Don't store `tempVars` as we can get the next available one from scope.

lib/scope.js

@@ -6,21 +6,13 @@
   }
   exports.Scope = (function() {
     Scope = function(parent, expressions, method) {
-      var _cache, _cache2, k, val;
+      var _cache;
       _cache = [parent, expressions, method];
       this.parent = _cache[0];
       this.expressions = _cache[1];
       this.method = _cache[2];
       this.variables = {};
-      this.tempVars = {};
-      if (this.parent) {
-        _cache2 = this.parent.tempVars;
-        for (k in _cache2) {
-          if (!__hasProp.call(_cache2, k)) continue;
-          val = _cache2[k];
-          (this.tempVars[k] = val);
-        }
-      } else {
+      if (!this.parent) {
         Scope.root = this;
       }
       return this;
@@ -57,12 +49,13 @@
       return !!(this.parent && this.parent.check(name));
     };
     Scope.prototype.temporary = function(type, index) {
-      return '_' + type + ((index) > 1 ? index : '');
+      return '_' + type + (index ? (index + 1) : '');
     };
     Scope.prototype.freeVariable = function(type) {
-      var temp;
-      while (this.check(temp = this.temporary(type, this.tempVars[type] || (this.tempVars[type] = 1)))) {
-        this.tempVars[type]++;
+      var index, temp;
+      index = 0;
+      while (this.check(temp = this.temporary(type, index))) {
+        index++;
       }
       this.variables[temp] = 'var';
       return temp;

src/scope.coffee

@@ -20,11 +20,7 @@ exports.Scope = class Scope
   constructor: (parent, expressions, method) ->
     [@parent, @expressions, @method] = [parent, expressions, method]
     @variables = {}
-    @tempVars  = {}
-    if @parent
-      (@tempVars[k] = val) for k, val of @parent.tempVars
-    else
-      Scope.root = this
+    Scope.root = this if not @parent
 
   # Look up a variable name in lexical scope, and declare it if it does not
   # already exist.
@@ -53,12 +49,13 @@ exports.Scope = class Scope
 
   # Generate a temporary variable name at the given index.
   temporary: (type, index) ->
-    '_' + type + (if (index) > 1 then index else '')
+    '_' + type + (if index then (index + 1) else '')
 
   # If we need to store an intermediate result, find an available name for a
   # compiler-generated variable. `_var`, `_var2`, and so on...
   freeVariable: (type) ->
-    @tempVars[type]++ while @check temp = @temporary type, @tempVars[type] or= 1
+    index = 0
+    index++ while @check temp = @temporary type, index
     @variables[temp] = 'var'
     temp