diff --git a/src/lib/es2015.collection.d.ts b/src/lib/es2015.collection.d.ts
index e88f0d4c3b405..4b6f38206cf52 100644
--- a/src/lib/es2015.collection.d.ts
+++ b/src/lib/es2015.collection.d.ts
@@ -1,4 +1,4 @@
-interface Map<K, V> {
+interface Map<out K, out V> {
     clear(): void;
     /**
      * @returns true if an element in the Map existed and has been removed, or false if the element does not exist.
@@ -34,14 +34,14 @@ interface MapConstructor {
 }
 declare var Map: MapConstructor;
 
-interface ReadonlyMap<K, V> {
+interface ReadonlyMap<out K, out V> {
     forEach(callbackfn: (value: V, key: K, map: ReadonlyMap<K, V>) => void, thisArg?: any): void;
     get(key: K): V | undefined;
     has(key: K): boolean;
     readonly size: number;
 }
 
-interface WeakMap<K extends WeakKey, V> {
+interface WeakMap<out K extends WeakKey, out V> {
     /**
      * Removes the specified element from the WeakMap.
      * @returns true if the element was successfully removed, or false if it was not present.
@@ -68,7 +68,7 @@ interface WeakMapConstructor {
 }
 declare var WeakMap: WeakMapConstructor;
 
-interface Set<T> {
+interface Set<out T> {
     /**
      * Appends a new element with a specified value to the end of the Set.
      */
@@ -100,13 +100,13 @@ interface SetConstructor {
 }
 declare var Set: SetConstructor;
 
-interface ReadonlySet<T> {
+interface ReadonlySet<out T> {
     forEach(callbackfn: (value: T, value2: T, set: ReadonlySet<T>) => void, thisArg?: any): void;
     has(value: T): boolean;
     readonly size: number;
 }
 
-interface WeakSet<T extends WeakKey> {
+interface WeakSet<out T extends WeakKey> {
     /**
      * Appends a new value to the end of the WeakSet.
      */
diff --git a/src/lib/es2015.iterable.d.ts b/src/lib/es2015.iterable.d.ts
index 07b7322dd1a12..0e863780a9d1a 100644
--- a/src/lib/es2015.iterable.d.ts
+++ b/src/lib/es2015.iterable.d.ts
@@ -116,11 +116,11 @@ interface IArguments {
     [Symbol.iterator](): ArrayIterator<any>;
 }
 
-interface MapIterator<T> extends IteratorObject<T, BuiltinIteratorReturn, unknown> {
+interface MapIterator<out T> extends IteratorObject<T, BuiltinIteratorReturn, unknown> {
     [Symbol.iterator](): MapIterator<T>;
 }
 
-interface Map<K, V> {
+interface Map<out K, out V> {
     /** Returns an iterable of entries in the map. */
     [Symbol.iterator](): MapIterator<[K, V]>;
 
@@ -140,7 +140,7 @@ interface Map<K, V> {
     values(): MapIterator<V>;
 }
 
-interface ReadonlyMap<K, V> {
+interface ReadonlyMap<out K, out V> {
     /** Returns an iterable of entries in the map. */
     [Symbol.iterator](): MapIterator<[K, V]>;
 
@@ -165,17 +165,17 @@ interface MapConstructor {
     new <K, V>(iterable?: Iterable<readonly [K, V]> | null): Map<K, V>;
 }
 
-interface WeakMap<K extends WeakKey, V> {}
+interface WeakMap<out K extends WeakKey, out V> {}
 
 interface WeakMapConstructor {
     new <K extends WeakKey, V>(iterable: Iterable<readonly [K, V]>): WeakMap<K, V>;
 }
 
-interface SetIterator<T> extends IteratorObject<T, BuiltinIteratorReturn, unknown> {
+interface SetIterator<out T> extends IteratorObject<T, BuiltinIteratorReturn, unknown> {
     [Symbol.iterator](): SetIterator<T>;
 }
 
-interface Set<T> {
+interface Set<out T> {
     /** Iterates over values in the set. */
     [Symbol.iterator](): SetIterator<T>;
 
@@ -195,7 +195,7 @@ interface Set<T> {
     values(): SetIterator<T>;
 }
 
-interface ReadonlySet<T> {
+interface ReadonlySet<out T> {
     /** Iterates over values in the set. */
     [Symbol.iterator](): SetIterator<T>;
 
@@ -219,7 +219,7 @@ interface SetConstructor {
     new <T>(iterable?: Iterable<T> | null): Set<T>;
 }
 
-interface WeakSet<T extends WeakKey> {}
+interface WeakSet<out T extends WeakKey> {}
 
 interface WeakSetConstructor {
     new <T extends WeakKey = WeakKey>(iterable: Iterable<T>): WeakSet<T>;
@@ -245,7 +245,7 @@ interface PromiseConstructor {
     race<T>(values: Iterable<T | PromiseLike<T>>): Promise<Awaited<T>>;
 }
 
-interface StringIterator<T> extends IteratorObject<T, BuiltinIteratorReturn, unknown> {
+interface StringIterator<out T> extends IteratorObject<T, BuiltinIteratorReturn, unknown> {
     [Symbol.iterator](): StringIterator<T>;
 }
 
diff --git a/src/lib/es2015.symbol.wellknown.d.ts b/src/lib/es2015.symbol.wellknown.d.ts
index 1ab84be969fca..8b2d451b7c0d2 100644
--- a/src/lib/es2015.symbol.wellknown.d.ts
+++ b/src/lib/es2015.symbol.wellknown.d.ts
@@ -115,19 +115,19 @@ interface Date {
     [Symbol.toPrimitive](hint: string): string | number;
 }
 
-interface Map<K, V> {
+interface Map<out K, out V> {
     readonly [Symbol.toStringTag]: string;
 }
 
-interface WeakMap<K extends WeakKey, V> {
+interface WeakMap<out K extends WeakKey, out V> {
     readonly [Symbol.toStringTag]: string;
 }
 
-interface Set<T> {
+interface Set<out T> {
     readonly [Symbol.toStringTag]: string;
 }
 
-interface WeakSet<T extends WeakKey> {
+interface WeakSet<out T extends WeakKey> {
     readonly [Symbol.toStringTag]: string;
 }
 
diff --git a/src/lib/es5.d.ts b/src/lib/es5.d.ts
index 3ca96f12760be..b1b5610f03b84 100644
--- a/src/lib/es5.d.ts
+++ b/src/lib/es5.d.ts
@@ -1516,7 +1516,7 @@ interface TypedPropertyDescriptor<T> {
 
 declare type PromiseConstructorLike = new <T>(executor: (resolve: (value: T | PromiseLike<T>) => void, reject: (reason?: any) => void) => void) => PromiseLike<T>;
 
-interface PromiseLike<T> {
+interface PromiseLike<out T> {
     /**
      * Attaches callbacks for the resolution and/or rejection of the Promise.
      * @param onfulfilled The callback to execute when the Promise is resolved.
@@ -1529,7 +1529,7 @@ interface PromiseLike<T> {
 /**
  * Represents the completion of an asynchronous operation
  */
-interface Promise<T> {
+interface Promise<out T> {
     /**
      * Attaches callbacks for the resolution and/or rejection of the Promise.
      * @param onfulfilled The callback to execute when the Promise is resolved.
diff --git a/src/lib/esnext.collection.d.ts b/src/lib/esnext.collection.d.ts
index 712e8d34277da..b8d4b818d582c 100644
--- a/src/lib/esnext.collection.d.ts
+++ b/src/lib/esnext.collection.d.ts
@@ -1,6 +1,6 @@
 /// <reference lib="es2024.collection" />
 
-interface ReadonlySetLike<T> {
+interface ReadonlySetLike<out T> {
     /**
      * Despite its name, returns an iterator of the values in the set-like.
      */
@@ -15,7 +15,7 @@ interface ReadonlySetLike<T> {
     readonly size: number;
 }
 
-interface Set<T> {
+interface Set<out T> {
     /**
      * @returns a new Set containing all the elements in this Set and also all the elements in the argument.
      */
@@ -46,7 +46,7 @@ interface Set<T> {
     isDisjointFrom(other: ReadonlySetLike<unknown>): boolean;
 }
 
-interface ReadonlySet<T> {
+interface ReadonlySet<out T> {
     /**
      * @returns a new Set containing all the elements in this Set and also all the elements in the argument.
      */
diff --git a/tests/baselines/reference/completionsCommitCharactersGlobal.baseline b/tests/baselines/reference/completionsCommitCharactersGlobal.baseline
index 582d3363da492..4468c3ee6fab5 100644
--- a/tests/baselines/reference/completionsCommitCharactersGlobal.baseline
+++ b/tests/baselines/reference/completionsCommitCharactersGlobal.baseline
@@ -2693,9 +2693,9 @@
 // | type Parameters<T extends (...args: any) => any> = T extends (...args: infer P) => any ? P : never
 // | type Partial<T> = { [P in keyof T]?: T[P]; }
 // | type Pick<T, K extends keyof T> = { [P in K]: T[P]; }
-// | interface Promise<T>
+// | interface Promise<out T>
 // | type PromiseConstructorLike = new <T>(executor: (resolve: (value: T | PromiseLike<T>) => void, reject: (reason?: any) => void) => void) => PromiseLike<T>
-// | interface PromiseLike<T>
+// | interface PromiseLike<out T>
 // | type PropertyDecorator = (target: Object, propertyKey: string | symbol) => void
 // | interface PropertyDescriptor
 // | interface PropertyDescriptorMap
@@ -2873,9 +2873,9 @@
 // | type Parameters<T extends (...args: any) => any> = T extends (...args: infer P) => any ? P : never
 // | type Partial<T> = { [P in keyof T]?: T[P]; }
 // | type Pick<T, K extends keyof T> = { [P in K]: T[P]; }
-// | interface Promise<T>
+// | interface Promise<out T>
 // | type PromiseConstructorLike = new <T>(executor: (resolve: (value: T | PromiseLike<T>) => void, reject: (reason?: any) => void) => void) => PromiseLike<T>
-// | interface PromiseLike<T>
+// | interface PromiseLike<out T>
 // | type PropertyDecorator = (target: Object, propertyKey: string | symbol) => void
 // | interface PropertyDescriptor
 // | interface PropertyDescriptorMap
@@ -80790,6 +80790,14 @@
               "text": "<",
               "kind": "punctuation"
             },
+            {
+              "text": "out",
+              "kind": "keyword"
+            },
+            {
+              "text": " ",
+              "kind": "space"
+            },
             {
               "text": "T",
               "kind": "typeParameterName"
@@ -81097,6 +81105,14 @@
               "text": "<",
               "kind": "punctuation"
             },
+            {
+              "text": "out",
+              "kind": "keyword"
+            },
+            {
+              "text": " ",
+              "kind": "space"
+            },
             {
               "text": "T",
               "kind": "typeParameterName"
@@ -90261,6 +90277,14 @@
               "text": "<",
               "kind": "punctuation"
             },
+            {
+              "text": "out",
+              "kind": "keyword"
+            },
+            {
+              "text": " ",
+              "kind": "space"
+            },
             {
               "text": "T",
               "kind": "typeParameterName"
@@ -90568,6 +90592,14 @@
               "text": "<",
               "kind": "punctuation"
             },
+            {
+              "text": "out",
+              "kind": "keyword"
+            },
+            {
+              "text": " ",
+              "kind": "space"
+            },
             {
               "text": "T",
               "kind": "typeParameterName"
diff --git a/tests/baselines/reference/esNextWeakRefs_IterableWeakMap.types b/tests/baselines/reference/esNextWeakRefs_IterableWeakMap.types
index b409385e2c46e..d53b79137fc27 100644
--- a/tests/baselines/reference/esNextWeakRefs_IterableWeakMap.types
+++ b/tests/baselines/reference/esNextWeakRefs_IterableWeakMap.types
@@ -1,9 +1,5 @@
 //// [tests/cases/compiler/esNextWeakRefs_IterableWeakMap.ts] ////
 
-=== Performance Stats ===
-Type Count: 1,000
-Instantiation count: 2,500
-
 === esNextWeakRefs_IterableWeakMap.ts ===
 /** `static #cleanup` */
 const IterableWeakMap_cleanup = ({ ref, set }: {
diff --git a/tests/baselines/reference/goToTypeDefinitionModifiers.baseline.jsonc b/tests/baselines/reference/goToTypeDefinitionModifiers.baseline.jsonc
index 0971205dbcaaf..5462d0af44874 100644
--- a/tests/baselines/reference/goToTypeDefinitionModifiers.baseline.jsonc
+++ b/tests/baselines/reference/goToTypeDefinitionModifiers.baseline.jsonc
@@ -192,7 +192,7 @@
 // /**
 //  * Represents the completion of an asynchronous operation
 //  */
-// <|interface [|Promise|]<T> {
+// <|interface [|Promise|]<out T> {
 //     /**
 //      * Attaches callbacks for the resolution and/or rejection of the Promise.
 //      * @param onfulfilled The callback to execute when the Promise is resolved.
@@ -245,7 +245,7 @@
 // /**
 //  * Represents the completion of an asynchronous operation
 //  */
-// <|interface [|Promise|]<T> {
+// <|interface [|Promise|]<out T> {
 //     /**
 //      * Attaches callbacks for the resolution and/or rejection of the Promise.
 //      * @param onfulfilled The callback to execute when the Promise is resolved.
@@ -352,7 +352,7 @@
 // /**
 //  * Represents the completion of an asynchronous operation
 //  */
-// <|interface [|Promise|]<T> {
+// <|interface [|Promise|]<out T> {
 //     /**
 //      * Attaches callbacks for the resolution and/or rejection of the Promise.
 //      * @param onfulfilled The callback to execute when the Promise is resolved.
@@ -404,7 +404,7 @@
 // /**
 //  * Represents the completion of an asynchronous operation
 //  */
-// <|interface [|Promise|]<T> {
+// <|interface [|Promise|]<out T> {
 //     /**
 //      * Attaches callbacks for the resolution and/or rejection of the Promise.
 //      * @param onfulfilled The callback to execute when the Promise is resolved.
@@ -456,7 +456,7 @@
 // /**
 //  * Represents the completion of an asynchronous operation
 //  */
-// <|interface [|Promise|]<T> {
+// <|interface [|Promise|]<out T> {
 //     /**
 //      * Attaches callbacks for the resolution and/or rejection of the Promise.
 //      * @param onfulfilled The callback to execute when the Promise is resolved.
@@ -508,7 +508,7 @@
 // /**
 //  * Represents the completion of an asynchronous operation
 //  */
-// <|interface [|Promise|]<T> {
+// <|interface [|Promise|]<out T> {
 //     /**
 //      * Attaches callbacks for the resolution and/or rejection of the Promise.
 //      * @param onfulfilled The callback to execute when the Promise is resolved.
diff --git a/tests/baselines/reference/goToTypeDefinition_promiseType.baseline.jsonc b/tests/baselines/reference/goToTypeDefinition_promiseType.baseline.jsonc
index f84caf2e46250..bac40cf939f9e 100644
--- a/tests/baselines/reference/goToTypeDefinition_promiseType.baseline.jsonc
+++ b/tests/baselines/reference/goToTypeDefinition_promiseType.baseline.jsonc
@@ -12,7 +12,7 @@
 // /**
 //  * Represents the completion of an asynchronous operation
 //  */
-// <|interface [|{| defId: 1 |}Promise|]<T> {
+// <|interface [|{| defId: 1 |}Promise|]<out T> {
 //     /**
 //      * Attaches callbacks for the resolution and/or rejection of the Promise.
 //      * @param onfulfilled The callback to execute when the Promise is resolved.
@@ -73,7 +73,7 @@
 // /**
 //  * Represents the completion of an asynchronous operation
 //  */
-// <|interface [|{| defId: 1 |}Promise|]<T> {
+// <|interface [|{| defId: 1 |}Promise|]<out T> {
 //     /**
 //      * Attaches callbacks for the resolution and/or rejection of the Promise.
 //      * @param onfulfilled The callback to execute when the Promise is resolved.
diff --git a/tests/baselines/reference/importTag24.types b/tests/baselines/reference/importTag24.types
index 1a4387b3d0ca8..24d114075ce73 100644
--- a/tests/baselines/reference/importTag24.types
+++ b/tests/baselines/reference/importTag24.types
@@ -1,9 +1,5 @@
 //// [tests/cases/conformance/jsdoc/importTag24.ts] ////
 
-=== Performance Stats ===
-Type Count: 1,000
-Instantiation count: 2,500
-
 === types.d.ts ===
 export type Foo = string;
 >Foo : string
diff --git a/tests/baselines/reference/inferFromGenericFunctionReturnTypes3.types b/tests/baselines/reference/inferFromGenericFunctionReturnTypes3.types
index e20de1c2bbd86..c4a3eace14466 100644
--- a/tests/baselines/reference/inferFromGenericFunctionReturnTypes3.types
+++ b/tests/baselines/reference/inferFromGenericFunctionReturnTypes3.types
@@ -1,8 +1,5 @@
 //// [tests/cases/compiler/inferFromGenericFunctionReturnTypes3.ts] ////
 
-=== Performance Stats ===
-Type Count: 1,000
-
 === inferFromGenericFunctionReturnTypes3.ts ===
 // Repros from #5487
 
diff --git a/tests/baselines/reference/inferTypes1.types b/tests/baselines/reference/inferTypes1.types
index 7fc95b8e2fef0..33d5e8d331d6d 100644
--- a/tests/baselines/reference/inferTypes1.types
+++ b/tests/baselines/reference/inferTypes1.types
@@ -1,9 +1,5 @@
 //// [tests/cases/conformance/types/conditional/inferTypes1.ts] ////
 
-=== Performance Stats ===
-Type Count: 1,000
-Instantiation count: 1,000
-
 === inferTypes1.ts ===
 type Unpacked<T> =
 >Unpacked : Unpacked<T>
diff --git a/tests/baselines/reference/mapGroupBy.types b/tests/baselines/reference/mapGroupBy.types
index dde7f5accd85e..090af0f19de64 100644
--- a/tests/baselines/reference/mapGroupBy.types
+++ b/tests/baselines/reference/mapGroupBy.types
@@ -1,9 +1,5 @@
 //// [tests/cases/compiler/mapGroupBy.ts] ////
 
-=== Performance Stats ===
-Type Count: 1,000
-Instantiation count: 2,500
-
 === mapGroupBy.ts ===
 const basic = Map.groupBy([0, 2, 8], x => x < 5 ? 'small' : 'large');
 >basic : Map<"small" | "large", number[]>
diff --git a/tests/baselines/reference/narrowingPastLastAssignment.types b/tests/baselines/reference/narrowingPastLastAssignment.types
index f2c62a10d1381..5fee80992943b 100644
--- a/tests/baselines/reference/narrowingPastLastAssignment.types
+++ b/tests/baselines/reference/narrowingPastLastAssignment.types
@@ -1,9 +1,5 @@
 //// [tests/cases/compiler/narrowingPastLastAssignment.ts] ////
 
-=== Performance Stats ===
-Type Count: 1,000
-Instantiation count: 2,500
-
 === narrowingPastLastAssignment.ts ===
 function action(f: Function) {}
 >action : (f: Function) => void
diff --git a/tests/baselines/reference/objectGroupBy.types b/tests/baselines/reference/objectGroupBy.types
index f836f949d68a4..ec9a37f131b20 100644
--- a/tests/baselines/reference/objectGroupBy.types
+++ b/tests/baselines/reference/objectGroupBy.types
@@ -1,9 +1,5 @@
 //// [tests/cases/compiler/objectGroupBy.ts] ////
 
-=== Performance Stats ===
-Type Count: 1,000
-Instantiation count: 2,500
-
 === objectGroupBy.ts ===
 const basic = Object.groupBy([0, 2, 8], x => x < 5 ? 'small' : 'large');
 >basic : Partial<Record<"small" | "large", number[]>>
diff --git a/tests/baselines/reference/parenthesizedJSDocCastAtReturnStatement.types b/tests/baselines/reference/parenthesizedJSDocCastAtReturnStatement.types
index 61141eebd4c63..25270ffaee519 100644
--- a/tests/baselines/reference/parenthesizedJSDocCastAtReturnStatement.types
+++ b/tests/baselines/reference/parenthesizedJSDocCastAtReturnStatement.types
@@ -1,9 +1,5 @@
 //// [tests/cases/compiler/parenthesizedJSDocCastAtReturnStatement.ts] ////
 
-=== Performance Stats ===
-Type Count: 1,000
-Instantiation count: 2,500
-
 === index.js ===
 /** @type {Map<string, string | Set<string>>} */
 const cache = new Map()
diff --git a/tests/baselines/reference/quickinfoVerbosityLibType.baseline b/tests/baselines/reference/quickinfoVerbosityLibType.baseline
index d4ec5e2e93ab7..9eb897a61b0cf 100644
--- a/tests/baselines/reference/quickinfoVerbosityLibType.baseline
+++ b/tests/baselines/reference/quickinfoVerbosityLibType.baseline
@@ -38,7 +38,7 @@
 // type Foo<T> = Promise<T>;
 //               ^^^^^^^
 // | ----------------------------------------------------------------------
-// | interface Promise<T>
+// | interface Promise<out T>
 // | Represents the completion of an asynchronous operation
 // | (verbosity level: 0)
 // | ----------------------------------------------------------------------
@@ -490,6 +490,14 @@
           "text": "<",
           "kind": "punctuation"
         },
+        {
+          "text": "out",
+          "kind": "keyword"
+        },
+        {
+          "text": " ",
+          "kind": "space"
+        },
         {
           "text": "T",
           "kind": "typeParameterName"
diff --git a/tests/baselines/reference/returnConditionalExpressionJSDocCast.types b/tests/baselines/reference/returnConditionalExpressionJSDocCast.types
index 4b98f032cb8e9..39ad0ec09fd78 100644
--- a/tests/baselines/reference/returnConditionalExpressionJSDocCast.types
+++ b/tests/baselines/reference/returnConditionalExpressionJSDocCast.types
@@ -1,9 +1,5 @@
 //// [tests/cases/compiler/returnConditionalExpressionJSDocCast.ts] ////
 
-=== Performance Stats ===
-Type Count: 1,000
-Instantiation count: 2,500
-
 === file.js ===
 // Don't peek into conditional return expression if it's wrapped in a cast
 /** @type {Map<string, string>} */
diff --git a/tests/baselines/reference/substitutionTypePassedToExtends.types b/tests/baselines/reference/substitutionTypePassedToExtends.types
index 102d4d17d567f..c8aee67f83cec 100644
--- a/tests/baselines/reference/substitutionTypePassedToExtends.types
+++ b/tests/baselines/reference/substitutionTypePassedToExtends.types
@@ -1,9 +1,5 @@
 //// [tests/cases/compiler/substitutionTypePassedToExtends.ts] ////
 
-=== Performance Stats ===
-Type Count: 500 -> 1,000
-Instantiation count: 100 -> 2,500
-
 === substitutionTypePassedToExtends.ts ===
 type Foo1<A,B> = [A, B] extends unknown[][] ? Bar1<[A, B]> : 'else'
 >Foo1 : Foo1<A, B>
diff --git a/tests/baselines/reference/typeParameterConstModifiersReturnsAndYields.types b/tests/baselines/reference/typeParameterConstModifiersReturnsAndYields.types
index e5355c2453066..ac6b9e882df5a 100644
--- a/tests/baselines/reference/typeParameterConstModifiersReturnsAndYields.types
+++ b/tests/baselines/reference/typeParameterConstModifiersReturnsAndYields.types
@@ -1,7 +1,7 @@
 //// [tests/cases/conformance/types/typeParameters/typeParameterLists/typeParameterConstModifiersReturnsAndYields.ts] ////
 
 === Performance Stats ===
-Type Count: 2,500
+Type Count: 1,000
 Instantiation count: 2,500
 
 === typeParameterConstModifiersReturnsAndYields.ts ===