# AUR0160

## Error Message

`AUR0160: Expression error: expected identifier to come after binding behavior operator: {{expression}}`

## Description

This error occurs when a binding behavior operator (`&`) is used without providing a behavior name.

## Example Trigger

```html
<!-- ❌ Missing behavior name -->
<input value.bind="firstName &">
```

## Solution

Provide a binding behavior name after `&`.

```html
<!-- ✅ -->
<input value.bind="firstName & debounce:200">
```

## Troubleshooting

* Check for trailing `&` in expressions.
* Ensure the binding behavior is registered (otherwise you may get an evaluation error instead).