diff --git a/src/harness/fourslashInterfaceImpl.ts b/src/harness/fourslashInterfaceImpl.ts
index f3eb069e6f647..b525a55f755ac 100644
--- a/src/harness/fourslashInterfaceImpl.ts
+++ b/src/harness/fourslashInterfaceImpl.ts
@@ -1192,6 +1192,7 @@ export namespace Completion {
         typeEntry("Partial"),
         typeEntry("Required"),
         typeEntry("Readonly"),
+        typeEntry("Writable"),
         typeEntry("Pick"),
         typeEntry("Record"),
         typeEntry("Exclude"),
diff --git a/src/lib/es2015.core.d.ts b/src/lib/es2015.core.d.ts
index 3b1c76c5afc3c..e8eb13c33f935 100644
--- a/src/lib/es2015.core.d.ts
+++ b/src/lib/es2015.core.d.ts
@@ -257,13 +257,20 @@ interface NumberConstructor {
 }
 
 interface ObjectConstructor {
+    /**
+     * Copy the values of all of the enumerable own properties from one or more source objects to a
+     * target object. Returns the target object.
+     * @param target The target object to copy to.
+     */
+    assign<T extends {}>(target: T): T;
+
     /**
      * Copy the values of all of the enumerable own properties from one or more source objects to a
      * target object. Returns the target object.
      * @param target The target object to copy to.
      * @param source The source object from which to copy properties.
      */
-    assign<T extends {}, U>(target: T, source: U): T & U;
+    assign<T extends {}, U>(target: T, source: U): T & Writable<U>;
 
     /**
      * Copy the values of all of the enumerable own properties from one or more source objects to a
@@ -272,7 +279,7 @@ interface ObjectConstructor {
      * @param source1 The first source object from which to copy properties.
      * @param source2 The second source object from which to copy properties.
      */
-    assign<T extends {}, U, V>(target: T, source1: U, source2: V): T & U & V;
+    assign<T extends {}, U, V>(target: T, source1: U, source2: V): T & Writable<U> & Writable<V>;
 
     /**
      * Copy the values of all of the enumerable own properties from one or more source objects to a
@@ -282,21 +289,21 @@ interface ObjectConstructor {
      * @param source2 The second source object from which to copy properties.
      * @param source3 The third source object from which to copy properties.
      */
-    assign<T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & U & V & W;
+    assign<T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & Writable<U> & Writable<V> & Writable<W>;
 
     /**
      * Copy the values of all of the enumerable own properties from one or more source objects to a
      * target object. Returns the target object.
      * @param target The target object to copy to.
-     * @param sources One or more source objects from which to copy properties
+     * @param sources One or more source objects from which to copy properties.
      */
-    assign(target: object, ...sources: any[]): any;
+    assign(target: {}, ...sources: any[]): any;
 
     /**
      * Returns an array of all symbol properties found directly on object o.
      * @param o Object to retrieve the symbols from.
      */
-    getOwnPropertySymbols(o: any): symbol[];
+    getOwnPropertySymbols(o: {}): symbol[];
 
     /**
      * Returns the names of the enumerable string properties and methods of an object.
@@ -316,7 +323,7 @@ interface ObjectConstructor {
      * @param o The object to change its prototype.
      * @param proto The value of the new prototype or null.
      */
-    setPrototypeOf(o: any, proto: object | null): any;
+    setPrototypeOf(o: {}, proto: object | null): any;
 }
 
 interface ReadonlyArray<T> {
diff --git a/src/lib/es2017.object.d.ts b/src/lib/es2017.object.d.ts
index b3ace85bef182..3e5dcc95629fe 100644
--- a/src/lib/es2017.object.d.ts
+++ b/src/lib/es2017.object.d.ts
@@ -27,5 +27,5 @@ interface ObjectConstructor {
      * Returns an object containing all own property descriptors of an object
      * @param o Object that contains the properties and methods. This can be an object that you created or an existing Document Object Model (DOM) object.
      */
-    getOwnPropertyDescriptors<T>(o: T): {[P in keyof T]: TypedPropertyDescriptor<T[P]>} & { [x: string]: PropertyDescriptor };
+    getOwnPropertyDescriptors<T extends {}>(o: T): { [P in keyof T]: TypedPropertyDescriptor<T[P]> } & PropertyDescriptorMap;
 }
diff --git a/src/lib/es2019.object.d.ts b/src/lib/es2019.object.d.ts
index e3518b7b9d689..7efcb4b861f13 100644
--- a/src/lib/es2019.object.d.ts
+++ b/src/lib/es2019.object.d.ts
@@ -5,7 +5,7 @@ interface ObjectConstructor {
      * Returns an object created by key-value entries for properties and methods
      * @param entries An iterable object that contains key-value entries for properties and methods.
      */
-    fromEntries<T = any>(entries: Iterable<readonly [PropertyKey, T]>): { [k: string]: T };
+    fromEntries<T = any>(entries: Iterable<readonly [PropertyKey, T]>): { [k: PropertyKey]: T };
 
     /**
      * Returns an object created by key-value entries for properties and methods
diff --git a/src/lib/es2022.object.d.ts b/src/lib/es2022.object.d.ts
index 7325ef3c343e2..0a07706ba941c 100644
--- a/src/lib/es2022.object.d.ts
+++ b/src/lib/es2022.object.d.ts
@@ -4,5 +4,5 @@ interface ObjectConstructor {
      * @param o An object.
      * @param v A property name.
      */
-    hasOwn(o: object, v: PropertyKey): boolean;
+    hasOwn(o: {}, v: PropertyKey): boolean;
 }
diff --git a/src/lib/es5.d.ts b/src/lib/es5.d.ts
index a74b3cb4c2111..3d7959392fad1 100644
--- a/src/lib/es5.d.ts
+++ b/src/lib/es5.d.ts
@@ -146,7 +146,7 @@ interface ObjectConstructor {
      * Returns the prototype of an object.
      * @param o The object that references the prototype.
      */
-    getPrototypeOf(o: any): any;
+    getPrototypeOf(o: {}): any;
 
     /**
      * Gets the own property descriptor of the specified object.
@@ -154,14 +154,14 @@ interface ObjectConstructor {
      * @param o Object that contains the property.
      * @param p Name of the property.
      */
-    getOwnPropertyDescriptor(o: any, p: PropertyKey): PropertyDescriptor | undefined;
+    getOwnPropertyDescriptor(o: {}, p: PropertyKey): PropertyDescriptor | undefined;
 
     /**
      * Returns the names of the own properties of an object. The own properties of an object are those that are defined directly
      * on that object, and are not inherited from the object's prototype. The properties of an object include both fields (objects) and functions.
      * @param o Object that contains the own properties.
      */
-    getOwnPropertyNames(o: any): string[];
+    getOwnPropertyNames(o: {}): string[];
 
     /**
      * Creates an object that has the specified prototype or that has null prototype.
@@ -182,14 +182,14 @@ interface ObjectConstructor {
      * @param p The property name.
      * @param attributes Descriptor for the property. It can be for a data property or an accessor property.
      */
-    defineProperty<T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>): T;
+    defineProperty<T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>): T;
 
     /**
      * Adds one or more properties to an object, and/or modifies attributes of existing properties.
      * @param o Object on which to add or modify the properties. This can be a native JavaScript object or a DOM object.
      * @param properties JavaScript object that contains one or more descriptor objects. Each descriptor object describes a data property or an accessor property.
      */
-    defineProperties<T>(o: T, properties: PropertyDescriptorMap & ThisType<any>): T;
+    defineProperties<T extends object>(o: T, properties: PropertyDescriptorMap & ThisType<any>): T;
 
     /**
      * Prevents the modification of attributes of existing properties, and prevents the addition of new properties.
@@ -207,7 +207,7 @@ interface ObjectConstructor {
      * Prevents the modification of existing property attributes and values, and prevents the addition of new properties.
      * @param o Object on which to lock the attributes.
      */
-    freeze<T extends {[idx: string]: U | null | undefined | object}, U extends string | bigint | number | boolean | symbol>(o: T): Readonly<T>;
+    freeze<T extends { [idx: string]: U | null | undefined | object }, U extends string | bigint | number | boolean | symbol>(o: T): Readonly<T>;
 
     /**
      * Prevents the modification of existing property attributes and values, and prevents the addition of new properties.
@@ -225,19 +225,37 @@ interface ObjectConstructor {
      * Returns true if existing property attributes cannot be modified in an object and new properties cannot be added to the object.
      * @param o Object to test.
      */
-    isSealed(o: any): boolean;
+    isSealed(o: object): boolean;
+
+    /**
+     * Returns true if existing property attributes cannot be modified in an object and new properties cannot be added to the object.
+     * @param o Object to test.
+     */
+    isSealed(o: any): true;
+
+    /**
+     * Returns true if existing property attributes and values cannot be modified in an object, and new properties cannot be added to the object.
+     * @param o Object to test.
+     */
+    isFrozen(o: object): boolean;
 
     /**
      * Returns true if existing property attributes and values cannot be modified in an object, and new properties cannot be added to the object.
      * @param o Object to test.
      */
-    isFrozen(o: any): boolean;
+    isFrozen(o: any): true;
 
     /**
      * Returns a value that indicates whether new properties can be added to an object.
      * @param o Object to test.
      */
-    isExtensible(o: any): boolean;
+    isExtensible(o: object): boolean;
+
+    /**
+     * Returns a value that indicates whether new properties can be added to an object.
+     * @param o Object to test.
+     */
+    isExtensible(o: any): false;
 
     /**
      * Returns the names of the enumerable string properties and methods of an object.
@@ -1555,6 +1573,13 @@ type Readonly<T> = {
     readonly [P in keyof T]: T[P];
 };
 
+/**
+ * Make all properties in T writable
+ */
+type Writable<T> = {
+    -readonly [P in keyof T]: T[P];
+};
+
 /**
  * From T, pick a set of properties whose keys are in the union K
  */
diff --git a/src/testRunner/parallel/worker.ts b/src/testRunner/parallel/worker.ts
index 05c1038488291..b333556164974 100644
--- a/src/testRunner/parallel/worker.ts
+++ b/src/testRunner/parallel/worker.ts
@@ -196,7 +196,7 @@ export function start() {
             newSuite.addTest(test);
             root.addSuite(newSuite);
             Object.setPrototypeOf(newSuite.ctx, root.ctx);
-            Object.setPrototypeOf(test.ctx, root.ctx);
+            Object.setPrototypeOf(test.ctx!, root.ctx);
             test.parent = newSuite;
             suite = newSuite;
         }
diff --git a/tests/baselines/reference/checkExportsObjectAssignProperty.types b/tests/baselines/reference/checkExportsObjectAssignProperty.types
index 60fcd84477a12..77277f90ce369 100644
--- a/tests/baselines/reference/checkExportsObjectAssignProperty.types
+++ b/tests/baselines/reference/checkExportsObjectAssignProperty.types
@@ -176,9 +176,9 @@ m2.setonlyAccessor = 0;
 === tests/cases/conformance/jsdoc/mod1.js ===
 Object.defineProperty(exports, "thing", { value: 42, writable: true });
 >Object.defineProperty(exports, "thing", { value: 42, writable: true }) : typeof import("tests/cases/conformance/jsdoc/mod1")
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >exports : typeof import("tests/cases/conformance/jsdoc/mod1")
 >"thing" : "thing"
 >{ value: 42, writable: true } : { value: number; writable: true; }
@@ -189,9 +189,9 @@ Object.defineProperty(exports, "thing", { value: 42, writable: true });
 
 Object.defineProperty(exports, "readonlyProp", { value: "Smith", writable: false });
 >Object.defineProperty(exports, "readonlyProp", { value: "Smith", writable: false }) : typeof import("tests/cases/conformance/jsdoc/mod1")
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >exports : typeof import("tests/cases/conformance/jsdoc/mod1")
 >"readonlyProp" : "readonlyProp"
 >{ value: "Smith", writable: false } : { value: string; writable: false; }
@@ -202,9 +202,9 @@ Object.defineProperty(exports, "readonlyProp", { value: "Smith", writable: false
 
 Object.defineProperty(exports, "rwAccessors", { get() { return 98122 }, set(_) { /*ignore*/ } });
 >Object.defineProperty(exports, "rwAccessors", { get() { return 98122 }, set(_) { /*ignore*/ } }) : typeof import("tests/cases/conformance/jsdoc/mod1")
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >exports : typeof import("tests/cases/conformance/jsdoc/mod1")
 >"rwAccessors" : "rwAccessors"
 >{ get() { return 98122 }, set(_) { /*ignore*/ } } : { get(): number; set(_: any): void; }
@@ -215,9 +215,9 @@ Object.defineProperty(exports, "rwAccessors", { get() { return 98122 }, set(_) {
 
 Object.defineProperty(exports, "readonlyAccessor", { get() { return 21.75 } });
 >Object.defineProperty(exports, "readonlyAccessor", { get() { return 21.75 } }) : typeof import("tests/cases/conformance/jsdoc/mod1")
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >exports : typeof import("tests/cases/conformance/jsdoc/mod1")
 >"readonlyAccessor" : "readonlyAccessor"
 >{ get() { return 21.75 } } : { get(): number; }
@@ -226,9 +226,9 @@ Object.defineProperty(exports, "readonlyAccessor", { get() { return 21.75 } });
 
 Object.defineProperty(exports, "setonlyAccessor", {
 >Object.defineProperty(exports, "setonlyAccessor", {    /** @param {string} str */    set(str) {        this.rwAccessors = Number(str)     }}) : typeof import("tests/cases/conformance/jsdoc/mod1")
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >exports : typeof import("tests/cases/conformance/jsdoc/mod1")
 >"setonlyAccessor" : "setonlyAccessor"
 >{    /** @param {string} str */    set(str) {        this.rwAccessors = Number(str)     }} : { set(str: string): void; }
@@ -252,9 +252,9 @@ Object.defineProperty(exports, "setonlyAccessor", {
 === tests/cases/conformance/jsdoc/mod2.js ===
 Object.defineProperty(module.exports, "thing", { value: "yes", writable: true });
 >Object.defineProperty(module.exports, "thing", { value: "yes", writable: true }) : typeof module.exports
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >module.exports : typeof module.exports
 >module : { exports: typeof module.exports; }
 >exports : typeof module.exports
@@ -267,9 +267,9 @@ Object.defineProperty(module.exports, "thing", { value: "yes", writable: true })
 
 Object.defineProperty(module.exports, "readonlyProp", { value: "Smith", writable: false });
 >Object.defineProperty(module.exports, "readonlyProp", { value: "Smith", writable: false }) : typeof module.exports
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >module.exports : typeof module.exports
 >module : { exports: typeof module.exports; }
 >exports : typeof module.exports
@@ -282,9 +282,9 @@ Object.defineProperty(module.exports, "readonlyProp", { value: "Smith", writable
 
 Object.defineProperty(module.exports, "rwAccessors", { get() { return 98122 }, set(_) { /*ignore*/ } });
 >Object.defineProperty(module.exports, "rwAccessors", { get() { return 98122 }, set(_) { /*ignore*/ } }) : typeof module.exports
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >module.exports : typeof module.exports
 >module : { exports: typeof module.exports; }
 >exports : typeof module.exports
@@ -297,9 +297,9 @@ Object.defineProperty(module.exports, "rwAccessors", { get() { return 98122 }, s
 
 Object.defineProperty(module.exports, "readonlyAccessor", { get() { return 21.75 } });
 >Object.defineProperty(module.exports, "readonlyAccessor", { get() { return 21.75 } }) : typeof module.exports
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >module.exports : typeof module.exports
 >module : { exports: typeof module.exports; }
 >exports : typeof module.exports
@@ -310,9 +310,9 @@ Object.defineProperty(module.exports, "readonlyAccessor", { get() { return 21.75
 
 Object.defineProperty(module.exports, "setonlyAccessor", {
 >Object.defineProperty(module.exports, "setonlyAccessor", {    /** @param {string} str */    set(str) {        this.rwAccessors = Number(str)     }}) : typeof module.exports
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >module.exports : typeof module.exports
 >module : { exports: typeof module.exports; }
 >exports : typeof module.exports
diff --git a/tests/baselines/reference/checkExportsObjectAssignPrototypeProperty.types b/tests/baselines/reference/checkExportsObjectAssignPrototypeProperty.types
index 6ea6a5ff129b8..1a24db4e9ec46 100644
--- a/tests/baselines/reference/checkExportsObjectAssignPrototypeProperty.types
+++ b/tests/baselines/reference/checkExportsObjectAssignPrototypeProperty.types
@@ -129,9 +129,9 @@ Person.prototype.describe = function () {
 };
 Object.defineProperty(Person.prototype, "thing", { value: 42, writable: true });
 >Object.defineProperty(Person.prototype, "thing", { value: 42, writable: true }) : any
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Person.prototype : any
 >Person : typeof Person
 >prototype : any
@@ -144,9 +144,9 @@ Object.defineProperty(Person.prototype, "thing", { value: 42, writable: true });
 
 Object.defineProperty(Person.prototype, "readonlyProp", { value: "Smith", writable: false });
 >Object.defineProperty(Person.prototype, "readonlyProp", { value: "Smith", writable: false }) : any
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Person.prototype : any
 >Person : typeof Person
 >prototype : any
@@ -159,9 +159,9 @@ Object.defineProperty(Person.prototype, "readonlyProp", { value: "Smith", writab
 
 Object.defineProperty(Person.prototype, "rwAccessors", { get() { return 98122 }, set(_) { /*ignore*/ } });
 >Object.defineProperty(Person.prototype, "rwAccessors", { get() { return 98122 }, set(_) { /*ignore*/ } }) : any
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Person.prototype : any
 >Person : typeof Person
 >prototype : any
@@ -174,9 +174,9 @@ Object.defineProperty(Person.prototype, "rwAccessors", { get() { return 98122 },
 
 Object.defineProperty(Person.prototype, "readonlyAccessor", { get() { return 21.75 } });
 >Object.defineProperty(Person.prototype, "readonlyAccessor", { get() { return 21.75 } }) : any
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Person.prototype : any
 >Person : typeof Person
 >prototype : any
@@ -187,9 +187,9 @@ Object.defineProperty(Person.prototype, "readonlyAccessor", { get() { return 21.
 
 Object.defineProperty(Person.prototype, "setonlyAccessor", {
 >Object.defineProperty(Person.prototype, "setonlyAccessor", {    /** @param {string} str */    set(str) {        this.rwAccessors = Number(str)    }}) : any
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Person.prototype : any
 >Person : typeof Person
 >prototype : any
diff --git a/tests/baselines/reference/checkObjectDefineProperty.types b/tests/baselines/reference/checkObjectDefineProperty.types
index 05f8b200c51f8..a96c2e2209571 100644
--- a/tests/baselines/reference/checkObjectDefineProperty.types
+++ b/tests/baselines/reference/checkObjectDefineProperty.types
@@ -89,9 +89,9 @@ const x = {};
 
 Object.defineProperty(x, "name", { value: "Charles", writable: true });
 >Object.defineProperty(x, "name", { value: "Charles", writable: true }) : typeof x
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >x : typeof x
 >"name" : "name"
 >{ value: "Charles", writable: true } : { value: string; writable: true; }
@@ -102,9 +102,9 @@ Object.defineProperty(x, "name", { value: "Charles", writable: true });
 
 Object.defineProperty(x, "middleInit", { value: "H" });
 >Object.defineProperty(x, "middleInit", { value: "H" }) : typeof x
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >x : typeof x
 >"middleInit" : "middleInit"
 >{ value: "H" } : { value: string; }
@@ -113,9 +113,9 @@ Object.defineProperty(x, "middleInit", { value: "H" });
 
 Object.defineProperty(x, "lastName", { value: "Smith", writable: false });
 >Object.defineProperty(x, "lastName", { value: "Smith", writable: false }) : typeof x
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >x : typeof x
 >"lastName" : "lastName"
 >{ value: "Smith", writable: false } : { value: string; writable: false; }
@@ -126,9 +126,9 @@ Object.defineProperty(x, "lastName", { value: "Smith", writable: false });
 
 Object.defineProperty(x, "zip", { get() { return 98122 }, set(_) { /*ignore*/ } });
 >Object.defineProperty(x, "zip", { get() { return 98122 }, set(_) { /*ignore*/ } }) : typeof x
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >x : typeof x
 >"zip" : "zip"
 >{ get() { return 98122 }, set(_) { /*ignore*/ } } : { get(): number; set(_: any): void; }
@@ -139,9 +139,9 @@ Object.defineProperty(x, "zip", { get() { return 98122 }, set(_) { /*ignore*/ }
 
 Object.defineProperty(x, "houseNumber", { get() { return 21.75 } });
 >Object.defineProperty(x, "houseNumber", { get() { return 21.75 } }) : typeof x
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >x : typeof x
 >"houseNumber" : "houseNumber"
 >{ get() { return 21.75 } } : { get(): number; }
@@ -150,9 +150,9 @@ Object.defineProperty(x, "houseNumber", { get() { return 21.75 } });
 
 Object.defineProperty(x, "zipStr", {
 >Object.defineProperty(x, "zipStr", {    /** @param {string} str */    set(str) {        this.zip = Number(str)     }}) : typeof x
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >x : typeof x
 >"zipStr" : "zipStr"
 >{    /** @param {string} str */    set(str) {        this.zip = Number(str)     }} : { set(str: string): void; }
diff --git a/tests/baselines/reference/checkOtherObjectAssignProperty.types b/tests/baselines/reference/checkOtherObjectAssignProperty.types
index 180ea63989945..0ffa9620bc5fc 100644
--- a/tests/baselines/reference/checkOtherObjectAssignProperty.types
+++ b/tests/baselines/reference/checkOtherObjectAssignProperty.types
@@ -89,9 +89,9 @@ const obj = { value: 42, writable: true };
 
 Object.defineProperty(exports, "thing", obj);
 >Object.defineProperty(exports, "thing", obj) : typeof import("tests/cases/conformance/jsdoc/mod1")
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >exports : typeof import("tests/cases/conformance/jsdoc/mod1")
 >"thing" : "thing"
 >obj : { value: number; writable: boolean; }
@@ -106,9 +106,9 @@ let str = /** @type {string} */("other");
 
 Object.defineProperty(exports, str, { value: 42, writable: true });
 >Object.defineProperty(exports, str, { value: 42, writable: true }) : typeof import("tests/cases/conformance/jsdoc/mod1")
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >exports : typeof import("tests/cases/conformance/jsdoc/mod1")
 >str : string
 >{ value: 42, writable: true } : { value: number; writable: true; }
@@ -123,9 +123,9 @@ const propName = "prop"
 
 Object.defineProperty(exports, propName, { value: 42, writable: true });
 >Object.defineProperty(exports, propName, { value: 42, writable: true }) : typeof import("tests/cases/conformance/jsdoc/mod1")
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >exports : typeof import("tests/cases/conformance/jsdoc/mod1")
 >propName : "prop"
 >{ value: 42, writable: true } : { value: number; writable: true; }
@@ -137,18 +137,18 @@ Object.defineProperty(exports, propName, { value: 42, writable: true });
 
 Object.defineProperty(exports, "bad1", { });
 >Object.defineProperty(exports, "bad1", { }) : typeof import("tests/cases/conformance/jsdoc/mod1")
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >exports : typeof import("tests/cases/conformance/jsdoc/mod1")
 >"bad1" : "bad1"
 >{ } : {}
 
 Object.defineProperty(exports, "bad2", { get() { return 12 }, value: "no" });
 >Object.defineProperty(exports, "bad2", { get() { return 12 }, value: "no" }) : typeof import("tests/cases/conformance/jsdoc/mod1")
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >exports : typeof import("tests/cases/conformance/jsdoc/mod1")
 >"bad2" : "bad2"
 >{ get() { return 12 }, value: "no" } : { get(): number; value: string; }
@@ -159,9 +159,9 @@ Object.defineProperty(exports, "bad2", { get() { return 12 }, value: "no" });
 
 Object.defineProperty(exports, "bad3", { writable: true });
 >Object.defineProperty(exports, "bad3", { writable: true }) : typeof import("tests/cases/conformance/jsdoc/mod1")
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >exports : typeof import("tests/cases/conformance/jsdoc/mod1")
 >"bad3" : "bad3"
 >{ writable: true } : { writable: true; }
diff --git a/tests/baselines/reference/completionsStringMethods.baseline b/tests/baselines/reference/completionsStringMethods.baseline
index 0ef6b4203714d..13c750ed9ead3 100644
--- a/tests/baselines/reference/completionsStringMethods.baseline
+++ b/tests/baselines/reference/completionsStringMethods.baseline
@@ -1105,7 +1105,7 @@
                   "target": {
                     "fileName": "lib.d.ts",
                     "textSpan": {
-                      "start": 18529,
+                      "start": 19171,
                       "length": 28
                     }
                   }
@@ -1128,7 +1128,7 @@
                   "target": {
                     "fileName": "lib.d.ts",
                     "textSpan": {
-                      "start": 18529,
+                      "start": 19171,
                       "length": 28
                     }
                   }
diff --git a/tests/baselines/reference/conditionalTypeDoesntSpinForever.symbols b/tests/baselines/reference/conditionalTypeDoesntSpinForever.symbols
index b5dcb78015b3f..3e2f1b61b791a 100644
--- a/tests/baselines/reference/conditionalTypeDoesntSpinForever.symbols
+++ b/tests/baselines/reference/conditionalTypeDoesntSpinForever.symbols
@@ -77,9 +77,9 @@ export enum PubSubRecordIsStoredInRedisAsA {
 
         buildPubSubRecordType(Object.assign({}, soFar, {name: instance as TYPE}) as SO_FAR & {name: TYPE}) as BuildPubSubRecordType<SO_FAR & {name: TYPE}>
 >buildPubSubRecordType : Symbol(buildPubSubRecordType, Decl(conditionalTypeDoesntSpinForever.ts, 108, 7))
->Object.assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>Object.assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
 >Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
->assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
 >soFar : Symbol(soFar, Decl(conditionalTypeDoesntSpinForever.ts, 21, 45))
 >name : Symbol(name, Decl(conditionalTypeDoesntSpinForever.ts, 24, 56))
 >instance : Symbol(instance, Decl(conditionalTypeDoesntSpinForever.ts, 23, 19))
@@ -133,9 +133,9 @@ export enum PubSubRecordIsStoredInRedisAsA {
 
         buildPubSubRecordType(Object.assign({}, soFar, {storedAs: PubSubRecordIsStoredInRedisAsA.jsonEncodedRedisString})) as
 >buildPubSubRecordType : Symbol(buildPubSubRecordType, Decl(conditionalTypeDoesntSpinForever.ts, 108, 7))
->Object.assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>Object.assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
 >Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
->assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
 >soFar : Symbol(soFar, Decl(conditionalTypeDoesntSpinForever.ts, 34, 44))
 >storedAs : Symbol(storedAs, Decl(conditionalTypeDoesntSpinForever.ts, 37, 56))
 >PubSubRecordIsStoredInRedisAsA.jsonEncodedRedisString : Symbol(PubSubRecordIsStoredInRedisAsA.jsonEncodedRedisString, Decl(conditionalTypeDoesntSpinForever.ts, 4, 28))
@@ -154,9 +154,9 @@ export enum PubSubRecordIsStoredInRedisAsA {
 
         buildPubSubRecordType(Object.assign({}, soFar, {storedAs: PubSubRecordIsStoredInRedisAsA.redisHash})) as
 >buildPubSubRecordType : Symbol(buildPubSubRecordType, Decl(conditionalTypeDoesntSpinForever.ts, 108, 7))
->Object.assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>Object.assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
 >Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
->assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
 >soFar : Symbol(soFar, Decl(conditionalTypeDoesntSpinForever.ts, 34, 44))
 >storedAs : Symbol(storedAs, Decl(conditionalTypeDoesntSpinForever.ts, 40, 56))
 >PubSubRecordIsStoredInRedisAsA.redisHash : Symbol(PubSubRecordIsStoredInRedisAsA.redisHash, Decl(conditionalTypeDoesntSpinForever.ts, 3, 44))
@@ -217,9 +217,9 @@ export enum PubSubRecordIsStoredInRedisAsA {
 
         buildPubSubRecordType(Object.assign({}, soFar, {identifier: instance as TYPE}) as SO_FAR & {identifier: TYPE}) as BuildPubSubRecordType<SO_FAR & {identifier: TYPE}>
 >buildPubSubRecordType : Symbol(buildPubSubRecordType, Decl(conditionalTypeDoesntSpinForever.ts, 108, 7))
->Object.assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>Object.assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
 >Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
->assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
 >soFar : Symbol(soFar, Decl(conditionalTypeDoesntSpinForever.ts, 51, 51))
 >identifier : Symbol(identifier, Decl(conditionalTypeDoesntSpinForever.ts, 54, 56))
 >instance : Symbol(instance, Decl(conditionalTypeDoesntSpinForever.ts, 53, 25))
@@ -271,9 +271,9 @@ export enum PubSubRecordIsStoredInRedisAsA {
 
         buildPubSubRecordType(Object.assign({}, soFar, {record: instance as TYPE}) as SO_FAR & {record: TYPE}) as BuildPubSubRecordType<SO_FAR & {record: TYPE}>
 >buildPubSubRecordType : Symbol(buildPubSubRecordType, Decl(conditionalTypeDoesntSpinForever.ts, 108, 7))
->Object.assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>Object.assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
 >Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
->assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
 >soFar : Symbol(soFar, Decl(conditionalTypeDoesntSpinForever.ts, 63, 47))
 >record : Symbol(record, Decl(conditionalTypeDoesntSpinForever.ts, 66, 56))
 >instance : Symbol(instance, Decl(conditionalTypeDoesntSpinForever.ts, 65, 21))
@@ -327,9 +327,9 @@ export enum PubSubRecordIsStoredInRedisAsA {
 
         buildPubSubRecordType(Object.assign({}, soFar, {maxMsToWaitBeforePublishing: instance})) as BuildPubSubRecordType<SO_FAR & {maxMsToWaitBeforePublishing: number}>,
 >buildPubSubRecordType : Symbol(buildPubSubRecordType, Decl(conditionalTypeDoesntSpinForever.ts, 108, 7))
->Object.assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>Object.assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
 >Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
->assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
 >soFar : Symbol(soFar, Decl(conditionalTypeDoesntSpinForever.ts, 76, 68))
 >maxMsToWaitBeforePublishing : Symbol(maxMsToWaitBeforePublishing, Decl(conditionalTypeDoesntSpinForever.ts, 79, 56))
 >instance : Symbol(instance, Decl(conditionalTypeDoesntSpinForever.ts, 78, 36))
@@ -342,9 +342,9 @@ export enum PubSubRecordIsStoredInRedisAsA {
 
         buildPubSubRecordType(Object.assign({}, soFar, {maxMsToWaitBeforePublishing: 0})) as BuildPubSubRecordType<SO_FAR & {maxMsToWaitBeforePublishing: 0}>,
 >buildPubSubRecordType : Symbol(buildPubSubRecordType, Decl(conditionalTypeDoesntSpinForever.ts, 108, 7))
->Object.assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>Object.assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
 >Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
->assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
 >soFar : Symbol(soFar, Decl(conditionalTypeDoesntSpinForever.ts, 76, 68))
 >maxMsToWaitBeforePublishing : Symbol(maxMsToWaitBeforePublishing, Decl(conditionalTypeDoesntSpinForever.ts, 81, 56))
 >BuildPubSubRecordType : Symbol(BuildPubSubRecordType, Decl(conditionalTypeDoesntSpinForever.ts, 98, 4))
@@ -450,9 +450,9 @@ export enum PubSubRecordIsStoredInRedisAsA {
 >SO_FAR : Symbol(SO_FAR, Decl(conditionalTypeDoesntSpinForever.ts, 108, 33))
 >soFar : Symbol(soFar, Decl(conditionalTypeDoesntSpinForever.ts, 108, 41))
 >SO_FAR : Symbol(SO_FAR, Decl(conditionalTypeDoesntSpinForever.ts, 108, 33))
->Object.assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>Object.assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
 >Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
->assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
 
     {},
     buildNameFieldConstructor(soFar),
diff --git a/tests/baselines/reference/conditionalTypeDoesntSpinForever.types b/tests/baselines/reference/conditionalTypeDoesntSpinForever.types
index a7b17a7cc6d0a..83bb366ca0913 100644
--- a/tests/baselines/reference/conditionalTypeDoesntSpinForever.types
+++ b/tests/baselines/reference/conditionalTypeDoesntSpinForever.types
@@ -68,10 +68,10 @@ export enum PubSubRecordIsStoredInRedisAsA {
 >buildPubSubRecordType(Object.assign({}, soFar, {name: instance as TYPE}) as SO_FAR & {name: TYPE}) : BuildPubSubRecordType<SO_FAR & { name: TYPE; }>
 >buildPubSubRecordType : <SO_FAR>(soFar: SO_FAR) => BuildPubSubRecordType<SO_FAR>
 >Object.assign({}, soFar, {name: instance as TYPE}) as SO_FAR & {name: TYPE} : SO_FAR & { name: TYPE; }
->Object.assign({}, soFar, {name: instance as TYPE}) : SO_FAR & { name: TYPE; }
->Object.assign : { <T extends {}, U>(target: T, source: U): T & U; <T extends {}, U, V>(target: T, source1: U, source2: V): T & U & V; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & U & V & W; (target: object, ...sources: any[]): any; }
+>Object.assign({}, soFar, {name: instance as TYPE}) : Writable<SO_FAR> & Writable<{ name: TYPE; }>
+>Object.assign : { <T extends {}>(target: T): T; <T extends {}, U>(target: T, source: U): T & Writable<U>; <T extends {}, U, V>(target: T, source1: U, source2: V): T & Writable<U> & Writable<V>; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & Writable<U> & Writable<V> & Writable<W>; (target: {}, ...sources: any[]): any; }
 >Object : ObjectConstructor
->assign : { <T extends {}, U>(target: T, source: U): T & U; <T extends {}, U, V>(target: T, source1: U, source2: V): T & U & V; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & U & V & W; (target: object, ...sources: any[]): any; }
+>assign : { <T extends {}>(target: T): T; <T extends {}, U>(target: T, source: U): T & Writable<U>; <T extends {}, U, V>(target: T, source1: U, source2: V): T & Writable<U> & Writable<V>; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & Writable<U> & Writable<V> & Writable<W>; (target: {}, ...sources: any[]): any; }
 >{} : {}
 >soFar : SO_FAR
 >{name: instance as TYPE} : { name: TYPE; }
@@ -120,12 +120,12 @@ export enum PubSubRecordIsStoredInRedisAsA {
 
         buildPubSubRecordType(Object.assign({}, soFar, {storedAs: PubSubRecordIsStoredInRedisAsA.jsonEncodedRedisString})) as
 >buildPubSubRecordType(Object.assign({}, soFar, {storedAs: PubSubRecordIsStoredInRedisAsA.jsonEncodedRedisString})) as          BuildPubSubRecordType<SO_FAR & {storedAs: PubSubRecordIsStoredInRedisAsA.jsonEncodedRedisString}> : BuildPubSubRecordType<SO_FAR & { storedAs: PubSubRecordIsStoredInRedisAsA.jsonEncodedRedisString; }>
->buildPubSubRecordType(Object.assign({}, soFar, {storedAs: PubSubRecordIsStoredInRedisAsA.jsonEncodedRedisString})) : BuildPubSubRecordType<SO_FAR & { storedAs: PubSubRecordIsStoredInRedisAsA; }>
+>buildPubSubRecordType(Object.assign({}, soFar, {storedAs: PubSubRecordIsStoredInRedisAsA.jsonEncodedRedisString})) : BuildPubSubRecordType<Writable<SO_FAR> & Writable<{ storedAs: PubSubRecordIsStoredInRedisAsA.jsonEncodedRedisString; }>>
 >buildPubSubRecordType : <SO_FAR>(soFar: SO_FAR) => BuildPubSubRecordType<SO_FAR>
->Object.assign({}, soFar, {storedAs: PubSubRecordIsStoredInRedisAsA.jsonEncodedRedisString}) : SO_FAR & { storedAs: PubSubRecordIsStoredInRedisAsA; }
->Object.assign : { <T extends {}, U>(target: T, source: U): T & U; <T extends {}, U, V>(target: T, source1: U, source2: V): T & U & V; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & U & V & W; (target: object, ...sources: any[]): any; }
+>Object.assign({}, soFar, {storedAs: PubSubRecordIsStoredInRedisAsA.jsonEncodedRedisString}) : Writable<SO_FAR> & Writable<{ storedAs: PubSubRecordIsStoredInRedisAsA.jsonEncodedRedisString; }>
+>Object.assign : { <T extends {}>(target: T): T; <T extends {}, U>(target: T, source: U): T & Writable<U>; <T extends {}, U, V>(target: T, source1: U, source2: V): T & Writable<U> & Writable<V>; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & Writable<U> & Writable<V> & Writable<W>; (target: {}, ...sources: any[]): any; }
 >Object : ObjectConstructor
->assign : { <T extends {}, U>(target: T, source: U): T & U; <T extends {}, U, V>(target: T, source1: U, source2: V): T & U & V; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & U & V & W; (target: object, ...sources: any[]): any; }
+>assign : { <T extends {}>(target: T): T; <T extends {}, U>(target: T, source: U): T & Writable<U>; <T extends {}, U, V>(target: T, source1: U, source2: V): T & Writable<U> & Writable<V>; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & Writable<U> & Writable<V> & Writable<W>; (target: {}, ...sources: any[]): any; }
 >{} : {}
 >soFar : SO_FAR
 >{storedAs: PubSubRecordIsStoredInRedisAsA.jsonEncodedRedisString} : { storedAs: PubSubRecordIsStoredInRedisAsA.jsonEncodedRedisString; }
@@ -144,12 +144,12 @@ export enum PubSubRecordIsStoredInRedisAsA {
 
         buildPubSubRecordType(Object.assign({}, soFar, {storedAs: PubSubRecordIsStoredInRedisAsA.redisHash})) as
 >buildPubSubRecordType(Object.assign({}, soFar, {storedAs: PubSubRecordIsStoredInRedisAsA.redisHash})) as          BuildPubSubRecordType<SO_FAR & {storedAs: PubSubRecordIsStoredInRedisAsA.redisHash}> : BuildPubSubRecordType<SO_FAR & { storedAs: PubSubRecordIsStoredInRedisAsA.redisHash; }>
->buildPubSubRecordType(Object.assign({}, soFar, {storedAs: PubSubRecordIsStoredInRedisAsA.redisHash})) : BuildPubSubRecordType<SO_FAR & { storedAs: PubSubRecordIsStoredInRedisAsA; }>
+>buildPubSubRecordType(Object.assign({}, soFar, {storedAs: PubSubRecordIsStoredInRedisAsA.redisHash})) : BuildPubSubRecordType<Writable<SO_FAR> & Writable<{ storedAs: PubSubRecordIsStoredInRedisAsA.redisHash; }>>
 >buildPubSubRecordType : <SO_FAR>(soFar: SO_FAR) => BuildPubSubRecordType<SO_FAR>
->Object.assign({}, soFar, {storedAs: PubSubRecordIsStoredInRedisAsA.redisHash}) : SO_FAR & { storedAs: PubSubRecordIsStoredInRedisAsA; }
->Object.assign : { <T extends {}, U>(target: T, source: U): T & U; <T extends {}, U, V>(target: T, source1: U, source2: V): T & U & V; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & U & V & W; (target: object, ...sources: any[]): any; }
+>Object.assign({}, soFar, {storedAs: PubSubRecordIsStoredInRedisAsA.redisHash}) : Writable<SO_FAR> & Writable<{ storedAs: PubSubRecordIsStoredInRedisAsA.redisHash; }>
+>Object.assign : { <T extends {}>(target: T): T; <T extends {}, U>(target: T, source: U): T & Writable<U>; <T extends {}, U, V>(target: T, source1: U, source2: V): T & Writable<U> & Writable<V>; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & Writable<U> & Writable<V> & Writable<W>; (target: {}, ...sources: any[]): any; }
 >Object : ObjectConstructor
->assign : { <T extends {}, U>(target: T, source: U): T & U; <T extends {}, U, V>(target: T, source1: U, source2: V): T & U & V; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & U & V & W; (target: object, ...sources: any[]): any; }
+>assign : { <T extends {}>(target: T): T; <T extends {}, U>(target: T, source: U): T & Writable<U>; <T extends {}, U, V>(target: T, source1: U, source2: V): T & Writable<U> & Writable<V>; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & Writable<U> & Writable<V> & Writable<W>; (target: {}, ...sources: any[]): any; }
 >{} : {}
 >soFar : SO_FAR
 >{storedAs: PubSubRecordIsStoredInRedisAsA.redisHash} : { storedAs: PubSubRecordIsStoredInRedisAsA.redisHash; }
@@ -212,10 +212,10 @@ export enum PubSubRecordIsStoredInRedisAsA {
 >buildPubSubRecordType(Object.assign({}, soFar, {identifier: instance as TYPE}) as SO_FAR & {identifier: TYPE}) : BuildPubSubRecordType<SO_FAR & { identifier: TYPE; }>
 >buildPubSubRecordType : <SO_FAR>(soFar: SO_FAR) => BuildPubSubRecordType<SO_FAR>
 >Object.assign({}, soFar, {identifier: instance as TYPE}) as SO_FAR & {identifier: TYPE} : SO_FAR & { identifier: TYPE; }
->Object.assign({}, soFar, {identifier: instance as TYPE}) : SO_FAR & Record<"record", unknown> & { identifier: TYPE; }
->Object.assign : { <T extends {}, U>(target: T, source: U): T & U; <T extends {}, U, V>(target: T, source1: U, source2: V): T & U & V; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & U & V & W; (target: object, ...sources: any[]): any; }
+>Object.assign({}, soFar, {identifier: instance as TYPE}) : Writable<SO_FAR & Record<"record", unknown>> & Writable<{ identifier: TYPE; }>
+>Object.assign : { <T extends {}>(target: T): T; <T extends {}, U>(target: T, source: U): T & Writable<U>; <T extends {}, U, V>(target: T, source1: U, source2: V): T & Writable<U> & Writable<V>; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & Writable<U> & Writable<V> & Writable<W>; (target: {}, ...sources: any[]): any; }
 >Object : ObjectConstructor
->assign : { <T extends {}, U>(target: T, source: U): T & U; <T extends {}, U, V>(target: T, source1: U, source2: V): T & U & V; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & U & V & W; (target: object, ...sources: any[]): any; }
+>assign : { <T extends {}>(target: T): T; <T extends {}, U>(target: T, source: U): T & Writable<U>; <T extends {}, U, V>(target: T, source1: U, source2: V): T & Writable<U> & Writable<V>; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & Writable<U> & Writable<V> & Writable<W>; (target: {}, ...sources: any[]): any; }
 >{} : {}
 >soFar : SO_FAR & Record<"record", unknown>
 >{identifier: instance as TYPE} : { identifier: TYPE; }
@@ -264,10 +264,10 @@ export enum PubSubRecordIsStoredInRedisAsA {
 >buildPubSubRecordType(Object.assign({}, soFar, {record: instance as TYPE}) as SO_FAR & {record: TYPE}) : BuildPubSubRecordType<SO_FAR & { record: TYPE; }>
 >buildPubSubRecordType : <SO_FAR>(soFar: SO_FAR) => BuildPubSubRecordType<SO_FAR>
 >Object.assign({}, soFar, {record: instance as TYPE}) as SO_FAR & {record: TYPE} : SO_FAR & { record: TYPE; }
->Object.assign({}, soFar, {record: instance as TYPE}) : SO_FAR & { record: TYPE; }
->Object.assign : { <T extends {}, U>(target: T, source: U): T & U; <T extends {}, U, V>(target: T, source1: U, source2: V): T & U & V; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & U & V & W; (target: object, ...sources: any[]): any; }
+>Object.assign({}, soFar, {record: instance as TYPE}) : Writable<SO_FAR> & Writable<{ record: TYPE; }>
+>Object.assign : { <T extends {}>(target: T): T; <T extends {}, U>(target: T, source: U): T & Writable<U>; <T extends {}, U, V>(target: T, source1: U, source2: V): T & Writable<U> & Writable<V>; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & Writable<U> & Writable<V> & Writable<W>; (target: {}, ...sources: any[]): any; }
 >Object : ObjectConstructor
->assign : { <T extends {}, U>(target: T, source: U): T & U; <T extends {}, U, V>(target: T, source1: U, source2: V): T & U & V; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & U & V & W; (target: object, ...sources: any[]): any; }
+>assign : { <T extends {}>(target: T): T; <T extends {}, U>(target: T, source: U): T & Writable<U>; <T extends {}, U, V>(target: T, source1: U, source2: V): T & Writable<U> & Writable<V>; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & Writable<U> & Writable<V> & Writable<W>; (target: {}, ...sources: any[]): any; }
 >{} : {}
 >soFar : SO_FAR
 >{record: instance as TYPE} : { record: TYPE; }
@@ -318,12 +318,12 @@ export enum PubSubRecordIsStoredInRedisAsA {
 
         buildPubSubRecordType(Object.assign({}, soFar, {maxMsToWaitBeforePublishing: instance})) as BuildPubSubRecordType<SO_FAR & {maxMsToWaitBeforePublishing: number}>,
 >buildPubSubRecordType(Object.assign({}, soFar, {maxMsToWaitBeforePublishing: instance})) as BuildPubSubRecordType<SO_FAR & {maxMsToWaitBeforePublishing: number}> : BuildPubSubRecordType<SO_FAR & { maxMsToWaitBeforePublishing: number; }>
->buildPubSubRecordType(Object.assign({}, soFar, {maxMsToWaitBeforePublishing: instance})) : BuildPubSubRecordType<SO_FAR & { maxMsToWaitBeforePublishing: number; }>
+>buildPubSubRecordType(Object.assign({}, soFar, {maxMsToWaitBeforePublishing: instance})) : BuildPubSubRecordType<Writable<SO_FAR> & Writable<{ maxMsToWaitBeforePublishing: number; }>>
 >buildPubSubRecordType : <SO_FAR>(soFar: SO_FAR) => BuildPubSubRecordType<SO_FAR>
->Object.assign({}, soFar, {maxMsToWaitBeforePublishing: instance}) : SO_FAR & { maxMsToWaitBeforePublishing: number; }
->Object.assign : { <T extends {}, U>(target: T, source: U): T & U; <T extends {}, U, V>(target: T, source1: U, source2: V): T & U & V; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & U & V & W; (target: object, ...sources: any[]): any; }
+>Object.assign({}, soFar, {maxMsToWaitBeforePublishing: instance}) : Writable<SO_FAR> & Writable<{ maxMsToWaitBeforePublishing: number; }>
+>Object.assign : { <T extends {}>(target: T): T; <T extends {}, U>(target: T, source: U): T & Writable<U>; <T extends {}, U, V>(target: T, source1: U, source2: V): T & Writable<U> & Writable<V>; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & Writable<U> & Writable<V> & Writable<W>; (target: {}, ...sources: any[]): any; }
 >Object : ObjectConstructor
->assign : { <T extends {}, U>(target: T, source: U): T & U; <T extends {}, U, V>(target: T, source1: U, source2: V): T & U & V; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & U & V & W; (target: object, ...sources: any[]): any; }
+>assign : { <T extends {}>(target: T): T; <T extends {}, U>(target: T, source: U): T & Writable<U>; <T extends {}, U, V>(target: T, source1: U, source2: V): T & Writable<U> & Writable<V>; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & Writable<U> & Writable<V> & Writable<W>; (target: {}, ...sources: any[]): any; }
 >{} : {}
 >soFar : SO_FAR
 >{maxMsToWaitBeforePublishing: instance} : { maxMsToWaitBeforePublishing: number; }
@@ -337,16 +337,16 @@ export enum PubSubRecordIsStoredInRedisAsA {
 
         buildPubSubRecordType(Object.assign({}, soFar, {maxMsToWaitBeforePublishing: 0})) as BuildPubSubRecordType<SO_FAR & {maxMsToWaitBeforePublishing: 0}>,
 >buildPubSubRecordType(Object.assign({}, soFar, {maxMsToWaitBeforePublishing: 0})) as BuildPubSubRecordType<SO_FAR & {maxMsToWaitBeforePublishing: 0}> : BuildPubSubRecordType<SO_FAR & { maxMsToWaitBeforePublishing: 0; }>
->buildPubSubRecordType(Object.assign({}, soFar, {maxMsToWaitBeforePublishing: 0})) : BuildPubSubRecordType<SO_FAR & { maxMsToWaitBeforePublishing: number; }>
+>buildPubSubRecordType(Object.assign({}, soFar, {maxMsToWaitBeforePublishing: 0})) : BuildPubSubRecordType<Writable<SO_FAR> & Writable<{ maxMsToWaitBeforePublishing: 0; }>>
 >buildPubSubRecordType : <SO_FAR>(soFar: SO_FAR) => BuildPubSubRecordType<SO_FAR>
->Object.assign({}, soFar, {maxMsToWaitBeforePublishing: 0}) : SO_FAR & { maxMsToWaitBeforePublishing: number; }
->Object.assign : { <T extends {}, U>(target: T, source: U): T & U; <T extends {}, U, V>(target: T, source1: U, source2: V): T & U & V; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & U & V & W; (target: object, ...sources: any[]): any; }
+>Object.assign({}, soFar, {maxMsToWaitBeforePublishing: 0}) : Writable<SO_FAR> & Writable<{ maxMsToWaitBeforePublishing: 0; }>
+>Object.assign : { <T extends {}>(target: T): T; <T extends {}, U>(target: T, source: U): T & Writable<U>; <T extends {}, U, V>(target: T, source1: U, source2: V): T & Writable<U> & Writable<V>; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & Writable<U> & Writable<V> & Writable<W>; (target: {}, ...sources: any[]): any; }
 >Object : ObjectConstructor
->assign : { <T extends {}, U>(target: T, source: U): T & U; <T extends {}, U, V>(target: T, source1: U, source2: V): T & U & V; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & U & V & W; (target: object, ...sources: any[]): any; }
+>assign : { <T extends {}>(target: T): T; <T extends {}, U>(target: T, source: U): T & Writable<U>; <T extends {}, U, V>(target: T, source1: U, source2: V): T & Writable<U> & Writable<V>; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & Writable<U> & Writable<V> & Writable<W>; (target: {}, ...sources: any[]): any; }
 >{} : {}
 >soFar : SO_FAR
->{maxMsToWaitBeforePublishing: 0} : { maxMsToWaitBeforePublishing: number; }
->maxMsToWaitBeforePublishing : number
+>{maxMsToWaitBeforePublishing: 0} : { maxMsToWaitBeforePublishing: 0; }
+>maxMsToWaitBeforePublishing : 0
 >0 : 0
 >maxMsToWaitBeforePublishing : 0
     }
@@ -441,9 +441,9 @@ export enum PubSubRecordIsStoredInRedisAsA {
 >soFar : SO_FAR
 >Object.assign(    {},    buildNameFieldConstructor(soFar),    buildIdentifierFieldConstructor(soFar),    buildRecordFieldConstructor(soFar),    buildStoredAsConstructor(soFar),    buildMaxMsToWaitBeforePublishingFieldConstructor(soFar),    buildType(soFar)  ) as BuildPubSubRecordType<SO_FAR> : BuildPubSubRecordType<SO_FAR>
 >Object.assign(    {},    buildNameFieldConstructor(soFar),    buildIdentifierFieldConstructor(soFar),    buildRecordFieldConstructor(soFar),    buildStoredAsConstructor(soFar),    buildMaxMsToWaitBeforePublishingFieldConstructor(soFar),    buildType(soFar)  ) : any
->Object.assign : { <T extends {}, U>(target: T, source: U): T & U; <T extends {}, U, V>(target: T, source1: U, source2: V): T & U & V; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & U & V & W; (target: object, ...sources: any[]): any; }
+>Object.assign : { <T extends {}>(target: T): T; <T extends {}, U>(target: T, source: U): T & Writable<U>; <T extends {}, U, V>(target: T, source1: U, source2: V): T & Writable<U> & Writable<V>; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & Writable<U> & Writable<V> & Writable<W>; (target: {}, ...sources: any[]): any; }
 >Object : ObjectConstructor
->assign : { <T extends {}, U>(target: T, source: U): T & U; <T extends {}, U, V>(target: T, source1: U, source2: V): T & U & V; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & U & V & W; (target: object, ...sources: any[]): any; }
+>assign : { <T extends {}>(target: T): T; <T extends {}, U>(target: T, source: U): T & Writable<U>; <T extends {}, U, V>(target: T, source1: U, source2: V): T & Writable<U> & Writable<V>; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & Writable<U> & Writable<V> & Writable<W>; (target: {}, ...sources: any[]): any; }
 
     {},
 >{} : {}
diff --git a/tests/baselines/reference/declarationEmitObjectAssignedDefaultExport.symbols b/tests/baselines/reference/declarationEmitObjectAssignedDefaultExport.symbols
index 659edb5ddca3c..981f13e3820d6 100644
--- a/tests/baselines/reference/declarationEmitObjectAssignedDefaultExport.symbols
+++ b/tests/baselines/reference/declarationEmitObjectAssignedDefaultExport.symbols
@@ -113,9 +113,9 @@ export const C = styled.div``;
 >div : Symbol(StyledInterface.div, Decl(index.d.ts, 12, 34))
 
 export default Object.assign(A, {
->Object.assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>Object.assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
 >Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
->assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
 >A : Symbol(A, Decl(index.ts, 2, 5))
 
     B,
diff --git a/tests/baselines/reference/declarationEmitObjectAssignedDefaultExport.types b/tests/baselines/reference/declarationEmitObjectAssignedDefaultExport.types
index 9d05d21a2fdd6..acc7ad58c4137 100644
--- a/tests/baselines/reference/declarationEmitObjectAssignedDefaultExport.types
+++ b/tests/baselines/reference/declarationEmitObjectAssignedDefaultExport.types
@@ -77,10 +77,10 @@ export const C = styled.div``;
 >`` : ""
 
 export default Object.assign(A, {
->Object.assign(A, {    B,    C}) : string & import("tests/cases/compiler/node_modules/styled-components/index").StyledComponentBase<"div", import("tests/cases/compiler/node_modules/styled-components/index").DefaultTheme, {}, never> & import("tests/cases/compiler/node_modules/styled-components/node_modules/hoist-non-react-statics/index").NonReactStatics<"div"> & { B: import("tests/cases/compiler/node_modules/styled-components/index").StyledComponent<"div", import("tests/cases/compiler/node_modules/styled-components/index").DefaultTheme, {}, never>; C: import("tests/cases/compiler/node_modules/styled-components/index").StyledComponent<"div", import("tests/cases/compiler/node_modules/styled-components/index").DefaultTheme, {}, never>; }
->Object.assign : { <T extends {}, U>(target: T, source: U): T & U; <T extends {}, U, V>(target: T, source1: U, source2: V): T & U & V; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & U & V & W; (target: object, ...sources: any[]): any; }
+>Object.assign(A, {    B,    C}) : string & import("tests/cases/compiler/node_modules/styled-components/index").StyledComponentBase<"div", import("tests/cases/compiler/node_modules/styled-components/index").DefaultTheme, {}, never> & import("tests/cases/compiler/node_modules/styled-components/node_modules/hoist-non-react-statics/index").NonReactStatics<"div"> & Writable<{ B: import("tests/cases/compiler/node_modules/styled-components/index").StyledComponent<"div", import("tests/cases/compiler/node_modules/styled-components/index").DefaultTheme, {}, never>; C: import("tests/cases/compiler/node_modules/styled-components/index").StyledComponent<"div", import("tests/cases/compiler/node_modules/styled-components/index").DefaultTheme, {}, never>; }>
+>Object.assign : { <T extends {}>(target: T): T; <T extends {}, U>(target: T, source: U): T & Writable<U>; <T extends {}, U, V>(target: T, source1: U, source2: V): T & Writable<U> & Writable<V>; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & Writable<U> & Writable<V> & Writable<W>; (target: {}, ...sources: any[]): any; }
 >Object : ObjectConstructor
->assign : { <T extends {}, U>(target: T, source: U): T & U; <T extends {}, U, V>(target: T, source1: U, source2: V): T & U & V; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & U & V & W; (target: object, ...sources: any[]): any; }
+>assign : { <T extends {}>(target: T): T; <T extends {}, U>(target: T, source: U): T & Writable<U>; <T extends {}, U, V>(target: T, source1: U, source2: V): T & Writable<U> & Writable<V>; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & Writable<U> & Writable<V> & Writable<W>; (target: {}, ...sources: any[]): any; }
 >A : import("tests/cases/compiler/node_modules/styled-components/index").StyledComponent<"div", import("tests/cases/compiler/node_modules/styled-components/index").DefaultTheme, {}, never>
 >{    B,    C} : { B: import("tests/cases/compiler/node_modules/styled-components/index").StyledComponent<"div", import("tests/cases/compiler/node_modules/styled-components/index").DefaultTheme, {}, never>; C: import("tests/cases/compiler/node_modules/styled-components/index").StyledComponent<"div", import("tests/cases/compiler/node_modules/styled-components/index").DefaultTheme, {}, never>; }
 
diff --git a/tests/baselines/reference/declarationsWithRecursiveInternalTypesProduceUniqueTypeParams.js b/tests/baselines/reference/declarationsWithRecursiveInternalTypesProduceUniqueTypeParams.js
index 837fe49b428d3..a387ceede2b8a 100644
--- a/tests/baselines/reference/declarationsWithRecursiveInternalTypesProduceUniqueTypeParams.js
+++ b/tests/baselines/reference/declarationsWithRecursiveInternalTypesProduceUniqueTypeParams.js
@@ -94,43 +94,43 @@ void p3.result.three;
 //// [declarationsWithRecursiveInternalTypesProduceUniqueTypeParams.d.ts]
 export type Key<U> = keyof U;
 export type Value<K extends Key<U>, U> = U[K];
-export declare const updateIfChanged: <T>(t: T) => (<K extends keyof T>(key: K) => (<K_1 extends keyof Value<K, T>>(key: K_1) => (<K_2 extends keyof Value<K_1, Value<K, T>>>(key: K_2) => (<K_3 extends keyof Value<K_2, Value<K_1, Value<K, T>>>>(key: K_3) => (<K_4 extends keyof Value<K_3, Value<K_2, Value<K_1, Value<K, T>>>>>(key: K_4) => (<K_5 extends keyof Value<K_4, Value<K_3, Value<K_2, Value<K_1, Value<K, T>>>>>>(key: K_5) => (<K_6 extends keyof Value<K_5, Value<K_4, Value<K_3, Value<K_2, Value<K_1, Value<K, T>>>>>>>(key: K_6) => (<K_7 extends keyof Value<K_6, Value<K_5, Value<K_4, Value<K_3, Value<K_2, Value<K_1, Value<K, T>>>>>>>>(key: K_7) => (<K_8 extends keyof Value<K_7, Value<K_6, Value<K_5, Value<K_4, Value<K_3, Value<K_2, Value<K_1, Value<K, T>>>>>>>>>(key: K_8) => (<K_9 extends keyof Value<K_8, Value<K_7, Value<K_6, Value<K_5, Value<K_4, Value<K_3, Value<K_2, Value<K_1, Value<K, T>>>>>>>>>>(key: K_9) => (<K_10 extends keyof Value<K_9, Value<K_8, Value<K_7, Value<K_6, Value<K_5, Value<K_4, Value<K_3, Value<K_2, Value<K_1, Value<K, T>>>>>>>>>>>(key: K_10) => any & {
+export declare const updateIfChanged: <T>(t: T) => (<K extends keyof T>(key: K) => (<K_1 extends keyof Value<K, T>>(key: K_1) => (<K_2 extends keyof Value<K_1, Value<K, T>>>(key: K_2) => (<K_3 extends keyof Value<K_2, Value<K_1, Value<K, T>>>>(key: K_3) => (<K_4 extends keyof Value<K_3, Value<K_2, Value<K_1, Value<K, T>>>>>(key: K_4) => (<K_5 extends keyof Value<K_4, Value<K_3, Value<K_2, Value<K_1, Value<K, T>>>>>>(key: K_5) => (<K_6 extends keyof Value<K_5, Value<K_4, Value<K_3, Value<K_2, Value<K_1, Value<K, T>>>>>>>(key: K_6) => (<K_7 extends keyof Value<K_6, Value<K_5, Value<K_4, Value<K_3, Value<K_2, Value<K_1, Value<K, T>>>>>>>>(key: K_7) => (<K_8 extends keyof Value<K_7, Value<K_6, Value<K_5, Value<K_4, Value<K_3, Value<K_2, Value<K_1, Value<K, T>>>>>>>>>(key: K_8) => (<K_9 extends keyof Value<K_8, Value<K_7, Value<K_6, Value<K_5, Value<K_4, Value<K_3, Value<K_2, Value<K_1, Value<K, T>>>>>>>>>>(key: K_9) => (<K_10 extends keyof Value<K_9, Value<K_8, Value<K_7, Value<K_6, Value<K_5, Value<K_4, Value<K_3, Value<K_2, Value<K_1, Value<K, T>>>>>>>>>>>(key: K_10) => any & Writable<{
     map: (updater: (u: Value<K_10, Value<K_9, Value<K_8, Value<K_7, Value<K_6, Value<K_5, Value<K_4, Value<K_3, Value<K_2, Value<K_1, Value<K, T>>>>>>>>>>>) => Value<K_10, Value<K_9, Value<K_8, Value<K_7, Value<K_6, Value<K_5, Value<K_4, Value<K_3, Value<K_2, Value<K_1, Value<K, T>>>>>>>>>>>) => T;
     set: (newU: Value<K_10, Value<K_9, Value<K_8, Value<K_7, Value<K_6, Value<K_5, Value<K_4, Value<K_3, Value<K_2, Value<K_1, Value<K, T>>>>>>>>>>>) => T;
-}) & {
+}>) & Writable<{
     map: (updater: (u: Value<K_9, Value<K_8, Value<K_7, Value<K_6, Value<K_5, Value<K_4, Value<K_3, Value<K_2, Value<K_1, Value<K, T>>>>>>>>>>) => Value<K_9, Value<K_8, Value<K_7, Value<K_6, Value<K_5, Value<K_4, Value<K_3, Value<K_2, Value<K_1, Value<K, T>>>>>>>>>>) => T;
     set: (newU: Value<K_9, Value<K_8, Value<K_7, Value<K_6, Value<K_5, Value<K_4, Value<K_3, Value<K_2, Value<K_1, Value<K, T>>>>>>>>>>) => T;
-}) & {
+}>) & Writable<{
     map: (updater: (u: Value<K_8, Value<K_7, Value<K_6, Value<K_5, Value<K_4, Value<K_3, Value<K_2, Value<K_1, Value<K, T>>>>>>>>>) => Value<K_8, Value<K_7, Value<K_6, Value<K_5, Value<K_4, Value<K_3, Value<K_2, Value<K_1, Value<K, T>>>>>>>>>) => T;
     set: (newU: Value<K_8, Value<K_7, Value<K_6, Value<K_5, Value<K_4, Value<K_3, Value<K_2, Value<K_1, Value<K, T>>>>>>>>>) => T;
-}) & {
+}>) & Writable<{
     map: (updater: (u: Value<K_7, Value<K_6, Value<K_5, Value<K_4, Value<K_3, Value<K_2, Value<K_1, Value<K, T>>>>>>>>) => Value<K_7, Value<K_6, Value<K_5, Value<K_4, Value<K_3, Value<K_2, Value<K_1, Value<K, T>>>>>>>>) => T;
     set: (newU: Value<K_7, Value<K_6, Value<K_5, Value<K_4, Value<K_3, Value<K_2, Value<K_1, Value<K, T>>>>>>>>) => T;
-}) & {
+}>) & Writable<{
     map: (updater: (u: Value<K_6, Value<K_5, Value<K_4, Value<K_3, Value<K_2, Value<K_1, Value<K, T>>>>>>>) => Value<K_6, Value<K_5, Value<K_4, Value<K_3, Value<K_2, Value<K_1, Value<K, T>>>>>>>) => T;
     set: (newU: Value<K_6, Value<K_5, Value<K_4, Value<K_3, Value<K_2, Value<K_1, Value<K, T>>>>>>>) => T;
-}) & {
+}>) & Writable<{
     map: (updater: (u: Value<K_5, Value<K_4, Value<K_3, Value<K_2, Value<K_1, Value<K, T>>>>>>) => Value<K_5, Value<K_4, Value<K_3, Value<K_2, Value<K_1, Value<K, T>>>>>>) => T;
     set: (newU: Value<K_5, Value<K_4, Value<K_3, Value<K_2, Value<K_1, Value<K, T>>>>>>) => T;
-}) & {
+}>) & Writable<{
     map: (updater: (u: Value<K_4, Value<K_3, Value<K_2, Value<K_1, Value<K, T>>>>>) => Value<K_4, Value<K_3, Value<K_2, Value<K_1, Value<K, T>>>>>) => T;
     set: (newU: Value<K_4, Value<K_3, Value<K_2, Value<K_1, Value<K, T>>>>>) => T;
-}) & {
+}>) & Writable<{
     map: (updater: (u: Value<K_3, Value<K_2, Value<K_1, Value<K, T>>>>) => Value<K_3, Value<K_2, Value<K_1, Value<K, T>>>>) => T;
     set: (newU: Value<K_3, Value<K_2, Value<K_1, Value<K, T>>>>) => T;
-}) & {
+}>) & Writable<{
     map: (updater: (u: Value<K_2, Value<K_1, Value<K, T>>>) => Value<K_2, Value<K_1, Value<K, T>>>) => T;
     set: (newU: Value<K_2, Value<K_1, Value<K, T>>>) => T;
-}) & {
+}>) & Writable<{
     map: (updater: (u: Value<K_1, Value<K, T>>) => Value<K_1, Value<K, T>>) => T;
     set: (newU: Value<K_1, Value<K, T>>) => T;
-}) & {
+}>) & Writable<{
     map: (updater: (u: Value<K, T>) => Value<K, T>) => T;
     set: (newU: Value<K, T>) => T;
-}) & {
+}>) & Writable<{
     map: (updater: (u: T) => T) => T;
     set: (newU: T) => T;
-};
+}>;
 export declare const testRecFun: <T extends Object>(parent: T) => {
     result: T;
     deeper: <U extends Object>(child: U) => {
diff --git a/tests/baselines/reference/declarationsWithRecursiveInternalTypesProduceUniqueTypeParams.symbols b/tests/baselines/reference/declarationsWithRecursiveInternalTypesProduceUniqueTypeParams.symbols
index 08c4eccca0829..bfbdd6084157c 100644
--- a/tests/baselines/reference/declarationsWithRecursiveInternalTypesProduceUniqueTypeParams.symbols
+++ b/tests/baselines/reference/declarationsWithRecursiveInternalTypesProduceUniqueTypeParams.symbols
@@ -47,9 +47,9 @@ export const updateIfChanged = <T>(t: T) => {
 >newU : Symbol(newU, Decl(declarationsWithRecursiveInternalTypesProduceUniqueTypeParams.ts, 8, 21))
 
         return Object.assign(
->Object.assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>Object.assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
 >Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
->assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
 
             <K extends Key<U>>(key: K) =>
 >K : Symbol(K, Decl(declarationsWithRecursiveInternalTypesProduceUniqueTypeParams.ts, 10, 13))
@@ -76,9 +76,9 @@ export const updateIfChanged = <T>(t: T) => {
 
                     return update(Object.assign(Array.isArray(u) ? [] : {}, u, { [key]: v }));
 >update : Symbol(update, Decl(declarationsWithRecursiveInternalTypesProduceUniqueTypeParams.ts, 7, 28))
->Object.assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>Object.assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
 >Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
->assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
 >Array.isArray : Symbol(ArrayConstructor.isArray, Decl(lib.es5.d.ts, --, --))
 >Array : Symbol(Array, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
 >isArray : Symbol(ArrayConstructor.isArray, Decl(lib.es5.d.ts, --, --))
diff --git a/tests/baselines/reference/declarationsWithRecursiveInternalTypesProduceUniqueTypeParams.types b/tests/baselines/reference/declarationsWithRecursiveInternalTypesProduceUniqueTypeParams.types
index 4e4bf5b76933a..1bef7f2379546 100644
--- a/tests/baselines/reference/declarationsWithRecursiveInternalTypesProduceUniqueTypeParams.types
+++ b/tests/baselines/reference/declarationsWithRecursiveInternalTypesProduceUniqueTypeParams.types
@@ -10,13 +10,13 @@ export type Value<K extends Key<U>, U> = U[K];
 >Value : Value<K, U>
 
 export const updateIfChanged = <T>(t: T) => {
->updateIfChanged : <T>(t: T) => (<K extends keyof T>(key: K) => (<K extends keyof Value<K, T>>(key: K) => (<K extends keyof Value<K, Value<K, T>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, T>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, T>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>>(key: K) => any & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, T>>>>) => Value<K, Value<K, Value<K, Value<K, T>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, T>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, T>>>) => Value<K, Value<K, Value<K, T>>>) => T; set: (newU: Value<K, Value<K, Value<K, T>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, T>>) => Value<K, Value<K, T>>) => T; set: (newU: Value<K, Value<K, T>>) => T; }) & { map: (updater: (u: Value<K, T>) => Value<K, T>) => T; set: (newU: Value<K, T>) => T; }) & { map: (updater: (u: T) => T) => T; set: (newU: T) => T; }
-><T>(t: T) => {    const reduce = <U>(u: U, update: (u: U) => T) => {        const set = (newU: U) => Object.is(u, newU) ? t : update(newU);        return Object.assign(            <K extends Key<U>>(key: K) =>                reduce<Value<K, U>>(u[key as keyof U] as Value<K, U>, (v: Value<K, U>) => {                    return update(Object.assign(Array.isArray(u) ? [] : {}, u, { [key]: v }));                }),            { map: (updater: (u: U) => U) => set(updater(u)), set });    };    return reduce<T>(t, (t: T) => t);} : <T>(t: T) => (<K extends keyof T>(key: K) => (<K extends keyof Value<K, T>>(key: K) => (<K extends keyof Value<K, Value<K, T>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, T>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, T>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>>(key: K) => any & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, T>>>>) => Value<K, Value<K, Value<K, Value<K, T>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, T>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, T>>>) => Value<K, Value<K, Value<K, T>>>) => T; set: (newU: Value<K, Value<K, Value<K, T>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, T>>) => Value<K, Value<K, T>>) => T; set: (newU: Value<K, Value<K, T>>) => T; }) & { map: (updater: (u: Value<K, T>) => Value<K, T>) => T; set: (newU: Value<K, T>) => T; }) & { map: (updater: (u: T) => T) => T; set: (newU: T) => T; }
+>updateIfChanged : <T>(t: T) => (<K extends keyof T>(key: K) => (<K extends keyof Value<K, T>>(key: K) => (<K extends keyof Value<K, Value<K, T>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, T>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, T>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>>(key: K) => any & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, T>>>>) => Value<K, Value<K, Value<K, Value<K, T>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, T>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, T>>>) => Value<K, Value<K, Value<K, T>>>) => T; set: (newU: Value<K, Value<K, Value<K, T>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, T>>) => Value<K, Value<K, T>>) => T; set: (newU: Value<K, Value<K, T>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, T>) => Value<K, T>) => T; set: (newU: Value<K, T>) => T; }>) & Writable<{ map: (updater: (u: T) => T) => T; set: (newU: T) => T; }>
+><T>(t: T) => {    const reduce = <U>(u: U, update: (u: U) => T) => {        const set = (newU: U) => Object.is(u, newU) ? t : update(newU);        return Object.assign(            <K extends Key<U>>(key: K) =>                reduce<Value<K, U>>(u[key as keyof U] as Value<K, U>, (v: Value<K, U>) => {                    return update(Object.assign(Array.isArray(u) ? [] : {}, u, { [key]: v }));                }),            { map: (updater: (u: U) => U) => set(updater(u)), set });    };    return reduce<T>(t, (t: T) => t);} : <T>(t: T) => (<K extends keyof T>(key: K) => (<K extends keyof Value<K, T>>(key: K) => (<K extends keyof Value<K, Value<K, T>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, T>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, T>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>>(key: K) => any & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, T>>>>) => Value<K, Value<K, Value<K, Value<K, T>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, T>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, T>>>) => Value<K, Value<K, Value<K, T>>>) => T; set: (newU: Value<K, Value<K, Value<K, T>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, T>>) => Value<K, Value<K, T>>) => T; set: (newU: Value<K, Value<K, T>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, T>) => Value<K, T>) => T; set: (newU: Value<K, T>) => T; }>) & Writable<{ map: (updater: (u: T) => T) => T; set: (newU: T) => T; }>
 >t : T
 
     const reduce = <U>(u: U, update: (u: U) => T) => {
->reduce : <U>(u: U, update: (u: U) => T) => (<K extends keyof U>(key: K) => (<K extends keyof Value<K, U>>(key: K) => (<K extends keyof Value<K, Value<K, U>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, U>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, U>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>(key: K) => any & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, U>>>>) => Value<K, Value<K, Value<K, Value<K, U>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, U>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, U>>>) => Value<K, Value<K, Value<K, U>>>) => T; set: (newU: Value<K, Value<K, Value<K, U>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, U>>) => Value<K, Value<K, U>>) => T; set: (newU: Value<K, Value<K, U>>) => T; }) & { map: (updater: (u: Value<K, U>) => Value<K, U>) => T; set: (newU: Value<K, U>) => T; }) & { map: (updater: (u: U) => U) => T; set: (newU: U) => T; }
-><U>(u: U, update: (u: U) => T) => {        const set = (newU: U) => Object.is(u, newU) ? t : update(newU);        return Object.assign(            <K extends Key<U>>(key: K) =>                reduce<Value<K, U>>(u[key as keyof U] as Value<K, U>, (v: Value<K, U>) => {                    return update(Object.assign(Array.isArray(u) ? [] : {}, u, { [key]: v }));                }),            { map: (updater: (u: U) => U) => set(updater(u)), set });    } : <U>(u: U, update: (u: U) => T) => (<K extends keyof U>(key: K) => (<K extends keyof Value<K, U>>(key: K) => (<K extends keyof Value<K, Value<K, U>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, U>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, U>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>(key: K) => any & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, U>>>>) => Value<K, Value<K, Value<K, Value<K, U>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, U>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, U>>>) => Value<K, Value<K, Value<K, U>>>) => T; set: (newU: Value<K, Value<K, Value<K, U>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, U>>) => Value<K, Value<K, U>>) => T; set: (newU: Value<K, Value<K, U>>) => T; }) & { map: (updater: (u: Value<K, U>) => Value<K, U>) => T; set: (newU: Value<K, U>) => T; }) & { map: (updater: (u: U) => U) => T; set: (newU: U) => T; }
+>reduce : <U>(u: U, update: (u: U) => T) => (<K extends keyof U>(key: K) => (<K extends keyof Value<K, U>>(key: K) => (<K extends keyof Value<K, Value<K, U>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, U>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, U>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>(key: K) => any & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, U>>>>) => Value<K, Value<K, Value<K, Value<K, U>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, U>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, U>>>) => Value<K, Value<K, Value<K, U>>>) => T; set: (newU: Value<K, Value<K, Value<K, U>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, U>>) => Value<K, Value<K, U>>) => T; set: (newU: Value<K, Value<K, U>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, U>) => Value<K, U>) => T; set: (newU: Value<K, U>) => T; }>) & Writable<{ map: (updater: (u: U) => U) => T; set: (newU: U) => T; }>
+><U>(u: U, update: (u: U) => T) => {        const set = (newU: U) => Object.is(u, newU) ? t : update(newU);        return Object.assign(            <K extends Key<U>>(key: K) =>                reduce<Value<K, U>>(u[key as keyof U] as Value<K, U>, (v: Value<K, U>) => {                    return update(Object.assign(Array.isArray(u) ? [] : {}, u, { [key]: v }));                }),            { map: (updater: (u: U) => U) => set(updater(u)), set });    } : <U>(u: U, update: (u: U) => T) => (<K extends keyof U>(key: K) => (<K extends keyof Value<K, U>>(key: K) => (<K extends keyof Value<K, Value<K, U>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, U>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, U>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>(key: K) => any & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, U>>>>) => Value<K, Value<K, Value<K, Value<K, U>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, U>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, U>>>) => Value<K, Value<K, Value<K, U>>>) => T; set: (newU: Value<K, Value<K, Value<K, U>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, U>>) => Value<K, Value<K, U>>) => T; set: (newU: Value<K, Value<K, U>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, U>) => Value<K, U>) => T; set: (newU: Value<K, U>) => T; }>) & Writable<{ map: (updater: (u: U) => U) => T; set: (newU: U) => T; }>
 >u : U
 >update : (u: U) => T
 >u : U
@@ -38,18 +38,18 @@ export const updateIfChanged = <T>(t: T) => {
 >newU : U
 
         return Object.assign(
->Object.assign(            <K extends Key<U>>(key: K) =>                reduce<Value<K, U>>(u[key as keyof U] as Value<K, U>, (v: Value<K, U>) => {                    return update(Object.assign(Array.isArray(u) ? [] : {}, u, { [key]: v }));                }),            { map: (updater: (u: U) => U) => set(updater(u)), set }) : (<K extends keyof U>(key: K) => (<K extends keyof Value<K, U>>(key: K) => (<K extends keyof Value<K, Value<K, U>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, U>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, U>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>(key: K) => any & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, U>>>>) => Value<K, Value<K, Value<K, Value<K, U>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, U>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, U>>>) => Value<K, Value<K, Value<K, U>>>) => T; set: (newU: Value<K, Value<K, Value<K, U>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, U>>) => Value<K, Value<K, U>>) => T; set: (newU: Value<K, Value<K, U>>) => T; }) & { map: (updater: (u: Value<K, U>) => Value<K, U>) => T; set: (newU: Value<K, U>) => T; }) & { map: (updater: (u: U) => U) => T; set: (newU: U) => T; }
->Object.assign : { <T extends {}, U>(target: T, source: U): T & U; <T extends {}, U, V>(target: T, source1: U, source2: V): T & U & V; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & U & V & W; (target: object, ...sources: any[]): any; }
+>Object.assign(            <K extends Key<U>>(key: K) =>                reduce<Value<K, U>>(u[key as keyof U] as Value<K, U>, (v: Value<K, U>) => {                    return update(Object.assign(Array.isArray(u) ? [] : {}, u, { [key]: v }));                }),            { map: (updater: (u: U) => U) => set(updater(u)), set }) : (<K extends keyof U>(key: K) => (<K extends keyof Value<K, U>>(key: K) => (<K extends keyof Value<K, Value<K, U>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, U>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, U>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>(key: K) => any & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, U>>>>) => Value<K, Value<K, Value<K, Value<K, U>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, U>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, U>>>) => Value<K, Value<K, Value<K, U>>>) => T; set: (newU: Value<K, Value<K, Value<K, U>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, U>>) => Value<K, Value<K, U>>) => T; set: (newU: Value<K, Value<K, U>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, U>) => Value<K, U>) => T; set: (newU: Value<K, U>) => T; }>) & Writable<{ map: (updater: (u: U) => U) => T; set: (newU: U) => T; }>
+>Object.assign : { <T extends {}>(target: T): T; <T extends {}, U>(target: T, source: U): T & Writable<U>; <T extends {}, U, V>(target: T, source1: U, source2: V): T & Writable<U> & Writable<V>; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & Writable<U> & Writable<V> & Writable<W>; (target: {}, ...sources: any[]): any; }
 >Object : ObjectConstructor
->assign : { <T extends {}, U>(target: T, source: U): T & U; <T extends {}, U, V>(target: T, source1: U, source2: V): T & U & V; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & U & V & W; (target: object, ...sources: any[]): any; }
+>assign : { <T extends {}>(target: T): T; <T extends {}, U>(target: T, source: U): T & Writable<U>; <T extends {}, U, V>(target: T, source1: U, source2: V): T & Writable<U> & Writable<V>; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & Writable<U> & Writable<V> & Writable<W>; (target: {}, ...sources: any[]): any; }
 
             <K extends Key<U>>(key: K) =>
-><K extends Key<U>>(key: K) =>                reduce<Value<K, U>>(u[key as keyof U] as Value<K, U>, (v: Value<K, U>) => {                    return update(Object.assign(Array.isArray(u) ? [] : {}, u, { [key]: v }));                }) : <K extends keyof U>(key: K) => (<K extends keyof Value<K, U>>(key: K) => (<K extends keyof Value<K, Value<K, U>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, U>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, U>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>(key: K) => any & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, U>>>>) => Value<K, Value<K, Value<K, Value<K, U>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, U>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, U>>>) => Value<K, Value<K, Value<K, U>>>) => T; set: (newU: Value<K, Value<K, Value<K, U>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, U>>) => Value<K, Value<K, U>>) => T; set: (newU: Value<K, Value<K, U>>) => T; }) & { map: (updater: (u: Value<K, U>) => Value<K, U>) => T; set: (newU: Value<K, U>) => T; }
+><K extends Key<U>>(key: K) =>                reduce<Value<K, U>>(u[key as keyof U] as Value<K, U>, (v: Value<K, U>) => {                    return update(Object.assign(Array.isArray(u) ? [] : {}, u, { [key]: v }));                }) : <K extends keyof U>(key: K) => (<K extends keyof Value<K, U>>(key: K) => (<K extends keyof Value<K, Value<K, U>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, U>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, U>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>(key: K) => any & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, U>>>>) => Value<K, Value<K, Value<K, Value<K, U>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, U>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, U>>>) => Value<K, Value<K, Value<K, U>>>) => T; set: (newU: Value<K, Value<K, Value<K, U>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, U>>) => Value<K, Value<K, U>>) => T; set: (newU: Value<K, Value<K, U>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, U>) => Value<K, U>) => T; set: (newU: Value<K, U>) => T; }>
 >key : K
 
                 reduce<Value<K, U>>(u[key as keyof U] as Value<K, U>, (v: Value<K, U>) => {
->reduce<Value<K, U>>(u[key as keyof U] as Value<K, U>, (v: Value<K, U>) => {                    return update(Object.assign(Array.isArray(u) ? [] : {}, u, { [key]: v }));                }) : (<K extends keyof Value<K, U>>(key: K) => (<K extends keyof Value<K, Value<K, U>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, U>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, U>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>>(key: K) => any & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, U>>>>) => Value<K, Value<K, Value<K, Value<K, U>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, U>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, U>>>) => Value<K, Value<K, Value<K, U>>>) => T; set: (newU: Value<K, Value<K, Value<K, U>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, U>>) => Value<K, Value<K, U>>) => T; set: (newU: Value<K, Value<K, U>>) => T; }) & { map: (updater: (u: Value<K, U>) => Value<K, U>) => T; set: (newU: Value<K, U>) => T; }
->reduce : <U>(u: U, update: (u: U) => T) => (<K extends keyof U>(key: K) => (<K extends keyof Value<K, U>>(key: K) => (<K extends keyof Value<K, Value<K, U>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, U>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, U>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>(key: K) => any & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, U>>>>) => Value<K, Value<K, Value<K, Value<K, U>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, U>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, U>>>) => Value<K, Value<K, Value<K, U>>>) => T; set: (newU: Value<K, Value<K, Value<K, U>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, U>>) => Value<K, Value<K, U>>) => T; set: (newU: Value<K, Value<K, U>>) => T; }) & { map: (updater: (u: Value<K, U>) => Value<K, U>) => T; set: (newU: Value<K, U>) => T; }) & { map: (updater: (u: U) => U) => T; set: (newU: U) => T; }
+>reduce<Value<K, U>>(u[key as keyof U] as Value<K, U>, (v: Value<K, U>) => {                    return update(Object.assign(Array.isArray(u) ? [] : {}, u, { [key]: v }));                }) : (<K extends keyof Value<K, U>>(key: K) => (<K extends keyof Value<K, Value<K, U>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, U>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, U>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>>(key: K) => any & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, U>>>>) => Value<K, Value<K, Value<K, Value<K, U>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, U>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, U>>>) => Value<K, Value<K, Value<K, U>>>) => T; set: (newU: Value<K, Value<K, Value<K, U>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, U>>) => Value<K, Value<K, U>>) => T; set: (newU: Value<K, Value<K, U>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, U>) => Value<K, U>) => T; set: (newU: Value<K, U>) => T; }>
+>reduce : <U>(u: U, update: (u: U) => T) => (<K extends keyof U>(key: K) => (<K extends keyof Value<K, U>>(key: K) => (<K extends keyof Value<K, Value<K, U>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, U>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, U>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>(key: K) => any & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, U>>>>) => Value<K, Value<K, Value<K, Value<K, U>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, U>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, U>>>) => Value<K, Value<K, Value<K, U>>>) => T; set: (newU: Value<K, Value<K, Value<K, U>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, U>>) => Value<K, Value<K, U>>) => T; set: (newU: Value<K, Value<K, U>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, U>) => Value<K, U>) => T; set: (newU: Value<K, U>) => T; }>) & Writable<{ map: (updater: (u: U) => U) => T; set: (newU: U) => T; }>
 >u[key as keyof U] as Value<K, U> : Value<K, U>
 >u[key as keyof U] : U[keyof U]
 >u : U
@@ -61,10 +61,10 @@ export const updateIfChanged = <T>(t: T) => {
                     return update(Object.assign(Array.isArray(u) ? [] : {}, u, { [key]: v }));
 >update(Object.assign(Array.isArray(u) ? [] : {}, u, { [key]: v })) : T
 >update : (u: U) => T
->Object.assign(Array.isArray(u) ? [] : {}, u, { [key]: v }) : U & { [x: string]: Value<K, U>; }
->Object.assign : { <T extends {}, U>(target: T, source: U): T & U; <T extends {}, U, V>(target: T, source1: U, source2: V): T & U & V; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & U & V & W; (target: object, ...sources: any[]): any; }
+>Object.assign(Array.isArray(u) ? [] : {}, u, { [key]: v }) : Writable<U> & Writable<{ [x: string]: Value<K, U>; }>
+>Object.assign : { <T extends {}>(target: T): T; <T extends {}, U>(target: T, source: U): T & Writable<U>; <T extends {}, U, V>(target: T, source1: U, source2: V): T & Writable<U> & Writable<V>; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & Writable<U> & Writable<V> & Writable<W>; (target: {}, ...sources: any[]): any; }
 >Object : ObjectConstructor
->assign : { <T extends {}, U>(target: T, source: U): T & U; <T extends {}, U, V>(target: T, source1: U, source2: V): T & U & V; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & U & V & W; (target: object, ...sources: any[]): any; }
+>assign : { <T extends {}>(target: T): T; <T extends {}, U>(target: T, source: U): T & Writable<U>; <T extends {}, U, V>(target: T, source1: U, source2: V): T & Writable<U> & Writable<V>; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & Writable<U> & Writable<V> & Writable<W>; (target: {}, ...sources: any[]): any; }
 >Array.isArray(u) ? [] : {} : undefined[] | {}
 >Array.isArray(u) : boolean
 >Array.isArray : (arg: any) => arg is any[]
@@ -95,8 +95,8 @@ export const updateIfChanged = <T>(t: T) => {
 
     };
     return reduce<T>(t, (t: T) => t);
->reduce<T>(t, (t: T) => t) : (<K extends keyof T>(key: K) => (<K extends keyof Value<K, T>>(key: K) => (<K extends keyof Value<K, Value<K, T>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, T>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, T>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>>(key: K) => any & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, T>>>>) => Value<K, Value<K, Value<K, Value<K, T>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, T>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, T>>>) => Value<K, Value<K, Value<K, T>>>) => T; set: (newU: Value<K, Value<K, Value<K, T>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, T>>) => Value<K, Value<K, T>>) => T; set: (newU: Value<K, Value<K, T>>) => T; }) & { map: (updater: (u: Value<K, T>) => Value<K, T>) => T; set: (newU: Value<K, T>) => T; }) & { map: (updater: (u: T) => T) => T; set: (newU: T) => T; }
->reduce : <U>(u: U, update: (u: U) => T) => (<K extends keyof U>(key: K) => (<K extends keyof Value<K, U>>(key: K) => (<K extends keyof Value<K, Value<K, U>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, U>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, U>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>(key: K) => any & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, U>>>>) => Value<K, Value<K, Value<K, Value<K, U>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, U>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, U>>>) => Value<K, Value<K, Value<K, U>>>) => T; set: (newU: Value<K, Value<K, Value<K, U>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, U>>) => Value<K, Value<K, U>>) => T; set: (newU: Value<K, Value<K, U>>) => T; }) & { map: (updater: (u: Value<K, U>) => Value<K, U>) => T; set: (newU: Value<K, U>) => T; }) & { map: (updater: (u: U) => U) => T; set: (newU: U) => T; }
+>reduce<T>(t, (t: T) => t) : (<K extends keyof T>(key: K) => (<K extends keyof Value<K, T>>(key: K) => (<K extends keyof Value<K, Value<K, T>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, T>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, T>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>>(key: K) => any & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, T>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, T>>>>) => Value<K, Value<K, Value<K, Value<K, T>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, T>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, T>>>) => Value<K, Value<K, Value<K, T>>>) => T; set: (newU: Value<K, Value<K, Value<K, T>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, T>>) => Value<K, Value<K, T>>) => T; set: (newU: Value<K, Value<K, T>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, T>) => Value<K, T>) => T; set: (newU: Value<K, T>) => T; }>) & Writable<{ map: (updater: (u: T) => T) => T; set: (newU: T) => T; }>
+>reduce : <U>(u: U, update: (u: U) => T) => (<K extends keyof U>(key: K) => (<K extends keyof Value<K, U>>(key: K) => (<K extends keyof Value<K, Value<K, U>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, U>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, U>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>(key: K) => any & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, Value<K, U>>>>) => Value<K, Value<K, Value<K, Value<K, U>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, U>>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, Value<K, U>>>) => Value<K, Value<K, Value<K, U>>>) => T; set: (newU: Value<K, Value<K, Value<K, U>>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, Value<K, U>>) => Value<K, Value<K, U>>) => T; set: (newU: Value<K, Value<K, U>>) => T; }>) & Writable<{ map: (updater: (u: Value<K, U>) => Value<K, U>) => T; set: (newU: Value<K, U>) => T; }>) & Writable<{ map: (updater: (u: U) => U) => T; set: (newU: U) => T; }>
 >t : T
 >(t: T) => t : (t: T) => T
 >t : T
diff --git a/tests/baselines/reference/duplicateNumericIndexers.errors.txt b/tests/baselines/reference/duplicateNumericIndexers.errors.txt
index 826a48d1c815b..2238bfad3a4dc 100644
--- a/tests/baselines/reference/duplicateNumericIndexers.errors.txt
+++ b/tests/baselines/reference/duplicateNumericIndexers.errors.txt
@@ -10,8 +10,8 @@ tests/cases/conformance/types/members/duplicateNumericIndexers.ts(24,5): error T
 tests/cases/conformance/types/members/duplicateNumericIndexers.ts(25,5): error TS2374: Duplicate index signature for type 'number'.
 tests/cases/conformance/types/members/duplicateNumericIndexers.ts(29,5): error TS2374: Duplicate index signature for type 'number'.
 tests/cases/conformance/types/members/duplicateNumericIndexers.ts(30,5): error TS2374: Duplicate index signature for type 'number'.
-lib.es5.d.ts(520,5): error TS2374: Duplicate index signature for type 'number'.
-lib.es5.d.ts(1484,5): error TS2374: Duplicate index signature for type 'number'.
+lib.es5.d.ts(538,5): error TS2374: Duplicate index signature for type 'number'.
+lib.es5.d.ts(1502,5): error TS2374: Duplicate index signature for type 'number'.
 
 
 ==== tests/cases/conformance/types/members/duplicateNumericIndexers.ts (12 errors) ====
diff --git a/tests/baselines/reference/ensureNoCrashExportAssignmentDefineProperrtyPotentialMerge.types b/tests/baselines/reference/ensureNoCrashExportAssignmentDefineProperrtyPotentialMerge.types
index c566d1897b08d..cf4beacdfc810 100644
--- a/tests/baselines/reference/ensureNoCrashExportAssignmentDefineProperrtyPotentialMerge.types
+++ b/tests/baselines/reference/ensureNoCrashExportAssignmentDefineProperrtyPotentialMerge.types
@@ -14,9 +14,9 @@ module.exports = 12;
 
 Object.defineProperty(module, "exports", { value: "oh no" });
 >Object.defineProperty(module, "exports", { value: "oh no" }) : typeof module
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >module : typeof module
 >"exports" : "exports"
 >{ value: "oh no" } : { value: string; }
@@ -59,9 +59,9 @@ B.NS = require("./namespacey");
 
 Object.defineProperty(B, "NS", { value: "why though", writable: true });
 >Object.defineProperty(B, "NS", { value: "why though", writable: true }) : typeof B
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >B : typeof B
 >"NS" : "NS"
 >{ value: "why though", writable: true } : { value: string; writable: true; }
diff --git a/tests/baselines/reference/es2018ObjectAssign.symbols b/tests/baselines/reference/es2018ObjectAssign.symbols
index 3ed140cb570d3..3f27f2158d345 100644
--- a/tests/baselines/reference/es2018ObjectAssign.symbols
+++ b/tests/baselines/reference/es2018ObjectAssign.symbols
@@ -1,9 +1,9 @@
 === tests/cases/compiler/es2018ObjectAssign.ts ===
 const test = Object.assign({}, { test: true });
 >test : Symbol(test, Decl(es2018ObjectAssign.ts, 0, 5))
->Object.assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>Object.assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
 >Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
->assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
 >test : Symbol(test, Decl(es2018ObjectAssign.ts, 0, 32))
 
 declare const p: Promise<number>;
diff --git a/tests/baselines/reference/es2018ObjectAssign.types b/tests/baselines/reference/es2018ObjectAssign.types
index e8cc1927c5caf..7e85abc8fe285 100644
--- a/tests/baselines/reference/es2018ObjectAssign.types
+++ b/tests/baselines/reference/es2018ObjectAssign.types
@@ -1,10 +1,10 @@
 === tests/cases/compiler/es2018ObjectAssign.ts ===
 const test = Object.assign({}, { test: true });
->test : { test: boolean; }
->Object.assign({}, { test: true }) : { test: boolean; }
->Object.assign : { <T extends {}, U>(target: T, source: U): T & U; <T extends {}, U, V>(target: T, source1: U, source2: V): T & U & V; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & U & V & W; (target: object, ...sources: any[]): any; }
+>test : Writable<{ test: boolean; }>
+>Object.assign({}, { test: true }) : Writable<{ test: boolean; }>
+>Object.assign : { <T extends {}>(target: T): T; <T extends {}, U>(target: T, source: U): T & Writable<U>; <T extends {}, U, V>(target: T, source1: U, source2: V): T & Writable<U> & Writable<V>; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & Writable<U> & Writable<V> & Writable<W>; (target: {}, ...sources: any[]): any; }
 >Object : ObjectConstructor
->assign : { <T extends {}, U>(target: T, source: U): T & U; <T extends {}, U, V>(target: T, source1: U, source2: V): T & U & V; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & U & V & W; (target: object, ...sources: any[]): any; }
+>assign : { <T extends {}>(target: T): T; <T extends {}, U>(target: T, source: U): T & Writable<U>; <T extends {}, U, V>(target: T, source1: U, source2: V): T & Writable<U> & Writable<V>; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & Writable<U> & Writable<V> & Writable<W>; (target: {}, ...sources: any[]): any; }
 >{} : {}
 >{ test: true } : { test: true; }
 >test : true
diff --git a/tests/baselines/reference/esNextWeakRefs_IterableWeakMap.types b/tests/baselines/reference/esNextWeakRefs_IterableWeakMap.types
index 79e54575127f7..8845f1a09b15a 100644
--- a/tests/baselines/reference/esNextWeakRefs_IterableWeakMap.types
+++ b/tests/baselines/reference/esNextWeakRefs_IterableWeakMap.types
@@ -307,9 +307,9 @@ export class IterableWeakMap<K extends object, V> implements WeakMap<K, V> {
 
 Object.defineProperties(IterableWeakMap.prototype, {
 >Object.defineProperties(IterableWeakMap.prototype, {    [Symbol.iterator]: {        configurable: true,        enumerable: false,        writable: true,        value: Object.getOwnPropertyDescriptor(            IterableWeakMap.prototype,            "entries",        )!.value,    },    [Symbol.toStringTag]: {        configurable: true,        enumerable: false,        writable: false,        value: "IterableWeakMap",    },}) : IterableWeakMap<any, any>
->Object.defineProperties : <T>(o: T, properties: PropertyDescriptorMap & ThisType<any>) => T
+>Object.defineProperties : <T extends object>(o: T, properties: PropertyDescriptorMap & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperties : <T>(o: T, properties: PropertyDescriptorMap & ThisType<any>) => T
+>defineProperties : <T extends object>(o: T, properties: PropertyDescriptorMap & ThisType<any>) => T
 >IterableWeakMap.prototype : IterableWeakMap<any, any>
 >IterableWeakMap : typeof IterableWeakMap
 >prototype : IterableWeakMap<any, any>
@@ -339,9 +339,9 @@ Object.defineProperties(IterableWeakMap.prototype, {
 >Object.getOwnPropertyDescriptor(            IterableWeakMap.prototype,            "entries",        )!.value : any
 >Object.getOwnPropertyDescriptor(            IterableWeakMap.prototype,            "entries",        )! : PropertyDescriptor
 >Object.getOwnPropertyDescriptor(            IterableWeakMap.prototype,            "entries",        ) : PropertyDescriptor | undefined
->Object.getOwnPropertyDescriptor : (o: any, p: PropertyKey) => PropertyDescriptor | undefined
+>Object.getOwnPropertyDescriptor : (o: {}, p: PropertyKey) => PropertyDescriptor | undefined
 >Object : ObjectConstructor
->getOwnPropertyDescriptor : (o: any, p: PropertyKey) => PropertyDescriptor | undefined
+>getOwnPropertyDescriptor : (o: {}, p: PropertyKey) => PropertyDescriptor | undefined
 
             IterableWeakMap.prototype,
 >IterableWeakMap.prototype : IterableWeakMap<any, any>
diff --git a/tests/baselines/reference/excessPropertyCheckWithEmptyObject.types b/tests/baselines/reference/excessPropertyCheckWithEmptyObject.types
index 3c748f7fd923b..6e19f04737b72 100644
--- a/tests/baselines/reference/excessPropertyCheckWithEmptyObject.types
+++ b/tests/baselines/reference/excessPropertyCheckWithEmptyObject.types
@@ -4,9 +4,9 @@
 // Excess property error expected here
 Object.defineProperty(window, "prop", { value: "v1.0.0", readonly: false });
 >Object.defineProperty(window, "prop", { value: "v1.0.0", readonly: false }) : Window & typeof globalThis
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >window : Window & typeof globalThis
 >"prop" : "prop"
 >{ value: "v1.0.0", readonly: false } : { value: string; readonly: boolean; }
diff --git a/tests/baselines/reference/getterSetterNonAccessor.types b/tests/baselines/reference/getterSetterNonAccessor.types
index 5f9a658b575f0..b81b5a6dcad1d 100644
--- a/tests/baselines/reference/getterSetterNonAccessor.types
+++ b/tests/baselines/reference/getterSetterNonAccessor.types
@@ -9,9 +9,9 @@ function setFunc(v){}
 
 Object.defineProperty({}, "0", <PropertyDescriptor>({
 >Object.defineProperty({}, "0", <PropertyDescriptor>({          get: getFunc,          set: setFunc,          configurable: true      })) : {}
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >{} : {}
 >"0" : "0"
 ><PropertyDescriptor>({          get: getFunc,          set: setFunc,          configurable: true      }) : PropertyDescriptor
diff --git a/tests/baselines/reference/importAliasModuleExports.types b/tests/baselines/reference/importAliasModuleExports.types
index 2067e8b8d74e4..982fbb7cfba05 100644
--- a/tests/baselines/reference/importAliasModuleExports.types
+++ b/tests/baselines/reference/importAliasModuleExports.types
@@ -42,9 +42,9 @@ A.prototype.func = function() { this._func = 0; }
 
 Object.defineProperty(A.prototype, "def", { value: 0 });
 >Object.defineProperty(A.prototype, "def", { value: 0 }) : A
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >A.prototype : A
 >A : typeof A
 >prototype : A
diff --git a/tests/baselines/reference/intersectionsAndEmptyObjects.symbols b/tests/baselines/reference/intersectionsAndEmptyObjects.symbols
index 7158ee012b987..83d3e6abe116b 100644
--- a/tests/baselines/reference/intersectionsAndEmptyObjects.symbols
+++ b/tests/baselines/reference/intersectionsAndEmptyObjects.symbols
@@ -116,9 +116,9 @@ const intersectDictionaries = <F1 extends Dictionary, F2 extends Dictionary>(
 ): F1 & F2 => Object.assign({}, d1, d2);
 >F1 : Symbol(F1, Decl(intersectionsAndEmptyObjects.ts, 30, 31))
 >F2 : Symbol(F2, Decl(intersectionsAndEmptyObjects.ts, 30, 53))
->Object.assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>Object.assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
 >Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
->assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
 >d1 : Symbol(d1, Decl(intersectionsAndEmptyObjects.ts, 30, 77))
 >d2 : Symbol(d2, Decl(intersectionsAndEmptyObjects.ts, 31, 9))
 
diff --git a/tests/baselines/reference/intersectionsAndEmptyObjects.types b/tests/baselines/reference/intersectionsAndEmptyObjects.types
index fc28f024e45e9..3d6a9caac238b 100644
--- a/tests/baselines/reference/intersectionsAndEmptyObjects.types
+++ b/tests/baselines/reference/intersectionsAndEmptyObjects.types
@@ -75,10 +75,10 @@ const intersectDictionaries = <F1 extends Dictionary, F2 extends Dictionary>(
 >d2 : F2
 
 ): F1 & F2 => Object.assign({}, d1, d2);
->Object.assign({}, d1, d2) : {} & F1 & F2
->Object.assign : { <T extends {}, U>(target: T, source: U): T & U; <T extends {}, U, V>(target: T, source1: U, source2: V): T & U & V; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & U & V & W; (target: object, ...sources: any[]): any; }
+>Object.assign({}, d1, d2) : Writable<F1> & Writable<F2>
+>Object.assign : { <T extends {}>(target: T): T; <T extends {}, U>(target: T, source: U): T & Writable<U>; <T extends {}, U, V>(target: T, source1: U, source2: V): T & Writable<U> & Writable<V>; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & Writable<U> & Writable<V> & Writable<W>; (target: {}, ...sources: any[]): any; }
 >Object : ObjectConstructor
->assign : { <T extends {}, U>(target: T, source: U): T & U; <T extends {}, U, V>(target: T, source1: U, source2: V): T & U & V; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & U & V & W; (target: object, ...sources: any[]): any; }
+>assign : { <T extends {}>(target: T): T; <T extends {}, U>(target: T, source: U): T & Writable<U>; <T extends {}, U, V>(target: T, source1: U, source2: V): T & Writable<U> & Writable<V>; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & Writable<U> & Writable<V> & Writable<W>; (target: {}, ...sources: any[]): any; }
 >{} : {}
 >d1 : F1
 >d2 : F2
diff --git a/tests/baselines/reference/javascriptDefinePropertyPrototypeNonConstructor.types b/tests/baselines/reference/javascriptDefinePropertyPrototypeNonConstructor.types
index 7dbd38d69dffa..834380deb4edf 100644
--- a/tests/baselines/reference/javascriptDefinePropertyPrototypeNonConstructor.types
+++ b/tests/baselines/reference/javascriptDefinePropertyPrototypeNonConstructor.types
@@ -5,9 +5,9 @@ function Graphic() {
 
 Object.defineProperty(Graphic.prototype, "instance", {
 >Object.defineProperty(Graphic.prototype, "instance", {  get: function() {    return this;  }}) : any
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Graphic.prototype : any
 >Graphic : typeof Graphic
 >prototype : any
diff --git a/tests/baselines/reference/jsCheckObjectDefineThisNoCrash.types b/tests/baselines/reference/jsCheckObjectDefineThisNoCrash.types
index e175b0527772f..00acd0d924652 100644
--- a/tests/baselines/reference/jsCheckObjectDefineThisNoCrash.types
+++ b/tests/baselines/reference/jsCheckObjectDefineThisNoCrash.types
@@ -6,9 +6,9 @@ class C {
         // Neither of the following should be recognized as declarations yet
         Object.defineProperty(this, "_prop", { value: {} });
 >Object.defineProperty(this, "_prop", { value: {} }) : this
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >this : this
 >"_prop" : "_prop"
 >{ value: {} } : { value: {}; }
@@ -17,9 +17,9 @@ class C {
 
         Object.defineProperty(this._prop, "num", { value: 12 });
 >Object.defineProperty(this._prop, "num", { value: 12 }) : any
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >this._prop : any
 >this : this
 >_prop : any
diff --git a/tests/baselines/reference/jsDeclarationsExportDefinePropertyEmit.types b/tests/baselines/reference/jsDeclarationsExportDefinePropertyEmit.types
index fc664ec5d19a6..3bbfde8ecf84d 100644
--- a/tests/baselines/reference/jsDeclarationsExportDefinePropertyEmit.types
+++ b/tests/baselines/reference/jsDeclarationsExportDefinePropertyEmit.types
@@ -1,9 +1,9 @@
 === tests/cases/conformance/jsdoc/declarations/index.js ===
 Object.defineProperty(module.exports, "a", { value: function a() {} });
 >Object.defineProperty(module.exports, "a", { value: function a() {} }) : typeof module.exports
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >module.exports : typeof module.exports
 >module : { exports: typeof module.exports; }
 >exports : typeof module.exports
@@ -15,9 +15,9 @@ Object.defineProperty(module.exports, "a", { value: function a() {} });
 
 Object.defineProperty(module.exports, "b", { value: function b() {} });
 >Object.defineProperty(module.exports, "b", { value: function b() {} }) : typeof module.exports
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >module.exports : typeof module.exports
 >module : { exports: typeof module.exports; }
 >exports : typeof module.exports
@@ -29,9 +29,9 @@ Object.defineProperty(module.exports, "b", { value: function b() {} });
 
 Object.defineProperty(module.exports.b, "cat", { value: "cat" });
 >Object.defineProperty(module.exports.b, "cat", { value: "cat" }) : () => void
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >module.exports.b : () => void
 >module.exports : typeof module.exports
 >module : { exports: typeof module.exports; }
@@ -56,9 +56,9 @@ function d(a, b) { return /** @type {*} */(null); }
 
 Object.defineProperty(module.exports, "d", { value: d });
 >Object.defineProperty(module.exports, "d", { value: d }) : typeof module.exports
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >module.exports : typeof module.exports
 >module : { exports: typeof module.exports; }
 >exports : typeof module.exports
@@ -83,9 +83,9 @@ function e(a, b) { return /** @type {*} */(null); }
 
 Object.defineProperty(module.exports, "e", { value: e });
 >Object.defineProperty(module.exports, "e", { value: e }) : typeof module.exports
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >module.exports : typeof module.exports
 >module : { exports: typeof module.exports; }
 >exports : typeof module.exports
@@ -107,9 +107,9 @@ function f(a) {
 }
 Object.defineProperty(module.exports, "f", { value: f });
 >Object.defineProperty(module.exports, "f", { value: f }) : typeof module.exports
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >module.exports : typeof module.exports
 >module : { exports: typeof module.exports; }
 >exports : typeof module.exports
@@ -120,9 +120,9 @@ Object.defineProperty(module.exports, "f", { value: f });
 
 Object.defineProperty(module.exports.f, "self", { value: module.exports.f });
 >Object.defineProperty(module.exports.f, "self", { value: module.exports.f }) : <T>(a: T) => T
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >module.exports.f : <T>(a: T) => T
 >module.exports : typeof module.exports
 >module : { exports: typeof module.exports; }
@@ -158,9 +158,9 @@ function g(a, b) {
 }
 Object.defineProperty(module.exports, "g", { value: g });
 >Object.defineProperty(module.exports, "g", { value: g }) : typeof module.exports
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >module.exports : typeof module.exports
 >module : { exports: typeof module.exports; }
 >exports : typeof module.exports
@@ -191,9 +191,9 @@ function hh(a, b) {
 }
 Object.defineProperty(module.exports, "h", { value: hh });
 >Object.defineProperty(module.exports, "h", { value: hh }) : typeof module.exports
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >module.exports : typeof module.exports
 >module : { exports: typeof module.exports; }
 >exports : typeof module.exports
@@ -204,9 +204,9 @@ Object.defineProperty(module.exports, "h", { value: hh });
 
 Object.defineProperty(module.exports, "i", { value: function i(){} });
 >Object.defineProperty(module.exports, "i", { value: function i(){} }) : typeof module.exports
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >module.exports : typeof module.exports
 >module : { exports: typeof module.exports; }
 >exports : typeof module.exports
@@ -218,9 +218,9 @@ Object.defineProperty(module.exports, "i", { value: function i(){} });
 
 Object.defineProperty(module.exports, "ii", { value: module.exports.i });
 >Object.defineProperty(module.exports, "ii", { value: module.exports.i }) : typeof module.exports
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >module.exports : typeof module.exports
 >module : { exports: typeof module.exports; }
 >exports : typeof module.exports
@@ -236,9 +236,9 @@ Object.defineProperty(module.exports, "ii", { value: module.exports.i });
 // note that this last one doesn't make much sense in cjs, since exports aren't hoisted bindings
 Object.defineProperty(module.exports, "jj", { value: module.exports.j });
 >Object.defineProperty(module.exports, "jj", { value: module.exports.j }) : typeof module.exports
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >module.exports : typeof module.exports
 >module : { exports: typeof module.exports; }
 >exports : typeof module.exports
@@ -253,9 +253,9 @@ Object.defineProperty(module.exports, "jj", { value: module.exports.j });
 
 Object.defineProperty(module.exports, "j", { value: function j() {} });
 >Object.defineProperty(module.exports, "j", { value: function j() {} }) : typeof module.exports
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >module.exports : typeof module.exports
 >module : { exports: typeof module.exports; }
 >exports : typeof module.exports
diff --git a/tests/baselines/reference/jsDeclarationsGetterSetter.types b/tests/baselines/reference/jsDeclarationsGetterSetter.types
index 146600cc4151e..aa064fb2d5be8 100644
--- a/tests/baselines/reference/jsDeclarationsGetterSetter.types
+++ b/tests/baselines/reference/jsDeclarationsGetterSetter.types
@@ -42,9 +42,9 @@ export class D {}
 
 Object.defineProperty(D.prototype, "x", {
 >Object.defineProperty(D.prototype, "x", {    get() {        return 12;    }}) : D
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >D.prototype : D
 >D : typeof D
 >prototype : D
@@ -64,9 +64,9 @@ export class E {}
 
 Object.defineProperty(E.prototype, "x", {
 >Object.defineProperty(E.prototype, "x", {    /**     * @param {number} _arg     */    set(_arg) {}}) : E
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >E.prototype : E
 >E : typeof E
 >prototype : E
@@ -87,9 +87,9 @@ export class F {}
 
 Object.defineProperty(F.prototype, "x", {
 >Object.defineProperty(F.prototype, "x", {    get() {        return 12;    },    /**     * @param {number} _arg     */    set(_arg) {}}) : F
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >F.prototype : F
 >F : typeof F
 >prototype : F
diff --git a/tests/baselines/reference/jsExpandoObjectDefineProperty.types b/tests/baselines/reference/jsExpandoObjectDefineProperty.types
index fb25ede2da462..d1c059915ea2e 100644
--- a/tests/baselines/reference/jsExpandoObjectDefineProperty.types
+++ b/tests/baselines/reference/jsExpandoObjectDefineProperty.types
@@ -5,9 +5,9 @@ var chrome = {}
 
 Object.defineProperty(chrome, 'devtools', { value: {}, enumerable: true })
 >Object.defineProperty(chrome, 'devtools', { value: {}, enumerable: true }) : typeof chrome
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >chrome : typeof chrome
 >'devtools' : "devtools"
 >{ value: {}, enumerable: true } : { value: {}; enumerable: true; }
diff --git a/tests/baselines/reference/jsFileESModuleWithEnumTag.types b/tests/baselines/reference/jsFileESModuleWithEnumTag.types
index 4ecc2d0fdd6a5..57bf39e14d499 100644
--- a/tests/baselines/reference/jsFileESModuleWithEnumTag.types
+++ b/tests/baselines/reference/jsFileESModuleWithEnumTag.types
@@ -34,9 +34,9 @@ ChangeDetectionStrategy[ChangeDetectionStrategy.Default] = 'Default';
 
 Object.defineProperty(ChangeDetectionStrategy, "aField", {value: 42});
 >Object.defineProperty(ChangeDetectionStrategy, "aField", {value: 42}) : { OnPush: number; Default: number; }
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >ChangeDetectionStrategy : { OnPush: number; Default: number; }
 >"aField" : "aField"
 >{value: 42} : { value: number; }
diff --git a/tests/baselines/reference/lateBoundAssignmentDeclarationSupport3.types b/tests/baselines/reference/lateBoundAssignmentDeclarationSupport3.types
index 7f6c8d2c42ada..f04edbf31e6c5 100644
--- a/tests/baselines/reference/lateBoundAssignmentDeclarationSupport3.types
+++ b/tests/baselines/reference/lateBoundAssignmentDeclarationSupport3.types
@@ -32,9 +32,9 @@ const _str = "my-fake-sym";
 
 Object.defineProperty(module.exports, _sym, { value: "ok" });
 >Object.defineProperty(module.exports, _sym, { value: "ok" }) : typeof module.exports
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >module.exports : typeof module.exports
 >module : { exports: typeof module.exports; }
 >exports : typeof module.exports
@@ -45,9 +45,9 @@ Object.defineProperty(module.exports, _sym, { value: "ok" });
 
 Object.defineProperty(module.exports, _str, { value: "ok" });
 >Object.defineProperty(module.exports, _str, { value: "ok" }) : typeof module.exports
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >module.exports : typeof module.exports
 >module : { exports: typeof module.exports; }
 >exports : typeof module.exports
diff --git a/tests/baselines/reference/lateBoundAssignmentDeclarationSupport6.types b/tests/baselines/reference/lateBoundAssignmentDeclarationSupport6.types
index 754ff5f67dbfe..fb697a9cfdc79 100644
--- a/tests/baselines/reference/lateBoundAssignmentDeclarationSupport6.types
+++ b/tests/baselines/reference/lateBoundAssignmentDeclarationSupport6.types
@@ -51,9 +51,9 @@ F.prototype.defsAClass = true;
 
 Object.defineProperty(F.prototype, _str, {value: "ok"});
 >Object.defineProperty(F.prototype, _str, {value: "ok"}) : any
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >F.prototype : any
 >F : typeof F
 >prototype : any
@@ -64,9 +64,9 @@ Object.defineProperty(F.prototype, _str, {value: "ok"});
 
 Object.defineProperty(F.prototype, _sym, {value: "ok"});
 >Object.defineProperty(F.prototype, _sym, {value: "ok"}) : any
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >F.prototype : any
 >F : typeof F
 >prototype : any
diff --git a/tests/baselines/reference/objectFromEntries.types b/tests/baselines/reference/objectFromEntries.types
index 9812b4ae90c4b..a8921ba8418c4 100644
--- a/tests/baselines/reference/objectFromEntries.types
+++ b/tests/baselines/reference/objectFromEntries.types
@@ -1,10 +1,10 @@
 === tests/cases/compiler/objectFromEntries.ts ===
 const o = Object.fromEntries([['a', 1], ['b', 2], ['c', 3]]);
->o : { [k: string]: number; }
->Object.fromEntries([['a', 1], ['b', 2], ['c', 3]]) : { [k: string]: number; }
->Object.fromEntries : { <T = any>(entries: Iterable<readonly [PropertyKey, T]>): { [k: string]: T; }; (entries: Iterable<readonly any[]>): any; }
+>o : { [k: string]: number; [k: number]: number; [k: symbol]: number; }
+>Object.fromEntries([['a', 1], ['b', 2], ['c', 3]]) : { [k: string]: number; [k: number]: number; [k: symbol]: number; }
+>Object.fromEntries : { <T = any>(entries: Iterable<readonly [PropertyKey, T]>): { [k: string]: T; [k: number]: T; [k: symbol]: T; }; (entries: Iterable<readonly any[]>): any; }
 >Object : ObjectConstructor
->fromEntries : { <T = any>(entries: Iterable<readonly [PropertyKey, T]>): { [k: string]: T; }; (entries: Iterable<readonly any[]>): any; }
+>fromEntries : { <T = any>(entries: Iterable<readonly [PropertyKey, T]>): { [k: string]: T; [k: number]: T; [k: symbol]: T; }; (entries: Iterable<readonly any[]>): any; }
 >[['a', 1], ['b', 2], ['c', 3]] : [string, number][]
 >['a', 1] : [string, number]
 >'a' : "a"
@@ -17,20 +17,20 @@ const o = Object.fromEntries([['a', 1], ['b', 2], ['c', 3]]);
 >3 : 3
 
 const o2 = Object.fromEntries(new URLSearchParams());
->o2 : { [k: string]: string; }
->Object.fromEntries(new URLSearchParams()) : { [k: string]: string; }
->Object.fromEntries : { <T = any>(entries: Iterable<readonly [PropertyKey, T]>): { [k: string]: T; }; (entries: Iterable<readonly any[]>): any; }
+>o2 : { [k: string]: string; [k: number]: string; [k: symbol]: string; }
+>Object.fromEntries(new URLSearchParams()) : { [k: string]: string; [k: number]: string; [k: symbol]: string; }
+>Object.fromEntries : { <T = any>(entries: Iterable<readonly [PropertyKey, T]>): { [k: string]: T; [k: number]: T; [k: symbol]: T; }; (entries: Iterable<readonly any[]>): any; }
 >Object : ObjectConstructor
->fromEntries : { <T = any>(entries: Iterable<readonly [PropertyKey, T]>): { [k: string]: T; }; (entries: Iterable<readonly any[]>): any; }
+>fromEntries : { <T = any>(entries: Iterable<readonly [PropertyKey, T]>): { [k: string]: T; [k: number]: T; [k: symbol]: T; }; (entries: Iterable<readonly any[]>): any; }
 >new URLSearchParams() : URLSearchParams
 >URLSearchParams : { new (init?: string | URLSearchParams | string[][] | Record<string, string>): URLSearchParams; prototype: URLSearchParams; toString(): string; }
 
 const o3 = Object.fromEntries(new Map([[Symbol("key"), "value"]]));
->o3 : { [k: string]: string; }
->Object.fromEntries(new Map([[Symbol("key"), "value"]])) : { [k: string]: string; }
->Object.fromEntries : { <T = any>(entries: Iterable<readonly [PropertyKey, T]>): { [k: string]: T; }; (entries: Iterable<readonly any[]>): any; }
+>o3 : { [k: string]: string; [k: number]: string; [k: symbol]: string; }
+>Object.fromEntries(new Map([[Symbol("key"), "value"]])) : { [k: string]: string; [k: number]: string; [k: symbol]: string; }
+>Object.fromEntries : { <T = any>(entries: Iterable<readonly [PropertyKey, T]>): { [k: string]: T; [k: number]: T; [k: symbol]: T; }; (entries: Iterable<readonly any[]>): any; }
 >Object : ObjectConstructor
->fromEntries : { <T = any>(entries: Iterable<readonly [PropertyKey, T]>): { [k: string]: T; }; (entries: Iterable<readonly any[]>): any; }
+>fromEntries : { <T = any>(entries: Iterable<readonly [PropertyKey, T]>): { [k: string]: T; [k: number]: T; [k: symbol]: T; }; (entries: Iterable<readonly any[]>): any; }
 >new Map([[Symbol("key"), "value"]]) : Map<symbol, string>
 >Map : MapConstructor
 >[[Symbol("key"), "value"]] : [symbol, string][]
@@ -60,9 +60,9 @@ const frozenArray = Object.freeze([['a', 1], ['b', 2], ['c', 3]]);
 const o4 = Object.fromEntries(frozenArray);
 >o4 : any
 >Object.fromEntries(frozenArray) : any
->Object.fromEntries : { <T = any>(entries: Iterable<readonly [PropertyKey, T]>): { [k: string]: T; }; (entries: Iterable<readonly any[]>): any; }
+>Object.fromEntries : { <T = any>(entries: Iterable<readonly [PropertyKey, T]>): { [k: string]: T; [k: number]: T; [k: symbol]: T; }; (entries: Iterable<readonly any[]>): any; }
 >Object : ObjectConstructor
->fromEntries : { <T = any>(entries: Iterable<readonly [PropertyKey, T]>): { [k: string]: T; }; (entries: Iterable<readonly any[]>): any; }
+>fromEntries : { <T = any>(entries: Iterable<readonly [PropertyKey, T]>): { [k: string]: T; [k: number]: T; [k: symbol]: T; }; (entries: Iterable<readonly any[]>): any; }
 >frozenArray : readonly (string | number)[][]
 
 const frozenArray2: readonly [string, number][] = Object.freeze([['a', 1], ['b', 2], ['c', 3]]);
@@ -83,10 +83,10 @@ const frozenArray2: readonly [string, number][] = Object.freeze([['a', 1], ['b',
 >3 : 3
 
 const o5 = Object.fromEntries(frozenArray2);
->o5 : { [k: string]: number; }
->Object.fromEntries(frozenArray2) : { [k: string]: number; }
->Object.fromEntries : { <T = any>(entries: Iterable<readonly [PropertyKey, T]>): { [k: string]: T; }; (entries: Iterable<readonly any[]>): any; }
+>o5 : { [k: string]: number; [k: number]: number; [k: symbol]: number; }
+>Object.fromEntries(frozenArray2) : { [k: string]: number; [k: number]: number; [k: symbol]: number; }
+>Object.fromEntries : { <T = any>(entries: Iterable<readonly [PropertyKey, T]>): { [k: string]: T; [k: number]: T; [k: symbol]: T; }; (entries: Iterable<readonly any[]>): any; }
 >Object : ObjectConstructor
->fromEntries : { <T = any>(entries: Iterable<readonly [PropertyKey, T]>): { [k: string]: T; }; (entries: Iterable<readonly any[]>): any; }
+>fromEntries : { <T = any>(entries: Iterable<readonly [PropertyKey, T]>): { [k: string]: T; [k: number]: T; [k: symbol]: T; }; (entries: Iterable<readonly any[]>): any; }
 >frozenArray2 : readonly [string, number][]
 
diff --git a/tests/baselines/reference/objectLitGetterSetter.types b/tests/baselines/reference/objectLitGetterSetter.types
index 54c587890f8ac..f70bb3d8a3c9f 100644
--- a/tests/baselines/reference/objectLitGetterSetter.types
+++ b/tests/baselines/reference/objectLitGetterSetter.types
@@ -5,9 +5,9 @@
 
             Object.defineProperty(obj, "accProperty", <PropertyDescriptor>({
 >Object.defineProperty(obj, "accProperty", <PropertyDescriptor>({                get: function () {                    eval("public = 1;");                    return 11;                },                set: function (v) {                }            })) : {}
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >obj : {}
 >"accProperty" : "accProperty"
 ><PropertyDescriptor>({                get: function () {                    eval("public = 1;");                    return 11;                },                set: function (v) {                }            }) : PropertyDescriptor
diff --git a/tests/baselines/reference/objectMethodNullability.errors.txt b/tests/baselines/reference/objectMethodNullability.errors.txt
new file mode 100644
index 0000000000000..570b7e758ea56
--- /dev/null
+++ b/tests/baselines/reference/objectMethodNullability.errors.txt
@@ -0,0 +1,135 @@
+tests/cases/compiler/objectMethodNullability.ts(3,15): error TS2769: No overload matches this call.
+  Overload 1 of 5, '(target: {}): {}', gave the following error.
+    Argument of type 'undefined' is not assignable to parameter of type '{}'.
+  Overload 2 of 5, '(target: {}, ...sources: any[]): any', gave the following error.
+    Argument of type 'undefined' is not assignable to parameter of type '{}'.
+tests/cases/compiler/objectMethodNullability.ts(4,15): error TS2345: Argument of type 'undefined' is not assignable to parameter of type 'object | null'.
+tests/cases/compiler/objectMethodNullability.ts(5,25): error TS2345: Argument of type 'undefined' is not assignable to parameter of type 'object'.
+tests/cases/compiler/objectMethodNullability.ts(6,23): error TS2345: Argument of type 'undefined' is not assignable to parameter of type 'object'.
+tests/cases/compiler/objectMethodNullability.ts(7,16): error TS2769: No overload matches this call.
+  Overload 1 of 2, '(o: { [s: string]: unknown; } | ArrayLike<unknown>): [string, unknown][]', gave the following error.
+    Argument of type 'undefined' is not assignable to parameter of type '{ [s: string]: unknown; } | ArrayLike<unknown>'.
+  Overload 2 of 2, '(o: {}): [string, any][]', gave the following error.
+    Argument of type 'undefined' is not assignable to parameter of type '{}'.
+tests/cases/compiler/objectMethodNullability.ts(8,33): error TS2345: Argument of type 'undefined' is not assignable to parameter of type '{}'.
+tests/cases/compiler/objectMethodNullability.ts(9,34): error TS2345: Argument of type 'undefined' is not assignable to parameter of type '{}'.
+tests/cases/compiler/objectMethodNullability.ts(10,28): error TS2345: Argument of type 'undefined' is not assignable to parameter of type '{}'.
+tests/cases/compiler/objectMethodNullability.ts(11,30): error TS2345: Argument of type 'undefined' is not assignable to parameter of type '{}'.
+tests/cases/compiler/objectMethodNullability.ts(12,23): error TS2345: Argument of type 'undefined' is not assignable to parameter of type '{}'.
+tests/cases/compiler/objectMethodNullability.ts(13,15): error TS2345: Argument of type 'undefined' is not assignable to parameter of type '{}'.
+tests/cases/compiler/objectMethodNullability.ts(14,13): error TS2769: No overload matches this call.
+  Overload 1 of 2, '(o: {}): string[]', gave the following error.
+    Argument of type 'undefined' is not assignable to parameter of type '{}'.
+  Overload 2 of 2, '(o: object): string[]', gave the following error.
+    Argument of type 'undefined' is not assignable to parameter of type 'object'.
+tests/cases/compiler/objectMethodNullability.ts(15,23): error TS2345: Argument of type 'undefined' is not assignable to parameter of type '{}'.
+tests/cases/compiler/objectMethodNullability.ts(16,15): error TS2769: No overload matches this call.
+  Overload 1 of 2, '(o: ArrayLike<unknown> | { [s: string]: unknown; }): unknown[]', gave the following error.
+    Argument of type 'undefined' is not assignable to parameter of type 'ArrayLike<unknown> | { [s: string]: unknown; }'.
+  Overload 2 of 2, '(o: {}): any[]', gave the following error.
+    Argument of type 'undefined' is not assignable to parameter of type '{}'.
+tests/cases/compiler/objectMethodNullability.ts(18,15): error TS2345: Argument of type 'number' is not assignable to parameter of type 'object'.
+tests/cases/compiler/objectMethodNullability.ts(19,25): error TS2345: Argument of type 'number' is not assignable to parameter of type 'object'.
+tests/cases/compiler/objectMethodNullability.ts(20,23): error TS2345: Argument of type 'number' is not assignable to parameter of type 'object'.
+
+
+==== tests/cases/compiler/objectMethodNullability.ts (17 errors) ====
+    // All of the following should produce an error:
+    
+    Object.assign(undefined);
+                  ~~~~~~~~~
+!!! error TS2769: No overload matches this call.
+!!! error TS2769:   Overload 1 of 5, '(target: {}): {}', gave the following error.
+!!! error TS2769:     Argument of type 'undefined' is not assignable to parameter of type '{}'.
+!!! error TS2769:   Overload 2 of 5, '(target: {}, ...sources: any[]): any', gave the following error.
+!!! error TS2769:     Argument of type 'undefined' is not assignable to parameter of type '{}'.
+    Object.create(undefined);
+                  ~~~~~~~~~
+!!! error TS2345: Argument of type 'undefined' is not assignable to parameter of type 'object | null'.
+    Object.defineProperties(undefined, {});
+                            ~~~~~~~~~
+!!! error TS2345: Argument of type 'undefined' is not assignable to parameter of type 'object'.
+    Object.defineProperty(undefined, "foo", {});
+                          ~~~~~~~~~
+!!! error TS2345: Argument of type 'undefined' is not assignable to parameter of type 'object'.
+    Object.entries(undefined);
+                   ~~~~~~~~~
+!!! error TS2769: No overload matches this call.
+!!! error TS2769:   Overload 1 of 2, '(o: { [s: string]: unknown; } | ArrayLike<unknown>): [string, unknown][]', gave the following error.
+!!! error TS2769:     Argument of type 'undefined' is not assignable to parameter of type '{ [s: string]: unknown; } | ArrayLike<unknown>'.
+!!! error TS2769:   Overload 2 of 2, '(o: {}): [string, any][]', gave the following error.
+!!! error TS2769:     Argument of type 'undefined' is not assignable to parameter of type '{}'.
+    Object.getOwnPropertyDescriptor(undefined, "foo");
+                                    ~~~~~~~~~
+!!! error TS2345: Argument of type 'undefined' is not assignable to parameter of type '{}'.
+    Object.getOwnPropertyDescriptors(undefined);
+                                     ~~~~~~~~~
+!!! error TS2345: Argument of type 'undefined' is not assignable to parameter of type '{}'.
+    Object.getOwnPropertyNames(undefined);
+                               ~~~~~~~~~
+!!! error TS2345: Argument of type 'undefined' is not assignable to parameter of type '{}'.
+    Object.getOwnPropertySymbols(undefined);
+                                 ~~~~~~~~~
+!!! error TS2345: Argument of type 'undefined' is not assignable to parameter of type '{}'.
+    Object.getPrototypeOf(undefined);
+                          ~~~~~~~~~
+!!! error TS2345: Argument of type 'undefined' is not assignable to parameter of type '{}'.
+    Object.hasOwn(undefined, "foo");
+                  ~~~~~~~~~
+!!! error TS2345: Argument of type 'undefined' is not assignable to parameter of type '{}'.
+    Object.keys(undefined);
+                ~~~~~~~~~
+!!! error TS2769: No overload matches this call.
+!!! error TS2769:   Overload 1 of 2, '(o: {}): string[]', gave the following error.
+!!! error TS2769:     Argument of type 'undefined' is not assignable to parameter of type '{}'.
+!!! error TS2769:   Overload 2 of 2, '(o: object): string[]', gave the following error.
+!!! error TS2769:     Argument of type 'undefined' is not assignable to parameter of type 'object'.
+    Object.setPrototypeOf(undefined, {});
+                          ~~~~~~~~~
+!!! error TS2345: Argument of type 'undefined' is not assignable to parameter of type '{}'.
+    Object.values(undefined);
+                  ~~~~~~~~~
+!!! error TS2769: No overload matches this call.
+!!! error TS2769:   Overload 1 of 2, '(o: ArrayLike<unknown> | { [s: string]: unknown; }): unknown[]', gave the following error.
+!!! error TS2769:     Argument of type 'undefined' is not assignable to parameter of type 'ArrayLike<unknown> | { [s: string]: unknown; }'.
+!!! error TS2769:   Overload 2 of 2, '(o: {}): any[]', gave the following error.
+!!! error TS2769:     Argument of type 'undefined' is not assignable to parameter of type '{}'.
+    
+    Object.create(0);
+                  ~
+!!! error TS2345: Argument of type 'number' is not assignable to parameter of type 'object'.
+    Object.defineProperties(0, {});
+                            ~
+!!! error TS2345: Argument of type 'number' is not assignable to parameter of type 'object'.
+    Object.defineProperty(0, "foo", {});
+                          ~
+!!! error TS2345: Argument of type 'number' is not assignable to parameter of type 'object'.
+    
+    // While the following should not:
+    
+    Object.assign(0);
+    Object.entries(0);
+    Object.getOwnPropertyDescriptor(0, "foo");
+    Object.getOwnPropertyDescriptors(0);
+    Object.getOwnPropertyNames(0);
+    Object.getOwnPropertySymbols(0);
+    Object.getPrototypeOf(0);
+    Object.hasOwn(0, "foo");
+    Object.keys(0);
+    Object.setPrototypeOf(0, {});
+    Object.values(0);
+    
+    Object.freeze(undefined);
+    Object.isExtensible(undefined);
+    Object.isFrozen(undefined);
+    Object.isSealed(undefined);
+    Object.preventExtensions(undefined);
+    Object.seal(undefined);
+    
+    Object.freeze(0);
+    Object.isExtensible(0);
+    Object.isFrozen(0);
+    Object.isSealed(0);
+    Object.preventExtensions(0);
+    Object.seal(0);
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/objectMethodNullability.js b/tests/baselines/reference/objectMethodNullability.js
new file mode 100644
index 0000000000000..0fbc2117922b2
--- /dev/null
+++ b/tests/baselines/reference/objectMethodNullability.js
@@ -0,0 +1,95 @@
+//// [objectMethodNullability.ts]
+// All of the following should produce an error:
+
+Object.assign(undefined);
+Object.create(undefined);
+Object.defineProperties(undefined, {});
+Object.defineProperty(undefined, "foo", {});
+Object.entries(undefined);
+Object.getOwnPropertyDescriptor(undefined, "foo");
+Object.getOwnPropertyDescriptors(undefined);
+Object.getOwnPropertyNames(undefined);
+Object.getOwnPropertySymbols(undefined);
+Object.getPrototypeOf(undefined);
+Object.hasOwn(undefined, "foo");
+Object.keys(undefined);
+Object.setPrototypeOf(undefined, {});
+Object.values(undefined);
+
+Object.create(0);
+Object.defineProperties(0, {});
+Object.defineProperty(0, "foo", {});
+
+// While the following should not:
+
+Object.assign(0);
+Object.entries(0);
+Object.getOwnPropertyDescriptor(0, "foo");
+Object.getOwnPropertyDescriptors(0);
+Object.getOwnPropertyNames(0);
+Object.getOwnPropertySymbols(0);
+Object.getPrototypeOf(0);
+Object.hasOwn(0, "foo");
+Object.keys(0);
+Object.setPrototypeOf(0, {});
+Object.values(0);
+
+Object.freeze(undefined);
+Object.isExtensible(undefined);
+Object.isFrozen(undefined);
+Object.isSealed(undefined);
+Object.preventExtensions(undefined);
+Object.seal(undefined);
+
+Object.freeze(0);
+Object.isExtensible(0);
+Object.isFrozen(0);
+Object.isSealed(0);
+Object.preventExtensions(0);
+Object.seal(0);
+
+
+//// [objectMethodNullability.js]
+"use strict";
+// All of the following should produce an error:
+Object.assign(undefined);
+Object.create(undefined);
+Object.defineProperties(undefined, {});
+Object.defineProperty(undefined, "foo", {});
+Object.entries(undefined);
+Object.getOwnPropertyDescriptor(undefined, "foo");
+Object.getOwnPropertyDescriptors(undefined);
+Object.getOwnPropertyNames(undefined);
+Object.getOwnPropertySymbols(undefined);
+Object.getPrototypeOf(undefined);
+Object.hasOwn(undefined, "foo");
+Object.keys(undefined);
+Object.setPrototypeOf(undefined, {});
+Object.values(undefined);
+Object.create(0);
+Object.defineProperties(0, {});
+Object.defineProperty(0, "foo", {});
+// While the following should not:
+Object.assign(0);
+Object.entries(0);
+Object.getOwnPropertyDescriptor(0, "foo");
+Object.getOwnPropertyDescriptors(0);
+Object.getOwnPropertyNames(0);
+Object.getOwnPropertySymbols(0);
+Object.getPrototypeOf(0);
+Object.hasOwn(0, "foo");
+Object.keys(0);
+Object.setPrototypeOf(0, {});
+Object.values(0);
+Object.freeze(undefined);
+Object.isExtensible(undefined);
+Object.isFrozen(undefined);
+Object.isSealed(undefined);
+Object.preventExtensions(undefined);
+Object.seal(undefined);
+Object.freeze(0);
+Object.isExtensible(0);
+Object.isFrozen(0);
+Object.isSealed(0);
+Object.preventExtensions(0);
+Object.seal(0);
diff --git a/tests/baselines/reference/objectMethodNullability.symbols b/tests/baselines/reference/objectMethodNullability.symbols
new file mode 100644
index 0000000000000..ee25962e68871
--- /dev/null
+++ b/tests/baselines/reference/objectMethodNullability.symbols
@@ -0,0 +1,225 @@
+=== tests/cases/compiler/objectMethodNullability.ts ===
+// All of the following should produce an error:
+
+Object.assign(undefined);
+>Object.assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>undefined : Symbol(undefined)
+
+Object.create(undefined);
+>Object.create : Symbol(ObjectConstructor.create, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>create : Symbol(ObjectConstructor.create, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>undefined : Symbol(undefined)
+
+Object.defineProperties(undefined, {});
+>Object.defineProperties : Symbol(ObjectConstructor.defineProperties, Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>defineProperties : Symbol(ObjectConstructor.defineProperties, Decl(lib.es5.d.ts, --, --))
+>undefined : Symbol(undefined)
+
+Object.defineProperty(undefined, "foo", {});
+>Object.defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>undefined : Symbol(undefined)
+
+Object.entries(undefined);
+>Object.entries : Symbol(ObjectConstructor.entries, Decl(lib.es2017.object.d.ts, --, --), Decl(lib.es2017.object.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>entries : Symbol(ObjectConstructor.entries, Decl(lib.es2017.object.d.ts, --, --), Decl(lib.es2017.object.d.ts, --, --))
+>undefined : Symbol(undefined)
+
+Object.getOwnPropertyDescriptor(undefined, "foo");
+>Object.getOwnPropertyDescriptor : Symbol(ObjectConstructor.getOwnPropertyDescriptor, Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>getOwnPropertyDescriptor : Symbol(ObjectConstructor.getOwnPropertyDescriptor, Decl(lib.es5.d.ts, --, --))
+>undefined : Symbol(undefined)
+
+Object.getOwnPropertyDescriptors(undefined);
+>Object.getOwnPropertyDescriptors : Symbol(ObjectConstructor.getOwnPropertyDescriptors, Decl(lib.es2017.object.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>getOwnPropertyDescriptors : Symbol(ObjectConstructor.getOwnPropertyDescriptors, Decl(lib.es2017.object.d.ts, --, --))
+>undefined : Symbol(undefined)
+
+Object.getOwnPropertyNames(undefined);
+>Object.getOwnPropertyNames : Symbol(ObjectConstructor.getOwnPropertyNames, Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>getOwnPropertyNames : Symbol(ObjectConstructor.getOwnPropertyNames, Decl(lib.es5.d.ts, --, --))
+>undefined : Symbol(undefined)
+
+Object.getOwnPropertySymbols(undefined);
+>Object.getOwnPropertySymbols : Symbol(ObjectConstructor.getOwnPropertySymbols, Decl(lib.es2015.core.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>getOwnPropertySymbols : Symbol(ObjectConstructor.getOwnPropertySymbols, Decl(lib.es2015.core.d.ts, --, --))
+>undefined : Symbol(undefined)
+
+Object.getPrototypeOf(undefined);
+>Object.getPrototypeOf : Symbol(ObjectConstructor.getPrototypeOf, Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>getPrototypeOf : Symbol(ObjectConstructor.getPrototypeOf, Decl(lib.es5.d.ts, --, --))
+>undefined : Symbol(undefined)
+
+Object.hasOwn(undefined, "foo");
+>Object.hasOwn : Symbol(ObjectConstructor.hasOwn, Decl(lib.es2022.object.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>hasOwn : Symbol(ObjectConstructor.hasOwn, Decl(lib.es2022.object.d.ts, --, --))
+>undefined : Symbol(undefined)
+
+Object.keys(undefined);
+>Object.keys : Symbol(ObjectConstructor.keys, Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>keys : Symbol(ObjectConstructor.keys, Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>undefined : Symbol(undefined)
+
+Object.setPrototypeOf(undefined, {});
+>Object.setPrototypeOf : Symbol(ObjectConstructor.setPrototypeOf, Decl(lib.es2015.core.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>setPrototypeOf : Symbol(ObjectConstructor.setPrototypeOf, Decl(lib.es2015.core.d.ts, --, --))
+>undefined : Symbol(undefined)
+
+Object.values(undefined);
+>Object.values : Symbol(ObjectConstructor.values, Decl(lib.es2017.object.d.ts, --, --), Decl(lib.es2017.object.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>values : Symbol(ObjectConstructor.values, Decl(lib.es2017.object.d.ts, --, --), Decl(lib.es2017.object.d.ts, --, --))
+>undefined : Symbol(undefined)
+
+Object.create(0);
+>Object.create : Symbol(ObjectConstructor.create, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>create : Symbol(ObjectConstructor.create, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+
+Object.defineProperties(0, {});
+>Object.defineProperties : Symbol(ObjectConstructor.defineProperties, Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>defineProperties : Symbol(ObjectConstructor.defineProperties, Decl(lib.es5.d.ts, --, --))
+
+Object.defineProperty(0, "foo", {});
+>Object.defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+
+// While the following should not:
+
+Object.assign(0);
+>Object.assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+
+Object.entries(0);
+>Object.entries : Symbol(ObjectConstructor.entries, Decl(lib.es2017.object.d.ts, --, --), Decl(lib.es2017.object.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>entries : Symbol(ObjectConstructor.entries, Decl(lib.es2017.object.d.ts, --, --), Decl(lib.es2017.object.d.ts, --, --))
+
+Object.getOwnPropertyDescriptor(0, "foo");
+>Object.getOwnPropertyDescriptor : Symbol(ObjectConstructor.getOwnPropertyDescriptor, Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>getOwnPropertyDescriptor : Symbol(ObjectConstructor.getOwnPropertyDescriptor, Decl(lib.es5.d.ts, --, --))
+
+Object.getOwnPropertyDescriptors(0);
+>Object.getOwnPropertyDescriptors : Symbol(ObjectConstructor.getOwnPropertyDescriptors, Decl(lib.es2017.object.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>getOwnPropertyDescriptors : Symbol(ObjectConstructor.getOwnPropertyDescriptors, Decl(lib.es2017.object.d.ts, --, --))
+
+Object.getOwnPropertyNames(0);
+>Object.getOwnPropertyNames : Symbol(ObjectConstructor.getOwnPropertyNames, Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>getOwnPropertyNames : Symbol(ObjectConstructor.getOwnPropertyNames, Decl(lib.es5.d.ts, --, --))
+
+Object.getOwnPropertySymbols(0);
+>Object.getOwnPropertySymbols : Symbol(ObjectConstructor.getOwnPropertySymbols, Decl(lib.es2015.core.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>getOwnPropertySymbols : Symbol(ObjectConstructor.getOwnPropertySymbols, Decl(lib.es2015.core.d.ts, --, --))
+
+Object.getPrototypeOf(0);
+>Object.getPrototypeOf : Symbol(ObjectConstructor.getPrototypeOf, Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>getPrototypeOf : Symbol(ObjectConstructor.getPrototypeOf, Decl(lib.es5.d.ts, --, --))
+
+Object.hasOwn(0, "foo");
+>Object.hasOwn : Symbol(ObjectConstructor.hasOwn, Decl(lib.es2022.object.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>hasOwn : Symbol(ObjectConstructor.hasOwn, Decl(lib.es2022.object.d.ts, --, --))
+
+Object.keys(0);
+>Object.keys : Symbol(ObjectConstructor.keys, Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>keys : Symbol(ObjectConstructor.keys, Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+
+Object.setPrototypeOf(0, {});
+>Object.setPrototypeOf : Symbol(ObjectConstructor.setPrototypeOf, Decl(lib.es2015.core.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>setPrototypeOf : Symbol(ObjectConstructor.setPrototypeOf, Decl(lib.es2015.core.d.ts, --, --))
+
+Object.values(0);
+>Object.values : Symbol(ObjectConstructor.values, Decl(lib.es2017.object.d.ts, --, --), Decl(lib.es2017.object.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>values : Symbol(ObjectConstructor.values, Decl(lib.es2017.object.d.ts, --, --), Decl(lib.es2017.object.d.ts, --, --))
+
+Object.freeze(undefined);
+>Object.freeze : Symbol(ObjectConstructor.freeze, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>freeze : Symbol(ObjectConstructor.freeze, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>undefined : Symbol(undefined)
+
+Object.isExtensible(undefined);
+>Object.isExtensible : Symbol(ObjectConstructor.isExtensible, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>isExtensible : Symbol(ObjectConstructor.isExtensible, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>undefined : Symbol(undefined)
+
+Object.isFrozen(undefined);
+>Object.isFrozen : Symbol(ObjectConstructor.isFrozen, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>isFrozen : Symbol(ObjectConstructor.isFrozen, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>undefined : Symbol(undefined)
+
+Object.isSealed(undefined);
+>Object.isSealed : Symbol(ObjectConstructor.isSealed, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>isSealed : Symbol(ObjectConstructor.isSealed, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>undefined : Symbol(undefined)
+
+Object.preventExtensions(undefined);
+>Object.preventExtensions : Symbol(ObjectConstructor.preventExtensions, Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>preventExtensions : Symbol(ObjectConstructor.preventExtensions, Decl(lib.es5.d.ts, --, --))
+>undefined : Symbol(undefined)
+
+Object.seal(undefined);
+>Object.seal : Symbol(ObjectConstructor.seal, Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>seal : Symbol(ObjectConstructor.seal, Decl(lib.es5.d.ts, --, --))
+>undefined : Symbol(undefined)
+
+Object.freeze(0);
+>Object.freeze : Symbol(ObjectConstructor.freeze, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>freeze : Symbol(ObjectConstructor.freeze, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+
+Object.isExtensible(0);
+>Object.isExtensible : Symbol(ObjectConstructor.isExtensible, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>isExtensible : Symbol(ObjectConstructor.isExtensible, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+
+Object.isFrozen(0);
+>Object.isFrozen : Symbol(ObjectConstructor.isFrozen, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>isFrozen : Symbol(ObjectConstructor.isFrozen, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+
+Object.isSealed(0);
+>Object.isSealed : Symbol(ObjectConstructor.isSealed, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>isSealed : Symbol(ObjectConstructor.isSealed, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+
+Object.preventExtensions(0);
+>Object.preventExtensions : Symbol(ObjectConstructor.preventExtensions, Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>preventExtensions : Symbol(ObjectConstructor.preventExtensions, Decl(lib.es5.d.ts, --, --))
+
+Object.seal(0);
+>Object.seal : Symbol(ObjectConstructor.seal, Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>seal : Symbol(ObjectConstructor.seal, Decl(lib.es5.d.ts, --, --))
+
diff --git a/tests/baselines/reference/objectMethodNullability.types b/tests/baselines/reference/objectMethodNullability.types
new file mode 100644
index 0000000000000..8a9d71816061b
--- /dev/null
+++ b/tests/baselines/reference/objectMethodNullability.types
@@ -0,0 +1,297 @@
+=== tests/cases/compiler/objectMethodNullability.ts ===
+// All of the following should produce an error:
+
+Object.assign(undefined);
+>Object.assign(undefined) : {}
+>Object.assign : { <T extends {}>(target: T): T; <T extends {}, U>(target: T, source: U): T & Writable<U>; <T extends {}, U, V>(target: T, source1: U, source2: V): T & Writable<U> & Writable<V>; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & Writable<U> & Writable<V> & Writable<W>; (target: {}, ...sources: any[]): any; }
+>Object : ObjectConstructor
+>assign : { <T extends {}>(target: T): T; <T extends {}, U>(target: T, source: U): T & Writable<U>; <T extends {}, U, V>(target: T, source1: U, source2: V): T & Writable<U> & Writable<V>; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & Writable<U> & Writable<V> & Writable<W>; (target: {}, ...sources: any[]): any; }
+>undefined : undefined
+
+Object.create(undefined);
+>Object.create(undefined) : any
+>Object.create : { (o: object | null): any; (o: object | null, properties: PropertyDescriptorMap & ThisType<any>): any; }
+>Object : ObjectConstructor
+>create : { (o: object | null): any; (o: object | null, properties: PropertyDescriptorMap & ThisType<any>): any; }
+>undefined : undefined
+
+Object.defineProperties(undefined, {});
+>Object.defineProperties(undefined, {}) : object
+>Object.defineProperties : <T extends object>(o: T, properties: PropertyDescriptorMap & ThisType<any>) => T
+>Object : ObjectConstructor
+>defineProperties : <T extends object>(o: T, properties: PropertyDescriptorMap & ThisType<any>) => T
+>undefined : undefined
+>{} : {}
+
+Object.defineProperty(undefined, "foo", {});
+>Object.defineProperty(undefined, "foo", {}) : object
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object : ObjectConstructor
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>undefined : undefined
+>"foo" : "foo"
+>{} : {}
+
+Object.entries(undefined);
+>Object.entries(undefined) : [string, unknown][]
+>Object.entries : { <T>(o: { [s: string]: T; } | ArrayLike<T>): [string, T][]; (o: {}): [string, any][]; }
+>Object : ObjectConstructor
+>entries : { <T>(o: { [s: string]: T; } | ArrayLike<T>): [string, T][]; (o: {}): [string, any][]; }
+>undefined : undefined
+
+Object.getOwnPropertyDescriptor(undefined, "foo");
+>Object.getOwnPropertyDescriptor(undefined, "foo") : PropertyDescriptor | undefined
+>Object.getOwnPropertyDescriptor : (o: {}, p: PropertyKey) => PropertyDescriptor | undefined
+>Object : ObjectConstructor
+>getOwnPropertyDescriptor : (o: {}, p: PropertyKey) => PropertyDescriptor | undefined
+>undefined : undefined
+>"foo" : "foo"
+
+Object.getOwnPropertyDescriptors(undefined);
+>Object.getOwnPropertyDescriptors(undefined) : {} & PropertyDescriptorMap
+>Object.getOwnPropertyDescriptors : <T extends {}>(o: T) => { [P in keyof T]: TypedPropertyDescriptor<T[P]>; } & PropertyDescriptorMap
+>Object : ObjectConstructor
+>getOwnPropertyDescriptors : <T extends {}>(o: T) => { [P in keyof T]: TypedPropertyDescriptor<T[P]>; } & PropertyDescriptorMap
+>undefined : undefined
+
+Object.getOwnPropertyNames(undefined);
+>Object.getOwnPropertyNames(undefined) : string[]
+>Object.getOwnPropertyNames : (o: {}) => string[]
+>Object : ObjectConstructor
+>getOwnPropertyNames : (o: {}) => string[]
+>undefined : undefined
+
+Object.getOwnPropertySymbols(undefined);
+>Object.getOwnPropertySymbols(undefined) : symbol[]
+>Object.getOwnPropertySymbols : (o: {}) => symbol[]
+>Object : ObjectConstructor
+>getOwnPropertySymbols : (o: {}) => symbol[]
+>undefined : undefined
+
+Object.getPrototypeOf(undefined);
+>Object.getPrototypeOf(undefined) : any
+>Object.getPrototypeOf : (o: {}) => any
+>Object : ObjectConstructor
+>getPrototypeOf : (o: {}) => any
+>undefined : undefined
+
+Object.hasOwn(undefined, "foo");
+>Object.hasOwn(undefined, "foo") : boolean
+>Object.hasOwn : (o: {}, v: PropertyKey) => boolean
+>Object : ObjectConstructor
+>hasOwn : (o: {}, v: PropertyKey) => boolean
+>undefined : undefined
+>"foo" : "foo"
+
+Object.keys(undefined);
+>Object.keys(undefined) : string[]
+>Object.keys : { (o: object): string[]; (o: {}): string[]; }
+>Object : ObjectConstructor
+>keys : { (o: object): string[]; (o: {}): string[]; }
+>undefined : undefined
+
+Object.setPrototypeOf(undefined, {});
+>Object.setPrototypeOf(undefined, {}) : any
+>Object.setPrototypeOf : (o: {}, proto: object | null) => any
+>Object : ObjectConstructor
+>setPrototypeOf : (o: {}, proto: object | null) => any
+>undefined : undefined
+>{} : {}
+
+Object.values(undefined);
+>Object.values(undefined) : unknown[]
+>Object.values : { <T>(o: { [s: string]: T; } | ArrayLike<T>): T[]; (o: {}): any[]; }
+>Object : ObjectConstructor
+>values : { <T>(o: { [s: string]: T; } | ArrayLike<T>): T[]; (o: {}): any[]; }
+>undefined : undefined
+
+Object.create(0);
+>Object.create(0) : any
+>Object.create : { (o: object | null): any; (o: object | null, properties: PropertyDescriptorMap & ThisType<any>): any; }
+>Object : ObjectConstructor
+>create : { (o: object | null): any; (o: object | null, properties: PropertyDescriptorMap & ThisType<any>): any; }
+>0 : 0
+
+Object.defineProperties(0, {});
+>Object.defineProperties(0, {}) : object
+>Object.defineProperties : <T extends object>(o: T, properties: PropertyDescriptorMap & ThisType<any>) => T
+>Object : ObjectConstructor
+>defineProperties : <T extends object>(o: T, properties: PropertyDescriptorMap & ThisType<any>) => T
+>0 : 0
+>{} : {}
+
+Object.defineProperty(0, "foo", {});
+>Object.defineProperty(0, "foo", {}) : object
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object : ObjectConstructor
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>0 : 0
+>"foo" : "foo"
+>{} : {}
+
+// While the following should not:
+
+Object.assign(0);
+>Object.assign(0) : 0
+>Object.assign : { <T extends {}>(target: T): T; <T extends {}, U>(target: T, source: U): T & Writable<U>; <T extends {}, U, V>(target: T, source1: U, source2: V): T & Writable<U> & Writable<V>; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & Writable<U> & Writable<V> & Writable<W>; (target: {}, ...sources: any[]): any; }
+>Object : ObjectConstructor
+>assign : { <T extends {}>(target: T): T; <T extends {}, U>(target: T, source: U): T & Writable<U>; <T extends {}, U, V>(target: T, source1: U, source2: V): T & Writable<U> & Writable<V>; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & Writable<U> & Writable<V> & Writable<W>; (target: {}, ...sources: any[]): any; }
+>0 : 0
+
+Object.entries(0);
+>Object.entries(0) : [string, any][]
+>Object.entries : { <T>(o: { [s: string]: T; } | ArrayLike<T>): [string, T][]; (o: {}): [string, any][]; }
+>Object : ObjectConstructor
+>entries : { <T>(o: { [s: string]: T; } | ArrayLike<T>): [string, T][]; (o: {}): [string, any][]; }
+>0 : 0
+
+Object.getOwnPropertyDescriptor(0, "foo");
+>Object.getOwnPropertyDescriptor(0, "foo") : PropertyDescriptor | undefined
+>Object.getOwnPropertyDescriptor : (o: {}, p: PropertyKey) => PropertyDescriptor | undefined
+>Object : ObjectConstructor
+>getOwnPropertyDescriptor : (o: {}, p: PropertyKey) => PropertyDescriptor | undefined
+>0 : 0
+>"foo" : "foo"
+
+Object.getOwnPropertyDescriptors(0);
+>Object.getOwnPropertyDescriptors(0) : number & PropertyDescriptorMap
+>Object.getOwnPropertyDescriptors : <T extends {}>(o: T) => { [P in keyof T]: TypedPropertyDescriptor<T[P]>; } & PropertyDescriptorMap
+>Object : ObjectConstructor
+>getOwnPropertyDescriptors : <T extends {}>(o: T) => { [P in keyof T]: TypedPropertyDescriptor<T[P]>; } & PropertyDescriptorMap
+>0 : 0
+
+Object.getOwnPropertyNames(0);
+>Object.getOwnPropertyNames(0) : string[]
+>Object.getOwnPropertyNames : (o: {}) => string[]
+>Object : ObjectConstructor
+>getOwnPropertyNames : (o: {}) => string[]
+>0 : 0
+
+Object.getOwnPropertySymbols(0);
+>Object.getOwnPropertySymbols(0) : symbol[]
+>Object.getOwnPropertySymbols : (o: {}) => symbol[]
+>Object : ObjectConstructor
+>getOwnPropertySymbols : (o: {}) => symbol[]
+>0 : 0
+
+Object.getPrototypeOf(0);
+>Object.getPrototypeOf(0) : any
+>Object.getPrototypeOf : (o: {}) => any
+>Object : ObjectConstructor
+>getPrototypeOf : (o: {}) => any
+>0 : 0
+
+Object.hasOwn(0, "foo");
+>Object.hasOwn(0, "foo") : boolean
+>Object.hasOwn : (o: {}, v: PropertyKey) => boolean
+>Object : ObjectConstructor
+>hasOwn : (o: {}, v: PropertyKey) => boolean
+>0 : 0
+>"foo" : "foo"
+
+Object.keys(0);
+>Object.keys(0) : string[]
+>Object.keys : { (o: object): string[]; (o: {}): string[]; }
+>Object : ObjectConstructor
+>keys : { (o: object): string[]; (o: {}): string[]; }
+>0 : 0
+
+Object.setPrototypeOf(0, {});
+>Object.setPrototypeOf(0, {}) : any
+>Object.setPrototypeOf : (o: {}, proto: object | null) => any
+>Object : ObjectConstructor
+>setPrototypeOf : (o: {}, proto: object | null) => any
+>0 : 0
+>{} : {}
+
+Object.values(0);
+>Object.values(0) : any[]
+>Object.values : { <T>(o: { [s: string]: T; } | ArrayLike<T>): T[]; (o: {}): any[]; }
+>Object : ObjectConstructor
+>values : { <T>(o: { [s: string]: T; } | ArrayLike<T>): T[]; (o: {}): any[]; }
+>0 : 0
+
+Object.freeze(undefined);
+>Object.freeze(undefined) : undefined
+>Object.freeze : { <T extends Function>(f: T): T; <T extends { [idx: string]: object | U | null | undefined; }, U extends string | number | bigint | boolean | symbol>(o: T): Readonly<T>; <T>(o: T): Readonly<T>; }
+>Object : ObjectConstructor
+>freeze : { <T extends Function>(f: T): T; <T extends { [idx: string]: object | U | null | undefined; }, U extends string | number | bigint | boolean | symbol>(o: T): Readonly<T>; <T>(o: T): Readonly<T>; }
+>undefined : undefined
+
+Object.isExtensible(undefined);
+>Object.isExtensible(undefined) : false
+>Object.isExtensible : { (o: object): boolean; (o: any): false; }
+>Object : ObjectConstructor
+>isExtensible : { (o: object): boolean; (o: any): false; }
+>undefined : undefined
+
+Object.isFrozen(undefined);
+>Object.isFrozen(undefined) : true
+>Object.isFrozen : { (o: object): boolean; (o: any): true; }
+>Object : ObjectConstructor
+>isFrozen : { (o: object): boolean; (o: any): true; }
+>undefined : undefined
+
+Object.isSealed(undefined);
+>Object.isSealed(undefined) : true
+>Object.isSealed : { (o: object): boolean; (o: any): true; }
+>Object : ObjectConstructor
+>isSealed : { (o: object): boolean; (o: any): true; }
+>undefined : undefined
+
+Object.preventExtensions(undefined);
+>Object.preventExtensions(undefined) : undefined
+>Object.preventExtensions : <T>(o: T) => T
+>Object : ObjectConstructor
+>preventExtensions : <T>(o: T) => T
+>undefined : undefined
+
+Object.seal(undefined);
+>Object.seal(undefined) : undefined
+>Object.seal : <T>(o: T) => T
+>Object : ObjectConstructor
+>seal : <T>(o: T) => T
+>undefined : undefined
+
+Object.freeze(0);
+>Object.freeze(0) : number
+>Object.freeze : { <T extends Function>(f: T): T; <T extends { [idx: string]: object | U | null | undefined; }, U extends string | number | bigint | boolean | symbol>(o: T): Readonly<T>; <T>(o: T): Readonly<T>; }
+>Object : ObjectConstructor
+>freeze : { <T extends Function>(f: T): T; <T extends { [idx: string]: object | U | null | undefined; }, U extends string | number | bigint | boolean | symbol>(o: T): Readonly<T>; <T>(o: T): Readonly<T>; }
+>0 : 0
+
+Object.isExtensible(0);
+>Object.isExtensible(0) : false
+>Object.isExtensible : { (o: object): boolean; (o: any): false; }
+>Object : ObjectConstructor
+>isExtensible : { (o: object): boolean; (o: any): false; }
+>0 : 0
+
+Object.isFrozen(0);
+>Object.isFrozen(0) : true
+>Object.isFrozen : { (o: object): boolean; (o: any): true; }
+>Object : ObjectConstructor
+>isFrozen : { (o: object): boolean; (o: any): true; }
+>0 : 0
+
+Object.isSealed(0);
+>Object.isSealed(0) : true
+>Object.isSealed : { (o: object): boolean; (o: any): true; }
+>Object : ObjectConstructor
+>isSealed : { (o: object): boolean; (o: any): true; }
+>0 : 0
+
+Object.preventExtensions(0);
+>Object.preventExtensions(0) : 0
+>Object.preventExtensions : <T>(o: T) => T
+>Object : ObjectConstructor
+>preventExtensions : <T>(o: T) => T
+>0 : 0
+
+Object.seal(0);
+>Object.seal(0) : 0
+>Object.seal : <T>(o: T) => T
+>Object : ObjectConstructor
+>seal : <T>(o: T) => T
+>0 : 0
+
diff --git a/tests/baselines/reference/parserUsingConstructorAsIdentifier.types b/tests/baselines/reference/parserUsingConstructorAsIdentifier.types
index 0034fa0e136e5..29122ff0c0f67 100644
--- a/tests/baselines/reference/parserUsingConstructorAsIdentifier.types
+++ b/tests/baselines/reference/parserUsingConstructorAsIdentifier.types
@@ -90,9 +90,9 @@
 
                 Object.defineProperty(constructor.prototype, "constructor", { value: constructor, writable: true, configurable: true, enumerable: true });
 >Object.defineProperty(constructor.prototype, "constructor", { value: constructor, writable: true, configurable: true, enumerable: true }) : any
->Object.defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>Object.defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >Object : ObjectConstructor
->defineProperty : <T>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
+>defineProperty : <T extends object>(o: T, p: PropertyKey, attributes: PropertyDescriptor & ThisType<any>) => T
 >constructor.prototype : any
 >constructor : any
 >prototype : any
diff --git a/tests/baselines/reference/unionAndIntersectionInference1.symbols b/tests/baselines/reference/unionAndIntersectionInference1.symbols
index 815e70ddce106..c3591912e67e4 100644
--- a/tests/baselines/reference/unionAndIntersectionInference1.symbols
+++ b/tests/baselines/reference/unionAndIntersectionInference1.symbols
@@ -272,9 +272,9 @@ const assign = <T, U>(a: T, b: U) => Object.assign(a, b);
 >T : Symbol(T, Decl(unionAndIntersectionInference1.ts, 94, 16))
 >b : Symbol(b, Decl(unionAndIntersectionInference1.ts, 94, 27))
 >U : Symbol(U, Decl(unionAndIntersectionInference1.ts, 94, 18))
->Object.assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>Object.assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
 >Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
->assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
 >a : Symbol(a, Decl(unionAndIntersectionInference1.ts, 94, 22))
 >b : Symbol(b, Decl(unionAndIntersectionInference1.ts, 94, 27))
 
diff --git a/tests/baselines/reference/unionAndIntersectionInference1.types b/tests/baselines/reference/unionAndIntersectionInference1.types
index ec56cbbd1c4ac..3979a3a7bdb9f 100644
--- a/tests/baselines/reference/unionAndIntersectionInference1.types
+++ b/tests/baselines/reference/unionAndIntersectionInference1.types
@@ -241,22 +241,22 @@ const func = <T>() => {};
 ><T>() => {} : <T>() => void
 
 const assign = <T, U>(a: T, b: U) => Object.assign(a, b);
->assign : <T, U>(a: T, b: U) => T & U
-><T, U>(a: T, b: U) => Object.assign(a, b) : <T, U>(a: T, b: U) => T & U
+>assign : <T, U>(a: T, b: U) => T & Writable<U>
+><T, U>(a: T, b: U) => Object.assign(a, b) : <T, U>(a: T, b: U) => T & Writable<U>
 >a : T
 >b : U
->Object.assign(a, b) : T & U
->Object.assign : { <T extends {}, U>(target: T, source: U): T & U; <T extends {}, U, V>(target: T, source1: U, source2: V): T & U & V; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & U & V & W; (target: object, ...sources: any[]): any; }
+>Object.assign(a, b) : T & Writable<U>
+>Object.assign : { <T extends {}>(target: T): T; <T extends {}, U>(target: T, source: U): T & Writable<U>; <T extends {}, U, V>(target: T, source1: U, source2: V): T & Writable<U> & Writable<V>; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & Writable<U> & Writable<V> & Writable<W>; (target: {}, ...sources: any[]): any; }
 >Object : ObjectConstructor
->assign : { <T extends {}, U>(target: T, source: U): T & U; <T extends {}, U, V>(target: T, source1: U, source2: V): T & U & V; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & U & V & W; (target: object, ...sources: any[]): any; }
+>assign : { <T extends {}>(target: T): T; <T extends {}, U>(target: T, source: U): T & Writable<U>; <T extends {}, U, V>(target: T, source1: U, source2: V): T & Writable<U> & Writable<V>; <T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & Writable<U> & Writable<V> & Writable<W>; (target: {}, ...sources: any[]): any; }
 >a : T
 >b : U
 
 const res: (() => void) & { func: any } = assign(() => {}, { func });
 >res : (() => void) & { func: any; }
 >func : any
->assign(() => {}, { func }) : (() => void) & { func: <T>() => void; }
->assign : <T, U>(a: T, b: U) => T & U
+>assign(() => {}, { func }) : (() => void) & Writable<{ func: <T>() => void; }>
+>assign : <T, U>(a: T, b: U) => T & Writable<U>
 >() => {} : () => void
 >{ func } : { func: <T>() => void; }
 >func : <T>() => void
diff --git a/tests/cases/compiler/objectMethodNullability.ts b/tests/cases/compiler/objectMethodNullability.ts
new file mode 100644
index 0000000000000..4c3038be83c7e
--- /dev/null
+++ b/tests/cases/compiler/objectMethodNullability.ts
@@ -0,0 +1,51 @@
+// @lib: esnext
+// @strict: true
+
+// All of the following should produce an error:
+
+Object.assign(undefined);
+Object.create(undefined);
+Object.defineProperties(undefined, {});
+Object.defineProperty(undefined, "foo", {});
+Object.entries(undefined);
+Object.getOwnPropertyDescriptor(undefined, "foo");
+Object.getOwnPropertyDescriptors(undefined);
+Object.getOwnPropertyNames(undefined);
+Object.getOwnPropertySymbols(undefined);
+Object.getPrototypeOf(undefined);
+Object.hasOwn(undefined, "foo");
+Object.keys(undefined);
+Object.setPrototypeOf(undefined, {});
+Object.values(undefined);
+
+Object.create(0);
+Object.defineProperties(0, {});
+Object.defineProperty(0, "foo", {});
+
+// While the following should not:
+
+Object.assign(0);
+Object.entries(0);
+Object.getOwnPropertyDescriptor(0, "foo");
+Object.getOwnPropertyDescriptors(0);
+Object.getOwnPropertyNames(0);
+Object.getOwnPropertySymbols(0);
+Object.getPrototypeOf(0);
+Object.hasOwn(0, "foo");
+Object.keys(0);
+Object.setPrototypeOf(0, {});
+Object.values(0);
+
+Object.freeze(undefined);
+Object.isExtensible(undefined);
+Object.isFrozen(undefined);
+Object.isSealed(undefined);
+Object.preventExtensions(undefined);
+Object.seal(undefined);
+
+Object.freeze(0);
+Object.isExtensible(0);
+Object.isFrozen(0);
+Object.isSealed(0);
+Object.preventExtensions(0);
+Object.seal(0);