diff --git a/tests/baselines/reference/typeGuardsOnClassProperty.errors.txt b/tests/baselines/reference/typeGuardsOnClassProperty.errors.txt
new file mode 100644
index 0000000000000..4e6a8b83ae349
--- /dev/null
+++ b/tests/baselines/reference/typeGuardsOnClassProperty.errors.txt
@@ -0,0 +1,37 @@
+tests/cases/conformance/expressions/typeGuards/typeGuardsOnClassProperty.ts(14,70): error TS2339: Property 'join' does not exist on type 'string | string[]'.
+tests/cases/conformance/expressions/typeGuards/typeGuardsOnClassProperty.ts(26,44): error TS2339: Property 'toLowerCase' does not exist on type 'string | number'.
+
+
+==== tests/cases/conformance/expressions/typeGuards/typeGuardsOnClassProperty.ts (2 errors) ====
+    // Note that type guards affect types of variables and parameters only and 
+    // have no effect on members of objects such as properties. 
+    
+    // Note that the class's property must be copied to a local variable for
+    // the type guard to have an effect
+    class D {
+        data: string | string[];
+        getData() {
+            var data = this.data;
+            return typeof data === "string" ? data : data.join(" ");
+        }
+    
+        getData1() {
+            return typeof this.data === "string" ? this.data : this.data.join(" ");
+                                                                         ~~~~
+!!! error TS2339: Property 'join' does not exist on type 'string | string[]'.
+        }
+    }
+    
+    var o: {
+        prop1: number|string;
+        prop2: boolean|string;
+    } = {
+            prop1: "string" ,
+            prop2: true
+        }
+    
+    if (typeof o.prop1 === "string" && o.prop1.toLowerCase()) {}
+                                               ~~~~~~~~~~~
+!!! error TS2339: Property 'toLowerCase' does not exist on type 'string | number'.
+    var prop1 = o.prop1;
+    if (typeof prop1 === "string" && prop1.toLocaleLowerCase()) { }
\ No newline at end of file
diff --git a/tests/baselines/reference/typeGuardsOnClassProperty.js b/tests/baselines/reference/typeGuardsOnClassProperty.js
new file mode 100644
index 0000000000000..de4fcb50638da
--- /dev/null
+++ b/tests/baselines/reference/typeGuardsOnClassProperty.js
@@ -0,0 +1,54 @@
+//// [typeGuardsOnClassProperty.ts]
+// Note that type guards affect types of variables and parameters only and 
+// have no effect on members of objects such as properties. 
+
+// Note that the class's property must be copied to a local variable for
+// the type guard to have an effect
+class D {
+    data: string | string[];
+    getData() {
+        var data = this.data;
+        return typeof data === "string" ? data : data.join(" ");
+    }
+
+    getData1() {
+        return typeof this.data === "string" ? this.data : this.data.join(" ");
+    }
+}
+
+var o: {
+    prop1: number|string;
+    prop2: boolean|string;
+} = {
+        prop1: "string" ,
+        prop2: true
+    }
+
+if (typeof o.prop1 === "string" && o.prop1.toLowerCase()) {}
+var prop1 = o.prop1;
+if (typeof prop1 === "string" && prop1.toLocaleLowerCase()) { }
+
+//// [typeGuardsOnClassProperty.js]
+// Note that type guards affect types of variables and parameters only and 
+// have no effect on members of objects such as properties. 
+// Note that the class's property must be copied to a local variable for
+// the type guard to have an effect
+var D = (function () {
+    function D() {
+    }
+    D.prototype.getData = function () {
+        var data = this.data;
+        return typeof data === "string" ? data : data.join(" ");
+    };
+    D.prototype.getData1 = function () {
+        return typeof this.data === "string" ? this.data : this.data.join(" ");
+    };
+    return D;
+})();
+var o = {
+    prop1: "string",
+    prop2: true
+};
+if (typeof o.prop1 === "string" && o.prop1.toLowerCase()) { }
+var prop1 = o.prop1;
+if (typeof prop1 === "string" && prop1.toLocaleLowerCase()) { }
diff --git a/tests/cases/conformance/expressions/typeGuards/typeGuardsOnClassProperty.ts b/tests/cases/conformance/expressions/typeGuards/typeGuardsOnClassProperty.ts
new file mode 100644
index 0000000000000..2c26b10c6a1b0
--- /dev/null
+++ b/tests/cases/conformance/expressions/typeGuards/typeGuardsOnClassProperty.ts
@@ -0,0 +1,28 @@
+// Note that type guards affect types of variables and parameters only and 
+// have no effect on members of objects such as properties. 
+
+// Note that the class's property must be copied to a local variable for
+// the type guard to have an effect
+class D {
+    data: string | string[];
+    getData() {
+        var data = this.data;
+        return typeof data === "string" ? data : data.join(" ");
+    }
+
+    getData1() {
+        return typeof this.data === "string" ? this.data : this.data.join(" ");
+    }
+}
+
+var o: {
+    prop1: number|string;
+    prop2: boolean|string;
+} = {
+        prop1: "string" ,
+        prop2: true
+    }
+
+if (typeof o.prop1 === "string" && o.prop1.toLowerCase()) {}
+var prop1 = o.prop1;
+if (typeof prop1 === "string" && prop1.toLocaleLowerCase()) { }
\ No newline at end of file