Don't try to add an implicit undefined for mapped properties outside of strictNullChecks

src/compiler/checker.ts

@@ -6267,7 +6267,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
                     return true;
                 }
                 if (requiresAddingUndefined && annotationType) {
-                    annotationType = getOptionalType(annotationType, !isParameter(node));
+                    annotationType = addOptionality(annotationType, !isParameter(node));
                 }
                 return !!annotationType && typeNodeIsEquivalentToType(node, type, annotationType) && existingTypeNodeIsNotReferenceOrIsReferenceWithCompatibleTypeArgumentCount(existing, type);
             },

tests/baselines/reference/declarationEmitOptionalMappedTypePropertyNoStrictNullChecks1.js

@@ -0,0 +1,48 @@
+//// [tests/cases/compiler/declarationEmitOptionalMappedTypePropertyNoStrictNullChecks1.ts] ////
+
+//// [createApi.ts]
+type Id<T> = {
+  [K in keyof T]: T[K];
+} & {};
+
+export declare function createApi<Definitions>(_: { endpoints: Definitions }): {
+  [K in keyof Definitions as `use${Capitalize<K & string>}Query`]: () => Id<{
+    status: "uninitialized";
+    originalArgs?: undefined;
+  }>;
+};
+
+//// [index.ts]
+import { createApi } from "./createApi";
+
+const slice = createApi({
+  endpoints: {
+    test: {
+      url: `/user`,
+    },
+  },
+});
+
+export const { useTestQuery } = slice;
+
+
+
+
+//// [createApi.d.ts]
+type Id<T> = {
+    [K in keyof T]: T[K];
+} & {};
+export declare function createApi<Definitions>(_: {
+    endpoints: Definitions;
+}): {
+    [K in keyof Definitions as `use${Capitalize<K & string>}Query`]: () => Id<{
+        status: "uninitialized";
+        originalArgs?: undefined;
+    }>;
+};
+export {};
+//// [index.d.ts]
+export declare const useTestQuery: () => {
+    status: "uninitialized";
+    originalArgs?: undefined;
+};

tests/baselines/reference/declarationEmitOptionalMappedTypePropertyNoStrictNullChecks1.symbols

@@ -0,0 +1,63 @@
+//// [tests/cases/compiler/declarationEmitOptionalMappedTypePropertyNoStrictNullChecks1.ts] ////
+
+=== createApi.ts ===
+type Id<T> = {
+>Id : Symbol(Id, Decl(createApi.ts, 0, 0))
+>T : Symbol(T, Decl(createApi.ts, 0, 8))
+
+  [K in keyof T]: T[K];
+>K : Symbol(K, Decl(createApi.ts, 1, 3))
+>T : Symbol(T, Decl(createApi.ts, 0, 8))
+>T : Symbol(T, Decl(createApi.ts, 0, 8))
+>K : Symbol(K, Decl(createApi.ts, 1, 3))
+
+} & {};
+
+export declare function createApi<Definitions>(_: { endpoints: Definitions }): {
+>createApi : Symbol(createApi, Decl(createApi.ts, 2, 7))
+>Definitions : Symbol(Definitions, Decl(createApi.ts, 4, 34))
+>_ : Symbol(_, Decl(createApi.ts, 4, 47))
+>endpoints : Symbol(endpoints, Decl(createApi.ts, 4, 51))
+>Definitions : Symbol(Definitions, Decl(createApi.ts, 4, 34))
+
+  [K in keyof Definitions as `use${Capitalize<K & string>}Query`]: () => Id<{
+>K : Symbol(K, Decl(createApi.ts, 5, 3))
+>Definitions : Symbol(Definitions, Decl(createApi.ts, 4, 34))
+>Capitalize : Symbol(Capitalize, Decl(lib.es5.d.ts, --, --))
+>K : Symbol(K, Decl(createApi.ts, 5, 3))
+>Id : Symbol(Id, Decl(createApi.ts, 0, 0))
+
+    status: "uninitialized";
+>status : Symbol(status, Decl(createApi.ts, 5, 77))
+
+    originalArgs?: undefined;
+>originalArgs : Symbol(originalArgs, Decl(createApi.ts, 6, 28))
+
+  }>;
+};
+
+=== index.ts ===
+import { createApi } from "./createApi";
+>createApi : Symbol(createApi, Decl(index.ts, 0, 8))
+
+const slice = createApi({
+>slice : Symbol(slice, Decl(index.ts, 2, 5))
+>createApi : Symbol(createApi, Decl(index.ts, 0, 8))
+
+  endpoints: {
+>endpoints : Symbol(endpoints, Decl(index.ts, 2, 25))
+
+    test: {
+>test : Symbol(test, Decl(index.ts, 3, 14))
+
+      url: `/user`,
+>url : Symbol(url, Decl(index.ts, 4, 11))
+
+    },
+  },
+});
+
+export const { useTestQuery } = slice;
+>useTestQuery : Symbol(useTestQuery, Decl(index.ts, 10, 14))
+>slice : Symbol(slice, Decl(index.ts, 2, 5))
+

tests/baselines/reference/declarationEmitOptionalMappedTypePropertyNoStrictNullChecks1.types

@@ -0,0 +1,73 @@
+//// [tests/cases/compiler/declarationEmitOptionalMappedTypePropertyNoStrictNullChecks1.ts] ////
+
+=== createApi.ts ===
+type Id<T> = {
+>Id : { [K in keyof T]: T[K]; }
+>   : ^^^ ^^^^^^^^^^^^^^^^^^^^^
+
+  [K in keyof T]: T[K];
+} & {};
+
+export declare function createApi<Definitions>(_: { endpoints: Definitions }): {
+>createApi : <Definitions>(_: { endpoints: Definitions; }) => { [K in keyof Definitions as `use${Capitalize<K & string>}Query`]: () => Id<{ status: "uninitialized"; originalArgs?: undefined; }>; }
+>          : ^           ^^ ^^                           ^^^^^                                                                                                                                      
+>_ : { endpoints: Definitions; }
+>  : ^^^^^^^^^^^^^           ^^^
+>endpoints : Definitions
+>          : ^^^^^^^^^^^
+
+  [K in keyof Definitions as `use${Capitalize<K & string>}Query`]: () => Id<{
+    status: "uninitialized";
+>status : "uninitialized"
+>       : ^^^^^^^^^^^^^^^
+
+    originalArgs?: undefined;
+>originalArgs : undefined
+>             : ^^^^^^^^^
+
+  }>;
+};
+
+=== index.ts ===
+import { createApi } from "./createApi";
+>createApi : <Definitions>(_: { endpoints: Definitions; }) => { [K in keyof Definitions as `use${Capitalize<K & string>}Query`]: () => { status: "uninitialized"; originalArgs?: undefined; }; }
+>          : ^           ^^ ^^                           ^^^^^                                                                         ^^^^^^^^^^               ^^^^^^^^^^^^^^^^^         ^^^   
+
+const slice = createApi({
+>slice : { useTestQuery: () => { status: "uninitialized"; originalArgs?: undefined; }; }
+>      : ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^               ^^^^^^^^^^^^^^^^^         ^^^^^^
+>createApi({  endpoints: {    test: {      url: `/user`,    },  },}) : { useTestQuery: () => { status: "uninitialized"; originalArgs?: undefined; }; }
+>                                                                    : ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^               ^^^^^^^^^^^^^^^^^         ^^^^^^
+>createApi : <Definitions>(_: { endpoints: Definitions; }) => { [K in keyof Definitions as `use${Capitalize<K & string>}Query`]: () => { status: "uninitialized"; originalArgs?: undefined; }; }
+>          : ^           ^^ ^^                           ^^^^^                                                                         ^^^^^^^^^^               ^^^^^^^^^^^^^^^^^         ^^^   
+>{  endpoints: {    test: {      url: `/user`,    },  },} : { endpoints: { test: { url: string; }; }; }
+>                                                         : ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+  endpoints: {
+>endpoints : { test: { url: string; }; }
+>          : ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+>{    test: {      url: `/user`,    },  } : { test: { url: string; }; }
+>                                         : ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+    test: {
+>test : { url: string; }
+>     : ^^^^^^^^^^^^^^^^
+>{      url: `/user`,    } : { url: string; }
+>                          : ^^^^^^^^^^^^^^^^
+
+      url: `/user`,
+>url : string
+>    : ^^^^^^
+>`/user` : "/user"
+>        : ^^^^^^^
+
+    },
+  },
+});
+
+export const { useTestQuery } = slice;
+>useTestQuery : () => { status: "uninitialized"; originalArgs?: undefined; }
+>             : ^^^^^^^^^^^^^^^^               ^^^^^^^^^^^^^^^^^         ^^^
+>slice : { useTestQuery: () => { status: "uninitialized"; originalArgs?: undefined; }; }
+>      : ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^               ^^^^^^^^^^^^^^^^^         ^^^^^^
+

tests/baselines/reference/declarationEmitOptionalMappedTypePropertyNoStrictNullChecks2.js

@@ -0,0 +1,48 @@
+//// [tests/cases/compiler/declarationEmitOptionalMappedTypePropertyNoStrictNullChecks2.ts] ////
+
+//// [createApi.ts]
+type Id<T> = {
+  [K in keyof T]: T[K];
+} & {};
+
+export declare function createApi<Definitions>(_: { endpoints: Definitions }): {
+  [K in keyof Definitions as `use${Capitalize<K & string>}Query`]: () => Id<{
+    status: "uninitialized";
+    originalArgs?: any[];
+  }>;
+};
+
+//// [index.ts]
+import { createApi } from "./createApi";
+
+const slice = createApi({
+  endpoints: {
+    test: {
+      url: `/user`,
+    },
+  },
+});
+
+export const { useTestQuery } = slice;
+
+
+
+
+//// [createApi.d.ts]
+type Id<T> = {
+    [K in keyof T]: T[K];
+} & {};
+export declare function createApi<Definitions>(_: {
+    endpoints: Definitions;
+}): {
+    [K in keyof Definitions as `use${Capitalize<K & string>}Query`]: () => Id<{
+        status: "uninitialized";
+        originalArgs?: any[];
+    }>;
+};
+export {};
+//// [index.d.ts]
+export declare const useTestQuery: () => {
+    status: "uninitialized";
+    originalArgs?: any[];
+};

tests/baselines/reference/declarationEmitOptionalMappedTypePropertyNoStrictNullChecks2.symbols

@@ -0,0 +1,63 @@
+//// [tests/cases/compiler/declarationEmitOptionalMappedTypePropertyNoStrictNullChecks2.ts] ////
+
+=== createApi.ts ===
+type Id<T> = {
+>Id : Symbol(Id, Decl(createApi.ts, 0, 0))
+>T : Symbol(T, Decl(createApi.ts, 0, 8))
+
+  [K in keyof T]: T[K];
+>K : Symbol(K, Decl(createApi.ts, 1, 3))
+>T : Symbol(T, Decl(createApi.ts, 0, 8))
+>T : Symbol(T, Decl(createApi.ts, 0, 8))
+>K : Symbol(K, Decl(createApi.ts, 1, 3))
+
+} & {};
+
+export declare function createApi<Definitions>(_: { endpoints: Definitions }): {
+>createApi : Symbol(createApi, Decl(createApi.ts, 2, 7))
+>Definitions : Symbol(Definitions, Decl(createApi.ts, 4, 34))
+>_ : Symbol(_, Decl(createApi.ts, 4, 47))
+>endpoints : Symbol(endpoints, Decl(createApi.ts, 4, 51))
+>Definitions : Symbol(Definitions, Decl(createApi.ts, 4, 34))
+
+  [K in keyof Definitions as `use${Capitalize<K & string>}Query`]: () => Id<{
+>K : Symbol(K, Decl(createApi.ts, 5, 3))
+>Definitions : Symbol(Definitions, Decl(createApi.ts, 4, 34))
+>Capitalize : Symbol(Capitalize, Decl(lib.es5.d.ts, --, --))
+>K : Symbol(K, Decl(createApi.ts, 5, 3))
+>Id : Symbol(Id, Decl(createApi.ts, 0, 0))
+
+    status: "uninitialized";
+>status : Symbol(status, Decl(createApi.ts, 5, 77))
+
+    originalArgs?: any[];
+>originalArgs : Symbol(originalArgs, Decl(createApi.ts, 6, 28))
+
+  }>;
+};
+
+=== index.ts ===
+import { createApi } from "./createApi";
+>createApi : Symbol(createApi, Decl(index.ts, 0, 8))
+
+const slice = createApi({
+>slice : Symbol(slice, Decl(index.ts, 2, 5))
+>createApi : Symbol(createApi, Decl(index.ts, 0, 8))
+
+  endpoints: {
+>endpoints : Symbol(endpoints, Decl(index.ts, 2, 25))
+
+    test: {
+>test : Symbol(test, Decl(index.ts, 3, 14))
+
+      url: `/user`,
+>url : Symbol(url, Decl(index.ts, 4, 11))
+
+    },
+  },
+});
+
+export const { useTestQuery } = slice;
+>useTestQuery : Symbol(useTestQuery, Decl(index.ts, 10, 14))
+>slice : Symbol(slice, Decl(index.ts, 2, 5))
+

tests/baselines/reference/declarationEmitOptionalMappedTypePropertyNoStrictNullChecks2.types

@@ -0,0 +1,73 @@
+//// [tests/cases/compiler/declarationEmitOptionalMappedTypePropertyNoStrictNullChecks2.ts] ////
+
+=== createApi.ts ===
+type Id<T> = {
+>Id : { [K in keyof T]: T[K]; }
+>   : ^^^ ^^^^^^^^^^^^^^^^^^^^^
+
+  [K in keyof T]: T[K];
+} & {};
+
+export declare function createApi<Definitions>(_: { endpoints: Definitions }): {
+>createApi : <Definitions>(_: { endpoints: Definitions; }) => { [K in keyof Definitions as `use${Capitalize<K & string>}Query`]: () => Id<{ status: "uninitialized"; originalArgs?: any[]; }>; }
+>          : ^           ^^ ^^                           ^^^^^                                                                                                                                  
+>_ : { endpoints: Definitions; }
+>  : ^^^^^^^^^^^^^           ^^^
+>endpoints : Definitions
+>          : ^^^^^^^^^^^
+
+  [K in keyof Definitions as `use${Capitalize<K & string>}Query`]: () => Id<{
+    status: "uninitialized";
+>status : "uninitialized"
+>       : ^^^^^^^^^^^^^^^
+
+    originalArgs?: any[];
+>originalArgs : any[]
+>             : ^^^^^
+
+  }>;
+};
+
+=== index.ts ===
+import { createApi } from "./createApi";
+>createApi : <Definitions>(_: { endpoints: Definitions; }) => { [K in keyof Definitions as `use${Capitalize<K & string>}Query`]: () => { status: "uninitialized"; originalArgs?: any[]; }; }
+>          : ^           ^^ ^^                           ^^^^^                                                                         ^^^^^^^^^^               ^^^^^^^^^^^^^^^^^     ^^^   
+
+const slice = createApi({
+>slice : { useTestQuery: () => { status: "uninitialized"; originalArgs?: any[]; }; }
+>      : ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^               ^^^^^^^^^^^^^^^^^     ^^^^^^
+>createApi({  endpoints: {    test: {      url: `/user`,    },  },}) : { useTestQuery: () => { status: "uninitialized"; originalArgs?: any[]; }; }
+>                                                                    : ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^               ^^^^^^^^^^^^^^^^^     ^^^^^^
+>createApi : <Definitions>(_: { endpoints: Definitions; }) => { [K in keyof Definitions as `use${Capitalize<K & string>}Query`]: () => { status: "uninitialized"; originalArgs?: any[]; }; }
+>          : ^           ^^ ^^                           ^^^^^                                                                         ^^^^^^^^^^               ^^^^^^^^^^^^^^^^^     ^^^   
+>{  endpoints: {    test: {      url: `/user`,    },  },} : { endpoints: { test: { url: string; }; }; }
+>                                                         : ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+  endpoints: {
+>endpoints : { test: { url: string; }; }
+>          : ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+>{    test: {      url: `/user`,    },  } : { test: { url: string; }; }
+>                                         : ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+    test: {
+>test : { url: string; }
+>     : ^^^^^^^^^^^^^^^^
+>{      url: `/user`,    } : { url: string; }
+>                          : ^^^^^^^^^^^^^^^^
+
+      url: `/user`,
+>url : string
+>    : ^^^^^^
+>`/user` : "/user"
+>        : ^^^^^^^
+
+    },
+  },
+});
+
+export const { useTestQuery } = slice;
+>useTestQuery : () => { status: "uninitialized"; originalArgs?: any[]; }
+>             : ^^^^^^^^^^^^^^^^               ^^^^^^^^^^^^^^^^^     ^^^
+>slice : { useTestQuery: () => { status: "uninitialized"; originalArgs?: any[]; }; }
+>      : ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^               ^^^^^^^^^^^^^^^^^     ^^^^^^
+