From 0723904bfb00ffc41d1bbda2a11ae7d7f8ac5bc8 Mon Sep 17 00:00:00 2001
From: ExE Boss <3889017+ExE-Boss@users.noreply.github.com>
Date: Fri, 19 Feb 2021 01:43:36 +0100
Subject: [PATCH] =?UTF-8?q?feat(lib/es2021):=20Add=C2=A0type=C2=A0paramete?=
 =?UTF-8?q?r=20to=C2=A0`FinalizationRegistry`=20(#42274)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

* feat(lib/es2021): Add type parameter to `FinalizationRegistry`

* test(lib/es2021): Add test for generic `FinalizationRegistry`
---
 src/lib/esnext.weakref.d.ts                   |  10 +-
 .../esNextWeakRefs_IterableWeakMap.js         | 189 +++++++++
 .../esNextWeakRefs_IterableWeakMap.symbols    | 358 ++++++++++++++++
 .../esNextWeakRefs_IterableWeakMap.types      | 383 ++++++++++++++++++
 .../esNextWeakRefs_IterableWeakMap.ts         | 107 +++++
 5 files changed, 1042 insertions(+), 5 deletions(-)
 create mode 100644 tests/baselines/reference/esNextWeakRefs_IterableWeakMap.js
 create mode 100644 tests/baselines/reference/esNextWeakRefs_IterableWeakMap.symbols
 create mode 100644 tests/baselines/reference/esNextWeakRefs_IterableWeakMap.types
 create mode 100644 tests/cases/compiler/esNextWeakRefs_IterableWeakMap.ts

diff --git a/src/lib/esnext.weakref.d.ts b/src/lib/esnext.weakref.d.ts
index 337aa11f3e..d36ddb6a19 100644
--- a/src/lib/esnext.weakref.d.ts
+++ b/src/lib/esnext.weakref.d.ts
@@ -15,12 +15,12 @@ interface WeakRefConstructor {
      * Creates a WeakRef instance for the given target object.
      * @param target The target object for the WeakRef instance.
      */
-    new<T extends object>(target?: T): WeakRef<T>;
+    new<T extends object>(target: T): WeakRef<T>;
 }
 
 declare var WeakRef: WeakRefConstructor;
 
-interface FinalizationRegistry {
+interface FinalizationRegistry<T> {
     readonly [Symbol.toStringTag]: "FinalizationRegistry";
 
     /**
@@ -32,7 +32,7 @@ interface FinalizationRegistry {
      * object. If provided (and not undefined), this must be an object. If not provided, the target
      * cannot be unregistered.
      */
-    register(target: object, heldValue: any, unregisterToken?: object): void;
+    register(target: object, heldValue: T, unregisterToken?: object): void;
 
     /**
      * Unregisters an object from the registry.
@@ -43,13 +43,13 @@ interface FinalizationRegistry {
 }
 
 interface FinalizationRegistryConstructor {
-    readonly prototype: FinalizationRegistry;
+    readonly prototype: FinalizationRegistry<any>;
 
     /**
      * Creates a finalization registry with an associated cleanup callback
      * @param cleanupCallback The callback to call after an object in the registry has been reclaimed.
      */
-    new(cleanupCallback: (heldValue: any) => void): FinalizationRegistry;
+    new<T>(cleanupCallback: (heldValue: T) => void): FinalizationRegistry<T>;
 }
 
 declare var FinalizationRegistry: FinalizationRegistryConstructor;
diff --git a/tests/baselines/reference/esNextWeakRefs_IterableWeakMap.js b/tests/baselines/reference/esNextWeakRefs_IterableWeakMap.js
new file mode 100644
index 0000000000..4597c8585c
--- /dev/null
+++ b/tests/baselines/reference/esNextWeakRefs_IterableWeakMap.js
@@ -0,0 +1,189 @@
+//// [esNextWeakRefs_IterableWeakMap.ts]
+/** `static #cleanup` */
+const IterableWeakMap_cleanup = ({ ref, set }: {
+    readonly ref: WeakRef<object>;
+    readonly set: Set<WeakRef<object>>;
+}) => {
+    set.delete(ref);
+};
+
+// Based on: https://github.com/tc39/proposal-weakrefs/blob/master/README.md#iterable-weakmaps
+export class IterableWeakMap<K extends object, V> implements WeakMap<K, V> {
+    declare readonly [Symbol.toStringTag]: "IterableWeakMap";
+
+    #weakMap = new WeakMap<K, { readonly ref: WeakRef<K>; value: V }>();
+    #refSet = new Set<WeakRef<K>>();
+    #finalizationGroup = new FinalizationRegistry(IterableWeakMap_cleanup);
+
+    constructor(iterable: Iterable<[key: K, value: V]> | null = null) {
+        if (iterable !== null) {
+            for (const { 0: key, 1: value } of iterable) {
+                this.set(key, value);
+            }
+        }
+    }
+
+    set(key: K, value: V): this {
+        const entry = this.#weakMap.get(key);
+        if (entry !== undefined) {
+            entry.value = value;
+        } else {
+            const ref = new WeakRef(key);
+
+            this.#weakMap.set(key, { ref, value });
+            this.#refSet.add(ref);
+            this.#finalizationGroup.register(key, {
+                set: this.#refSet,
+                ref,
+            }, ref);
+        }
+        return this;
+    }
+
+    has(key: K): boolean {
+        return this.#weakMap.has(key);
+    }
+
+    get(key: K): V | undefined {
+        return this.#weakMap.get(key)?.value;
+    }
+
+    delete(key: K): boolean {
+        const entry = this.#weakMap.get(key);
+        if (entry === undefined) {
+            return false;
+        }
+
+        const { ref } = entry;
+        this.#weakMap.delete(key);
+        this.#refSet.delete(ref);
+        this.#finalizationGroup.unregister(ref);
+        return true;
+    }
+
+    declare [Symbol.iterator]: this["entries"];
+    *entries(): Generator<[key: K, value: V], void> {
+        for (const ref of this.#refSet) {
+            const key = ref.deref();
+            if (key === undefined) continue;
+            const { value } = this.#weakMap.get(key)!;
+            yield [key, value];
+        }
+    }
+
+    *keys() {
+        for (const { 0: key } of this) {
+            yield key;
+        }
+    }
+
+    *values() {
+        for (const { 1: value } of this) {
+            yield value;
+        }
+    }
+}
+
+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",
+    },
+});
+
+
+//// [esNextWeakRefs_IterableWeakMap.js]
+/** `static #cleanup` */
+const IterableWeakMap_cleanup = ({ ref, set }) => {
+    set.delete(ref);
+};
+// Based on: https://github.com/tc39/proposal-weakrefs/blob/master/README.md#iterable-weakmaps
+export class IterableWeakMap {
+    #weakMap = new WeakMap();
+    #refSet = new Set();
+    #finalizationGroup = new FinalizationRegistry(IterableWeakMap_cleanup);
+    constructor(iterable = null) {
+        if (iterable !== null) {
+            for (const { 0: key, 1: value } of iterable) {
+                this.set(key, value);
+            }
+        }
+    }
+    set(key, value) {
+        const entry = this.#weakMap.get(key);
+        if (entry !== undefined) {
+            entry.value = value;
+        }
+        else {
+            const ref = new WeakRef(key);
+            this.#weakMap.set(key, { ref, value });
+            this.#refSet.add(ref);
+            this.#finalizationGroup.register(key, {
+                set: this.#refSet,
+                ref,
+            }, ref);
+        }
+        return this;
+    }
+    has(key) {
+        return this.#weakMap.has(key);
+    }
+    get(key) {
+        return this.#weakMap.get(key)?.value;
+    }
+    delete(key) {
+        const entry = this.#weakMap.get(key);
+        if (entry === undefined) {
+            return false;
+        }
+        const { ref } = entry;
+        this.#weakMap.delete(key);
+        this.#refSet.delete(ref);
+        this.#finalizationGroup.unregister(ref);
+        return true;
+    }
+    *entries() {
+        for (const ref of this.#refSet) {
+            const key = ref.deref();
+            if (key === undefined)
+                continue;
+            const { value } = this.#weakMap.get(key);
+            yield [key, value];
+        }
+    }
+    *keys() {
+        for (const { 0: key } of this) {
+            yield key;
+        }
+    }
+    *values() {
+        for (const { 1: value } of this) {
+            yield value;
+        }
+    }
+}
+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",
+    },
+});
diff --git a/tests/baselines/reference/esNextWeakRefs_IterableWeakMap.symbols b/tests/baselines/reference/esNextWeakRefs_IterableWeakMap.symbols
new file mode 100644
index 0000000000..d07a230756
--- /dev/null
+++ b/tests/baselines/reference/esNextWeakRefs_IterableWeakMap.symbols
@@ -0,0 +1,358 @@
+=== tests/cases/compiler/esNextWeakRefs_IterableWeakMap.ts ===
+/** `static #cleanup` */
+const IterableWeakMap_cleanup = ({ ref, set }: {
+>IterableWeakMap_cleanup : Symbol(IterableWeakMap_cleanup, Decl(esNextWeakRefs_IterableWeakMap.ts, 1, 5))
+>ref : Symbol(ref, Decl(esNextWeakRefs_IterableWeakMap.ts, 1, 34))
+>set : Symbol(set, Decl(esNextWeakRefs_IterableWeakMap.ts, 1, 39))
+
+    readonly ref: WeakRef<object>;
+>ref : Symbol(ref, Decl(esNextWeakRefs_IterableWeakMap.ts, 1, 48))
+>WeakRef : Symbol(WeakRef, Decl(lib.esnext.weakref.d.ts, --, --), Decl(lib.esnext.weakref.d.ts, --, --))
+
+    readonly set: Set<WeakRef<object>>;
+>set : Symbol(set, Decl(esNextWeakRefs_IterableWeakMap.ts, 2, 34))
+>Set : Symbol(Set, Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>WeakRef : Symbol(WeakRef, Decl(lib.esnext.weakref.d.ts, --, --), Decl(lib.esnext.weakref.d.ts, --, --))
+
+}) => {
+    set.delete(ref);
+>set.delete : Symbol(Set.delete, Decl(lib.es2015.collection.d.ts, --, --))
+>set : Symbol(set, Decl(esNextWeakRefs_IterableWeakMap.ts, 1, 39))
+>delete : Symbol(Set.delete, Decl(lib.es2015.collection.d.ts, --, --))
+>ref : Symbol(ref, Decl(esNextWeakRefs_IterableWeakMap.ts, 1, 34))
+
+};
+
+// Based on: https://github.com/tc39/proposal-weakrefs/blob/master/README.md#iterable-weakmaps
+export class IterableWeakMap<K extends object, V> implements WeakMap<K, V> {
+>IterableWeakMap : Symbol(IterableWeakMap, Decl(esNextWeakRefs_IterableWeakMap.ts, 6, 2))
+>K : Symbol(K, Decl(esNextWeakRefs_IterableWeakMap.ts, 9, 29))
+>V : Symbol(V, Decl(esNextWeakRefs_IterableWeakMap.ts, 9, 46))
+>WeakMap : Symbol(WeakMap, Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>K : Symbol(K, Decl(esNextWeakRefs_IterableWeakMap.ts, 9, 29))
+>V : Symbol(V, Decl(esNextWeakRefs_IterableWeakMap.ts, 9, 46))
+
+    declare readonly [Symbol.toStringTag]: "IterableWeakMap";
+>[Symbol.toStringTag] : Symbol(IterableWeakMap[Symbol.toStringTag], Decl(esNextWeakRefs_IterableWeakMap.ts, 9, 76))
+>Symbol.toStringTag : Symbol(SymbolConstructor.toStringTag, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>Symbol : Symbol(Symbol, Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2019.symbol.d.ts, --, --))
+>toStringTag : Symbol(SymbolConstructor.toStringTag, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+
+    #weakMap = new WeakMap<K, { readonly ref: WeakRef<K>; value: V }>();
+>#weakMap : Symbol(IterableWeakMap.#weakMap, Decl(esNextWeakRefs_IterableWeakMap.ts, 10, 61))
+>WeakMap : Symbol(WeakMap, Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>K : Symbol(K, Decl(esNextWeakRefs_IterableWeakMap.ts, 9, 29))
+>ref : Symbol(ref, Decl(esNextWeakRefs_IterableWeakMap.ts, 12, 31))
+>WeakRef : Symbol(WeakRef, Decl(lib.esnext.weakref.d.ts, --, --), Decl(lib.esnext.weakref.d.ts, --, --))
+>K : Symbol(K, Decl(esNextWeakRefs_IterableWeakMap.ts, 9, 29))
+>value : Symbol(value, Decl(esNextWeakRefs_IterableWeakMap.ts, 12, 57))
+>V : Symbol(V, Decl(esNextWeakRefs_IterableWeakMap.ts, 9, 46))
+
+    #refSet = new Set<WeakRef<K>>();
+>#refSet : Symbol(IterableWeakMap.#refSet, Decl(esNextWeakRefs_IterableWeakMap.ts, 12, 72))
+>Set : Symbol(Set, Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>WeakRef : Symbol(WeakRef, Decl(lib.esnext.weakref.d.ts, --, --), Decl(lib.esnext.weakref.d.ts, --, --))
+>K : Symbol(K, Decl(esNextWeakRefs_IterableWeakMap.ts, 9, 29))
+
+    #finalizationGroup = new FinalizationRegistry(IterableWeakMap_cleanup);
+>#finalizationGroup : Symbol(IterableWeakMap.#finalizationGroup, Decl(esNextWeakRefs_IterableWeakMap.ts, 13, 36))
+>FinalizationRegistry : Symbol(FinalizationRegistry, Decl(lib.esnext.weakref.d.ts, --, --), Decl(lib.esnext.weakref.d.ts, --, --))
+>IterableWeakMap_cleanup : Symbol(IterableWeakMap_cleanup, Decl(esNextWeakRefs_IterableWeakMap.ts, 1, 5))
+
+    constructor(iterable: Iterable<[key: K, value: V]> | null = null) {
+>iterable : Symbol(iterable, Decl(esNextWeakRefs_IterableWeakMap.ts, 16, 16))
+>Iterable : Symbol(Iterable, Decl(lib.es2015.iterable.d.ts, --, --))
+>K : Symbol(K, Decl(esNextWeakRefs_IterableWeakMap.ts, 9, 29))
+>V : Symbol(V, Decl(esNextWeakRefs_IterableWeakMap.ts, 9, 46))
+
+        if (iterable !== null) {
+>iterable : Symbol(iterable, Decl(esNextWeakRefs_IterableWeakMap.ts, 16, 16))
+
+            for (const { 0: key, 1: value } of iterable) {
+>key : Symbol(key, Decl(esNextWeakRefs_IterableWeakMap.ts, 18, 24))
+>value : Symbol(value, Decl(esNextWeakRefs_IterableWeakMap.ts, 18, 32))
+>iterable : Symbol(iterable, Decl(esNextWeakRefs_IterableWeakMap.ts, 16, 16))
+
+                this.set(key, value);
+>this.set : Symbol(IterableWeakMap.set, Decl(esNextWeakRefs_IterableWeakMap.ts, 22, 5))
+>this : Symbol(IterableWeakMap, Decl(esNextWeakRefs_IterableWeakMap.ts, 6, 2))
+>set : Symbol(IterableWeakMap.set, Decl(esNextWeakRefs_IterableWeakMap.ts, 22, 5))
+>key : Symbol(key, Decl(esNextWeakRefs_IterableWeakMap.ts, 18, 24))
+>value : Symbol(value, Decl(esNextWeakRefs_IterableWeakMap.ts, 18, 32))
+            }
+        }
+    }
+
+    set(key: K, value: V): this {
+>set : Symbol(IterableWeakMap.set, Decl(esNextWeakRefs_IterableWeakMap.ts, 22, 5))
+>key : Symbol(key, Decl(esNextWeakRefs_IterableWeakMap.ts, 24, 8))
+>K : Symbol(K, Decl(esNextWeakRefs_IterableWeakMap.ts, 9, 29))
+>value : Symbol(value, Decl(esNextWeakRefs_IterableWeakMap.ts, 24, 15))
+>V : Symbol(V, Decl(esNextWeakRefs_IterableWeakMap.ts, 9, 46))
+
+        const entry = this.#weakMap.get(key);
+>entry : Symbol(entry, Decl(esNextWeakRefs_IterableWeakMap.ts, 25, 13))
+>this.#weakMap.get : Symbol(WeakMap.get, Decl(lib.es2015.collection.d.ts, --, --))
+>this.#weakMap : Symbol(IterableWeakMap.#weakMap, Decl(esNextWeakRefs_IterableWeakMap.ts, 10, 61))
+>this : Symbol(IterableWeakMap, Decl(esNextWeakRefs_IterableWeakMap.ts, 6, 2))
+>get : Symbol(WeakMap.get, Decl(lib.es2015.collection.d.ts, --, --))
+>key : Symbol(key, Decl(esNextWeakRefs_IterableWeakMap.ts, 24, 8))
+
+        if (entry !== undefined) {
+>entry : Symbol(entry, Decl(esNextWeakRefs_IterableWeakMap.ts, 25, 13))
+>undefined : Symbol(undefined)
+
+            entry.value = value;
+>entry.value : Symbol(value, Decl(esNextWeakRefs_IterableWeakMap.ts, 12, 57))
+>entry : Symbol(entry, Decl(esNextWeakRefs_IterableWeakMap.ts, 25, 13))
+>value : Symbol(value, Decl(esNextWeakRefs_IterableWeakMap.ts, 12, 57))
+>value : Symbol(value, Decl(esNextWeakRefs_IterableWeakMap.ts, 24, 15))
+
+        } else {
+            const ref = new WeakRef(key);
+>ref : Symbol(ref, Decl(esNextWeakRefs_IterableWeakMap.ts, 29, 17))
+>WeakRef : Symbol(WeakRef, Decl(lib.esnext.weakref.d.ts, --, --), Decl(lib.esnext.weakref.d.ts, --, --))
+>key : Symbol(key, Decl(esNextWeakRefs_IterableWeakMap.ts, 24, 8))
+
+            this.#weakMap.set(key, { ref, value });
+>this.#weakMap.set : Symbol(WeakMap.set, Decl(lib.es2015.collection.d.ts, --, --))
+>this.#weakMap : Symbol(IterableWeakMap.#weakMap, Decl(esNextWeakRefs_IterableWeakMap.ts, 10, 61))
+>this : Symbol(IterableWeakMap, Decl(esNextWeakRefs_IterableWeakMap.ts, 6, 2))
+>set : Symbol(WeakMap.set, Decl(lib.es2015.collection.d.ts, --, --))
+>key : Symbol(key, Decl(esNextWeakRefs_IterableWeakMap.ts, 24, 8))
+>ref : Symbol(ref, Decl(esNextWeakRefs_IterableWeakMap.ts, 31, 36))
+>value : Symbol(value, Decl(esNextWeakRefs_IterableWeakMap.ts, 31, 41))
+
+            this.#refSet.add(ref);
+>this.#refSet.add : Symbol(Set.add, Decl(lib.es2015.collection.d.ts, --, --))
+>this.#refSet : Symbol(IterableWeakMap.#refSet, Decl(esNextWeakRefs_IterableWeakMap.ts, 12, 72))
+>this : Symbol(IterableWeakMap, Decl(esNextWeakRefs_IterableWeakMap.ts, 6, 2))
+>add : Symbol(Set.add, Decl(lib.es2015.collection.d.ts, --, --))
+>ref : Symbol(ref, Decl(esNextWeakRefs_IterableWeakMap.ts, 29, 17))
+
+            this.#finalizationGroup.register(key, {
+>this.#finalizationGroup.register : Symbol(FinalizationRegistry.register, Decl(lib.esnext.weakref.d.ts, --, --))
+>this.#finalizationGroup : Symbol(IterableWeakMap.#finalizationGroup, Decl(esNextWeakRefs_IterableWeakMap.ts, 13, 36))
+>this : Symbol(IterableWeakMap, Decl(esNextWeakRefs_IterableWeakMap.ts, 6, 2))
+>register : Symbol(FinalizationRegistry.register, Decl(lib.esnext.weakref.d.ts, --, --))
+>key : Symbol(key, Decl(esNextWeakRefs_IterableWeakMap.ts, 24, 8))
+
+                set: this.#refSet,
+>set : Symbol(set, Decl(esNextWeakRefs_IterableWeakMap.ts, 33, 51))
+>this.#refSet : Symbol(IterableWeakMap.#refSet, Decl(esNextWeakRefs_IterableWeakMap.ts, 12, 72))
+>this : Symbol(IterableWeakMap, Decl(esNextWeakRefs_IterableWeakMap.ts, 6, 2))
+
+                ref,
+>ref : Symbol(ref, Decl(esNextWeakRefs_IterableWeakMap.ts, 34, 34))
+
+            }, ref);
+>ref : Symbol(ref, Decl(esNextWeakRefs_IterableWeakMap.ts, 29, 17))
+        }
+        return this;
+>this : Symbol(IterableWeakMap, Decl(esNextWeakRefs_IterableWeakMap.ts, 6, 2))
+    }
+
+    has(key: K): boolean {
+>has : Symbol(IterableWeakMap.has, Decl(esNextWeakRefs_IterableWeakMap.ts, 39, 5))
+>key : Symbol(key, Decl(esNextWeakRefs_IterableWeakMap.ts, 41, 8))
+>K : Symbol(K, Decl(esNextWeakRefs_IterableWeakMap.ts, 9, 29))
+
+        return this.#weakMap.has(key);
+>this.#weakMap.has : Symbol(WeakMap.has, Decl(lib.es2015.collection.d.ts, --, --))
+>this.#weakMap : Symbol(IterableWeakMap.#weakMap, Decl(esNextWeakRefs_IterableWeakMap.ts, 10, 61))
+>this : Symbol(IterableWeakMap, Decl(esNextWeakRefs_IterableWeakMap.ts, 6, 2))
+>has : Symbol(WeakMap.has, Decl(lib.es2015.collection.d.ts, --, --))
+>key : Symbol(key, Decl(esNextWeakRefs_IterableWeakMap.ts, 41, 8))
+    }
+
+    get(key: K): V | undefined {
+>get : Symbol(IterableWeakMap.get, Decl(esNextWeakRefs_IterableWeakMap.ts, 43, 5))
+>key : Symbol(key, Decl(esNextWeakRefs_IterableWeakMap.ts, 45, 8))
+>K : Symbol(K, Decl(esNextWeakRefs_IterableWeakMap.ts, 9, 29))
+>V : Symbol(V, Decl(esNextWeakRefs_IterableWeakMap.ts, 9, 46))
+
+        return this.#weakMap.get(key)?.value;
+>this.#weakMap.get(key)?.value : Symbol(value, Decl(esNextWeakRefs_IterableWeakMap.ts, 12, 57))
+>this.#weakMap.get : Symbol(WeakMap.get, Decl(lib.es2015.collection.d.ts, --, --))
+>this.#weakMap : Symbol(IterableWeakMap.#weakMap, Decl(esNextWeakRefs_IterableWeakMap.ts, 10, 61))
+>this : Symbol(IterableWeakMap, Decl(esNextWeakRefs_IterableWeakMap.ts, 6, 2))
+>get : Symbol(WeakMap.get, Decl(lib.es2015.collection.d.ts, --, --))
+>key : Symbol(key, Decl(esNextWeakRefs_IterableWeakMap.ts, 45, 8))
+>value : Symbol(value, Decl(esNextWeakRefs_IterableWeakMap.ts, 12, 57))
+    }
+
+    delete(key: K): boolean {
+>delete : Symbol(IterableWeakMap.delete, Decl(esNextWeakRefs_IterableWeakMap.ts, 47, 5))
+>key : Symbol(key, Decl(esNextWeakRefs_IterableWeakMap.ts, 49, 11))
+>K : Symbol(K, Decl(esNextWeakRefs_IterableWeakMap.ts, 9, 29))
+
+        const entry = this.#weakMap.get(key);
+>entry : Symbol(entry, Decl(esNextWeakRefs_IterableWeakMap.ts, 50, 13))
+>this.#weakMap.get : Symbol(WeakMap.get, Decl(lib.es2015.collection.d.ts, --, --))
+>this.#weakMap : Symbol(IterableWeakMap.#weakMap, Decl(esNextWeakRefs_IterableWeakMap.ts, 10, 61))
+>this : Symbol(IterableWeakMap, Decl(esNextWeakRefs_IterableWeakMap.ts, 6, 2))
+>get : Symbol(WeakMap.get, Decl(lib.es2015.collection.d.ts, --, --))
+>key : Symbol(key, Decl(esNextWeakRefs_IterableWeakMap.ts, 49, 11))
+
+        if (entry === undefined) {
+>entry : Symbol(entry, Decl(esNextWeakRefs_IterableWeakMap.ts, 50, 13))
+>undefined : Symbol(undefined)
+
+            return false;
+        }
+
+        const { ref } = entry;
+>ref : Symbol(ref, Decl(esNextWeakRefs_IterableWeakMap.ts, 55, 15))
+>entry : Symbol(entry, Decl(esNextWeakRefs_IterableWeakMap.ts, 50, 13))
+
+        this.#weakMap.delete(key);
+>this.#weakMap.delete : Symbol(WeakMap.delete, Decl(lib.es2015.collection.d.ts, --, --))
+>this.#weakMap : Symbol(IterableWeakMap.#weakMap, Decl(esNextWeakRefs_IterableWeakMap.ts, 10, 61))
+>this : Symbol(IterableWeakMap, Decl(esNextWeakRefs_IterableWeakMap.ts, 6, 2))
+>delete : Symbol(WeakMap.delete, Decl(lib.es2015.collection.d.ts, --, --))
+>key : Symbol(key, Decl(esNextWeakRefs_IterableWeakMap.ts, 49, 11))
+
+        this.#refSet.delete(ref);
+>this.#refSet.delete : Symbol(Set.delete, Decl(lib.es2015.collection.d.ts, --, --))
+>this.#refSet : Symbol(IterableWeakMap.#refSet, Decl(esNextWeakRefs_IterableWeakMap.ts, 12, 72))
+>this : Symbol(IterableWeakMap, Decl(esNextWeakRefs_IterableWeakMap.ts, 6, 2))
+>delete : Symbol(Set.delete, Decl(lib.es2015.collection.d.ts, --, --))
+>ref : Symbol(ref, Decl(esNextWeakRefs_IterableWeakMap.ts, 55, 15))
+
+        this.#finalizationGroup.unregister(ref);
+>this.#finalizationGroup.unregister : Symbol(FinalizationRegistry.unregister, Decl(lib.esnext.weakref.d.ts, --, --))
+>this.#finalizationGroup : Symbol(IterableWeakMap.#finalizationGroup, Decl(esNextWeakRefs_IterableWeakMap.ts, 13, 36))
+>this : Symbol(IterableWeakMap, Decl(esNextWeakRefs_IterableWeakMap.ts, 6, 2))
+>unregister : Symbol(FinalizationRegistry.unregister, Decl(lib.esnext.weakref.d.ts, --, --))
+>ref : Symbol(ref, Decl(esNextWeakRefs_IterableWeakMap.ts, 55, 15))
+
+        return true;
+    }
+
+    declare [Symbol.iterator]: this["entries"];
+>[Symbol.iterator] : Symbol(IterableWeakMap[Symbol.iterator], Decl(esNextWeakRefs_IterableWeakMap.ts, 60, 5))
+>Symbol.iterator : Symbol(SymbolConstructor.iterator, Decl(lib.es2015.iterable.d.ts, --, --))
+>Symbol : Symbol(Symbol, Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2019.symbol.d.ts, --, --))
+>iterator : Symbol(SymbolConstructor.iterator, Decl(lib.es2015.iterable.d.ts, --, --))
+
+    *entries(): Generator<[key: K, value: V], void> {
+>entries : Symbol(IterableWeakMap.entries, Decl(esNextWeakRefs_IterableWeakMap.ts, 62, 47))
+>Generator : Symbol(Generator, Decl(lib.es2015.generator.d.ts, --, --))
+>K : Symbol(K, Decl(esNextWeakRefs_IterableWeakMap.ts, 9, 29))
+>V : Symbol(V, Decl(esNextWeakRefs_IterableWeakMap.ts, 9, 46))
+
+        for (const ref of this.#refSet) {
+>ref : Symbol(ref, Decl(esNextWeakRefs_IterableWeakMap.ts, 64, 18))
+>this.#refSet : Symbol(IterableWeakMap.#refSet, Decl(esNextWeakRefs_IterableWeakMap.ts, 12, 72))
+>this : Symbol(IterableWeakMap, Decl(esNextWeakRefs_IterableWeakMap.ts, 6, 2))
+
+            const key = ref.deref();
+>key : Symbol(key, Decl(esNextWeakRefs_IterableWeakMap.ts, 65, 17))
+>ref.deref : Symbol(WeakRef.deref, Decl(lib.esnext.weakref.d.ts, --, --))
+>ref : Symbol(ref, Decl(esNextWeakRefs_IterableWeakMap.ts, 64, 18))
+>deref : Symbol(WeakRef.deref, Decl(lib.esnext.weakref.d.ts, --, --))
+
+            if (key === undefined) continue;
+>key : Symbol(key, Decl(esNextWeakRefs_IterableWeakMap.ts, 65, 17))
+>undefined : Symbol(undefined)
+
+            const { value } = this.#weakMap.get(key)!;
+>value : Symbol(value, Decl(esNextWeakRefs_IterableWeakMap.ts, 67, 19))
+>this.#weakMap.get : Symbol(WeakMap.get, Decl(lib.es2015.collection.d.ts, --, --))
+>this.#weakMap : Symbol(IterableWeakMap.#weakMap, Decl(esNextWeakRefs_IterableWeakMap.ts, 10, 61))
+>this : Symbol(IterableWeakMap, Decl(esNextWeakRefs_IterableWeakMap.ts, 6, 2))
+>get : Symbol(WeakMap.get, Decl(lib.es2015.collection.d.ts, --, --))
+>key : Symbol(key, Decl(esNextWeakRefs_IterableWeakMap.ts, 65, 17))
+
+            yield [key, value];
+>key : Symbol(key, Decl(esNextWeakRefs_IterableWeakMap.ts, 65, 17))
+>value : Symbol(value, Decl(esNextWeakRefs_IterableWeakMap.ts, 67, 19))
+        }
+    }
+
+    *keys() {
+>keys : Symbol(IterableWeakMap.keys, Decl(esNextWeakRefs_IterableWeakMap.ts, 70, 5))
+
+        for (const { 0: key } of this) {
+>key : Symbol(key, Decl(esNextWeakRefs_IterableWeakMap.ts, 73, 20))
+>this : Symbol(IterableWeakMap, Decl(esNextWeakRefs_IterableWeakMap.ts, 6, 2))
+
+            yield key;
+>key : Symbol(key, Decl(esNextWeakRefs_IterableWeakMap.ts, 73, 20))
+        }
+    }
+
+    *values() {
+>values : Symbol(IterableWeakMap.values, Decl(esNextWeakRefs_IterableWeakMap.ts, 76, 5))
+
+        for (const { 1: value } of this) {
+>value : Symbol(value, Decl(esNextWeakRefs_IterableWeakMap.ts, 79, 20))
+>this : Symbol(IterableWeakMap, Decl(esNextWeakRefs_IterableWeakMap.ts, 6, 2))
+
+            yield value;
+>value : Symbol(value, Decl(esNextWeakRefs_IterableWeakMap.ts, 79, 20))
+        }
+    }
+}
+
+Object.defineProperties(IterableWeakMap.prototype, {
+>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, --, --))
+>IterableWeakMap.prototype : Symbol(IterableWeakMap.prototype)
+>IterableWeakMap : Symbol(IterableWeakMap, Decl(esNextWeakRefs_IterableWeakMap.ts, 6, 2))
+>prototype : Symbol(IterableWeakMap.prototype)
+
+    [Symbol.iterator]: {
+>[Symbol.iterator] : Symbol([Symbol.iterator], Decl(esNextWeakRefs_IterableWeakMap.ts, 85, 52))
+>Symbol.iterator : Symbol(SymbolConstructor.iterator, Decl(lib.es2015.iterable.d.ts, --, --))
+>Symbol : Symbol(Symbol, Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2019.symbol.d.ts, --, --))
+>iterator : Symbol(SymbolConstructor.iterator, Decl(lib.es2015.iterable.d.ts, --, --))
+
+        configurable: true,
+>configurable : Symbol(configurable, Decl(esNextWeakRefs_IterableWeakMap.ts, 86, 24))
+
+        enumerable: false,
+>enumerable : Symbol(enumerable, Decl(esNextWeakRefs_IterableWeakMap.ts, 87, 27))
+
+        writable: true,
+>writable : Symbol(writable, Decl(esNextWeakRefs_IterableWeakMap.ts, 88, 26))
+
+        value: Object.getOwnPropertyDescriptor(
+>value : Symbol(value, Decl(esNextWeakRefs_IterableWeakMap.ts, 89, 23))
+>Object.getOwnPropertyDescriptor(            IterableWeakMap.prototype,            "entries",        )!.value : Symbol(PropertyDescriptor.value, Decl(lib.es5.d.ts, --, --))
+>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, --, --))
+
+            IterableWeakMap.prototype,
+>IterableWeakMap.prototype : Symbol(IterableWeakMap.prototype)
+>IterableWeakMap : Symbol(IterableWeakMap, Decl(esNextWeakRefs_IterableWeakMap.ts, 6, 2))
+>prototype : Symbol(IterableWeakMap.prototype)
+
+            "entries",
+        )!.value,
+>value : Symbol(PropertyDescriptor.value, Decl(lib.es5.d.ts, --, --))
+
+    },
+    [Symbol.toStringTag]: {
+>[Symbol.toStringTag] : Symbol([Symbol.toStringTag], Decl(esNextWeakRefs_IterableWeakMap.ts, 94, 6))
+>Symbol.toStringTag : Symbol(SymbolConstructor.toStringTag, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>Symbol : Symbol(Symbol, Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2019.symbol.d.ts, --, --))
+>toStringTag : Symbol(SymbolConstructor.toStringTag, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+
+        configurable: true,
+>configurable : Symbol(configurable, Decl(esNextWeakRefs_IterableWeakMap.ts, 95, 27))
+
+        enumerable: false,
+>enumerable : Symbol(enumerable, Decl(esNextWeakRefs_IterableWeakMap.ts, 96, 27))
+
+        writable: false,
+>writable : Symbol(writable, Decl(esNextWeakRefs_IterableWeakMap.ts, 97, 26))
+
+        value: "IterableWeakMap",
+>value : Symbol(value, Decl(esNextWeakRefs_IterableWeakMap.ts, 98, 24))
+
+    },
+});
+
diff --git a/tests/baselines/reference/esNextWeakRefs_IterableWeakMap.types b/tests/baselines/reference/esNextWeakRefs_IterableWeakMap.types
new file mode 100644
index 0000000000..5b7566bd5d
--- /dev/null
+++ b/tests/baselines/reference/esNextWeakRefs_IterableWeakMap.types
@@ -0,0 +1,383 @@
+=== tests/cases/compiler/esNextWeakRefs_IterableWeakMap.ts ===
+/** `static #cleanup` */
+const IterableWeakMap_cleanup = ({ ref, set }: {
+>IterableWeakMap_cleanup : ({ ref, set }: { readonly ref: WeakRef<object>; readonly set: Set<WeakRef<object>>; }) => void
+>({ ref, set }: {    readonly ref: WeakRef<object>;    readonly set: Set<WeakRef<object>>;}) => {    set.delete(ref);} : ({ ref, set }: { readonly ref: WeakRef<object>; readonly set: Set<WeakRef<object>>; }) => void
+>ref : WeakRef<object>
+>set : Set<WeakRef<object>>
+
+    readonly ref: WeakRef<object>;
+>ref : WeakRef<object>
+
+    readonly set: Set<WeakRef<object>>;
+>set : Set<WeakRef<object>>
+
+}) => {
+    set.delete(ref);
+>set.delete(ref) : boolean
+>set.delete : (value: WeakRef<object>) => boolean
+>set : Set<WeakRef<object>>
+>delete : (value: WeakRef<object>) => boolean
+>ref : WeakRef<object>
+
+};
+
+// Based on: https://github.com/tc39/proposal-weakrefs/blob/master/README.md#iterable-weakmaps
+export class IterableWeakMap<K extends object, V> implements WeakMap<K, V> {
+>IterableWeakMap : IterableWeakMap<K, V>
+
+    declare readonly [Symbol.toStringTag]: "IterableWeakMap";
+>[Symbol.toStringTag] : "IterableWeakMap"
+>Symbol.toStringTag : symbol
+>Symbol : SymbolConstructor
+>toStringTag : symbol
+
+    #weakMap = new WeakMap<K, { readonly ref: WeakRef<K>; value: V }>();
+>#weakMap : WeakMap<K, { readonly ref: WeakRef<K>; value: V; }>
+>new WeakMap<K, { readonly ref: WeakRef<K>; value: V }>() : WeakMap<K, { readonly ref: WeakRef<K>; value: V; }>
+>WeakMap : WeakMapConstructor
+>ref : WeakRef<K>
+>value : V
+
+    #refSet = new Set<WeakRef<K>>();
+>#refSet : Set<WeakRef<K>>
+>new Set<WeakRef<K>>() : Set<WeakRef<K>>
+>Set : SetConstructor
+
+    #finalizationGroup = new FinalizationRegistry(IterableWeakMap_cleanup);
+>#finalizationGroup : FinalizationRegistry<{ readonly ref: WeakRef<object>; readonly set: Set<WeakRef<object>>; }>
+>new FinalizationRegistry(IterableWeakMap_cleanup) : FinalizationRegistry<{ readonly ref: WeakRef<object>; readonly set: Set<WeakRef<object>>; }>
+>FinalizationRegistry : FinalizationRegistryConstructor
+>IterableWeakMap_cleanup : ({ ref, set }: { readonly ref: WeakRef<object>; readonly set: Set<WeakRef<object>>; }) => void
+
+    constructor(iterable: Iterable<[key: K, value: V]> | null = null) {
+>iterable : Iterable<[key: K, value: V]> | null
+>null : null
+>null : null
+
+        if (iterable !== null) {
+>iterable !== null : boolean
+>iterable : Iterable<[key: K, value: V]> | null
+>null : null
+
+            for (const { 0: key, 1: value } of iterable) {
+>key : K
+>value : V
+>iterable : Iterable<[key: K, value: V]>
+
+                this.set(key, value);
+>this.set(key, value) : this
+>this.set : (key: K, value: V) => this
+>this : this
+>set : (key: K, value: V) => this
+>key : K
+>value : V
+            }
+        }
+    }
+
+    set(key: K, value: V): this {
+>set : (key: K, value: V) => this
+>key : K
+>value : V
+
+        const entry = this.#weakMap.get(key);
+>entry : { readonly ref: WeakRef<K>; value: V; } | undefined
+>this.#weakMap.get(key) : { readonly ref: WeakRef<K>; value: V; } | undefined
+>this.#weakMap.get : (key: K) => { readonly ref: WeakRef<K>; value: V; } | undefined
+>this.#weakMap : WeakMap<K, { readonly ref: WeakRef<K>; value: V; }>
+>this : this
+>get : (key: K) => { readonly ref: WeakRef<K>; value: V; } | undefined
+>key : K
+
+        if (entry !== undefined) {
+>entry !== undefined : boolean
+>entry : { readonly ref: WeakRef<K>; value: V; } | undefined
+>undefined : undefined
+
+            entry.value = value;
+>entry.value = value : V
+>entry.value : V
+>entry : { readonly ref: WeakRef<K>; value: V; }
+>value : V
+>value : V
+
+        } else {
+            const ref = new WeakRef(key);
+>ref : WeakRef<K>
+>new WeakRef(key) : WeakRef<K>
+>WeakRef : WeakRefConstructor
+>key : K
+
+            this.#weakMap.set(key, { ref, value });
+>this.#weakMap.set(key, { ref, value }) : WeakMap<K, { readonly ref: WeakRef<K>; value: V; }>
+>this.#weakMap.set : (key: K, value: { readonly ref: WeakRef<K>; value: V; }) => WeakMap<K, { readonly ref: WeakRef<K>; value: V; }>
+>this.#weakMap : WeakMap<K, { readonly ref: WeakRef<K>; value: V; }>
+>this : this
+>set : (key: K, value: { readonly ref: WeakRef<K>; value: V; }) => WeakMap<K, { readonly ref: WeakRef<K>; value: V; }>
+>key : K
+>{ ref, value } : { ref: WeakRef<K>; value: V; }
+>ref : WeakRef<K>
+>value : V
+
+            this.#refSet.add(ref);
+>this.#refSet.add(ref) : Set<WeakRef<K>>
+>this.#refSet.add : (value: WeakRef<K>) => Set<WeakRef<K>>
+>this.#refSet : Set<WeakRef<K>>
+>this : this
+>add : (value: WeakRef<K>) => Set<WeakRef<K>>
+>ref : WeakRef<K>
+
+            this.#finalizationGroup.register(key, {
+>this.#finalizationGroup.register(key, {                set: this.#refSet,                ref,            }, ref) : void
+>this.#finalizationGroup.register : (target: object, heldValue: { readonly ref: WeakRef<object>; readonly set: Set<WeakRef<object>>; }, unregisterToken?: object | undefined) => void
+>this.#finalizationGroup : FinalizationRegistry<{ readonly ref: WeakRef<object>; readonly set: Set<WeakRef<object>>; }>
+>this : this
+>register : (target: object, heldValue: { readonly ref: WeakRef<object>; readonly set: Set<WeakRef<object>>; }, unregisterToken?: object | undefined) => void
+>key : K
+>{                set: this.#refSet,                ref,            } : { set: Set<WeakRef<K>>; ref: WeakRef<K>; }
+
+                set: this.#refSet,
+>set : Set<WeakRef<K>>
+>this.#refSet : Set<WeakRef<K>>
+>this : this
+
+                ref,
+>ref : WeakRef<K>
+
+            }, ref);
+>ref : WeakRef<K>
+        }
+        return this;
+>this : this
+    }
+
+    has(key: K): boolean {
+>has : (key: K) => boolean
+>key : K
+
+        return this.#weakMap.has(key);
+>this.#weakMap.has(key) : boolean
+>this.#weakMap.has : (key: K) => boolean
+>this.#weakMap : WeakMap<K, { readonly ref: WeakRef<K>; value: V; }>
+>this : this
+>has : (key: K) => boolean
+>key : K
+    }
+
+    get(key: K): V | undefined {
+>get : (key: K) => V | undefined
+>key : K
+
+        return this.#weakMap.get(key)?.value;
+>this.#weakMap.get(key)?.value : V | undefined
+>this.#weakMap.get(key) : { readonly ref: WeakRef<K>; value: V; } | undefined
+>this.#weakMap.get : (key: K) => { readonly ref: WeakRef<K>; value: V; } | undefined
+>this.#weakMap : WeakMap<K, { readonly ref: WeakRef<K>; value: V; }>
+>this : this
+>get : (key: K) => { readonly ref: WeakRef<K>; value: V; } | undefined
+>key : K
+>value : V | undefined
+    }
+
+    delete(key: K): boolean {
+>delete : (key: K) => boolean
+>key : K
+
+        const entry = this.#weakMap.get(key);
+>entry : { readonly ref: WeakRef<K>; value: V; } | undefined
+>this.#weakMap.get(key) : { readonly ref: WeakRef<K>; value: V; } | undefined
+>this.#weakMap.get : (key: K) => { readonly ref: WeakRef<K>; value: V; } | undefined
+>this.#weakMap : WeakMap<K, { readonly ref: WeakRef<K>; value: V; }>
+>this : this
+>get : (key: K) => { readonly ref: WeakRef<K>; value: V; } | undefined
+>key : K
+
+        if (entry === undefined) {
+>entry === undefined : boolean
+>entry : { readonly ref: WeakRef<K>; value: V; } | undefined
+>undefined : undefined
+
+            return false;
+>false : false
+        }
+
+        const { ref } = entry;
+>ref : WeakRef<K>
+>entry : { readonly ref: WeakRef<K>; value: V; }
+
+        this.#weakMap.delete(key);
+>this.#weakMap.delete(key) : boolean
+>this.#weakMap.delete : (key: K) => boolean
+>this.#weakMap : WeakMap<K, { readonly ref: WeakRef<K>; value: V; }>
+>this : this
+>delete : (key: K) => boolean
+>key : K
+
+        this.#refSet.delete(ref);
+>this.#refSet.delete(ref) : boolean
+>this.#refSet.delete : (value: WeakRef<K>) => boolean
+>this.#refSet : Set<WeakRef<K>>
+>this : this
+>delete : (value: WeakRef<K>) => boolean
+>ref : WeakRef<K>
+
+        this.#finalizationGroup.unregister(ref);
+>this.#finalizationGroup.unregister(ref) : void
+>this.#finalizationGroup.unregister : (unregisterToken: object) => void
+>this.#finalizationGroup : FinalizationRegistry<{ readonly ref: WeakRef<object>; readonly set: Set<WeakRef<object>>; }>
+>this : this
+>unregister : (unregisterToken: object) => void
+>ref : WeakRef<K>
+
+        return true;
+>true : true
+    }
+
+    declare [Symbol.iterator]: this["entries"];
+>[Symbol.iterator] : this["entries"]
+>Symbol.iterator : symbol
+>Symbol : SymbolConstructor
+>iterator : symbol
+
+    *entries(): Generator<[key: K, value: V], void> {
+>entries : () => Generator<[key: K, value: V], void>
+
+        for (const ref of this.#refSet) {
+>ref : WeakRef<K>
+>this.#refSet : Set<WeakRef<K>>
+>this : this
+
+            const key = ref.deref();
+>key : K | undefined
+>ref.deref() : K | undefined
+>ref.deref : () => K | undefined
+>ref : WeakRef<K>
+>deref : () => K | undefined
+
+            if (key === undefined) continue;
+>key === undefined : boolean
+>key : K | undefined
+>undefined : undefined
+
+            const { value } = this.#weakMap.get(key)!;
+>value : V
+>this.#weakMap.get(key)! : { readonly ref: WeakRef<K>; value: V; }
+>this.#weakMap.get(key) : { readonly ref: WeakRef<K>; value: V; } | undefined
+>this.#weakMap.get : (key: K) => { readonly ref: WeakRef<K>; value: V; } | undefined
+>this.#weakMap : WeakMap<K, { readonly ref: WeakRef<K>; value: V; }>
+>this : this
+>get : (key: K) => { readonly ref: WeakRef<K>; value: V; } | undefined
+>key : K
+
+            yield [key, value];
+>yield [key, value] : unknown
+>[key, value] : [K, V]
+>key : K
+>value : V
+        }
+    }
+
+    *keys() {
+>keys : () => Generator<K, void, unknown>
+
+        for (const { 0: key } of this) {
+>key : K
+>this : this
+
+            yield key;
+>yield key : any
+>key : K
+        }
+    }
+
+    *values() {
+>values : () => Generator<V, void, unknown>
+
+        for (const { 1: value } of this) {
+>value : V
+>this : this
+
+            yield value;
+>yield value : any
+>value : 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",    },}) : any
+>Object.defineProperties : (o: any, properties: PropertyDescriptorMap & ThisType<any>) => any
+>Object : ObjectConstructor
+>defineProperties : (o: any, properties: PropertyDescriptorMap & ThisType<any>) => any
+>IterableWeakMap.prototype : IterableWeakMap<any, any>
+>IterableWeakMap : typeof IterableWeakMap
+>prototype : IterableWeakMap<any, any>
+>{    [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",    },} : { [Symbol.iterator]: { configurable: true; enumerable: false; writable: true; value: any; }; [Symbol.toStringTag]: { configurable: true; enumerable: false; writable: false; value: string; }; }
+
+    [Symbol.iterator]: {
+>[Symbol.iterator] : { configurable: true; enumerable: false; writable: true; value: any; }
+>Symbol.iterator : symbol
+>Symbol : SymbolConstructor
+>iterator : symbol
+>{        configurable: true,        enumerable: false,        writable: true,        value: Object.getOwnPropertyDescriptor(            IterableWeakMap.prototype,            "entries",        )!.value,    } : { configurable: true; enumerable: false; writable: true; value: any; }
+
+        configurable: true,
+>configurable : true
+>true : true
+
+        enumerable: false,
+>enumerable : false
+>false : false
+
+        writable: true,
+>writable : true
+>true : true
+
+        value: Object.getOwnPropertyDescriptor(
+>value : any
+>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 : ObjectConstructor
+>getOwnPropertyDescriptor : (o: any, p: PropertyKey) => PropertyDescriptor | undefined
+
+            IterableWeakMap.prototype,
+>IterableWeakMap.prototype : IterableWeakMap<any, any>
+>IterableWeakMap : typeof IterableWeakMap
+>prototype : IterableWeakMap<any, any>
+
+            "entries",
+>"entries" : "entries"
+
+        )!.value,
+>value : any
+
+    },
+    [Symbol.toStringTag]: {
+>[Symbol.toStringTag] : { configurable: true; enumerable: false; writable: false; value: string; }
+>Symbol.toStringTag : symbol
+>Symbol : SymbolConstructor
+>toStringTag : symbol
+>{        configurable: true,        enumerable: false,        writable: false,        value: "IterableWeakMap",    } : { configurable: true; enumerable: false; writable: false; value: string; }
+
+        configurable: true,
+>configurable : true
+>true : true
+
+        enumerable: false,
+>enumerable : false
+>false : false
+
+        writable: false,
+>writable : false
+>false : false
+
+        value: "IterableWeakMap",
+>value : string
+>"IterableWeakMap" : "IterableWeakMap"
+
+    },
+});
+
diff --git a/tests/cases/compiler/esNextWeakRefs_IterableWeakMap.ts b/tests/cases/compiler/esNextWeakRefs_IterableWeakMap.ts
new file mode 100644
index 0000000000..220b56a3d8
--- /dev/null
+++ b/tests/cases/compiler/esNextWeakRefs_IterableWeakMap.ts
@@ -0,0 +1,107 @@
+// @lib: ESNext
+// @target: ESNext
+// @useDefineForClassFields: true
+// @strictNullChecks: true
+
+/** `static #cleanup` */
+const IterableWeakMap_cleanup = ({ ref, set }: {
+    readonly ref: WeakRef<object>;
+    readonly set: Set<WeakRef<object>>;
+}) => {
+    set.delete(ref);
+};
+
+// Based on: https://github.com/tc39/proposal-weakrefs/blob/master/README.md#iterable-weakmaps
+export class IterableWeakMap<K extends object, V> implements WeakMap<K, V> {
+    declare readonly [Symbol.toStringTag]: "IterableWeakMap";
+
+    #weakMap = new WeakMap<K, { readonly ref: WeakRef<K>; value: V }>();
+    #refSet = new Set<WeakRef<K>>();
+    #finalizationGroup = new FinalizationRegistry(IterableWeakMap_cleanup);
+
+    constructor(iterable: Iterable<[key: K, value: V]> | null = null) {
+        if (iterable !== null) {
+            for (const { 0: key, 1: value } of iterable) {
+                this.set(key, value);
+            }
+        }
+    }
+
+    set(key: K, value: V): this {
+        const entry = this.#weakMap.get(key);
+        if (entry !== undefined) {
+            entry.value = value;
+        } else {
+            const ref = new WeakRef(key);
+
+            this.#weakMap.set(key, { ref, value });
+            this.#refSet.add(ref);
+            this.#finalizationGroup.register(key, {
+                set: this.#refSet,
+                ref,
+            }, ref);
+        }
+        return this;
+    }
+
+    has(key: K): boolean {
+        return this.#weakMap.has(key);
+    }
+
+    get(key: K): V | undefined {
+        return this.#weakMap.get(key)?.value;
+    }
+
+    delete(key: K): boolean {
+        const entry = this.#weakMap.get(key);
+        if (entry === undefined) {
+            return false;
+        }
+
+        const { ref } = entry;
+        this.#weakMap.delete(key);
+        this.#refSet.delete(ref);
+        this.#finalizationGroup.unregister(ref);
+        return true;
+    }
+
+    declare [Symbol.iterator]: this["entries"];
+    *entries(): Generator<[key: K, value: V], void> {
+        for (const ref of this.#refSet) {
+            const key = ref.deref();
+            if (key === undefined) continue;
+            const { value } = this.#weakMap.get(key)!;
+            yield [key, value];
+        }
+    }
+
+    *keys() {
+        for (const { 0: key } of this) {
+            yield key;
+        }
+    }
+
+    *values() {
+        for (const { 1: value } of this) {
+            yield value;
+        }
+    }
+}
+
+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",
+    },
+});