Description:
------------
I suspect this is a bug as the behaviour is a little worrying.

I was using the following in a Laravel program

    $fieldLabel = // has a field label been manually defined
      ($fieldLabel =  $this->hasAttribute($fieldValue, 'FieldLabel'))
      ? $fieldLabel
      : ($this->parseFieldType($fieldValue) != 'hidden')         
        ? ucfirst($fieldKey)
        : '';

However when $label was defined it was resolving to 
$fieldLabel = ucfirst($fieldKey); 

(ie. the second ternary).

the resolution was to parenthesise the second ternary (which I should have done in the first place):

    $fieldLabel = // has a field label been manually defined
      ($fieldLabel =  $this->hasAttribute($fieldValue, 'FieldLabel'))
      ? $fieldLabel
      : (($this->parseFieldType($fieldValue) != 'hidden')         
        ? ucfirst($fieldKey)
        : '');

The bug, in my eyes, is that aforementioned code should have thrown an exception as the ternary statement gave an ambiguous result.

best

Jon

Test script:
---------------
// here is the same issue again in a simpler form, tested with 
// "php artisan tinker"

$foo = 1;

$bar = ($bar = $foo) ? $bar : ($bar = 2) ? 2 : 'null';

Expected result:
----------------
either an exception as the statement is ambiguous or 1;

I would suggest the former.

Actual result:
--------------
2