core.js:9847 NG0303: Can't bind to 'ngForIn' since it isn't a known property of 'div'. code example

Example: core.js:12799 Can't bind to 'ngForIn' since it isn't a known property of 'ng-container'.

<!--I typed in instead of 'of' in the ngFor expression.-->
<div *ngFor="#talk of talks">