diff --git a/lib/chai/core/assertions.js b/lib/chai/core/assertions.js
index de52bbdfb..f3bc6d6f4 100644
--- a/lib/chai/core/assertions.js
+++ b/lib/chai/core/assertions.js
@@ -159,7 +159,7 @@ module.exports = function (chai, _) {
    *     expect(null).to.be.a('null');
    *     expect(undefined).to.be.an('undefined');
    *     expect(new Error).to.be.an('error');
-   *     expect(new Promise).to.be.a('promise');
+   *     expect(Promise.resolve()).to.be.a('promise');
    *     expect(new Float32Array).to.be.a('float32array');
    *     expect(Symbol()).to.be.a('symbol');
    *