**Fix "@@" if the intermediary value resembles color keyword.**
To reproduce the error, try compiling a less file that looks like so:
```.color-keyword {
@red: 'hello';
@name: red;
name: @@name;
}```
you get an error similar to this:
PHP Warning: Undefined property: Less_Tree_Color::$value in .../less.php/lib/Less/Tree/Variable.php on line 31
Warning: Undefined property: Less_Tree_Color::$value in .../less.php/lib/Less/Tree/Variable.php on line 31
PHP Fatal error: Uncaught Less_Exception_Compiler: variable @ is undefined in file .../less.php/test.less in test.less on line 4, column 8
2| @red: 'hello';
3| @name: red;
4| name: @@name;
5| }
6| .../less.php/lib/Less/Tree/Variable.php:50
**Stack trace:**
#0 ...less.php/lib/Less/Tree/Expression.php(46): Less_Tree_Variable->compile(Object(Less_Environment))
#1 .../less.php/lib/Less/Tree/Value.php(25): Less_Tree_Expression->compile(Object(Less_Environment))
#2 ../less.php/lib/Less/Tree/Rule.php(82): Less_Tree_Value->compile(Object(Less_Environment))
#3 ../less.php/lib/Less/Tree/Ruleset.php(96): Less_Tree_Rule->compile(Object(Less_Environment))
#4 .../less.php/lib/Less/Tree/Ruleset.php(96): Less_Tree_Ruleset->compile(Object(Less_Environment))
#5 .../less.php/lib/Less/Parser.php(182): Less_Tree_Ruleset->compile(Object(Less_Environment))
#6.../less.php/bin/lessc(189): Less_Parser->getCss()
#7 {main}
thrown in .../less.php/lib/Less/Tree/Variable.php on line 50
The error only occurs if "@@" intermediary value looks like a color.