Index: src/promise.js |
diff --git a/src/promise.js b/src/promise.js |
index 82aa99027a1305ac8bf6b95672cccd89504173cd..c5649ef71cfd050bda873f96bb3042ba573db1ff 100644 |
--- a/src/promise.js |
+++ b/src/promise.js |
@@ -217,7 +217,7 @@ function PromiseThen(onResolve, onReject) { |
PromiseCoerce.table = new $WeakMap; |
function PromiseCoerce(constructor, x) { |
- if (!(IsPromise(x) || IS_NULL_OR_UNDEFINED(x))) { |
+ if (!IsPromise(x) && IS_SPEC_OBJECT(x)) { |
var then = x.then; |
if (typeof then === 'function') { |
if (PromiseCoerce.table.has(x)) { |