Library build generates invalid declaration "import '@angular/material/dialog.d'" in generated index.d.ts

[PanJoh]

Which @angular/* package(s) are the source of the bug?

compiler-cli

Is this a regression?

No

Description

Command

ng build uxf-core

Description

When building an Angular library, the generated index.d.ts contains the following import:

import * as _angular_material_dialog_d from '@angular/material/dialog.d';

It goes away, when we do the following changes in our source code.

From:
´´´ts
open<T, D = any, R = any>(component: ComponentType, config?: MatDialogConfig) {
return this.dialog.open<T, D, R>(component, {
...config,
panelClass: createPanelClass(config?.panelClass)
});
}
´´´´

To:
´´´ts
open<T, D = any, R = any>(component: ComponentType, config?: MatDialogConfig): MatDialogRef<R,T> {
return this.dialog.open<T, D, R>(component, {
...config,
panelClass: createPanelClass(config?.panelClass)
});
}
´´´´
Unfortunately we do not yet have a minimal reproduction, but the issue is consistently reproducible in our library build.

Please provide a link to a minimal reproduction of the bug

No response

Please provide the exception or error you saw

When the library is consumed as a package by another Angular application, the application build fails with:
 
> Error: node_modules/@uxf/core/index.d.ts:57:45 - error TS2037:
> Cannot find module '@angular/material/dialog.d'
> or its corresponding type declarations
> 
> 57 import * as _angular_material_dialog_d from '@angular/material/dialog.d';

Please provide the environment you discovered this bug in (run ng version)

Angular CLI: 20.3.22
Node: 24.18.0
Package Manager: npm 11.18.0
OS: win32 x64

Angular: 20.3.25
... animations, common, compiler, compiler-cli, core, forms
... language-service, platform-browser, platform-browser-dynamic
... platform-server, router, upgrad

Anything else?

No response

[alan-agius4]

This seems like a bug but we'll need to look at a reproduction to find and fix the problem. Can you setup a minimal repro please?

You can read here why this is needed. A good way to make a minimal repro is to create a new app via ng new repro-app and adding the minimum possible code to show the problem. Then you can push this repository to github and link it here.

This might be related to your directory structure so its really important to get an accurate repro to diagnose this.