Cannot find name 'PromiseSettledResult'

Question

I upgraded my angular app today to use Angular 20.3.2, and I can no longer serve or build the application. I get this error when trying:

Application bundle generation failed. [8.209 seconds] - 2025-09-23T10:16:06.437Z
[ng] ✘ [ERROR] TS2304: Cannot find name 'PromiseSettledResult'. [plugin angular-compiler]
[ng]     node_modules/@angular/core/discovery.d.d.ts:73:22:
[ng]       73 │     running?: Promise<PromiseSettledResult<void>[]>;

I'm building the app using the Ionic framework. Here's my environment when I run ionic info:

Ionic Framework               : @ionic/angular 8.7.4
   @angular-devkit/build-angular : 20.3.2
   @angular-devkit/schematics    : 20.3.2
   @angular/cli                  : 20.3.2
   @ionic/angular-toolkit        : 12.3.0

Capacitor:

   Capacitor CLI      : 7.4.3
   @capacitor/android : not installed
   @capacitor/core    : 7.4.3
   @capacitor/ios     : not installed

Utility:

   cordova-res : not installed globally
   native-run  : 2.0.1

Answer 1

This is due to a change inside the framework that will be fixed in the next patch release. (see related issue)

You have 3 fixes possible today :

• Add skipLibCheck: true to your tsconfig
• Add ES2020 to the lib entry of your tsconfig
• Drop all your lib entries, which then defaults to your target lib (which should be ES2022+)