diff --git a/build/scscript.js b/build/scscript.js
index 0dd4b1c..338feca 100644
--- a/build/scscript.js
+++ b/build/scscript.js
@@ -1,7 +1,7 @@
 (function(global) {
 "use strict";
 
-var sc = { VERSION: "0.0.20" };
+var sc = { VERSION: "0.0.21" };
 
 // src/sc/sc.js
 (function(sc) {
@@ -11,7 +11,7 @@ var sc = { VERSION: "0.0.20" };
   sc.libs = {};
 
   function SCScript(fn) {
-    return fn(sc.lang.$SC);
+    return fn(sc.lang.klass.$interpreter, sc.lang.$SC);
   }
 
   SCScript.install = function(installer) {
@@ -260,6 +260,17 @@ var sc = { VERSION: "0.0.20" };
       }
 
       stream.push(stmt.head, stmt.vars, stmt.tail);
+    },
+    begin_ref: function() {
+      var refId   = (this._refId | 0);
+      var refName = "_ref" + refId;
+      this.add("var", refName);
+      this._refId = refId + 1;
+      return refName;
+    },
+    end_ref: function() {
+      var refId = (this._refId | 0) - 1;
+      this._refId = Math.max(0, refId);
     }
   });
 
@@ -453,8 +464,10 @@ var sc = { VERSION: "0.0.20" };
     var elements = node.left;
     var operator = node.operator;
     var assignments;
+    var result;
+    var ref;
 
-    this.scope.add("var", "_ref");
+    ref = this.scope.begin_ref();
 
     assignments = this.withIndent(function() {
       var result, lastUsedIndex;
@@ -464,25 +477,29 @@ var sc = { VERSION: "0.0.20" };
       result = [
         this.stitchWith(elements, ",\n", function(item, i) {
           return this.addIndent(this._Assign(
-            item, operator, "_ref.at($SC.Integer(" + i + "))"
+            item, operator, ref + ".at($SC.Integer(" + i + "))"
           ));
         })
       ];
 
       if (node.remain) {
         result.push(",\n", this.addIndent(this._Assign(
-          node.remain, operator, "_ref.copyToEnd($SC.Integer(" + lastUsedIndex + "))"
+          node.remain, operator, ref + ".copyToEnd($SC.Integer(" + lastUsedIndex + "))"
         )));
       }
 
       return result;
     });
 
-    return [
-      "(_ref = ", this.generate(node.right), ",\n",
+    result = [
+      "(" + ref + " = ", this.generate(node.right), ",\n",
       assignments , ",\n",
-      this.addIndent("_ref)")
+      this.addIndent(ref + ")")
     ];
+
+    this.scope.end_ref();
+
+    return result;
   };
 
   CodeGen.prototype._Assign = function(left, operator, right) {
@@ -565,37 +582,53 @@ var sc = { VERSION: "0.0.20" };
     var args;
     var list;
     var hasActualArgument;
+    var result;
+    var ref;
 
     list = node.args.list;
     hasActualArgument = !!list.length;
 
-    args = [
-      this.stitchWith(list, ", ", function(item) {
-        return this.generate(item);
-      }),
-      this.insertKeyValueElement(node.args.keywords, hasActualArgument)
-    ];
+    if (node.stamp === "=") {
+      ref = this.scope.begin_ref();
+      result = [
+        "(" + ref + " = ", this.generate(list[0]), ", ",
+        this.generate(node.callee), ".", node.method.name, "(" + ref + "), ",
+        ref + ")"
+      ];
+      this.scope.end_ref();
+    } else {
+      args = [
+        this.stitchWith(list, ", ", function(item) {
+          return this.generate(item);
+        }),
+        this.insertKeyValueElement(node.args.keywords, hasActualArgument)
+      ];
+      result = [
+        this.generate(node.callee), ".", node.method.name, "(", args, ")"
+      ];
+    }
 
-    return [
-      this.generate(node.callee), ".", node.method.name, "(", args, ")"
-    ];
+    return result;
   };
 
   CodeGen.prototype._ExpandCall = function(node) {
     var result;
+    var ref;
 
-    this.scope.add("var", "_ref");
+    ref = this.scope.begin_ref();
 
     result = [
-      "(_ref = ",
+      "(" + ref + " = ",
       this.generate(node.callee),
-      ", _ref." + node.method.name + ".apply(_ref, ",
+      ", " + ref + "." + node.method.name + ".apply(" + ref + ", ",
       this.insertArrayElement(node.args.list), ".concat(",
       this.generate(node.args.expand), ".asArray()._",
       this.insertKeyValueElement(node.args.keywords, true),
       ")))"
     ];
 
+    this.scope.end_ref();
+
     return result;
   };
 
@@ -800,14 +833,17 @@ var sc = { VERSION: "0.0.20" };
   };
 
   CodeGen.prototype._InterpreterVariable = function(node, opts) {
-    var name;
+    var name, ref;
 
     if (opts) {
       // setter
+      ref = this.scope.begin_ref();
       name = [
-        "$this." + node.name + "_(", this.generate(opts.right), ")"
+        "(" + ref + " = ", this.generate(opts.right),
+        ", $this." + node.name + "_(" + ref + "), " + ref + ")"
       ];
       opts.used = true;
+      this.scope.end_ref();
     } else {
       // getter
       name = "$this." + node.name + "()";
@@ -2272,7 +2308,7 @@ var sc = { VERSION: "0.0.20" };
   };
 
   SCParser.prototype.parseSimpleAssignmentExpression = function() {
-    var node, left, right, token, marker;
+    var node, left, right, token, methodName, marker;
 
     node = left = this.parsePartialExpression();
 
@@ -2282,9 +2318,12 @@ var sc = { VERSION: "0.0.20" };
 
         token = this.lex();
         right = this.parseAssignmentExpression();
-        left.method.name = renameGetterToSetter(left.method.name);
+        methodName = renameGetterToSetter(left.method.name);
+        left.method.name = methodName;
         left.args.list   = node.args.list.concat(right);
-
+        if (methodName.charAt(methodName.length - 1) === "_") {
+          left.stamp = "=";
+        }
         node = marker.update().apply(left, true);
       } else {
         if (!isLeftHandSide(left)) {
@@ -4487,6 +4526,11 @@ var sc = { VERSION: "0.0.20" };
     __tag: 12
   });
 
+  function SCInterpreter() {
+    this.__initializeWith__("Object");
+  }
+  klass.define(SCInterpreter, "Interpreter");
+
   // $SC
   var $nil      = new SCNil();
   var $true     = new SCTrue();
@@ -4588,6 +4632,8 @@ var sc = { VERSION: "0.0.20" };
     return instance;
   };
 
+  sc.lang.klass.$interpreter = new SCInterpreter();
+
 })(sc);
 
 // src/sc/lang/klass/utils.js
@@ -8463,6 +8509,8 @@ var sc = { VERSION: "0.0.20" };
 // src/sc/lang/classlib/Core/Kernel.js
 (function(sc) {
 
+  var fn  = sc.lang.fn;
+
   sc.lang.klass.refine("Class", {
     // TODO: implements superclass
     // TODO: implements asClass
@@ -8495,6 +8543,45 @@ var sc = { VERSION: "0.0.20" };
     // TODO: implements superclasses
   });
 
+  sc.lang.klass.refine("Interpreter", function(spec, utils) {
+    var $nil = utils.$nil;
+
+    (function() {
+      var i, ch;
+
+      function getter(name) {
+        return function() {
+          return this["_" + name] || $nil;
+        };
+      }
+
+      function setter(name) {
+        return fn(function(value) {
+          this["_" + name] = value;
+          return this;
+        }, "value");
+      }
+
+      for (i = 97; i <= 122; i++) {
+        ch = String.fromCharCode(i);
+        spec[ch] = getter(ch);
+        spec[ch + "_"] = setter(ch);
+      }
+    })();
+
+    spec.$new = function() {
+      throw new Error("Interpreter.new is illegal.");
+    };
+
+    spec.clearAll = function() {
+      var i;
+      for (i = 97; i <= 122; i++) {
+        this["_" + String.fromCharCode(i)] = $nil;
+      }
+      return this;
+    };
+  });
+
 })(sc);
 
 // src/sc/lang/classlib/Core/Function.js
diff --git a/package.json b/package.json
index 3b8b3e5..577f4ea 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "scscript",
-  "version": "0.0.20",
+  "version": "0.0.21",
   "author": "Nao Yonamine <mohayonao@gmail.com>",
   "homepage": "http://mohayonao.github.io/SCScript/",
   "bugs": "https://github.com/mohayonao/SCScript/issues",
diff --git a/src/sc/lang/compiler/codegen.js b/src/sc/lang/compiler/codegen.js
index d7cf6f4..2a653f0 100644
--- a/src/sc/lang/compiler/codegen.js
+++ b/src/sc/lang/compiler/codegen.js
@@ -60,6 +60,17 @@
       }
 
       stream.push(stmt.head, stmt.vars, stmt.tail);
+    },
+    begin_ref: function() {
+      var refId   = (this._refId | 0);
+      var refName = "_ref" + refId;
+      this.add("var", refName);
+      this._refId = refId + 1;
+      return refName;
+    },
+    end_ref: function() {
+      var refId = (this._refId | 0) - 1;
+      this._refId = Math.max(0, refId);
     }
   });
 
@@ -254,8 +265,10 @@
     var elements = node.left;
     var operator = node.operator;
     var assignments;
+    var result;
+    var ref;
 
-    this.scope.add("var", "_ref");
+    ref = this.scope.begin_ref();
 
     assignments = this.withIndent(function() {
       var result, lastUsedIndex;
@@ -265,25 +278,29 @@
       result = [
         this.stitchWith(elements, ",\n", function(item, i) {
           return this.addIndent(this._Assign(
-            item, operator, "_ref.at($SC.Integer(" + i + "))"
+            item, operator, ref + ".at($SC.Integer(" + i + "))"
           ));
         })
       ];
 
       if (node.remain) {
         result.push(",\n", this.addIndent(this._Assign(
-          node.remain, operator, "_ref.copyToEnd($SC.Integer(" + lastUsedIndex + "))"
+          node.remain, operator, ref + ".copyToEnd($SC.Integer(" + lastUsedIndex + "))"
         )));
       }
 
       return result;
     });
 
-    return [
-      "(_ref = ", this.generate(node.right), ",\n",
+    result = [
+      "(" + ref + " = ", this.generate(node.right), ",\n",
       assignments , ",\n",
-      this.addIndent("_ref)")
+      this.addIndent(ref + ")")
     ];
+
+    this.scope.end_ref();
+
+    return result;
   };
 
   CodeGen.prototype._Assign = function(left, operator, right) {
@@ -366,37 +383,53 @@
     var args;
     var list;
     var hasActualArgument;
+    var result;
+    var ref;
 
     list = node.args.list;
     hasActualArgument = !!list.length;
 
-    args = [
-      this.stitchWith(list, ", ", function(item) {
-        return this.generate(item);
-      }),
-      this.insertKeyValueElement(node.args.keywords, hasActualArgument)
-    ];
+    if (node.stamp === "=") {
+      ref = this.scope.begin_ref();
+      result = [
+        "(" + ref + " = ", this.generate(list[0]), ", ",
+        this.generate(node.callee), ".", node.method.name, "(" + ref + "), ",
+        ref + ")"
+      ];
+      this.scope.end_ref();
+    } else {
+      args = [
+        this.stitchWith(list, ", ", function(item) {
+          return this.generate(item);
+        }),
+        this.insertKeyValueElement(node.args.keywords, hasActualArgument)
+      ];
+      result = [
+        this.generate(node.callee), ".", node.method.name, "(", args, ")"
+      ];
+    }
 
-    return [
-      this.generate(node.callee), ".", node.method.name, "(", args, ")"
-    ];
+    return result;
   };
 
   CodeGen.prototype._ExpandCall = function(node) {
     var result;
+    var ref;
 
-    this.scope.add("var", "_ref");
+    ref = this.scope.begin_ref();
 
     result = [
-      "(_ref = ",
+      "(" + ref + " = ",
       this.generate(node.callee),
-      ", _ref." + node.method.name + ".apply(_ref, ",
+      ", " + ref + "." + node.method.name + ".apply(" + ref + ", ",
       this.insertArrayElement(node.args.list), ".concat(",
       this.generate(node.args.expand), ".asArray()._",
       this.insertKeyValueElement(node.args.keywords, true),
       ")))"
     ];
 
+    this.scope.end_ref();
+
     return result;
   };
 
@@ -601,14 +634,17 @@
   };
 
   CodeGen.prototype._InterpreterVariable = function(node, opts) {
-    var name;
+    var name, ref;
 
     if (opts) {
       // setter
+      ref = this.scope.begin_ref();
       name = [
-        "$this." + node.name + "_(", this.generate(opts.right), ")"
+        "(" + ref + " = ", this.generate(opts.right),
+        ", $this." + node.name + "_(" + ref + "), " + ref + ")"
       ];
       opts.used = true;
+      this.scope.end_ref();
     } else {
       // getter
       name = "$this." + node.name + "()";
diff --git a/src/sc/lang/compiler/parser.js b/src/sc/lang/compiler/parser.js
index a7a615f..304ca79 100644
--- a/src/sc/lang/compiler/parser.js
+++ b/src/sc/lang/compiler/parser.js
@@ -390,7 +390,7 @@
   };
 
   SCParser.prototype.parseSimpleAssignmentExpression = function() {
-    var node, left, right, token, marker;
+    var node, left, right, token, methodName, marker;
 
     node = left = this.parsePartialExpression();
 
@@ -400,9 +400,12 @@
 
         token = this.lex();
         right = this.parseAssignmentExpression();
-        left.method.name = renameGetterToSetter(left.method.name);
+        methodName = renameGetterToSetter(left.method.name);
+        left.method.name = methodName;
         left.args.list   = node.args.list.concat(right);
-
+        if (methodName.charAt(methodName.length - 1) === "_") {
+          left.stamp = "=";
+        }
         node = marker.update().apply(left, true);
       } else {
         if (!isLeftHandSide(left)) {
diff --git a/src/sc/lang/compiler/test-cases.js b/src/sc/lang/compiler/test-cases.js
index 5dc9ad6..75b0fb2 100644
--- a/src/sc/lang/compiler/test-cases.js
+++ b/src/sc/lang/compiler/test-cases.js
@@ -573,7 +573,8 @@
     "a = 2pi": {
       compiled: [
         "SCScript(function($this, $SC) {",
-        "  return $this.a_($SC.Float(6.283185307179586));",
+        "  var _ref0;",
+        "  return (_ref0 = $SC.Float(6.283185307179586), $this.a_(_ref0), _ref0);",
         "});",
       ],
       ast: {
@@ -618,11 +619,11 @@
     "#a, b = c": {
       compiled: [
         "SCScript(function($this, $SC) {",
-        "  var _ref;",
-        "  return (_ref = $this.c(),",
-        "    $this.a_(_ref.at($SC.Integer(0))),",
-        "    $this.b_(_ref.at($SC.Integer(1))),",
-        "  _ref);",
+        "  var _ref0, _ref1;",
+        "  return (_ref0 = $this.c(),",
+        "    (_ref1 = _ref0.at($SC.Integer(0)), $this.a_(_ref1), _ref1),",
+        "    (_ref1 = _ref0.at($SC.Integer(1)), $this.b_(_ref1), _ref1),",
+        "  _ref0);",
         "});",
       ],
       ast: {
@@ -677,12 +678,12 @@
     "#a, b ... c = d": {
       compiled: [
         "SCScript(function($this, $SC) {",
-        "  var _ref;",
-        "  return (_ref = $this.d(),",
-        "    $this.a_(_ref.at($SC.Integer(0))),",
-        "    $this.b_(_ref.at($SC.Integer(1))),",
-        "    $this.c_(_ref.copyToEnd($SC.Integer(2))),",
-        "  _ref);",
+        "  var _ref0, _ref1;",
+        "  return (_ref0 = $this.d(),",
+        "    (_ref1 = _ref0.at($SC.Integer(0)), $this.a_(_ref1), _ref1),",
+        "    (_ref1 = _ref0.at($SC.Integer(1)), $this.b_(_ref1), _ref1),",
+        "    (_ref1 = _ref0.copyToEnd($SC.Integer(2)), $this.c_(_ref1), _ref1),",
+        "  _ref0);",
         "});",
       ],
       ast: {
@@ -746,17 +747,17 @@
     "#a, b = #c, d = [ 0, 1 ]": {
       compiled: [
         "SCScript(function($this, $SC) {",
-        "  var _ref;",
-        "  return (_ref = (_ref = $SC.Array([",
+        "  var _ref0, _ref1, _ref2;",
+        "  return (_ref0 = (_ref1 = $SC.Array([",
         "    $SC.Integer(0),",
         "    $SC.Integer(1),",
         "  ]),",
-        "    $this.c_(_ref.at($SC.Integer(0))),",
-        "    $this.d_(_ref.at($SC.Integer(1))),",
-        "  _ref),",
-        "    $this.a_(_ref.at($SC.Integer(0))),",
-        "    $this.b_(_ref.at($SC.Integer(1))),",
-        "  _ref);",
+        "    (_ref2 = _ref1.at($SC.Integer(0)), $this.c_(_ref2), _ref2),",
+        "    (_ref2 = _ref1.at($SC.Integer(1)), $this.d_(_ref2), _ref2),",
+        "  _ref1),",
+        "    (_ref1 = _ref0.at($SC.Integer(0)), $this.a_(_ref1), _ref1),",
+        "    (_ref1 = _ref0.at($SC.Integer(1)), $this.b_(_ref1), _ref1),",
+        "  _ref0);",
         "});",
       ],
       ast: {
@@ -908,7 +909,8 @@
     "a.b.c = 1": {
       compiled: [
         "SCScript(function($this, $SC) {",
-        "  return $this.a().b().c_($SC.Integer(1));",
+        "  var _ref0;",
+        "  return (_ref0 = $SC.Integer(1), $this.a().b().c_(_ref0), _ref0);",
         "});",
       ],
       ast: {
@@ -945,6 +947,7 @@
                 end  : { line: 1, column: 3 }
               }
             },
+            stamp: "=",
             method: {
               type: Syntax.Identifier,
               name: "c_",
@@ -2075,10 +2078,11 @@
     "a[b[c=0;1]=0;1]": {
       compiled: [
         "SCScript(function($this, $SC) {",
+        "  var _ref0;",
         "  return $this.a().at(" +
-          "($this.b().put(" +
-          "($this.c_($SC.Integer(0)), $SC.Integer(1)), $SC.Integer(0)" +
-          "), $SC.Integer(1))" +
+          "($this.b().put((" +
+          "(_ref0 = $SC.Integer(0), $this.c_(_ref0), _ref0), " +
+          "$SC.Integer(1)), $SC.Integer(0)), $SC.Integer(1))" +
           ");",
         "});",
       ],
@@ -3491,9 +3495,10 @@
     "a = #{}": {
       compiled: [
         "SCScript(function($this, $SC) {",
-        "  return $this.a_($SC.Function(function() {",
+        "  var _ref0;",
+        "  return (_ref0 = $SC.Function(function() {",
         "    return $SC.Nil();",
-        "  }, '', true));",
+        "  }, '', true), $this.a_(_ref0), _ref0);",
         "});",
       ],
       ast: {
@@ -3956,10 +3961,10 @@
     "var a; #a = [];": {
       compiled: [
         "SCScript(function($this, $SC) {",
-        "  var $a = $SC.Nil(), _ref;",
-        "  return (_ref = $SC.Array([]),",
-        "    $a = _ref.at($SC.Integer(0)),",
-        "  _ref);",
+        "  var $a = $SC.Nil(), _ref0;",
+        "  return (_ref0 = $SC.Array([]),",
+        "    $a = _ref0.at($SC.Integer(0)),",
+        "  _ref0);",
         "});",
       ],
       ast: {
@@ -4423,8 +4428,8 @@
     "max(0, 1, 2, *a, a: 5, b: 6)": {
       compiled: [
         "SCScript(function($this, $SC) {",
-        "  var _ref;",
-        "  return (_ref = $SC.Integer(0), _ref.max.apply(_ref, [",
+        "  var _ref0;",
+        "  return (_ref0 = $SC.Integer(0), _ref0.max.apply(_ref0, [",
         "    $SC.Integer(1),",
         "    $SC.Integer(2),",
         "  ].concat($this.a().asArray()._, { a: $SC.Integer(5), b: $SC.Integer(6) })));",
@@ -4527,8 +4532,8 @@
     "max(1, 2, *a)": {
       compiled: [
         "SCScript(function($this, $SC) {",
-        "  var _ref;",
-        "  return (_ref = $SC.Integer(1), _ref.max.apply(_ref, [",
+        "  var _ref0;",
+        "  return (_ref0 = $SC.Integer(1), _ref0.max.apply(_ref0, [",
         "    $SC.Integer(2),",
         "  ].concat($this.a().asArray()._)));",
         "});",
@@ -4669,8 +4674,8 @@
     "max(0, *a, a: 3)": {
       compiled: [
         "SCScript(function($this, $SC) {",
-        "  var _ref;",
-        "  return (_ref = $SC.Integer(0), _ref.max.apply(_ref, [" +
+        "  var _ref0;",
+        "  return (_ref0 = $SC.Integer(0), _ref0.max.apply(_ref0, [" +
           "].concat($this.a().asArray()._, { a: $SC.Integer(3) })));",
         "});",
       ],
@@ -4740,8 +4745,8 @@
     "max(0, *a)": {
       compiled: [
         "SCScript(function($this, $SC) {",
-        "  var _ref;",
-        "  return (_ref = $SC.Integer(0), _ref.max.apply(_ref, [" +
+        "  var _ref0;",
+        "  return (_ref0 = $SC.Integer(0), _ref0.max.apply(_ref0, [" +
           "].concat($this.a().asArray()._)));",
         "});",
       ],
@@ -5119,7 +5124,11 @@
     "a = (1; 2; 3)": {
       compiled: [
         "SCScript(function($this, $SC) {",
-        "  return $this.a_(($SC.Integer(1), $SC.Integer(2), $SC.Integer(3)));",
+        "  var _ref0;",
+        "  return (_ref0 = " +
+          "($SC.Integer(1), $SC.Integer(2), $SC.Integer(3)), " +
+          "$this.a_(_ref0), " +
+          "_ref0);",
         "});",
       ],
       ast: {
@@ -5186,11 +5195,12 @@
     "a = (var a = 1; a)": {
       compiled: [
         "SCScript(function($this, $SC) {",
-        "  return $this.a_((function() {",
+        "  var _ref0;",
+        "  return (_ref0 = (function() {",
         "    var $a = $SC.Nil();",
         "    $a = $SC.Integer(1);",
         "    return $a;",
-        "  })());",
+        "  })(), $this.a_(_ref0), _ref0);",
         "});",
       ],
       ast: {
@@ -6287,8 +6297,8 @@
     "a.value(*[])": {
       compiled: [
         "SCScript(function($this, $SC) {",
-        "  var _ref;",
-        "  return (_ref = $this.a(), _ref.value.apply(_ref, [" +
+        "  var _ref0;",
+        "  return (_ref0 = $this.a(), _ref0.value.apply(_ref0, [" +
           "].concat($SC.Array([]).asArray()._)));",
         "});",
       ],
@@ -6922,14 +6932,15 @@
     "x = ( a: 1, b: 2, 3: 4 )": {
       compiled: [
         "SCScript(function($this, $SC) {",
-        "  return $this.x_($SC.Event([",
+        "  var _ref0;",
+        "  return (_ref0 = $SC.Event([",
         "    $SC.Symbol('a'),",
         "    $SC.Integer(1),",
         "    $SC.Symbol('b'),",
         "    $SC.Integer(2),",
         "    $SC.Integer(3),",
         "    $SC.Integer(4),",
-        "  ]));",
+        "  ]), $this.x_(_ref0), _ref0);",
         "});",
       ],
       ast: {
@@ -7034,14 +7045,15 @@
     "x = ( a : 1, b : 2, c : 3 )": {
       compiled: [
         "SCScript(function($this, $SC) {",
-        "  return $this.x_($SC.Event([",
+        "  var _ref0;",
+        "  return (_ref0 = $SC.Event([",
         "    $this.a(),",
         "    $SC.Integer(1),",
         "    $this.b(),",
         "    $SC.Integer(2),",
         "    $this.c(),",
         "    $SC.Integer(3),",
-        "  ]));",
+        "  ]), $this.x_(_ref0), _ref0);",
         "});",
       ],
       ast: {
@@ -7143,12 +7155,13 @@
     "x = (1 + 2: 3, 4: 5)": {
       compiled: [
         "SCScript(function($this, $SC) {",
-        "  return $this.x_($SC.Event([",
+        "  var _ref0;",
+        "  return (_ref0 = $SC.Event([",
         "    $SC.Integer(1) ['+'] ($SC.Integer(2)),",
         "    $SC.Integer(3),",
         "    $SC.Integer(4),",
         "    $SC.Integer(5),",
-        "  ]));",
+        "  ]), $this.x_(_ref0), _ref0);",
         "});",
       ],
       ast: {
@@ -7252,9 +7265,10 @@
     "f = _ + _": {
       compiled: [
         "SCScript(function($this, $SC) {",
-        "  return $this.f_($SC.Function(function($_0, $_1) {",
+        "  var _ref0;",
+        "  return (_ref0 = $SC.Function(function($_0, $_1) {",
         "    return $_0 ['+'] ($_1);",
-        "  }));",
+        "  }), $this.f_(_ref0), _ref0);",
         "});",
       ],
       ast: {