diff --git a/lib/less/parser.js b/lib/less/parser.js
index 8480f90..25c6da5 100644
--- a/lib/less/parser.js
+++ b/lib/less/parser.js
@@ -374,10 +374,13 @@ less.Parser = function Parser(env) {
 
                     if (name) { return new(tree.Call)(name[1], args) }
                 },
+                wildcard: function () {
+                    if ($('*')) { return { wildcard: true } }
+                },
                 arguments: function () {
                     var args = [], arg;
 
-                    while (arg = $(this.expression)) {
+                    while (arg = $(this.entities.wildcard) || $(this.expression)) {
                         args.push(arg);
                         if (! $(',')) { break }
                     }
diff --git a/lib/less/tree/mixin.js b/lib/less/tree/mixin.js
index 30fb842..82d6f44 100644
--- a/lib/less/tree/mixin.js
+++ b/lib/less/tree/mixin.js
@@ -32,8 +32,8 @@ tree.mixin.Definition = function MixinDefinition(name, params, rules) {
     this.rules = rules;
     this._lookups = {};
     this.required = params.reduce(function (count, p) {
-        if (p.name && p.value) { return count }
-        else                   { return count + 1 }
+        if (p.name && !p.value) { return count + 1 }
+        else                    { return count }
     }, 0);
 };
 tree.mixin.Definition.prototype = {
@@ -61,13 +61,15 @@ tree.mixin.Definition.prototype = {
     match: function (args, env) {
         var argsLength = (args && args.length) || 0;
 
-        if (argsLength < this.required || argsLength > this.arity) {
+
+        if (argsLength < this.required) {
             return false;
         }
 
-        for (var i = 0; i < argsLength; i++) {
+        for (var i = 0; i < Math.min(argsLength, this.arity); i++) {
             if (!this.params[i].name) {
-                if (args[i].toCSS(env) != this.params[i].value.toCSS(env)) {
+                if (args[i].wildcard) { continue }
+                else if (args[i].toCSS(env) != this.params[i].value.toCSS(env)) {
                     return false;
                 }
             }
diff --git a/test/css/mixins-pattern.css b/test/css/mixins-pattern.css
index 9672bc5..2d68bfa 100644
--- a/test/css/mixins-pattern.css
+++ b/test/css/mixins-pattern.css
@@ -5,16 +5,25 @@
   three: 3;
 }
 .one {
+  zero: 0;
   one: 1;
   one-req: 1;
   two: 2;
   three: 3;
 }
 .two {
+  zero: 0;
+  one: 1;
+  one-req: 1;
   two: 2;
   three: 3;
 }
 .three {
+  zero: 0;
+  one: 1;
+  one-req: 1;
+  two: 2;
+  three-req: 3;
   three: 3;
 }
 .left {
@@ -31,3 +40,16 @@
   color: black;
   border-left: 4px;
 }
+.only-right {
+  both: 330;
+  right: 33;
+}
+.only-left {
+  both: 330;
+  left: 33;
+}
+.left-right {
+  both: 330;
+  left: 33;
+  right: 33;
+}
diff --git a/test/less/mixins-pattern.less b/test/less/mixins-pattern.less
index 57d0f06..445fa0e 100644
--- a/test/less/mixins-pattern.less
+++ b/test/less/mixins-pattern.less
@@ -8,7 +8,11 @@
     one-req: 1;    
 }
 .mixin (@a: 1px, @b: 2px) {
-    two: 2;    
+    two: 2;
+}
+
+.mixin (@a, @b, @c) {
+    three-req: 3;
 }
 
 .mixin (@a: 1px, @b: 2px, @c: 3px) {
@@ -65,9 +69,31 @@
 }
 
 .border-right {
-    .border(right, 4px);    
+    .border(right, 4px);
 }
 .border-left {
-    .border(left, 4px);    
+    .border(left, 4px);
 }
 
+//
+
+
+.border-radius (@r) {
+    both: @r * 10;
+}
+.border-radius (@r, left) {
+    left: @r;
+}
+.border-radius (@r, right) {
+    right: @r;
+}
+
+.only-right {
+    .border-radius(33, right);
+}
+.only-left {
+    .border-radius(33, left);
+}
+.left-right {
+    .border-radius(33);
+}