From 861de5056a7c977b505c279a65e75f0169912533 Mon Sep 17 00:00:00 2001
From: Wesley Wigham <wewigham@microsoft.com>
Date: Thu, 8 Nov 2018 16:36:51 -0800
Subject: [PATCH 1/2] Ensure all default type params are mapped to some default
 even in circular scenarios

---
 src/compiler/checker.ts                       |  6 +-
 .../reference/subclassThisTypeAssignable.js   | 34 +++++++
 .../subclassThisTypeAssignable.symbols        | 92 +++++++++++++++++++
 .../subclassThisTypeAssignable.types          | 49 ++++++++++
 .../compiler/subclassThisTypeAssignable.ts    | 24 +++++
 5 files changed, 203 insertions(+), 2 deletions(-)
 create mode 100644 tests/baselines/reference/subclassThisTypeAssignable.js
 create mode 100644 tests/baselines/reference/subclassThisTypeAssignable.symbols
 create mode 100644 tests/baselines/reference/subclassThisTypeAssignable.types
 create mode 100644 tests/cases/compiler/subclassThisTypeAssignable.ts

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 103200600b219..7cb4c60b399a1 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -7663,8 +7663,10 @@ namespace ts {
                 // Map an unsatisfied type parameter with a default type.
                 // If a type parameter does not have a default type, or if the default type
                 // is a forward reference, the empty object type is used.
+                const baseDefaultType = getDefaultTypeArgumentType(isJavaScriptImplicitAny);
+                const cicrularityMapper = createTypeMapper(typeParameters!, map(typeParameters!, () => baseDefaultType));
                 for (let i = numTypeArguments; i < numTypeParameters; i++) {
-                    result[i] = getConstraintFromTypeParameter(typeParameters![i]) || getDefaultTypeArgumentType(isJavaScriptImplicitAny);
+                    result[i] = instantiateType(getConstraintFromTypeParameter(typeParameters![i]) || baseDefaultType, cicrularityMapper);
                 }
                 for (let i = numTypeArguments; i < numTypeParameters; i++) {
                     const mapper = createTypeMapper(typeParameters!, result);
@@ -7672,7 +7674,7 @@ namespace ts {
                     if (isJavaScriptImplicitAny && defaultType && isTypeIdenticalTo(defaultType, emptyObjectType)) {
                         defaultType = anyType;
                     }
-                    result[i] = defaultType ? instantiateType(defaultType, mapper) : getDefaultTypeArgumentType(isJavaScriptImplicitAny);
+                    result[i] = defaultType ? instantiateType(defaultType, mapper) : baseDefaultType;
                 }
                 result.length = typeParameters!.length;
                 return result;
diff --git a/tests/baselines/reference/subclassThisTypeAssignable.js b/tests/baselines/reference/subclassThisTypeAssignable.js
new file mode 100644
index 0000000000000..e374b56e10b4f
--- /dev/null
+++ b/tests/baselines/reference/subclassThisTypeAssignable.js
@@ -0,0 +1,34 @@
+//// [subclassThisTypeAssignable.ts]
+interface Lifecycle<Attrs, State> {
+	oninit?(vnode: Vnode<Attrs, State>): number;
+	[_: number]: any;
+}
+
+interface Vnode<Attrs, State extends Lifecycle<Attrs, State> = Lifecycle<Attrs, State>> {
+	tag: Component<Attrs, State>;
+}
+
+interface Component<Attrs, State> {
+	view(this: State, vnode: Vnode<Attrs, State>): number;
+}
+
+interface ClassComponent<A> extends Lifecycle<A, ClassComponent<A>> {
+	oninit?(vnode: Vnode<A, this>): number;
+	view(vnode: Vnode<A, this>): number;
+}
+
+interface MyAttrs { id: number }
+class C implements ClassComponent<MyAttrs> {
+	view(v: Vnode<MyAttrs>) { return 0; }
+}
+
+const test8: ClassComponent<any> = new C();
+
+//// [subclassThisTypeAssignable.js]
+var C = /** @class */ (function () {
+    function C() {
+    }
+    C.prototype.view = function (v) { return 0; };
+    return C;
+}());
+var test8 = new C();
diff --git a/tests/baselines/reference/subclassThisTypeAssignable.symbols b/tests/baselines/reference/subclassThisTypeAssignable.symbols
new file mode 100644
index 0000000000000..e6fe66cf3d30b
--- /dev/null
+++ b/tests/baselines/reference/subclassThisTypeAssignable.symbols
@@ -0,0 +1,92 @@
+=== tests/cases/compiler/subclassThisTypeAssignable.ts ===
+interface Lifecycle<Attrs, State> {
+>Lifecycle : Symbol(Lifecycle, Decl(subclassThisTypeAssignable.ts, 0, 0))
+>Attrs : Symbol(Attrs, Decl(subclassThisTypeAssignable.ts, 0, 20))
+>State : Symbol(State, Decl(subclassThisTypeAssignable.ts, 0, 26))
+
+	oninit?(vnode: Vnode<Attrs, State>): number;
+>oninit : Symbol(Lifecycle.oninit, Decl(subclassThisTypeAssignable.ts, 0, 35))
+>vnode : Symbol(vnode, Decl(subclassThisTypeAssignable.ts, 1, 9))
+>Vnode : Symbol(Vnode, Decl(subclassThisTypeAssignable.ts, 3, 1))
+>Attrs : Symbol(Attrs, Decl(subclassThisTypeAssignable.ts, 0, 20))
+>State : Symbol(State, Decl(subclassThisTypeAssignable.ts, 0, 26))
+
+	[_: number]: any;
+>_ : Symbol(_, Decl(subclassThisTypeAssignable.ts, 2, 2))
+}
+
+interface Vnode<Attrs, State extends Lifecycle<Attrs, State> = Lifecycle<Attrs, State>> {
+>Vnode : Symbol(Vnode, Decl(subclassThisTypeAssignable.ts, 3, 1))
+>Attrs : Symbol(Attrs, Decl(subclassThisTypeAssignable.ts, 5, 16))
+>State : Symbol(State, Decl(subclassThisTypeAssignable.ts, 5, 22))
+>Lifecycle : Symbol(Lifecycle, Decl(subclassThisTypeAssignable.ts, 0, 0))
+>Attrs : Symbol(Attrs, Decl(subclassThisTypeAssignable.ts, 5, 16))
+>State : Symbol(State, Decl(subclassThisTypeAssignable.ts, 5, 22))
+>Lifecycle : Symbol(Lifecycle, Decl(subclassThisTypeAssignable.ts, 0, 0))
+>Attrs : Symbol(Attrs, Decl(subclassThisTypeAssignable.ts, 5, 16))
+>State : Symbol(State, Decl(subclassThisTypeAssignable.ts, 5, 22))
+
+	tag: Component<Attrs, State>;
+>tag : Symbol(Vnode.tag, Decl(subclassThisTypeAssignable.ts, 5, 89))
+>Component : Symbol(Component, Decl(subclassThisTypeAssignable.ts, 7, 1))
+>Attrs : Symbol(Attrs, Decl(subclassThisTypeAssignable.ts, 5, 16))
+>State : Symbol(State, Decl(subclassThisTypeAssignable.ts, 5, 22))
+}
+
+interface Component<Attrs, State> {
+>Component : Symbol(Component, Decl(subclassThisTypeAssignable.ts, 7, 1))
+>Attrs : Symbol(Attrs, Decl(subclassThisTypeAssignable.ts, 9, 20))
+>State : Symbol(State, Decl(subclassThisTypeAssignable.ts, 9, 26))
+
+	view(this: State, vnode: Vnode<Attrs, State>): number;
+>view : Symbol(Component.view, Decl(subclassThisTypeAssignable.ts, 9, 35))
+>this : Symbol(this, Decl(subclassThisTypeAssignable.ts, 10, 6))
+>State : Symbol(State, Decl(subclassThisTypeAssignable.ts, 9, 26))
+>vnode : Symbol(vnode, Decl(subclassThisTypeAssignable.ts, 10, 18))
+>Vnode : Symbol(Vnode, Decl(subclassThisTypeAssignable.ts, 3, 1))
+>Attrs : Symbol(Attrs, Decl(subclassThisTypeAssignable.ts, 9, 20))
+>State : Symbol(State, Decl(subclassThisTypeAssignable.ts, 9, 26))
+}
+
+interface ClassComponent<A> extends Lifecycle<A, ClassComponent<A>> {
+>ClassComponent : Symbol(ClassComponent, Decl(subclassThisTypeAssignable.ts, 11, 1))
+>A : Symbol(A, Decl(subclassThisTypeAssignable.ts, 13, 25))
+>Lifecycle : Symbol(Lifecycle, Decl(subclassThisTypeAssignable.ts, 0, 0))
+>A : Symbol(A, Decl(subclassThisTypeAssignable.ts, 13, 25))
+>ClassComponent : Symbol(ClassComponent, Decl(subclassThisTypeAssignable.ts, 11, 1))
+>A : Symbol(A, Decl(subclassThisTypeAssignable.ts, 13, 25))
+
+	oninit?(vnode: Vnode<A, this>): number;
+>oninit : Symbol(ClassComponent.oninit, Decl(subclassThisTypeAssignable.ts, 13, 69))
+>vnode : Symbol(vnode, Decl(subclassThisTypeAssignable.ts, 14, 9))
+>Vnode : Symbol(Vnode, Decl(subclassThisTypeAssignable.ts, 3, 1))
+>A : Symbol(A, Decl(subclassThisTypeAssignable.ts, 13, 25))
+
+	view(vnode: Vnode<A, this>): number;
+>view : Symbol(ClassComponent.view, Decl(subclassThisTypeAssignable.ts, 14, 40))
+>vnode : Symbol(vnode, Decl(subclassThisTypeAssignable.ts, 15, 6))
+>Vnode : Symbol(Vnode, Decl(subclassThisTypeAssignable.ts, 3, 1))
+>A : Symbol(A, Decl(subclassThisTypeAssignable.ts, 13, 25))
+}
+
+interface MyAttrs { id: number }
+>MyAttrs : Symbol(MyAttrs, Decl(subclassThisTypeAssignable.ts, 16, 1))
+>id : Symbol(MyAttrs.id, Decl(subclassThisTypeAssignable.ts, 18, 19))
+
+class C implements ClassComponent<MyAttrs> {
+>C : Symbol(C, Decl(subclassThisTypeAssignable.ts, 18, 32))
+>ClassComponent : Symbol(ClassComponent, Decl(subclassThisTypeAssignable.ts, 11, 1))
+>MyAttrs : Symbol(MyAttrs, Decl(subclassThisTypeAssignable.ts, 16, 1))
+
+	view(v: Vnode<MyAttrs>) { return 0; }
+>view : Symbol(C.view, Decl(subclassThisTypeAssignable.ts, 19, 44))
+>v : Symbol(v, Decl(subclassThisTypeAssignable.ts, 20, 6))
+>Vnode : Symbol(Vnode, Decl(subclassThisTypeAssignable.ts, 3, 1))
+>MyAttrs : Symbol(MyAttrs, Decl(subclassThisTypeAssignable.ts, 16, 1))
+}
+
+const test8: ClassComponent<any> = new C();
+>test8 : Symbol(test8, Decl(subclassThisTypeAssignable.ts, 23, 5))
+>ClassComponent : Symbol(ClassComponent, Decl(subclassThisTypeAssignable.ts, 11, 1))
+>C : Symbol(C, Decl(subclassThisTypeAssignable.ts, 18, 32))
+
diff --git a/tests/baselines/reference/subclassThisTypeAssignable.types b/tests/baselines/reference/subclassThisTypeAssignable.types
new file mode 100644
index 0000000000000..2a375f0b9a112
--- /dev/null
+++ b/tests/baselines/reference/subclassThisTypeAssignable.types
@@ -0,0 +1,49 @@
+=== tests/cases/compiler/subclassThisTypeAssignable.ts ===
+interface Lifecycle<Attrs, State> {
+	oninit?(vnode: Vnode<Attrs, State>): number;
+>oninit : (vnode: Vnode<Attrs, State>) => number
+>vnode : Vnode<Attrs, State>
+
+	[_: number]: any;
+>_ : number
+}
+
+interface Vnode<Attrs, State extends Lifecycle<Attrs, State> = Lifecycle<Attrs, State>> {
+	tag: Component<Attrs, State>;
+>tag : Component<Attrs, State>
+}
+
+interface Component<Attrs, State> {
+	view(this: State, vnode: Vnode<Attrs, State>): number;
+>view : (this: State, vnode: Vnode<Attrs, State>) => number
+>this : State
+>vnode : Vnode<Attrs, State>
+}
+
+interface ClassComponent<A> extends Lifecycle<A, ClassComponent<A>> {
+	oninit?(vnode: Vnode<A, this>): number;
+>oninit : (vnode: Vnode<A, this>) => number
+>vnode : Vnode<A, this>
+
+	view(vnode: Vnode<A, this>): number;
+>view : (vnode: Vnode<A, this>) => number
+>vnode : Vnode<A, this>
+}
+
+interface MyAttrs { id: number }
+>id : number
+
+class C implements ClassComponent<MyAttrs> {
+>C : C
+
+	view(v: Vnode<MyAttrs>) { return 0; }
+>view : (v: Vnode<MyAttrs, Lifecycle<MyAttrs, Lifecycle<{}, {}>>>) => number
+>v : Vnode<MyAttrs, Lifecycle<MyAttrs, Lifecycle<{}, {}>>>
+>0 : 0
+}
+
+const test8: ClassComponent<any> = new C();
+>test8 : ClassComponent<any>
+>new C() : C
+>C : typeof C
+
diff --git a/tests/cases/compiler/subclassThisTypeAssignable.ts b/tests/cases/compiler/subclassThisTypeAssignable.ts
new file mode 100644
index 0000000000000..bdaa0e6c4a2c0
--- /dev/null
+++ b/tests/cases/compiler/subclassThisTypeAssignable.ts
@@ -0,0 +1,24 @@
+interface Lifecycle<Attrs, State> {
+	oninit?(vnode: Vnode<Attrs, State>): number;
+	[_: number]: any;
+}
+
+interface Vnode<Attrs, State extends Lifecycle<Attrs, State> = Lifecycle<Attrs, State>> {
+	tag: Component<Attrs, State>;
+}
+
+interface Component<Attrs, State> {
+	view(this: State, vnode: Vnode<Attrs, State>): number;
+}
+
+interface ClassComponent<A> extends Lifecycle<A, ClassComponent<A>> {
+	oninit?(vnode: Vnode<A, this>): number;
+	view(vnode: Vnode<A, this>): number;
+}
+
+interface MyAttrs { id: number }
+class C implements ClassComponent<MyAttrs> {
+	view(v: Vnode<MyAttrs>) { return 0; }
+}
+
+const test8: ClassComponent<any> = new C();
\ No newline at end of file

From ac6c89fde6e8dc395eafdffaca0b9294f296e0e4 Mon Sep 17 00:00:00 2001
From: Wesley Wigham <wewigham@microsoft.com>
Date: Fri, 9 Nov 2018 15:12:04 -0800
Subject: [PATCH 2/2] Add js example, fix typo

---
 src/compiler/checker.ts                       |   4 +-
 .../reference/subclassThisTypeAssignable.js   |  13 +-
 .../subclassThisTypeAssignable.symbols        | 124 +++++++++---------
 .../subclassThisTypeAssignable.types          |   9 +-
 .../compiler/subclassThisTypeAssignable.ts    |   9 +-
 5 files changed, 94 insertions(+), 65 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 7cb4c60b399a1..f831a157483c6 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -7664,9 +7664,9 @@ namespace ts {
                 // If a type parameter does not have a default type, or if the default type
                 // is a forward reference, the empty object type is used.
                 const baseDefaultType = getDefaultTypeArgumentType(isJavaScriptImplicitAny);
-                const cicrularityMapper = createTypeMapper(typeParameters!, map(typeParameters!, () => baseDefaultType));
+                const circularityMapper = createTypeMapper(typeParameters!, map(typeParameters!, () => baseDefaultType));
                 for (let i = numTypeArguments; i < numTypeParameters; i++) {
-                    result[i] = instantiateType(getConstraintFromTypeParameter(typeParameters![i]) || baseDefaultType, cicrularityMapper);
+                    result[i] = instantiateType(getConstraintFromTypeParameter(typeParameters![i]) || baseDefaultType, circularityMapper);
                 }
                 for (let i = numTypeArguments; i < numTypeParameters; i++) {
                     const mapper = createTypeMapper(typeParameters!, result);
diff --git a/tests/baselines/reference/subclassThisTypeAssignable.js b/tests/baselines/reference/subclassThisTypeAssignable.js
index e374b56e10b4f..b82e4462a0514 100644
--- a/tests/baselines/reference/subclassThisTypeAssignable.js
+++ b/tests/baselines/reference/subclassThisTypeAssignable.js
@@ -1,4 +1,6 @@
-//// [subclassThisTypeAssignable.ts]
+//// [tests/cases/compiler/subclassThisTypeAssignable.ts] ////
+
+//// [tile1.ts]
 interface Lifecycle<Attrs, State> {
 	oninit?(vnode: Vnode<Attrs, State>): number;
 	[_: number]: any;
@@ -23,8 +25,12 @@ class C implements ClassComponent<MyAttrs> {
 }
 
 const test8: ClassComponent<any> = new C();
+//// [file1.js]
+/** @type {ClassComponent<any>} */
+const test9 = new C();
+
 
-//// [subclassThisTypeAssignable.js]
+//// [tile1.js]
 var C = /** @class */ (function () {
     function C() {
     }
@@ -32,3 +38,6 @@ var C = /** @class */ (function () {
     return C;
 }());
 var test8 = new C();
+//// [file1.js]
+/** @type {ClassComponent<any>} */
+var test9 = new C();
diff --git a/tests/baselines/reference/subclassThisTypeAssignable.symbols b/tests/baselines/reference/subclassThisTypeAssignable.symbols
index e6fe66cf3d30b..8cfc25b28a66c 100644
--- a/tests/baselines/reference/subclassThisTypeAssignable.symbols
+++ b/tests/baselines/reference/subclassThisTypeAssignable.symbols
@@ -1,92 +1,98 @@
-=== tests/cases/compiler/subclassThisTypeAssignable.ts ===
+=== tests/cases/compiler/tile1.ts ===
 interface Lifecycle<Attrs, State> {
->Lifecycle : Symbol(Lifecycle, Decl(subclassThisTypeAssignable.ts, 0, 0))
->Attrs : Symbol(Attrs, Decl(subclassThisTypeAssignable.ts, 0, 20))
->State : Symbol(State, Decl(subclassThisTypeAssignable.ts, 0, 26))
+>Lifecycle : Symbol(Lifecycle, Decl(tile1.ts, 0, 0))
+>Attrs : Symbol(Attrs, Decl(tile1.ts, 0, 20))
+>State : Symbol(State, Decl(tile1.ts, 0, 26))
 
 	oninit?(vnode: Vnode<Attrs, State>): number;
->oninit : Symbol(Lifecycle.oninit, Decl(subclassThisTypeAssignable.ts, 0, 35))
->vnode : Symbol(vnode, Decl(subclassThisTypeAssignable.ts, 1, 9))
->Vnode : Symbol(Vnode, Decl(subclassThisTypeAssignable.ts, 3, 1))
->Attrs : Symbol(Attrs, Decl(subclassThisTypeAssignable.ts, 0, 20))
->State : Symbol(State, Decl(subclassThisTypeAssignable.ts, 0, 26))
+>oninit : Symbol(Lifecycle.oninit, Decl(tile1.ts, 0, 35))
+>vnode : Symbol(vnode, Decl(tile1.ts, 1, 9))
+>Vnode : Symbol(Vnode, Decl(tile1.ts, 3, 1))
+>Attrs : Symbol(Attrs, Decl(tile1.ts, 0, 20))
+>State : Symbol(State, Decl(tile1.ts, 0, 26))
 
 	[_: number]: any;
->_ : Symbol(_, Decl(subclassThisTypeAssignable.ts, 2, 2))
+>_ : Symbol(_, Decl(tile1.ts, 2, 2))
 }
 
 interface Vnode<Attrs, State extends Lifecycle<Attrs, State> = Lifecycle<Attrs, State>> {
->Vnode : Symbol(Vnode, Decl(subclassThisTypeAssignable.ts, 3, 1))
->Attrs : Symbol(Attrs, Decl(subclassThisTypeAssignable.ts, 5, 16))
->State : Symbol(State, Decl(subclassThisTypeAssignable.ts, 5, 22))
->Lifecycle : Symbol(Lifecycle, Decl(subclassThisTypeAssignable.ts, 0, 0))
->Attrs : Symbol(Attrs, Decl(subclassThisTypeAssignable.ts, 5, 16))
->State : Symbol(State, Decl(subclassThisTypeAssignable.ts, 5, 22))
->Lifecycle : Symbol(Lifecycle, Decl(subclassThisTypeAssignable.ts, 0, 0))
->Attrs : Symbol(Attrs, Decl(subclassThisTypeAssignable.ts, 5, 16))
->State : Symbol(State, Decl(subclassThisTypeAssignable.ts, 5, 22))
+>Vnode : Symbol(Vnode, Decl(tile1.ts, 3, 1))
+>Attrs : Symbol(Attrs, Decl(tile1.ts, 5, 16))
+>State : Symbol(State, Decl(tile1.ts, 5, 22))
+>Lifecycle : Symbol(Lifecycle, Decl(tile1.ts, 0, 0))
+>Attrs : Symbol(Attrs, Decl(tile1.ts, 5, 16))
+>State : Symbol(State, Decl(tile1.ts, 5, 22))
+>Lifecycle : Symbol(Lifecycle, Decl(tile1.ts, 0, 0))
+>Attrs : Symbol(Attrs, Decl(tile1.ts, 5, 16))
+>State : Symbol(State, Decl(tile1.ts, 5, 22))
 
 	tag: Component<Attrs, State>;
->tag : Symbol(Vnode.tag, Decl(subclassThisTypeAssignable.ts, 5, 89))
->Component : Symbol(Component, Decl(subclassThisTypeAssignable.ts, 7, 1))
->Attrs : Symbol(Attrs, Decl(subclassThisTypeAssignable.ts, 5, 16))
->State : Symbol(State, Decl(subclassThisTypeAssignable.ts, 5, 22))
+>tag : Symbol(Vnode.tag, Decl(tile1.ts, 5, 89))
+>Component : Symbol(Component, Decl(tile1.ts, 7, 1))
+>Attrs : Symbol(Attrs, Decl(tile1.ts, 5, 16))
+>State : Symbol(State, Decl(tile1.ts, 5, 22))
 }
 
 interface Component<Attrs, State> {
->Component : Symbol(Component, Decl(subclassThisTypeAssignable.ts, 7, 1))
->Attrs : Symbol(Attrs, Decl(subclassThisTypeAssignable.ts, 9, 20))
->State : Symbol(State, Decl(subclassThisTypeAssignable.ts, 9, 26))
+>Component : Symbol(Component, Decl(tile1.ts, 7, 1))
+>Attrs : Symbol(Attrs, Decl(tile1.ts, 9, 20))
+>State : Symbol(State, Decl(tile1.ts, 9, 26))
 
 	view(this: State, vnode: Vnode<Attrs, State>): number;
->view : Symbol(Component.view, Decl(subclassThisTypeAssignable.ts, 9, 35))
->this : Symbol(this, Decl(subclassThisTypeAssignable.ts, 10, 6))
->State : Symbol(State, Decl(subclassThisTypeAssignable.ts, 9, 26))
->vnode : Symbol(vnode, Decl(subclassThisTypeAssignable.ts, 10, 18))
->Vnode : Symbol(Vnode, Decl(subclassThisTypeAssignable.ts, 3, 1))
->Attrs : Symbol(Attrs, Decl(subclassThisTypeAssignable.ts, 9, 20))
->State : Symbol(State, Decl(subclassThisTypeAssignable.ts, 9, 26))
+>view : Symbol(Component.view, Decl(tile1.ts, 9, 35))
+>this : Symbol(this, Decl(tile1.ts, 10, 6))
+>State : Symbol(State, Decl(tile1.ts, 9, 26))
+>vnode : Symbol(vnode, Decl(tile1.ts, 10, 18))
+>Vnode : Symbol(Vnode, Decl(tile1.ts, 3, 1))
+>Attrs : Symbol(Attrs, Decl(tile1.ts, 9, 20))
+>State : Symbol(State, Decl(tile1.ts, 9, 26))
 }
 
 interface ClassComponent<A> extends Lifecycle<A, ClassComponent<A>> {
->ClassComponent : Symbol(ClassComponent, Decl(subclassThisTypeAssignable.ts, 11, 1))
->A : Symbol(A, Decl(subclassThisTypeAssignable.ts, 13, 25))
->Lifecycle : Symbol(Lifecycle, Decl(subclassThisTypeAssignable.ts, 0, 0))
->A : Symbol(A, Decl(subclassThisTypeAssignable.ts, 13, 25))
->ClassComponent : Symbol(ClassComponent, Decl(subclassThisTypeAssignable.ts, 11, 1))
->A : Symbol(A, Decl(subclassThisTypeAssignable.ts, 13, 25))
+>ClassComponent : Symbol(ClassComponent, Decl(tile1.ts, 11, 1))
+>A : Symbol(A, Decl(tile1.ts, 13, 25))
+>Lifecycle : Symbol(Lifecycle, Decl(tile1.ts, 0, 0))
+>A : Symbol(A, Decl(tile1.ts, 13, 25))
+>ClassComponent : Symbol(ClassComponent, Decl(tile1.ts, 11, 1))
+>A : Symbol(A, Decl(tile1.ts, 13, 25))
 
 	oninit?(vnode: Vnode<A, this>): number;
->oninit : Symbol(ClassComponent.oninit, Decl(subclassThisTypeAssignable.ts, 13, 69))
->vnode : Symbol(vnode, Decl(subclassThisTypeAssignable.ts, 14, 9))
->Vnode : Symbol(Vnode, Decl(subclassThisTypeAssignable.ts, 3, 1))
->A : Symbol(A, Decl(subclassThisTypeAssignable.ts, 13, 25))
+>oninit : Symbol(ClassComponent.oninit, Decl(tile1.ts, 13, 69))
+>vnode : Symbol(vnode, Decl(tile1.ts, 14, 9))
+>Vnode : Symbol(Vnode, Decl(tile1.ts, 3, 1))
+>A : Symbol(A, Decl(tile1.ts, 13, 25))
 
 	view(vnode: Vnode<A, this>): number;
->view : Symbol(ClassComponent.view, Decl(subclassThisTypeAssignable.ts, 14, 40))
->vnode : Symbol(vnode, Decl(subclassThisTypeAssignable.ts, 15, 6))
->Vnode : Symbol(Vnode, Decl(subclassThisTypeAssignable.ts, 3, 1))
->A : Symbol(A, Decl(subclassThisTypeAssignable.ts, 13, 25))
+>view : Symbol(ClassComponent.view, Decl(tile1.ts, 14, 40))
+>vnode : Symbol(vnode, Decl(tile1.ts, 15, 6))
+>Vnode : Symbol(Vnode, Decl(tile1.ts, 3, 1))
+>A : Symbol(A, Decl(tile1.ts, 13, 25))
 }
 
 interface MyAttrs { id: number }
->MyAttrs : Symbol(MyAttrs, Decl(subclassThisTypeAssignable.ts, 16, 1))
->id : Symbol(MyAttrs.id, Decl(subclassThisTypeAssignable.ts, 18, 19))
+>MyAttrs : Symbol(MyAttrs, Decl(tile1.ts, 16, 1))
+>id : Symbol(MyAttrs.id, Decl(tile1.ts, 18, 19))
 
 class C implements ClassComponent<MyAttrs> {
->C : Symbol(C, Decl(subclassThisTypeAssignable.ts, 18, 32))
->ClassComponent : Symbol(ClassComponent, Decl(subclassThisTypeAssignable.ts, 11, 1))
->MyAttrs : Symbol(MyAttrs, Decl(subclassThisTypeAssignable.ts, 16, 1))
+>C : Symbol(C, Decl(tile1.ts, 18, 32))
+>ClassComponent : Symbol(ClassComponent, Decl(tile1.ts, 11, 1))
+>MyAttrs : Symbol(MyAttrs, Decl(tile1.ts, 16, 1))
 
 	view(v: Vnode<MyAttrs>) { return 0; }
->view : Symbol(C.view, Decl(subclassThisTypeAssignable.ts, 19, 44))
->v : Symbol(v, Decl(subclassThisTypeAssignable.ts, 20, 6))
->Vnode : Symbol(Vnode, Decl(subclassThisTypeAssignable.ts, 3, 1))
->MyAttrs : Symbol(MyAttrs, Decl(subclassThisTypeAssignable.ts, 16, 1))
+>view : Symbol(C.view, Decl(tile1.ts, 19, 44))
+>v : Symbol(v, Decl(tile1.ts, 20, 6))
+>Vnode : Symbol(Vnode, Decl(tile1.ts, 3, 1))
+>MyAttrs : Symbol(MyAttrs, Decl(tile1.ts, 16, 1))
 }
 
 const test8: ClassComponent<any> = new C();
->test8 : Symbol(test8, Decl(subclassThisTypeAssignable.ts, 23, 5))
->ClassComponent : Symbol(ClassComponent, Decl(subclassThisTypeAssignable.ts, 11, 1))
->C : Symbol(C, Decl(subclassThisTypeAssignable.ts, 18, 32))
+>test8 : Symbol(test8, Decl(tile1.ts, 23, 5))
+>ClassComponent : Symbol(ClassComponent, Decl(tile1.ts, 11, 1))
+>C : Symbol(C, Decl(tile1.ts, 18, 32))
+
+=== tests/cases/compiler/file1.js ===
+/** @type {ClassComponent<any>} */
+const test9 = new C();
+>test9 : Symbol(test9, Decl(file1.js, 1, 5))
+>C : Symbol(C, Decl(tile1.ts, 18, 32))
 
diff --git a/tests/baselines/reference/subclassThisTypeAssignable.types b/tests/baselines/reference/subclassThisTypeAssignable.types
index 2a375f0b9a112..711b0056277f8 100644
--- a/tests/baselines/reference/subclassThisTypeAssignable.types
+++ b/tests/baselines/reference/subclassThisTypeAssignable.types
@@ -1,4 +1,4 @@
-=== tests/cases/compiler/subclassThisTypeAssignable.ts ===
+=== tests/cases/compiler/tile1.ts ===
 interface Lifecycle<Attrs, State> {
 	oninit?(vnode: Vnode<Attrs, State>): number;
 >oninit : (vnode: Vnode<Attrs, State>) => number
@@ -47,3 +47,10 @@ const test8: ClassComponent<any> = new C();
 >new C() : C
 >C : typeof C
 
+=== tests/cases/compiler/file1.js ===
+/** @type {ClassComponent<any>} */
+const test9 = new C();
+>test9 : ClassComponent<any>
+>new C() : C
+>C : typeof C
+
diff --git a/tests/cases/compiler/subclassThisTypeAssignable.ts b/tests/cases/compiler/subclassThisTypeAssignable.ts
index bdaa0e6c4a2c0..a582fd0f4c30b 100644
--- a/tests/cases/compiler/subclassThisTypeAssignable.ts
+++ b/tests/cases/compiler/subclassThisTypeAssignable.ts
@@ -1,3 +1,7 @@
+// @allowJs: true
+// @checkJs: true
+// @outDir: ./out
+// @filename: tile1.ts
 interface Lifecycle<Attrs, State> {
 	oninit?(vnode: Vnode<Attrs, State>): number;
 	[_: number]: any;
@@ -21,4 +25,7 @@ class C implements ClassComponent<MyAttrs> {
 	view(v: Vnode<MyAttrs>) { return 0; }
 }
 
-const test8: ClassComponent<any> = new C();
\ No newline at end of file
+const test8: ClassComponent<any> = new C();
+// @filename: file1.js
+/** @type {ClassComponent<any>} */
+const test9 = new C();