Fixes to the non-assimilation promise constructor stuff.

lib/rsvp.js

@@ -9,6 +9,14 @@ var noop = function() {};
 var Promise = function(resolver) {
   var promise = this;
 
+  if (typeof resolver !== 'function') {
+    throw new TypeError('You must pass a resolver function as the sole argument to the promise constructor');
+  }
+
+  if (!(promise instanceof Promise)) {
+    return new Promise(resolver);
+  }
+
   var resolvePromise = function(value) {
     resolve(promise, value);
     resolvePromise = noop;
@@ -29,9 +37,7 @@ var Promise = function(resolver) {
     this.trigger('error', { detail: event.detail });
   }, this);
 
-  if (resolver) {
-    resolver(resolvePromise, rejectPromise);
-  }
+  resolver(resolvePromise, rejectPromise);
 };
 
 var invokeCallback = function(type, promise, callback, event) {
@@ -69,8 +75,10 @@ var invokeCallback = function(type, promise, callback, event) {
 };
 
 Promise.prototype = {
+  constructor: Promise,
+
   then: function(done, fail) {
-    var thenPromise = new Promise();
+    var thenPromise = new Promise(function() {});
 
     if (this.isFulfilled) {
       config.async(function() {
@@ -114,7 +122,7 @@ function reject(promise, value) {
 
 function all(promises) {
   var i, results = [];
-  var allPromise = new Promise();
+  var allPromise = new Promise(function() {});
   var remaining = promises.length;
 
   if (remaining === 0) {