diff --git a/lib/compiler/passes/generate-bytecode.js b/lib/compiler/passes/generate-bytecode.js
index c8d596e..c4173d2 100644
--- a/lib/compiler/passes/generate-bytecode.js
+++ b/lib/compiler/passes/generate-bytecode.js
@@ -1,7 +1,6 @@
 "use strict";
 
-let objects = require("../../utils/objects"),
-    asts    = require("../asts"),
+let asts    = require("../asts"),
     visitor = require("../visitor"),
     op      = require("../opcodes"),
     js      = require("../js");
@@ -204,6 +203,16 @@ function generateBytecode(ast) {
     );
   }
 
+  function cloneEnv(env) {
+    let clone = {};
+
+    Object.keys(env).forEach(name => {
+      clone[name] = env[name];
+    });
+
+    return clone;
+  }
+
   function buildSequence() {
     return Array.prototype.concat.apply([], arguments);
   }
@@ -221,7 +230,7 @@ function generateBytecode(ast) {
   }
 
   function buildCall(functionIndex, delta, env, sp) {
-    let params = objects.values(env).map(p => sp - p);
+    let params = Object.keys(env).map(name => sp - env[name]);
 
     return [op.CALL, functionIndex, delta, params.length].concat(params);
   }
@@ -232,7 +241,7 @@ function generateBytecode(ast) {
       [op.SILENT_FAILS_ON],
       generate(expression, {
         sp:     context.sp + 1,
-        env:    objects.clone(context.env),
+        env:    cloneEnv(context.env),
         action: null
       }),
       [op.SILENT_FAILS_OFF],
@@ -318,7 +327,7 @@ function generateBytecode(ast) {
         return buildSequence(
           generate(alternatives[0], {
             sp:     context.sp,
-            env:    objects.clone(context.env),
+            env:    cloneEnv(context.env),
             action: null
           }),
           alternatives.length > 1
@@ -338,7 +347,7 @@ function generateBytecode(ast) {
     },
 
     action: function(node, context) {
-      let env            = objects.clone(context.env),
+      let env            = cloneEnv(context.env),
           emitCall       = node.expression.type !== "sequence"
                         || node.expression.elements.length === 0,
           expressionCode = generate(node.expression, {
@@ -424,7 +433,7 @@ function generateBytecode(ast) {
     },
 
     labeled: function(node, context) {
-      let env = objects.clone(context.env);
+      let env = cloneEnv(context.env);
 
       context.env[node.label] = context.sp + 1;
 
@@ -440,7 +449,7 @@ function generateBytecode(ast) {
         [op.PUSH_CURR_POS],
         generate(node.expression, {
           sp:     context.sp + 1,
-          env:    objects.clone(context.env),
+          env:    cloneEnv(context.env),
           action: null
         }),
         buildCondition(
@@ -463,7 +472,7 @@ function generateBytecode(ast) {
       return buildSequence(
         generate(node.expression, {
           sp:     context.sp,
-          env:    objects.clone(context.env),
+          env:    cloneEnv(context.env),
           action: null
         }),
         buildCondition(
@@ -477,7 +486,7 @@ function generateBytecode(ast) {
     zero_or_more: function(node, context) {
       let expressionCode = generate(node.expression, {
             sp:     context.sp + 1,
-            env:    objects.clone(context.env),
+            env:    cloneEnv(context.env),
             action: null
           });
 
@@ -492,7 +501,7 @@ function generateBytecode(ast) {
     one_or_more: function(node, context) {
       let expressionCode = generate(node.expression, {
             sp:     context.sp + 1,
-            env:    objects.clone(context.env),
+            env:    cloneEnv(context.env),
             action: null
           });
 
@@ -510,7 +519,7 @@ function generateBytecode(ast) {
     group: function(node, context) {
       return generate(node.expression, {
         sp:     context.sp,
-        env:    objects.clone(context.env),
+        env:    cloneEnv(context.env),
         action: null
       });
     },