diff --git a/bower.json b/bower.json
index ac4aab9..ab4829e 100644
--- a/bower.json
+++ b/bower.json
@@ -4,7 +4,7 @@
     "Microsoft Corp."
   ],
   "homepage": "http://typescriptlang.org/",
-  "version": "2.6.0",
+  "version": "2.7.0",
   "license": "0BSD",
   "description": "Runtime library for TypeScript helper functions",
   "keywords": [
diff --git a/package.json b/package.json
index a8646d5..a068b42 100644
--- a/package.json
+++ b/package.json
@@ -2,7 +2,7 @@
     "name": "tslib",
     "author": "Microsoft Corp.",
     "homepage": "https://www.typescriptlang.org/",
-    "version": "2.6.3",
+    "version": "2.7.0",
     "license": "0BSD",
     "description": "Runtime library for TypeScript helper functions",
     "keywords": [
diff --git a/tslib.es6.js b/tslib.es6.js
index b212c25..fc18d15 100644
--- a/tslib.es6.js
+++ b/tslib.es6.js
@@ -12,7 +12,7 @@ LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
 OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 PERFORMANCE OF THIS SOFTWARE.
 ***************************************************************************** */
-/* global Reflect, Promise, SuppressedError, Symbol */
+/* global Reflect, Promise, SuppressedError, Symbol, Iterator */
 
 var extendStatics = function(d, b) {
     extendStatics = Object.setPrototypeOf ||
@@ -123,8 +123,8 @@ export function __awaiter(thisArg, _arguments, P, generator) {
 }
 
 export function __generator(thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
@@ -228,7 +228,7 @@ export function __await(v) {
 export function __asyncGenerator(thisArg, _arguments, generator) {
     if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -327,17 +327,22 @@ export function __disposeResources(env) {
         env.error = env.hasError ? new _SuppressedError(e, env.error, "An error was suppressed during disposal.") : e;
         env.hasError = true;
     }
+    var r, s = 0;
     function next() {
-        while (env.stack.length) {
-            var rec = env.stack.pop();
+        while (r = env.stack.pop()) {
             try {
-                var result = rec.dispose && rec.dispose.call(rec.value);
-                if (rec.async) return Promise.resolve(result).then(next, function(e) { fail(e); return next(); });
+                if (!r.async && s === 1) return s = 0, env.stack.push(r), Promise.resolve().then(next);
+                if (r.dispose) {
+                    var result = r.dispose.call(r.value);
+                    if (r.async) return s |= 2, Promise.resolve(result).then(next, function(e) { fail(e); return next(); });
+                }
+                else s |= 1;
             }
             catch (e) {
                 fail(e);
             }
         }
+        if (s === 1) return env.hasError ? Promise.reject(env.error) : Promise.resolve();
         if (env.hasError) throw env.error;
     }
     return next();
diff --git a/tslib.es6.mjs b/tslib.es6.mjs
index 0df91b1..17bb2ff 100644
--- a/tslib.es6.mjs
+++ b/tslib.es6.mjs
@@ -12,7 +12,7 @@ LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
 OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 PERFORMANCE OF THIS SOFTWARE.
 ***************************************************************************** */
-/* global Reflect, Promise, SuppressedError, Symbol */
+/* global Reflect, Promise, SuppressedError, Symbol, Iterator */
 
 var extendStatics = function(d, b) {
   extendStatics = Object.setPrototypeOf ||
@@ -123,8 +123,8 @@ export function __awaiter(thisArg, _arguments, P, generator) {
 }
 
 export function __generator(thisArg, body) {
-  var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-  return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+  var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+  return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
   function verb(n) { return function (v) { return step([n, v]); }; }
   function step(op) {
       if (f) throw new TypeError("Generator is already executing.");
@@ -228,7 +228,7 @@ export function __await(v) {
 export function __asyncGenerator(thisArg, _arguments, generator) {
   if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
   var g = generator.apply(thisArg, _arguments || []), i, q = [];
-  return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+  return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
   function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
   function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
   function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -326,17 +326,22 @@ export function __disposeResources(env) {
     env.error = env.hasError ? new _SuppressedError(e, env.error, "An error was suppressed during disposal.") : e;
     env.hasError = true;
   }
+  var r, s = 0;
   function next() {
-    while (env.stack.length) {
-      var rec = env.stack.pop();
+    while (r = env.stack.pop()) {
       try {
-        var result = rec.dispose && rec.dispose.call(rec.value);
-        if (rec.async) return Promise.resolve(result).then(next, function(e) { fail(e); return next(); });
+        if (!r.async && s === 1) return s = 0, env.stack.push(r), Promise.resolve().then(next);
+        if (r.dispose) {
+          var result = r.dispose.call(r.value);
+          if (r.async) return s |= 2, Promise.resolve(result).then(next, function(e) { fail(e); return next(); });
+        }
+        else s |= 1;
       }
       catch (e) {
-          fail(e);
+        fail(e);
       }
     }
+    if (s === 1) return env.hasError ? Promise.reject(env.error) : Promise.resolve();
     if (env.hasError) throw env.error;
   }
   return next();
diff --git a/tslib.js b/tslib.js
index 0f7c846..429c11a 100644
--- a/tslib.js
+++ b/tslib.js
@@ -12,7 +12,7 @@ LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
 OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 PERFORMANCE OF THIS SOFTWARE.
 ***************************************************************************** */
-/* global global, define, Symbol, Reflect, Promise, SuppressedError */
+/* global global, define, Symbol, Reflect, Promise, SuppressedError, Iterator */
 var __extends;
 var __assign;
 var __rest;
@@ -171,8 +171,8 @@ var __disposeResources;
     };
 
     __generator = function (thisArg, body) {
-        var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-        return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+        var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+        return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
         function verb(n) { return function (v) { return step([n, v]); }; }
         function step(op) {
             if (f) throw new TypeError("Generator is already executing.");
@@ -276,7 +276,7 @@ var __disposeResources;
     __asyncGenerator = function (thisArg, _arguments, generator) {
         if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
         var g = generator.apply(thisArg, _arguments || []), i, q = [];
-        return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+        return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
         function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
         function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
         function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -374,17 +374,22 @@ var __disposeResources;
             env.error = env.hasError ? new _SuppressedError(e, env.error, "An error was suppressed during disposal.") : e;
             env.hasError = true;
         }
+        var r, s = 0;
         function next() {
-            while (env.stack.length) {
-                var rec = env.stack.pop();
+            while (r = env.stack.pop()) {
                 try {
-                    var result = rec.dispose && rec.dispose.call(rec.value);
-                    if (rec.async) return Promise.resolve(result).then(next, function(e) { fail(e); return next(); });
+                    if (!r.async && s === 1) return s = 0, env.stack.push(r), Promise.resolve().then(next);
+                    if (r.dispose) {
+                        var result = r.dispose.call(r.value);
+                        if (r.async) return s |= 2, Promise.resolve(result).then(next, function(e) { fail(e); return next(); });
+                    }
+                    else s |= 1;
                 }
                 catch (e) {
                     fail(e);
                 }
             }
+            if (s === 1) return env.hasError ? Promise.reject(env.error) : Promise.resolve();
             if (env.hasError) throw env.error;
         }
         return next();