Laravel View Composer "Use of undefined constant"

Use $links, not links:

@section('content')
    All the stuff!
    {{ $links }}
@stop

Every variable in PHP should be preceded by a $ sign. If there's no $, PHP treats it as a constant.

It's just a simple syntax issue, everything you send to a view is a php variable so still needs to be referenced with the $

In your view, you are referencing links without the dollar sign.

If you update it to:

{{ $links }}

You'll be A-OK