For mat-chip-list as per the document the aria-role for chiplist as listbox with each chip has option as role,even I gave those two role as mentioned in the below code,
<mat-chip-list #chipList role="listbox" aria-label="filtervalues">
<span *ngFor="let x of values">
<span *ngFor="let y of x.items">
<mat-chip role="option">y</mat-chip>
</span>
</span>
</mat-chip-list>
unable to attain 100% accessibility,shows "aria attributes does not match their roles".How to overcome this error?