diff --git a/tests/cases/fourslash/thisPredicateFunctions.ts b/tests/cases/fourslash/thisPredicateFunctions.ts
new file mode 100644
index 00000000000..8df03ea312a
--- /dev/null
+++ b/tests/cases/fourslash/thisPredicateFunctions.ts
@@ -0,0 +1,95 @@
+/// <reference path="fourslash.ts" />
+
+//// class RoyalGuard {
+////     isLeader(): this is LeadGuard {
+////         return this instanceof LeadGuard;
+////     }
+////     isFollower(): this is FollowerGuard {
+////         return this instanceof FollowerGuard;
+////     }
+//// }
+////
+//// class LeadGuard extends RoyalGuard {
+////     lead(): void {};
+//// }
+////
+//// class FollowerGuard extends RoyalGuard {
+////     follow(): void {};
+//// }
+////
+//// let a: RoyalGuard = new FollowerGuard();
+//// if (a.is/*1*/Leader()) {
+////     a./*2*/;
+//// }
+//// else if (a.is/*3*/Follower()) {
+////     a./*4*/;
+//// }
+////
+//// interface GuardInterface {
+////    isLeader(): this is LeadGuard;
+////    isFollower(): this is FollowerGuard;
+//// }
+////
+//// let b: GuardInterface;
+//// if (b.is/*5*/Leader()) {
+////     b./*6*/;
+//// }
+//// else if (b.is/*7*/Follower()) {
+////     b./*8*/;
+//// }
+////
+//// if (((a.isLeader)())) {
+////     a./*9*/;
+//// }
+//// else if (((a).isFollower())) {
+////     a./*10*/;
+//// }
+////
+//// if (((a["isLeader"])())) {
+////     a./*11*/;
+//// }
+//// else if (((a)["isFollower"]())) {
+////     a./*12*/;
+//// }
+////
+//// let leader/*13*/Status = a.isLeader();
+//// function isLeaderGuard(g: RoyalGuard) {
+////    return g.isLeader();
+//// }
+//// let checked/*14*/LeaderStatus = isLeader/*15*/Guard(a);
+
+
+goTo.marker("1");
+verify.quickInfoIs("(method) RoyalGuard.isLeader(): this is LeadGuard");
+goTo.marker("2");
+verify.completionListContains("lead");
+goTo.marker("3");
+verify.quickInfoIs("(method) RoyalGuard.isFollower(): this is FollowerGuard");
+goTo.marker("4");
+verify.completionListContains("follow");
+
+goTo.marker("5");
+verify.quickInfoIs("(method) GuardInterface.isLeader(): this is LeadGuard");
+goTo.marker("6");
+verify.completionListContains("lead");
+goTo.marker("7");
+verify.quickInfoIs("(method) GuardInterface.isFollower(): this is FollowerGuard");
+goTo.marker("8");
+verify.completionListContains("follow");
+
+goTo.marker("9");
+verify.completionListContains("lead");
+goTo.marker("10");
+verify.completionListContains("follow");
+
+goTo.marker("11");
+verify.completionListContains("lead");
+goTo.marker("12");
+verify.completionListContains("follow");
+
+goTo.marker("13");
+verify.quickInfoIs("let leaderStatus: boolean");
+goTo.marker("14");
+verify.quickInfoIs("let checkedLeaderStatus: boolean");
+goTo.marker("15");
+verify.quickInfoIs("function isLeaderGuard(g: RoyalGuard): boolean");
\ No newline at end of file
diff --git a/tests/cases/fourslash/thisPredicateMembers.ts b/tests/cases/fourslash/thisPredicateMembers.ts
new file mode 100644
index 00000000000..b20a0de1997
--- /dev/null
+++ b/tests/cases/fourslash/thisPredicateMembers.ts
@@ -0,0 +1,137 @@
+/// <reference path="fourslash.ts" />
+
+//// class FileSystemObject {
+//// 	get is/*1*/File(): this is Item {
+//// 		return this instanceof Item;
+//// 	}
+//// 	set is/*2*/File(param) {
+//// 		// noop
+//// 	}
+//// 	get is/*3*/Directory(): this is Directory {
+//// 		return this instanceof Directory;
+//// 	}
+//// 	is/*4*/Networked: this is (Networked & this);
+//// 	constructor(public path: string) {}
+//// }
+////
+//// class Item extends FileSystemObject {
+//// 	constructor(path: string, public content: string) { super(path); }
+//// }
+//// class Directory extends FileSystemObject {
+//// 	children: FileSystemObject[];
+//// }
+//// interface Networked {
+//// 	host: string;
+//// }
+////
+//// interface Sundries {
+//// 	broken: boolean;
+//// }
+////
+//// interface Supplies {
+//// 	spoiled: boolean;
+//// }
+////
+//// interface Crate<T> {
+//// 	contents: T;
+//// 	is/*5*/Sundries: this is Crate<Sundries>;
+//// 	is/*6*/Supplies: this is Crate<Supplies>;
+//// 	is/*7*/PackedTight: this is (this & {extraContents: T});
+//// }
+////
+//// const obj: FileSystemObject = new Item("/foo", "");
+//// if (obj.is/*8*/File) {
+//// 	obj./*9*/;
+//// 	if (obj.is/*10*/Networked) {
+//// 		obj./*11*/;
+//// 	}
+//// }
+//// if (obj.is/*12*/Directory) {
+//// 	obj./*13*/;
+//// 	if (obj.is/*14*/Networked) {
+//// 		obj./*15*/;
+//// 	}
+//// }
+//// if (obj.is/*16*/Networked) {
+//// 	obj./*17*/;
+//// }
+////
+//// const crate: Crate<any>;
+//// if (crate.is/*18*/PackedTight) {
+//// 	crate./*19*/;
+//// }
+//// if (crate.is/*20*/Sundries) {
+//// 	crate.contents./*21*/;
+//// 	if (crate.is/*22*/PackedTight) {
+//// 		crate./*23*/
+//// 	}
+//// }
+//// if (crate.is/*24*/Supplies) {
+//// 	crate.contents./*25*/;
+//// 	if (crate.is/*26*/PackedTight) {
+//// 		crate./*27*/
+//// 	}
+//// }
+
+goTo.marker("1");
+verify.quickInfoIs("(property) FileSystemObject.isFile: this is Item");
+goTo.marker("2");
+verify.quickInfoIs("(property) FileSystemObject.isFile: this is Item");
+goTo.marker("3");
+verify.quickInfoIs("(property) FileSystemObject.isDirectory: this is Directory");
+goTo.marker("4");
+verify.quickInfoIs("(property) FileSystemObject.isNetworked: this is Networked & this");
+goTo.marker("5");
+verify.quickInfoIs("(property) Crate<T>.isSundries: this is Crate<Sundries>");
+goTo.marker("6");
+verify.quickInfoIs("(property) Crate<T>.isSupplies: this is Crate<Supplies>");
+goTo.marker("7");
+verify.quickInfoIs(`(property) Crate<T>.isPackedTight: this is this & {
+    extraContents: T;
+}`);
+goTo.marker("8");
+verify.quickInfoIs("(property) FileSystemObject.isFile: this is Item");
+goTo.marker("9");
+verify.completionListContains("content");
+goTo.marker("10");
+verify.quickInfoIs("(property) FileSystemObject.isNetworked: this is Networked & Item");
+goTo.marker("11");
+verify.completionListContains("host");
+goTo.marker("12");
+verify.quickInfoIs("(property) FileSystemObject.isDirectory: this is Directory");
+goTo.marker("13");
+verify.completionListContains("children");
+goTo.marker("14");
+verify.quickInfoIs("(property) FileSystemObject.isNetworked: this is Networked & Directory");
+goTo.marker("15");
+verify.completionListContains("host");
+goTo.marker("16");
+verify.quickInfoIs("(property) FileSystemObject.isNetworked: this is Networked & FileSystemObject");
+goTo.marker("17");
+verify.completionListContains("host");
+goTo.marker("18");
+verify.quickInfoIs(`(property) Crate<any>.isPackedTight: this is Crate<any> & {
+    extraContents: any;
+}`);
+goTo.marker("19");
+verify.completionListContains("extraContents");
+goTo.marker("20");
+verify.quickInfoIs("(property) Crate<any>.isSundries: this is Crate<Sundries>");
+goTo.marker("21");
+verify.completionListContains("broken");
+goTo.marker("22");
+verify.quickInfoIs(`(property) Crate<Sundries>.isPackedTight: this is Crate<Sundries> & {
+    extraContents: Sundries;
+}`);
+goTo.marker("23");
+verify.completionListContains("extraContents");
+goTo.marker("24");
+verify.quickInfoIs("(property) Crate<any>.isSupplies: this is Crate<Supplies>");
+goTo.marker("25");
+verify.completionListContains("spoiled");
+goTo.marker("26");
+verify.quickInfoIs(`(property) Crate<Supplies>.isPackedTight: this is Crate<Supplies> & {
+    extraContents: Supplies;
+}`);
+goTo.marker("27");
+verify.completionListContains("extraContents");
\ No newline at end of file