diff --git a/lib/scope.js b/lib/scope.js
index 2822fe29..a6bce387 100644
--- a/lib/scope.js
+++ b/lib/scope.js
@@ -13,7 +13,6 @@
             type: 'arguments'
           }
         ];
-        this.positions = {};
         if (this.parent) {
           this.garbage = this.parent.garbage;
         } else {
@@ -26,15 +25,19 @@
     })();
     Scope.root = null;
     Scope.prototype.add = function(name, type) {
-      if (this.positions.hasOwnProperty(name)) {
-        this.variables[this.positions[name]].type = type;
-      } else {
-        this.positions[name] = this.variables.push({
-          name: name,
-          type: type
-        }) - 1;
+      var _len, _ref2, i, variable;
+      _ref2 = this.variables;
+      for (i = 0, _len = _ref2.length; i < _len; i++) {
+        variable = _ref2[i];
+        if (variable.name === name) {
+          this.variables[i].type = type;
+          return;
+        }
       }
-      return this;
+      return this.variables.push({
+        name: name,
+        type: type
+      });
     };
     Scope.prototype.startLevel = function() {
       this.garbage.push([]);
diff --git a/src/scope.coffee b/src/scope.coffee
index 3955fae3..b0e63e3d 100644
--- a/src/scope.coffee
+++ b/src/scope.coffee
@@ -19,7 +19,6 @@ exports.Scope = class Scope
   # it wraps.
   constructor: (@parent, @expressions, @method) ->
     @variables = [{name: 'arguments', type: 'arguments'}]
-    @positions = {}
     if @parent
       @garbage = @parent.garbage
     else
@@ -28,11 +27,11 @@ exports.Scope = class Scope
 
   # Adds a new variable or overrides an existing one.
   add: (name, type) ->
-    if @positions.hasOwnProperty name
-      @variables[@positions[name]].type = type
-    else
-      @positions[name] = @variables.push({name, type}) - 1
-    this
+    for variable, i in @variables
+      if variable.name is name
+        @variables[i].type = type
+        return
+    @variables.push {name, type}
 
   # Create a new garbage level
   startLevel: ->