Fix super Method Calls in Class Private Methods (#9704)

This fixes an issue with the use of super method calls in class private methods. See https://github.com/babel/babel/issues/9580 for more info re: behavior of the bug.

packages/babel-helper-create-class-features-plugin/src/fields.js

@@ -501,10 +501,9 @@ function replaceThisContext(path, ref, superRef, file, loose) {
     file,
     getObjectRef() {
       state.needsClassRef = true;
-      return ref;
+      return path.node.static ? ref : t.thisExpression();
     },
   });
-  replacer.isStatic = true;
   replacer.replace();
   if (path.isProperty()) {
     path.traverse(thisContextVisitor, state);
@@ -532,7 +531,7 @@ export function buildFieldsInitNodes(
     const isField = prop.isProperty();
     const isMethod = !isField;
 
-    if (isStatic) {
+    if (isStatic || (isMethod && isPrivate)) {
       const replaced = replaceThisContext(prop, ref, superRef, state, loose);
       needsClassRef = needsClassRef || replaced;
     }

packages/babel-helper-replace-supers/src/index.js

@@ -15,9 +15,10 @@ import * as t from "@babel/types";
  *
  *   helpers.getPrototypeOf(CLASS.prototype)
  */
-function getPrototypeOfExpression(objectRef, isStatic, file) {
+function getPrototypeOfExpression(objectRef, isStatic, file, isPrivateMethod) {
   objectRef = t.cloneNode(objectRef);
-  const targetRef = isStatic
+  const targetRef =
+    isStatic || isPrivateMethod
       ? objectRef
       : t.memberExpression(objectRef, t.identifier("prototype"));
 
@@ -98,7 +99,12 @@ const specHandlers = {
 
   get(superMember) {
     return t.callExpression(this.file.addHelper("get"), [
-      getPrototypeOfExpression(this.getObjectRef(), this.isStatic, this.file),
+      getPrototypeOfExpression(
+        this.getObjectRef(),
+        this.isStatic,
+        this.file,
+        this.isPrivateMethod,
+      ),
       this.prop(superMember),
       t.thisExpression(),
     ]);
@@ -106,7 +112,12 @@ const specHandlers = {
 
   set(superMember, value) {
     return t.callExpression(this.file.addHelper("set"), [
-      getPrototypeOfExpression(this.getObjectRef(), this.isStatic, this.file),
+      getPrototypeOfExpression(
+        this.getObjectRef(),
+        this.isStatic,
+        this.file,
+        this.isPrivateMethod,
+      ),
       this.prop(superMember),
       value,
       t.thisExpression(),
@@ -170,8 +181,8 @@ export default class ReplaceSupers {
     const path = opts.methodPath;
 
     this.methodPath = path;
-    this.isStatic =
+    this.isStatic = path.isObjectMethod() || path.node.static;
-      path.isClassMethod({ static: true }) || path.isObjectMethod();
+    this.isPrivateMethod = path.isPrivate() && path.isMethod();
 
     this.file = opts.file;
     this.superRef = opts.superRef;
@@ -202,6 +213,7 @@ export default class ReplaceSupers {
     memberExpressionToFunctions(this.methodPath, visitor, {
       file: this.file,
       isStatic: this.isStatic,
+      isPrivateMethod: this.isPrivateMethod,
       getObjectRef: this.getObjectRef.bind(this),
       superRef: this.superRef,
       ...handler,

packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-loose/super/exec.js

@@ -0,0 +1,17 @@
+class Base {
+  superMethod() {
+    return 1017;
+  }
+}
+
+class Sub extends Base {
+  #privateMethod() {
+    return super.superMethod();
+  }
+
+  publicMethod() {
+    return this.#privateMethod();
+  }
+}
+
+expect((new Sub()).publicMethod()).toEqual(1017);

packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-loose/super/input.js

@@ -0,0 +1,15 @@
+class Base {
+  superMethod() {
+    return 1017;
+  }
+}
+
+class Sub extends Base {
+  #privateMethod() {
+    return super.superMethod();
+  }
+
+  publicMethod() {
+    return this.#privateMethod();
+  }
+}

packages/babel-plugin-proposal-private-methods/test/fixtures/private-method-loose/super/output.js

@@ -0,0 +1,26 @@
+class Base {
+  superMethod() {
+    return 1017;
+  }
+
+}
+
+class Sub extends Base {
+  constructor(...args) {
+    super(...args);
+    Object.defineProperty(this, _privateMethod, {
+      value: _privateMethod2
+    });
+  }
+
+  publicMethod() {
+    return babelHelpers.classPrivateFieldLooseBase(this, _privateMethod)[_privateMethod]();
+  }
+
+}
+
+var _privateMethod = babelHelpers.classPrivateFieldLooseKey("privateMethod");
+
+var _privateMethod2 = function _privateMethod2() {
+  return Base.prototype.superMethod.call(this);
+};

packages/babel-plugin-proposal-private-methods/test/fixtures/private-method/super/exec.js

@@ -0,0 +1,17 @@
+class Base {
+  superMethod() {
+    return 1017;
+  }
+}
+
+class Sub extends Base {
+  #privateMethod() {
+    return super.superMethod();
+  }
+
+  publicMethod() {
+    return this.#privateMethod();
+  }
+}
+
+expect((new Sub()).publicMethod()).toEqual(1017);

packages/babel-plugin-proposal-private-methods/test/fixtures/private-method/super/input.js

@@ -0,0 +1,15 @@
+class Base {
+  superMethod() {
+    return 1017;
+  }
+}
+
+class Sub extends Base {
+  #privateMethod() {
+    return super.superMethod();
+  }
+
+  publicMethod() {
+    return this.#privateMethod();
+  }
+}

packages/babel-plugin-proposal-private-methods/test/fixtures/private-method/super/output.js

@@ -0,0 +1,25 @@
+class Base {
+  superMethod() {
+    return 1017;
+  }
+
+}
+
+class Sub extends Base {
+  constructor(...args) {
+    super(...args);
+
+    _privateMethod.add(this);
+  }
+
+  publicMethod() {
+    return babelHelpers.classPrivateMethodGet(this, _privateMethod, _privateMethod2).call(this);
+  }
+
+}
+
+var _privateMethod = new WeakSet();
+
+var _privateMethod2 = function _privateMethod2() {
+  return babelHelpers.get(babelHelpers.getPrototypeOf(this), "superMethod", this).call(this);
+};