fixed bug with passing variables to functions

lib/less/tree/call.js

@@ -23,7 +23,7 @@ tree.Call.prototype = {
     // The function should receive the value, not the variable.
     //
     toCSS: function (context, env) {
-        var args = this.args.map(function (a) { return a.eval() });
+        var args = this.args.map(function (a) { return a.eval(context) });
 
         if (this.name in tree.functions) { // 1.
             return tree.functions[this.name].apply(tree.functions, args).toCSS();

test/css/functions.css

@@ -3,6 +3,7 @@
   width: 16;
   height: undefined("self");
   border-width: 5;
+  variable: 11;
 }
 #built-in {
   escaped: -Some::weird(#thing, y);

test/less/functions.less

@@ -1,8 +1,10 @@
 #functions {
+  @var: 10;
   color: color("evil red"); // #660000
   width: increment(15);
   height: undefined("self");
   border-width: add(2, 3);
+  variable: increment(@var);
 }
 
 #built-in {