@ngdoc error
@name ngOptions:iexp
@fullName Invalid Expression
@description
This error occurs when 'ngOptions' is passed an expression that isn't in an expected form.

Here's an example of correct syntax:

```
<select ng-model="color" ng-options="c.name for c in colors">
```

For more information on valid expression syntax, see 'ngOptions' in {@link ng.directive:select select} directive docs.