I am learning Angular (which is written in TypeScript) and I stumbled upon this error:

Class 'SnackbarService' incorrectly extends base class 'MatSnackBar'.
Types have separate declarations of a private property '_overlay'.

when trying to extend MatSnackBar from @angular/material.

This is my code:

import { MatSnackBar } from '@angular/material';

import { Overlay } from '@angular/cdk/overlay';

import { LiveAnnouncer } from '@angular/cdk/a11y';

...



export class SnackbarService extends MatSnackBar {



  constructor(

    private _overlay: Overlay, 

    private _liveAnnouncer: LiveAnnouncer,

    ...

  ) {

    super(_overlay, _liveAnnouncer, ...);

    }

  }

}

Any help with any type of explanation on why this happens would be really be appreciated.