diff --git a/lib/less/index.js b/lib/less/index.js
index c83153c5..f764f66e 100644
--- a/lib/less/index.js
+++ b/lib/less/index.js
@@ -21,14 +21,14 @@ less.render = function (input, options, callback) {
             }
             catch (err) { callback(err); return; }
             callback(null, css);
-        });
+            }, options);
     } else {
         return new PromiseConstructor(function (resolve, reject) {
             parser.parse(input, function (e, root) {
                 if (e) { return reject(e); }
                 try { resolve(root.toCSS(options)); }
                 catch (err) { reject( err); }
-            });
+                }, options);
         });
     }
 };
diff --git a/lib/less/parser/parser.js b/lib/less/parser/parser.js
index 8691ec5e..dfc6acee 100644
--- a/lib/less/parser/parser.js
+++ b/lib/less/parser/parser.js
@@ -1173,6 +1173,7 @@ var Parser = function Parser(env) {
                         value = this.detachedRuleset();
                     }
 
+                    parserInput.commentStore.length = 0;
                     if (!value) {
                         // a name returned by this.ruleProperty() is always an array of the form:
                         // [string-1, ..., string-n, ""] or [string-1, ..., string-n, "+"]
@@ -1433,6 +1434,8 @@ var Parser = function Parser(env) {
                         break;
                 }
 
+                parserInput.commentStore.length = 0;
+
                 if (hasIdentifier) {
                     value = this.entity();
                     if (!value) {
diff --git a/lib/less/tree/rule.js b/lib/less/tree/rule.js
index ec09dcf5..521a2f08 100644
--- a/lib/less/tree/rule.js
+++ b/lib/less/tree/rule.js
@@ -2,7 +2,7 @@ var Node = require("./node.js"),
     Value = require("./value.js"),
     Keyword = require("./keyword.js");
 
-var Rule = function (name, value, important, merge, index, currentFileInfo, inline) {
+var Rule = function (name, value, important, merge, index, currentFileInfo, inline, variable) {
     this.name = name;
     this.value = (value instanceof Node) ? value : new(Value)([value]); //value instanceof tree.Value || value instanceof tree.Ruleset ??
     this.important = important ? ' ' + important.trim() : '';
@@ -10,7 +10,8 @@ var Rule = function (name, value, important, merge, index, currentFileInfo, inli
     this.index = index;
     this.currentFileInfo = currentFileInfo;
     this.inline = inline || false;
-    this.variable = name.charAt && (name.charAt(0) === '@');
+    this.variable = (variable !== undefined) ? variable
+        : (name.charAt && (name.charAt(0) === '@'));
 };
 
 function evalName(env, name) {
@@ -37,13 +38,14 @@ Rule.prototype.genCSS = function (env, output) {
     output.add(this.important + ((this.inline || (env.lastRule && env.compress)) ? "" : ";"), this.currentFileInfo, this.index);
 };
 Rule.prototype.eval = function (env) {
-    var strictMathBypass = false, name = this.name, evaldValue;
+    var strictMathBypass = false, name = this.name, evaldValue, variable = this.variable;
     if (typeof name !== "string") {
         // expand 'primitive' name directly to get
         // things faster (~10% for benchmark.less):
         name = (name.length === 1)
             && (name[0] instanceof Keyword)
                 ? name[0].value : evalName(env, name);
+            variable = false; // never treat expanded interpolation as new variable name
     }
     if (name === "font" && !env.strictMath) {
         strictMathBypass = true;
@@ -61,7 +63,8 @@ Rule.prototype.eval = function (env) {
                           evaldValue,
                           this.important,
                           this.merge,
-                          this.index, this.currentFileInfo, this.inline);
+                          this.index, this.currentFileInfo, this.inline,
+                              variable);
     }
     catch(e) {
         if (typeof e.index !== 'number') {
diff --git a/test/css/comments.css b/test/css/comments.css
index a18ab808..31e23f7f 100644
--- a/test/css/comments.css
+++ b/test/css/comments.css
@@ -58,6 +58,12 @@
 .sr-only-focusable {
   clip: auto;
 }
+@-webkit-keyframes hover {
+  /* and Chrome */
+  0% {
+    color: red;
+  }
+}
 #last {
   color: blue;
 }
diff --git a/test/css/property-name-interp.css b/test/css/property-name-interp.css
index 2082b819..315815e3 100644
--- a/test/css/property-name-interp.css
+++ b/test/css/property-name-interp.css
@@ -1,5 +1,6 @@
 pi-test {
   border: 0;
+  @not-variable: @not-variable;
   ufo-width: 50%;
   *-z-border: 1px dashed blue;
   -www-border-top: 2px;
diff --git a/test/less/comments.less b/test/less/comments.less
index 2ecf0da6..3cb6d162 100644
--- a/test/less/comments.less
+++ b/test/less/comments.less
@@ -62,7 +62,7 @@
 */
 
 .selector /* .with */, .lots, /* of */ .comments {
-  color: grey, /* blue */ orange;
+  color/* survive */ /* me too */: grey, /* blue */ orange;
   -webkit-border-radius: 2px /* webkit only */;
   -moz-border-radius: (2px * 4) /* moz only with operation */;
 }
@@ -84,6 +84,12 @@
   clip: auto;
 }
 
+@-webkit-keyframes /* Safari */ hover /* and Chrome */ {
+  0% {
+    color: red;
+  }
+}
+
 #last { color: blue }
 //
 
diff --git a/test/less/property-name-interp.less b/test/less/property-name-interp.less
index a4e5b5c7..ad1dd419 100644
--- a/test/less/property-name-interp.less
+++ b/test/less/property-name-interp.less
@@ -7,7 +7,10 @@ pi-test {
     @d-d4: radius;
     @-:         -;
 
+    @var: ~'@not-variable';
+
     @{a}: 0;
+    @{var}: @var;
     @{prefix}width: 50%;
     *-z-@{a} :1px dashed blue;
     -www-@{a}-@{bb}: 2px;
diff --git a/test/modify-vars.js b/test/modify-vars.js
new file mode 100644
index 00000000..c4c6c5b4
--- /dev/null
+++ b/test/modify-vars.js
@@ -0,0 +1,17 @@
+var less = require('../lib/less'),
+  fs = require('fs')
+
+var input = fs.readFileSync("./test/less/modifyVars/extended.less", 'utf8')
+var expectedCss = fs.readFileSync('./test/css/modifyVars/extended.css', 'utf8')
+var options = {
+  modifyVars: JSON.parse(fs.readFileSync("./test/less/modifyVars/extended.json", 'utf8'))
+}
+
+less.render(input, options, function (err, css) {
+  if (err) console.log(err);
+  if (css === expectedCss) {
+    console.log("PASS")
+  } else {
+    console.log("FAIL")
+  }
+})
\ No newline at end of file