diff --git a/tests/cases/conformance/controlFlow/controlFlowBinaryOrExpression.ts b/tests/cases/conformance/controlFlow/controlFlowBinaryOrExpression.ts
index 75b24622e00..9dab32e0cb8 100644
--- a/tests/cases/conformance/controlFlow/controlFlowBinaryOrExpression.ts
+++ b/tests/cases/conformance/controlFlow/controlFlowBinaryOrExpression.ts
@@ -7,3 +7,29 @@ x; // string | number
 x = "";
 cond || (x = 0);
 x; // string | number
+
+export interface NodeList {
+    length: number;
+}
+
+export interface HTMLCollection {
+    length: number;
+}
+
+declare function isNodeList(sourceObj: any): sourceObj is NodeList;
+declare function isHTMLCollection(sourceObj: any): sourceObj is HTMLCollection;
+
+type EventTargetLike = {a: string} | HTMLCollection | NodeList;
+
+var sourceObj: EventTargetLike = <any>undefined;
+if (isNodeList(sourceObj)) {
+    sourceObj.length;
+}
+
+if (isHTMLCollection(sourceObj)) {
+    sourceObj.length;
+}
+
+if (isNodeList(sourceObj) || isHTMLCollection(sourceObj)) {
+    sourceObj.length;
+}