Transformation of static blocks breaks existing code

Bắt đầu với repository angular-monaco-repro được liên kết và so sánh các bản build bằng cách sử dụng @babel/plugin-transform-class-static-block 7.27.1 và 7.28.3 thông qua Webpack builder. Theo dõi nơi plugin đi vào bản build của Angular CLI, sau đó xác minh rằng CodeEditorWidget được tạo ra không còn phát sinh lỗi super-constructor đã được báo cáo với phiên bản plugin hiện tại.

Command

build

Is this a regression?

• Yes, this behavior used to work in the previous version

The previous version in which this bug was not present was

No response

Description

It appears that when Angular compiles using a recent version of Babel's plugin-transform-class-static-block, with the Webpack builder, the output is transformed in such a way it breaks existing code.

Angular code compiled and bundled with @babel/plugin-transform-class-static-block@7.27.1:

let CodeEditorWidget = class CodeEditorWidget extends _base_common_lifecycle_js__WEBPACK_IMPORTED_MODULE_5__.Disposable {
  static #_ = CodeEditorWidget_1 = this;
  static #_2 = this.dropIntoEditorDecorationOptions = _common_model_textModel_js__WEBPACK_IMPORTED_MODULE_27__.ModelDecorationOptions.register({
    description: 'workbench-dnd-target',
    className: 'dnd-target'
  }); //#endregion
  get isSimpleWidget() {
    return this._configuration.isSimpleWidget;
  }
  get contextMenuId() {
    return this._configuration.contextMenuId;
  }
  constructor(domElement, _options, codeEditorWidgetOptions, instantiationService, codeEditorService, commandService, contextKeyService, themeService, notificationService, accessibilityService, languageConfigurationService, languageFeaturesService) {
    var _this;
    super();
    _this = this;

   // Omitted for brevity
};

Angular code compiled and bundled with @babel/plugin-transform-class-static-block@7.28.3:

let CodeEditorWidget = (class CodeEditorWidget extends _base_common_lifecycle_js__WEBPACK_IMPORTED_MODULE_5__.Disposable {                 
  //#endregion
  get isSimpleWidget() {
    return this._configuration.isSimpleWidget;
  }
  get contextMenuId() {
    return this._configuration.contextMenuId;
  }
  constructor(domElement, _options, codeEditorWidgetOptions, instantiationService, codeEditorService, commandService, contextKeyService, themeService, notificationService, accessibilityService, languageConfigurationService, languageFeaturesService) {
    var _this = this;
    super();

    // Omitted for brevity

  static #_ = _staticBlock = () => (CodeEditorWidget_1 = this, this.dropIntoEditorDecorationOptions = _common_model_textModel_js__WEBPACK_IMPORTED_MODULE_27__.ModelDecorationOptions.register({
    description: 'workbench-dnd-target',
    className: 'dnd-target'
  }), this);
}, _staticBlock());

The workaround, which you will also see explained in the attached reproducer, is to override the version of the Babel's plugin to 7.27.1.

I don't understand why, and under which circumstance, that plugin is injected into the compilation process.

Minimal Reproduction

Steps to reproduce can be found on the reproducer's repository: https://github.com/lppedd/angular-monaco-repro

Exception or Error

ERROR ReferenceError: Must call super constructor in derived class before accessing 'this' or returning from derived constructor
  at new CodeEditorWidget (codeEditorWidget.js:69:252)
  at new StandaloneCodeEditor (standaloneCodeEditor.js:69:9)
  at new StandaloneEditor (standaloneCodeEditor.js:188:9)
  at InstantiationService._createInstance (instantiationService.js:130:24)
  at InstantiationService.createInstance (instantiationService.js:101:27)
  at Object.create (standaloneEditor.js:43:33)
  at App.ngAfterViewInit (app.ts:16:33)
  at callHookInternal (debug_node.mjs:860:14)
  at callHook (debug_node.mjs:887:13)
  at callHooks (debug_node.mjs:841:17)

Your Environment

Angular CLI: 20.3.8
Node: 22.18.0
Package Manager: npm 11.6.2
OS: win32 x64
    

Angular: 20.3.9
... common, compiler, compiler-cli, core, forms
... platform-browser, router

Package                         Version
---------------------------------------
@angular-devkit/architect       0.2003.8
@angular-devkit/build-angular   20.3.8
@angular-devkit/core            20.3.8
@angular-devkit/schematics      20.3.8
@angular/build                  20.3.8
@angular/cli                    20.3.8
@schematics/angular             20.3.8
rxjs                            7.8.2
typescript                      5.9.3
zone.js                         0.15.1

Anything else relevant?

No response