Fix compiler program de-duping

lib/handlebars/compiler/compiler.js

@@ -1,4 +1,5 @@
 import Exception from "../exception";
+import {isArray} from "../utils";
 
 export function Compiler() {}
 
@@ -19,20 +20,14 @@ Compiler.prototype = {
     for (var i = 0; i < len; i++) {
       var opcode = this.opcodes[i],
           otherOpcode = other.opcodes[i];
-      if (opcode.opcode !== otherOpcode.opcode || opcode.args.length !== otherOpcode.args.length) {
+      if (opcode.opcode !== otherOpcode.opcode || !argEquals(opcode.args, otherOpcode.args)) {
         return false;
       }
-      for (var j = 0; j < opcode.args.length; j++) {
-        if (opcode.args[j] !== otherOpcode.args[j]) {
-          return false;
-        }
-      }
     }
 
+    // We know that length is the same between the two arrays because they are directly tied
+    // to the opcode behavior above.
     len = this.children.length;
-    if (other.children.length !== len) {
-      return false;
-    }
     for (i = 0; i < len; i++) {
       if (!this.children[i].equals(other.children[i])) {
         return false;
@@ -449,3 +444,18 @@ export function compile(input, options, env) {
   };
   return ret;
 }
+
+function argEquals(a, b) {
+  if (a === b) {
+    return true;
+  }
+
+  if (isArray(a) && isArray(b) && a.length === b.length) {
+    for (var i = 0; i < a.length; i++) {
+      if (!argEquals(a[i], b[i])) {
+        return false;
+      }
+    }
+    return true;
+  }
+}