It seems to be impossible to setup matSuffix as a hostDirective.

Angular team lately made all material components standolone, which supposed to fix this issue but I still can’t make it working.

@Component({
  selector: 'app-custom-suffix',
  template: `
    <mat-icon 
      color="warn"
    >info_outline</mat-icon>
  `,
  hostDirectives: [
    MatSuffix,
    MatTooltip
  ],
  imports: [MatIconModule],
  standalone: true,
  providers: []
})
export class CustomSuffixComponent {
  constructor() {
    const tooltip = inject(MatTooltip);
    tooltip .message = 'test';
  }
}

<mat-form-field>
  ...
  <app-custom-suffix></app-custom-suffix> 
</mat-form-field>

Tooltip seems to be applied correctly, even though I could not setup it’s value within hostDirectives and needed to do it in constructor. MatSuffix on the other hand seems not to be applied at all.