"foo"},
+                "name": "foo"
+              },
+              "computed": false
+            },
+            {
+              "type": "PropertyDefinition",
+              "start":49,"end":77,"loc":{"start":{"line":4,"column":2},"end":{"line":4,"column":30}},
+              "declare": true,
+              "static": false,
+              "key": {
+                "type": "PrivateIdentifier",
+                "start":57,"end":61,"loc":{"start":{"line":4,"column":10},"end":{"line":4,"column":14}},
+                "name": "qux"
+              },
+              "typeAnnotation": {
+                "type": "TSTypeAnnotation",
+                "start":61,"end":76,"loc":{"start":{"line":4,"column":14},"end":{"line":4,"column":29}},
+                "typeAnnotation": {
+                  "type": "TSTypeReference",
+                  "start":63,"end":76,"loc":{"start":{"line":4,"column":16},"end":{"line":4,"column":29}},
+                  "typeName": {
+                    "type": "Identifier",
+                    "start":63,"end":68,"loc":{"start":{"line":4,"column":16},"end":{"line":4,"column":21},"identifierName":"Array"},
+                    "name": "Array"
+                  },
+                  "typeParameters": {
+                    "type": "TSTypeParameterInstantiation",
+                    "start":68,"end":76,"loc":{"start":{"line":4,"column":21},"end":{"line":4,"column":29}},
+                    "params": [
+                      {
+                        "type": "TSStringKeyword",
+                        "start":69,"end":75,"loc":{"start":{"line":4,"column":22},"end":{"line":4,"column":28}}
+                      }
+                    ]
+                  }
+                }
+              },
+              "value": null,
+              "computed": false
+            }
+          ]
+        }
+      }
+    ]
+  }
+}

packages/babel-parser/test/fixtures/estree/class-property/basic/input.js

@@ -0,0 +1,6 @@
+class A {
+  foo = "bar";
+  [bar] = foo;
+  static "qux" = "quux";
+  static [quux] = "qux";
+}

packages/babel-parser/test/fixtures/estree/class-property/basic/options.json

@@ -0,0 +1,3 @@
+{
+  "plugins": ["estree", "classProperties"]
+}

packages/babel-parser/test/fixtures/estree/class-property/basic/output.json

@@ -0,0 +1,96 @@
+{
+  "type": "File",
+  "start":0,"end":91,"loc":{"start":{"line":1,"column":0},"end":{"line":6,"column":1}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":91,"loc":{"start":{"line":1,"column":0},"end":{"line":6,"column":1}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ClassDeclaration",
+        "start":0,"end":91,"loc":{"start":{"line":1,"column":0},"end":{"line":6,"column":1}},
+        "id": {
+          "type": "Identifier",
+          "start":6,"end":7,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":7},"identifierName":"A"},
+          "name": "A"
+        },
+        "superClass": null,
+        "body": {
+          "type": "ClassBody",
+          "start":8,"end":91,"loc":{"start":{"line":1,"column":8},"end":{"line":6,"column":1}},
+          "body": [
+            {
+              "type": "PropertyDefinition",
+              "start":12,"end":24,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":14}},
+              "static": false,
+              "key": {
+                "type": "Identifier",
+                "start":12,"end":15,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":5},"identifierName":"foo"},
+                "name": "foo"
+              },
+              "computed": false,
+              "value": {
+                "type": "Literal",
+                "start":18,"end":23,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":13}},
+                "value": "bar",
+                "raw": "\"bar\""
+              }
+            },
+            {
+              "type": "PropertyDefinition",
+              "start":27,"end":39,"loc":{"start":{"line":3,"column":2},"end":{"line":3,"column":14}},
+              "static": false,
+              "computed": true,
+              "key": {
+                "type": "Identifier",
+                "start":28,"end":31,"loc":{"start":{"line":3,"column":3},"end":{"line":3,"column":6},"identifierName":"bar"},
+                "name": "bar"
+              },
+              "value": {
+                "type": "Identifier",
+                "start":35,"end":38,"loc":{"start":{"line":3,"column":10},"end":{"line":3,"column":13},"identifierName":"foo"},
+                "name": "foo"
+              }
+            },
+            {
+              "type": "PropertyDefinition",
+              "start":42,"end":64,"loc":{"start":{"line":4,"column":2},"end":{"line":4,"column":24}},
+              "static": true,
+              "key": {
+                "type": "Literal",
+                "start":49,"end":54,"loc":{"start":{"line":4,"column":9},"end":{"line":4,"column":14}},
+                "value": "qux",
+                "raw": "\"qux\""
+              },
+              "computed": false,
+              "value": {
+                "type": "Literal",
+                "start":57,"end":63,"loc":{"start":{"line":4,"column":17},"end":{"line":4,"column":23}},
+                "value": "quux",
+                "raw": "\"quux\""
+              }
+            },
+            {
+              "type": "PropertyDefinition",
+              "start":67,"end":89,"loc":{"start":{"line":5,"column":2},"end":{"line":5,"column":24}},
+              "static": true,
+              "computed": true,
+              "key": {
+                "type": "Identifier",
+                "start":75,"end":79,"loc":{"start":{"line":5,"column":10},"end":{"line":5,"column":14},"identifierName":"quux"},
+                "name": "quux"
+              },
+              "value": {
+                "type": "Literal",
+                "start":83,"end":88,"loc":{"start":{"line":5,"column":18},"end":{"line":5,"column":23}},
+                "value": "qux",
+                "raw": "\"qux\""
+              }
+            }
+          ]
+        }
+      }
+    ]
+  }
+}

packages/babel-parser/test/fixtures/estree/private-in/basic/input.js

@@ -0,0 +1,6 @@
+class A {
+  #foo = "bar";
+  static isA(obj) {
+    return #foo in obj;
+  }
+}

packages/babel-parser/test/fixtures/estree/private-in/basic/options.json

@@ -0,0 +1,3 @@
+{
+  "plugins": ["estree", "classPrivateProperties", "privateIn"]
+}

packages/babel-parser/test/fixtures/estree/private-in/basic/output.json

@@ -0,0 +1,97 @@
+{
+  "type": "File",
+  "start":0,"end":75,"loc":{"start":{"line":1,"column":0},"end":{"line":6,"column":1}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":75,"loc":{"start":{"line":1,"column":0},"end":{"line":6,"column":1}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ClassDeclaration",
+        "start":0,"end":75,"loc":{"start":{"line":1,"column":0},"end":{"line":6,"column":1}},
+        "id": {
+          "type": "Identifier",
+          "start":6,"end":7,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":7},"identifierName":"A"},
+          "name": "A"
+        },
+        "superClass": null,
+        "body": {
+          "type": "ClassBody",
+          "start":8,"end":75,"loc":{"start":{"line":1,"column":8},"end":{"line":6,"column":1}},
+          "body": [
+            {
+              "type": "PropertyDefinition",
+              "start":12,"end":25,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":15}},
+              "static": false,
+              "key": {
+                "type": "PrivateIdentifier",
+                "start":12,"end":16,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":6}},
+                "name": "foo"
+              },
+              "value": {
+                "type": "Literal",
+                "start":19,"end":24,"loc":{"start":{"line":2,"column":9},"end":{"line":2,"column":14}},
+                "value": "bar",
+                "raw": "\"bar\""
+              },
+              "computed": false
+            },
+            {
+              "type": "MethodDefinition",
+              "start":28,"end":73,"loc":{"start":{"line":3,"column":2},"end":{"line":5,"column":3}},
+              "static": true,
+              "key": {
+                "type": "Identifier",
+                "start":35,"end":38,"loc":{"start":{"line":3,"column":9},"end":{"line":3,"column":12},"identifierName":"isA"},
+                "name": "isA"
+              },
+              "computed": false,
+              "kind": "method",
+              "value": {
+                "type": "FunctionExpression",
+                "start":38,"end":73,"loc":{"start":{"line":3,"column":12},"end":{"line":5,"column":3}},
+                "id": null,
+                "generator": false,
+                "async": false,
+                "expression": false,
+                "params": [
+                  {
+                    "type": "Identifier",
+                    "start":39,"end":42,"loc":{"start":{"line":3,"column":13},"end":{"line":3,"column":16},"identifierName":"obj"},
+                    "name": "obj"
+                  }
+                ],
+                "body": {
+                  "type": "BlockStatement",
+                  "start":44,"end":73,"loc":{"start":{"line":3,"column":18},"end":{"line":5,"column":3}},
+                  "body": [
+                    {
+                      "type": "ReturnStatement",
+                      "start":50,"end":69,"loc":{"start":{"line":4,"column":4},"end":{"line":4,"column":23}},
+                      "argument": {
+                        "type": "BinaryExpression",
+                        "start":57,"end":68,"loc":{"start":{"line":4,"column":11},"end":{"line":4,"column":22}},
+                        "left": {
+                          "type": "PrivateIdentifier",
+                          "start":57,"end":61,"loc":{"start":{"line":4,"column":11},"end":{"line":4,"column":15}},
+                          "name": "foo"
+                        },
+                        "operator": "in",
+                        "right": {
+                          "type": "Identifier",
+                          "start":65,"end":68,"loc":{"start":{"line":4,"column":19},"end":{"line":4,"column":22},"identifierName":"obj"},
+                          "name": "obj"
+                        }
+                      }
+                    }
+                  ]
+                }
+              }
+            }
+          ]
+        }
+      }
+    ]
+  }
+}