diff --git a/tests/baselines/reference/instanceofOperatorWithLHSIsObject.js b/tests/baselines/reference/instanceofOperatorWithLHSIsObject.js
index 5ccf195cd88..c687027ae9b 100644
--- a/tests/baselines/reference/instanceofOperatorWithLHSIsObject.js
+++ b/tests/baselines/reference/instanceofOperatorWithLHSIsObject.js
@@ -7,10 +7,13 @@ var x2: Function;
 var a: {};
 var b: Object;
 var c: C;
+var d: string | C;
 
 var r1 = a instanceof x1;
 var r2 = b instanceof x2;
-var r3 = c instanceof x1;
+var r3 = c instanceof x1;
+var r4 = d instanceof x1;
+
 
 //// [instanceofOperatorWithLHSIsObject.js]
 var C = (function () {
@@ -23,6 +26,8 @@ var x2;
 var a;
 var b;
 var c;
+var d;
 var r1 = a instanceof x1;
 var r2 = b instanceof x2;
 var r3 = c instanceof x1;
+var r4 = d instanceof x1;
diff --git a/tests/baselines/reference/instanceofOperatorWithLHSIsObject.types b/tests/baselines/reference/instanceofOperatorWithLHSIsObject.types
index 26aea98028e..9962a23dced 100644
--- a/tests/baselines/reference/instanceofOperatorWithLHSIsObject.types
+++ b/tests/baselines/reference/instanceofOperatorWithLHSIsObject.types
@@ -20,6 +20,10 @@ var c: C;
 >c : C
 >C : C
 
+var d: string | C;
+>d : string | C
+>C : C
+
 var r1 = a instanceof x1;
 >r1 : boolean
 >a instanceof x1 : boolean
@@ -38,3 +42,9 @@ var r3 = c instanceof x1;
 >c : C
 >x1 : any
 
+var r4 = d instanceof x1;
+>r4 : boolean
+>d instanceof x1 : boolean
+>d : string | C
+>x1 : any
+
diff --git a/tests/cases/conformance/expressions/binaryOperators/instanceofOperator/instanceofOperatorWithLHSIsObject.ts b/tests/cases/conformance/expressions/binaryOperators/instanceofOperator/instanceofOperatorWithLHSIsObject.ts
index 285335e40e7..6b88cd39f2a 100644
--- a/tests/cases/conformance/expressions/binaryOperators/instanceofOperator/instanceofOperatorWithLHSIsObject.ts
+++ b/tests/cases/conformance/expressions/binaryOperators/instanceofOperator/instanceofOperatorWithLHSIsObject.ts
@@ -6,7 +6,9 @@ var x2: Function;
 var a: {};
 var b: Object;
 var c: C;
+var d: string | C;
 
 var r1 = a instanceof x1;
 var r2 = b instanceof x2;
-var r3 = c instanceof x1;
\ No newline at end of file
+var r3 = c instanceof x1;
+var r4 = d instanceof x1;