Fix comments test

lib/less/parser.js

@@ -832,6 +832,7 @@ less.Parser = function Parser(env) {
                         expressions = [];
                         while (arg = $(this.expression)) {
                             nameLoop = null;
+                            arg.throwAwayComments();
                             value = arg;
 
                             // Variable
@@ -1470,7 +1471,8 @@ less.Parser = function Parser(env) {
 
                 while (e = $(this.addition) || $(this.entity)) {
                     entities.push(e);
-                    if (!peek(/^\/\*/) && (delim = $('/'))) {
+                    // operations do not allow keyword "/" dimension (e.g. small/20px) so we support that here
+                    if (!peek(/^\/[\/*]/) && (delim = $('/'))) {
                         entities.push(new(tree.Anonymous)(delim));
                     }
                 }

lib/less/tree/expression.js

@@ -29,6 +29,11 @@ tree.Expression.prototype = {
         return this.value.map(function (e) {
             return e.toCSS ? e.toCSS(env) : '';
         }).join(' ');
+    },
+    throwAwayComments: function () {
+        this.value = this.value.filter(function(v) {
+            return !(v instanceof tree.Comment);
+        });
     }
 };