diff --git a/packages/spacebars/compile_tests.js b/packages/spacebars/compile_tests.js
index ca46188015..047fa2de83 100644
--- a/packages/spacebars/compile_tests.js
+++ b/packages/spacebars/compile_tests.js
@@ -74,11 +74,9 @@ Tinytest.add("spacebars - compiler output", function (test) {
       function() {
         var self = this;
         return function() {
-          return Spacebars.mustache2(self.lookup("foo"), {
-            hash: {
-              x: Spacebars.dot(self.lookup("bar"), "baz")
-            }
-          });
+          return Spacebars.mustache2(self.lookup("foo"), Spacebars.kw({
+            x: Spacebars.dot(self.lookup("bar"), "baz")
+          }));
         };
       });
 
@@ -139,7 +137,7 @@ Tinytest.add("spacebars - compiler output", function (test) {
         return function() {
           return Spacebars.include(Template["foo"] || self.lookup("foo"), {
             data: function() {
-              return Spacebars.dot(self.lookup("bar"), "baz");
+              return Spacebars.call2(Spacebars.dot(self.lookup("bar"), "baz"));
             }
           });
         };
@@ -151,7 +149,7 @@ Tinytest.add("spacebars - compiler output", function (test) {
         return function() {
           return Spacebars.include(Template["foo"] || self.lookup("foo"), {
             x: function() {
-              return Spacebars.dot(self.lookup("bar"), "baz");
+              return Spacebars.call2(Spacebars.dot(self.lookup("bar"), "baz"));
             }
           });
         };
diff --git a/packages/spacebars/spacebars.js b/packages/spacebars/spacebars.js
index 0d1803b79c..88df661b1d 100644
--- a/packages/spacebars/spacebars.js
+++ b/packages/spacebars/spacebars.js
@@ -1683,9 +1683,26 @@ Spacebars.combineAttributes = function (/*attrObjects*/) {
 // Executes `{{foo bar baz}}` when called on `(foo, bar, baz)`.
 // If `bar` and `baz` are functions, they are called before
 // `foo` is called on them.
+//
+// This is the shared part of Spacebars.mustache and
+// Spacebars.attrMustache, which differ in how they post-process the
+// result.
+Spacebars.mustacheImpl = function (value/*, args*/) {
+  var args = arguments;
+  // if we have any arguments (pos or kw), add an options argument
+  // if there isn't one.
+  if (args.length > 1 &&
+      ! (args[args.length - 1] instanceof Spacebars.kw)) {
+    // clone arguments into an actual array, then push.
+    args = Array.prototype.slice.call(arguments);
+    args.push(Spacebars.kw());
+  }
+
+  return Spacebars.call2.apply(null, args);
+};
+
 Spacebars.mustache2 = function (value/*, args*/) {
-  var args = ensureHash(arguments);
-  var result = Spacebars.call2.apply(null, args);
+  var result = Spacebars.mustacheImpl.apply(null, arguments);
 
   if (result instanceof Handlebars.SafeString)
     return HTML.Raw(result.toString());
@@ -1695,6 +1712,22 @@ Spacebars.mustache2 = function (value/*, args*/) {
     return String(result == null ? '' : result);
 };
 
+Spacebars.attrMustache = function (value/*, args*/) {
+  var result = Spacebars.mustacheImpl.apply(null, arguments);
+
+  if (result == null || result === '') {
+    return null;
+  } else if (typeof result === 'object') {
+    return result;
+  } else if (typeof result === 'string' && UI.isValidAttributeName(result)) {
+    var obj = {};
+    obj[result] = '';
+    return obj;
+  } else {
+    throw new Error("Expected valid attribute name, '', null, or object");
+  }
+};
+
 // Idempotently wrap in `HTML.Raw`.
 //
 // Called on the return value from `Spacebars.mustache2` in case the
@@ -1728,35 +1761,6 @@ Spacebars.call2 = function (value/*, args*/) {
   }
 };
 
-// If the last element of `args` is not a `Spacebars.kw` object,
-// return a new array with an appended `Spacebars.kw` object.
-// Otherwise just return `args`.  `args` may be an arguments
-// object; we won't mutate it.
-var ensureHash = function (args) {
-  if (! (args[args.length - 1] instanceof Spacebars.kw)) {
-    args = Array.prototype.slice.call(args);
-    args.push(Spacebars.kw());
-  }
-  return args;
-};
-
-Spacebars.attrMustache = function (value/*, args*/) {
-  var args = ensureHash(arguments);
-  var result = Spacebars.call2.apply(null, args);
-
-  if (result == null || result === '') {
-    return null;
-  } else if (typeof result === 'object') {
-    return result;
-  } else if (typeof result === 'string' && UI.isValidAttributeName(result)) {
-    var obj = {};
-    obj[result] = '';
-    return obj;
-  } else {
-    throw new Error("Expected valid attribute name, '', null, or object");
-  }
-};
-
 var codeGenMustache = function (tag, mustacheType) {
   var nameCode = codeGenPath2(tag.path);
   var argCode = codeGenArgs2(tag.args);
diff --git a/packages/templating/templating_tests.js b/packages/templating/templating_tests.js
index 85dcc2e258..bd45793d8b 100644
--- a/packages/templating/templating_tests.js
+++ b/packages/templating/templating_tests.js
@@ -187,9 +187,6 @@ Tinytest.add("templating - helpers and dots", function(test) {
   };
 
   var listFour = function(a, b, c, d, options) {
-    // XXX this fails because `options` is sometimes undefined.  on
-    // devel, options is always passed, with an empty hash even if
-    // there are no kwargs
     var keywordArgs = _.map(_.keys(options.hash), function(k) {
       var val = options.hash[k];
       return k+':'+val;
@@ -534,8 +531,6 @@ Tinytest.add('templating - helper typecast Issue #617', function (test) {
 
   var div = renderToDiv(Template.test_type_casting);
   var result = canonicalizeHtml(div.innerHTML);
-  // XXX this fails because of the missing last object argument.
-  // (see XXX comment within `listFour`)
   test.equal(
     result,
     // This corresponds to entries in templating_tests.html.