Blade templates broken when data comes from generator

[acarpio89]

• Laravel Version: 5.5.37
• PHP Version: 7.1.6
• Database Driver & Version: MySQL 5.6.35

Description:

The changes introduced in #23388 break templates that loop over generators:

Exception(code: 0): Cannot traverse an already closed generator at ...

Steps To Reproduce:

In your view composer, or wherever the data for your view is prepared:

while ($someCondition) {
    ...
    yield $results;
}

In your view:

@foreach ($results as $chunk)   <<< This line throws the exception
    @foreach ($chunk as $record)
        ...
    @endforeach
@endforeach

The offending line looks like this in the compiled template:

<?php $__currentLoopData = $results; $__env->addLoop($__currentLoopData); foreach($__currentLoopData as $chunk): $__env->incrementLoopIndices(); $loop = $__env->getLastLoop(); ?>

[acarpio89]

This can be easily reproduced in a fresh Laravel project:

-- routes/web.php

Route::get('results', function () {
    return view('results');
});

-- app/Results.php

class Results
{
    public function generate()
    {
        for ($count = 1; $count < 10; $count ++) {
            yield ['a', 'b', 'c'];
        }
    }
}

-- resources/views/results.blade.php

@inject('results', 'App\Results')

@foreach($results->generate() as $chunks)
    <div>
        @foreach($chunks as $chunk)
            {{ $chunk }}
        @endforeach
    </div>
@endforeach

Using Laravel 5.5.36 you get the expected result:

a b c
a b c
a b c
a b c
a b c
a b c
a b c
a b c
a b c

Using any version after merging #23388 results in:

Cannot traverse an already closed generator (View: my-project/resources/views/results.blade.php)

It should be reverted until it provides a solution that doesn't break basic PHP functionality.