Rename strictOptionalProperties -> exactOptionalPropertyTypes and remove from strict family (#44626)

src/compiler/checker.ts

@@ -343,12 +343,12 @@ namespace ts {
         const strictFunctionTypes = getStrictOptionValue(compilerOptions, "strictFunctionTypes");
         const strictBindCallApply = getStrictOptionValue(compilerOptions, "strictBindCallApply");
         const strictPropertyInitialization = getStrictOptionValue(compilerOptions, "strictPropertyInitialization");
-        const strictOptionalProperties = getStrictOptionValue(compilerOptions, "strictOptionalProperties");
         const noImplicitAny = getStrictOptionValue(compilerOptions, "noImplicitAny");
         const noImplicitThis = getStrictOptionValue(compilerOptions, "noImplicitThis");
         const useUnknownInCatchVariables = getStrictOptionValue(compilerOptions, "useUnknownInCatchVariables");
         const keyofStringsOnly = !!compilerOptions.keyofStringsOnly;
         const freshObjectLiteralFlag = compilerOptions.suppressExcessPropertyErrors ? 0 : ObjectFlags.FreshLiteral;
+        const exactOptionalPropertyTypes = compilerOptions.exactOptionalPropertyTypes;
 
         const checkBinaryExpression = createCheckBinaryExpression();
         const emitResolver = createResolver();
@@ -740,7 +740,7 @@ namespace ts {
         const undefinedType = createIntrinsicType(TypeFlags.Undefined, "undefined");
         const undefinedWideningType = strictNullChecks ? undefinedType : createIntrinsicType(TypeFlags.Undefined, "undefined", ObjectFlags.ContainsWideningType);
         const optionalType = createIntrinsicType(TypeFlags.Undefined, "undefined");
-        const missingType = strictOptionalProperties ? createIntrinsicType(TypeFlags.Undefined, "undefined") : undefinedType;
+        const missingType = exactOptionalPropertyTypes ? createIntrinsicType(TypeFlags.Undefined, "undefined") : undefinedType;
         const nullType = createIntrinsicType(TypeFlags.Null, "null");
         const nullWideningType = strictNullChecks ? nullType : createIntrinsicType(TypeFlags.Null, "null", ObjectFlags.ContainsWideningType);
         const stringType = createIntrinsicType(TypeFlags.String, "string");
@@ -13886,7 +13886,7 @@ namespace ts {
                 if (includes & TypeFlags.AnyOrUnknown) {
                     return includes & TypeFlags.Any ? includes & TypeFlags.IncludesWildcard ? wildcardType : anyType : unknownType;
                 }
-                if (strictOptionalProperties && includes & TypeFlags.Undefined) {
+                if (exactOptionalPropertyTypes && includes & TypeFlags.Undefined) {
                     const missingIndex = binarySearch(typeSet, missingType, getTypeId, compareValues);
                     if (missingIndex >= 0 && containsType(typeSet, undefinedType)) {
                         orderedRemoveItemAt(typeSet, missingIndex);
@@ -20358,15 +20358,15 @@ namespace ts {
         }
 
         function removeMissingType(type: Type, isOptional: boolean) {
-            return strictOptionalProperties && isOptional ? removeType(type, missingType) : type;
+            return exactOptionalPropertyTypes && isOptional ? removeType(type, missingType) : type;
         }
 
         function containsMissingType(type: Type) {
-            return strictOptionalProperties && (type === missingType || type.flags & TypeFlags.Union && containsType((type as UnionType).types, missingType));
+            return exactOptionalPropertyTypes && (type === missingType || type.flags & TypeFlags.Union && containsType((type as UnionType).types, missingType));
         }
 
         function removeMissingOrUndefinedType(type: Type): Type {
-            return strictOptionalProperties ? removeType(type, missingType) : getTypeWithFacts(type, TypeFacts.NEUndefined);
+            return exactOptionalPropertyTypes ? removeType(type, missingType) : getTypeWithFacts(type, TypeFacts.NEUndefined);
         }
 
         /**
@@ -21752,7 +21752,7 @@ namespace ts {
         }
 
         function isTypeOrBaseIdenticalTo(s: Type, t: Type) {
-            return strictOptionalProperties && t === missingType ? s === t :
+            return exactOptionalPropertyTypes && t === missingType ? s === t :
                 (isTypeIdenticalTo(s, t) || !!(t.flags & TypeFlags.String && s.flags & TypeFlags.StringLiteral || t.flags & TypeFlags.Number && s.flags & TypeFlags.NumberLiteral));
         }
 
@@ -26084,7 +26084,7 @@ namespace ts {
                         elementFlags.push(ElementFlags.Rest);
                     }
                 }
-                else if (strictOptionalProperties && e.kind === SyntaxKind.OmittedExpression) {
+                else if (exactOptionalPropertyTypes && e.kind === SyntaxKind.OmittedExpression) {
                     hasOmittedExpression = true;
                     elementTypes.push(missingType);
                     elementFlags.push(ElementFlags.Optional);

src/compiler/commandLineParser.ts

@@ -648,14 +648,6 @@ namespace ts {
             description: Diagnostics.Check_for_class_properties_that_are_declared_but_not_set_in_the_constructor,
             defaultValueDescription: Diagnostics.false_unless_strict_is_set
         },
-        {
-            name: "strictOptionalProperties",
-            type: "boolean",
-            affectsSemanticDiagnostics: true,
-            strictFlag: true,
-            category: Diagnostics.Type_Checking,
-            description: Diagnostics.Enable_strict_checking_of_optional_properties
-        },
         {
             name: "noImplicitThis",
             type: "boolean",
@@ -700,6 +692,13 @@ namespace ts {
             description: Diagnostics.Raise_an_error_when_a_function_parameter_isn_t_read,
             defaultValueDescription: "false"
         },
+        {
+            name: "exactOptionalPropertyTypes",
+            type: "boolean",
+            affectsSemanticDiagnostics: true,
+            category: Diagnostics.Type_Checking,
+            description: Diagnostics.Interpret_optional_property_types_as_written_rather_than_adding_undefined
+        },
         {
             name: "noImplicitReturns",
             type: "boolean",

src/compiler/diagnosticMessages.json

@@ -4853,7 +4853,7 @@
         "category": "Message",
         "code": 6242
     },
-    "Enable strict checking of optional properties.": {
+    "Interpret optional property types as written, rather than adding 'undefined'.": {
         "category": "Message",
         "code": 6243
     },

src/compiler/program.ts

@@ -3043,8 +3043,8 @@ namespace ts {
             if (options.strictPropertyInitialization && !getStrictOptionValue(options, "strictNullChecks")) {
                 createDiagnosticForOptionName(Diagnostics.Option_0_cannot_be_specified_without_specifying_option_1, "strictPropertyInitialization", "strictNullChecks");
             }
-            if (options.strictOptionalProperties && !getStrictOptionValue(options, "strictNullChecks")) {
-                createDiagnosticForOptionName(Diagnostics.Option_0_cannot_be_specified_without_specifying_option_1, "strictOptionalProperties", "strictNullChecks");
+            if (options.exactOptionalPropertyTypes && !getStrictOptionValue(options, "strictNullChecks")) {
+                createDiagnosticForOptionName(Diagnostics.Option_0_cannot_be_specified_without_specifying_option_1, "exactOptionalPropertyTypes", "strictNullChecks");
             }
 
             if (options.isolatedModules) {

src/compiler/types.ts

@@ -5972,6 +5972,7 @@ namespace ts {
         downlevelIteration?: boolean;
         emitBOM?: boolean;
         emitDecoratorMetadata?: boolean;
+        exactOptionalPropertyTypes?: boolean;
         experimentalDecorators?: boolean;
         forceConsistentCasingInFileNames?: boolean;
         /*@internal*/generateCpuProfile?: string;
@@ -6046,7 +6047,6 @@ namespace ts {
         strictBindCallApply?: boolean;  // Always combine with strict property
         strictNullChecks?: boolean;  // Always combine with strict property
         strictPropertyInitialization?: boolean;  // Always combine with strict property
-        strictOptionalProperties?: boolean;  // Always combine with strict property
         stripInternal?: boolean;
         suppressExcessPropertyErrors?: boolean;
         suppressImplicitAnyIndexErrors?: boolean;

src/compiler/utilities.ts

@@ -6098,7 +6098,6 @@ namespace ts {
         | "strictFunctionTypes"
         | "strictBindCallApply"
         | "strictPropertyInitialization"
-        | "strictOptionalProperties"
         | "alwaysStrict"
         | "useUnknownInCatchVariables"
         ;

tests/baselines/reference/api/tsserverlibrary.d.ts

@@ -2853,6 +2853,7 @@ declare namespace ts {
         downlevelIteration?: boolean;
         emitBOM?: boolean;
         emitDecoratorMetadata?: boolean;
+        exactOptionalPropertyTypes?: boolean;
         experimentalDecorators?: boolean;
         forceConsistentCasingInFileNames?: boolean;
         importHelpers?: boolean;
@@ -2913,7 +2914,6 @@ declare namespace ts {
         strictBindCallApply?: boolean;
         strictNullChecks?: boolean;
         strictPropertyInitialization?: boolean;
-        strictOptionalProperties?: boolean;
         stripInternal?: boolean;
         suppressExcessPropertyErrors?: boolean;
         suppressImplicitAnyIndexErrors?: boolean;

tests/baselines/reference/api/typescript.d.ts

@@ -2853,6 +2853,7 @@ declare namespace ts {
         downlevelIteration?: boolean;
         emitBOM?: boolean;
         emitDecoratorMetadata?: boolean;
+        exactOptionalPropertyTypes?: boolean;
         experimentalDecorators?: boolean;
         forceConsistentCasingInFileNames?: boolean;
         importHelpers?: boolean;
@@ -2913,7 +2914,6 @@ declare namespace ts {
         strictBindCallApply?: boolean;
         strictNullChecks?: boolean;
         strictPropertyInitialization?: boolean;
-        strictOptionalProperties?: boolean;
         stripInternal?: boolean;
         suppressExcessPropertyErrors?: boolean;
         suppressImplicitAnyIndexErrors?: boolean;

tests/baselines/reference/checkJsxIntersectionElementPropsType.types

@@ -16,7 +16,7 @@ declare class Component<P> {
 
 class C<T> extends Component<{ x?: boolean; } & T> {}
 >C : C<T>
->Component : Component<{ x?: boolean; } & T>
+>Component : Component<{ x?: boolean | undefined; } & T>
 >x : boolean | undefined
 
 const y = new C({foobar: "example"});

tests/baselines/reference/circularlyConstrainedMappedTypeContainingConditionalNoInfiniteInstantiationDepth.types

@@ -10,7 +10,7 @@ declare class Component<P> {
 >context : any
 
     readonly props: Readonly<P> & Readonly<{ children?: {} }>;
->props : Readonly<P> & Readonly<{ children?: {}; }>
+>props : Readonly<P> & Readonly<{ children?: {} | undefined; }>
 >children : {} | undefined
 }
 interface ComponentClass<P = {}> {
@@ -29,7 +29,7 @@ interface ComponentClass<P = {}> {
 }
 interface FunctionComponent<P = {}> {
     (props: P & { children?: {} }, context?: any): {} | null;
->props : P & { children?: {}; }
+>props : P & { children?: {} | undefined; }
 >children : {} | undefined
 >context : any
 >null : null

tests/baselines/reference/contextuallyTypedParametersWithInitializers.types

@@ -16,7 +16,7 @@ declare function id3<T extends (x: { foo: any }) => any>(input: T): T;
 
 declare function id4<T extends (x: { foo?: number }) => any>(input: T): T;
 >id4 : <T extends (x: {    foo?: number;}) => any>(input: T) => T
->x : { foo?: number; }
+>x : { foo?: number | undefined; }
 >foo : number | undefined
 >input : T
 
@@ -60,10 +60,10 @@ const f13 = id3(function ({ foo = 42 }) { return foo });
 >foo : any
 
 const f14 = id4(function ({ foo = 42 }) { return foo });
->f14 : ({ foo }: { foo?: number; }) => number
->id4(function ({ foo = 42 }) { return foo }) : ({ foo }: { foo?: number; }) => number
->id4 : <T extends (x: { foo?: number; }) => any>(input: T) => T
->function ({ foo = 42 }) { return foo } : ({ foo }: { foo?: number; }) => number
+>f14 : ({ foo }: { foo?: number | undefined; }) => number
+>id4(function ({ foo = 42 }) { return foo }) : ({ foo }: { foo?: number | undefined; }) => number
+>id4 : <T extends (x: { foo?: number | undefined; }) => any>(input: T) => T
+>function ({ foo = 42 }) { return foo } : ({ foo }: { foo?: number | undefined; }) => number
 >foo : number
 >42 : 42
 >foo : number

tests/baselines/reference/controlFlowOptionalChain.types

@@ -249,256 +249,256 @@ o3.x;
 >x : 1 | 2
 
 declare const o4: { x?: { y: boolean } };
->o4 : { x?: {    y: boolean;}; }
+>o4 : { x?: { y: boolean; } | undefined; }
 >x : { y: boolean; } | undefined
 >y : boolean
 
 if (o4.x?.y) {
 >o4.x?.y : boolean | undefined
 >o4.x : { y: boolean; } | undefined
->o4 : { x?: { y: boolean; }; }
+>o4 : { x?: { y: boolean; } | undefined; }
 >x : { y: boolean; } | undefined
 >y : boolean | undefined
 
     o4.x; // { y: boolean }
 >o4.x : { y: boolean; }
->o4 : { x?: { y: boolean; }; }
+>o4 : { x?: { y: boolean; } | undefined; }
 >x : { y: boolean; }
 
     o4.x.y; // true
 >o4.x.y : true
 >o4.x : { y: boolean; }
->o4 : { x?: { y: boolean; }; }
+>o4 : { x?: { y: boolean; } | undefined; }
 >x : { y: boolean; }
 >y : true
 
     o4.x?.y; // true
 >o4.x?.y : true
 >o4.x : { y: boolean; }
->o4 : { x?: { y: boolean; }; }
+>o4 : { x?: { y: boolean; } | undefined; }
 >x : { y: boolean; }
 >y : true
 }
 else {
     o4.x;
 >o4.x : { y: boolean; } | undefined
->o4 : { x?: { y: boolean; }; }
+>o4 : { x?: { y: boolean; } | undefined; }
 >x : { y: boolean; } | undefined
 
     o4.x?.y;
 >o4.x?.y : boolean | undefined
 >o4.x : { y: boolean; } | undefined
->o4 : { x?: { y: boolean; }; }
+>o4 : { x?: { y: boolean; } | undefined; }
 >x : { y: boolean; } | undefined
 >y : boolean | undefined
 
     o4.x.y;
 >o4.x.y : boolean
 >o4.x : { y: boolean; } | undefined
->o4 : { x?: { y: boolean; }; }
+>o4 : { x?: { y: boolean; } | undefined; }
 >x : { y: boolean; } | undefined
 >y : boolean
 }
 o4.x;
 >o4.x : { y: boolean; } | undefined
->o4 : { x?: { y: boolean; }; }
+>o4 : { x?: { y: boolean; } | undefined; }
 >x : { y: boolean; } | undefined
 
 o4.x?.y;
 >o4.x?.y : boolean | undefined
 >o4.x : { y: boolean; } | undefined
->o4 : { x?: { y: boolean; }; }
+>o4 : { x?: { y: boolean; } | undefined; }
 >x : { y: boolean; } | undefined
 >y : boolean | undefined
 
 o4.x.y;
 >o4.x.y : boolean
 >o4.x : { y: boolean; } | undefined
->o4 : { x?: { y: boolean; }; }
+>o4 : { x?: { y: boolean; } | undefined; }
 >x : { y: boolean; } | undefined
 >y : boolean
 
 declare const o5: { x?: { y: { z?: { w: boolean } } } };
->o5 : { x?: {    y: {        z?: {            w: boolean;        };    };}; }
+>o5 : { x?: { y: {    z?: {        w: boolean;    };}; } | undefined; }
 >x : { y: {    z?: {        w: boolean;    };}; } | undefined
->y : { z?: {    w: boolean;}; }
+>y : { z?: { w: boolean; } | undefined; }
 >z : { w: boolean; } | undefined
 >w : boolean
 
 if (o5.x?.y.z?.w) {
 >o5.x?.y.z?.w : boolean | undefined
 >o5.x?.y.z : { w: boolean; } | undefined
->o5.x?.y : { z?: { w: boolean; }; } | undefined
->o5.x : { y: { z?: { w: boolean; }; }; } | undefined
->o5 : { x?: { y: { z?: { w: boolean; }; }; }; }
->x : { y: { z?: { w: boolean; }; }; } | undefined
->y : { z?: { w: boolean; }; } | undefined
+>o5.x?.y : { z?: { w: boolean; } | undefined; } | undefined
+>o5.x : { y: { z?: { w: boolean; } | undefined; }; } | undefined
+>o5 : { x?: { y: { z?: { w: boolean; } | undefined; }; } | undefined; }
+>x : { y: { z?: { w: boolean; } | undefined; }; } | undefined
+>y : { z?: { w: boolean; } | undefined; } | undefined
 >z : { w: boolean; } | undefined
 >w : boolean | undefined
 
     o5.x;
->o5.x : { y: { z?: { w: boolean; }; }; }
->o5 : { x?: { y: { z?: { w: boolean; }; }; }; }
->x : { y: { z?: { w: boolean; }; }; }
+>o5.x : { y: { z?: { w: boolean; } | undefined; }; }
+>o5 : { x?: { y: { z?: { w: boolean; } | undefined; }; } | undefined; }
+>x : { y: { z?: { w: boolean; } | undefined; }; }
 
     o5.x.y;
->o5.x.y : { z?: { w: boolean; }; }
->o5.x : { y: { z?: { w: boolean; }; }; }
->o5 : { x?: { y: { z?: { w: boolean; }; }; }; }
->x : { y: { z?: { w: boolean; }; }; }
->y : { z?: { w: boolean; }; }
+>o5.x.y : { z?: { w: boolean; } | undefined; }
+>o5.x : { y: { z?: { w: boolean; } | undefined; }; }
+>o5 : { x?: { y: { z?: { w: boolean; } | undefined; }; } | undefined; }
+>x : { y: { z?: { w: boolean; } | undefined; }; }
+>y : { z?: { w: boolean; } | undefined; }
 
     o5.x.y.z;
 >o5.x.y.z : { w: boolean; }
->o5.x.y : { z?: { w: boolean; }; }
->o5.x : { y: { z?: { w: boolean; }; }; }
->o5 : { x?: { y: { z?: { w: boolean; }; }; }; }
->x : { y: { z?: { w: boolean; }; }; }
->y : { z?: { w: boolean; }; }
+>o5.x.y : { z?: { w: boolean; } | undefined; }
+>o5.x : { y: { z?: { w: boolean; } | undefined; }; }
+>o5 : { x?: { y: { z?: { w: boolean; } | undefined; }; } | undefined; }
+>x : { y: { z?: { w: boolean; } | undefined; }; }
+>y : { z?: { w: boolean; } | undefined; }
 >z : { w: boolean; }
 
     o5.x.y.z.w; // true
 >o5.x.y.z.w : true
 >o5.x.y.z : { w: boolean; }
->o5.x.y : { z?: { w: boolean; }; }
->o5.x : { y: { z?: { w: boolean; }; }; }
->o5 : { x?: { y: { z?: { w: boolean; }; }; }; }
->x : { y: { z?: { w: boolean; }; }; }
->y : { z?: { w: boolean; }; }
+>o5.x.y : { z?: { w: boolean; } | undefined; }
+>o5.x : { y: { z?: { w: boolean; } | undefined; }; }
+>o5 : { x?: { y: { z?: { w: boolean; } | undefined; }; } | undefined; }
+>x : { y: { z?: { w: boolean; } | undefined; }; }
+>y : { z?: { w: boolean; } | undefined; }
 >z : { w: boolean; }
 >w : true
 
     o5.x.y.z?.w; // true
 >o5.x.y.z?.w : true
 >o5.x.y.z : { w: boolean; }
->o5.x.y : { z?: { w: boolean; }; }
->o5.x : { y: { z?: { w: boolean; }; }; }
->o5 : { x?: { y: { z?: { w: boolean; }; }; }; }
->x : { y: { z?: { w: boolean; }; }; }
->y : { z?: { w: boolean; }; }
+>o5.x.y : { z?: { w: boolean; } | undefined; }
+>o5.x : { y: { z?: { w: boolean; } | undefined; }; }
+>o5 : { x?: { y: { z?: { w: boolean; } | undefined; }; } | undefined; }
+>x : { y: { z?: { w: boolean; } | undefined; }; }
+>y : { z?: { w: boolean; } | undefined; }
 >z : { w: boolean; }
 >w : true
 
     o5.x?.y.z.w; // true
 >o5.x?.y.z.w : true
 >o5.x?.y.z : { w: boolean; }
->o5.x?.y : { z?: { w: boolean; }; }
->o5.x : { y: { z?: { w: boolean; }; }; }
->o5 : { x?: { y: { z?: { w: boolean; }; }; }; }
->x : { y: { z?: { w: boolean; }; }; }
->y : { z?: { w: boolean; }; }
+>o5.x?.y : { z?: { w: boolean; } | undefined; }
+>o5.x : { y: { z?: { w: boolean; } | undefined; }; }
+>o5 : { x?: { y: { z?: { w: boolean; } | undefined; }; } | undefined; }
+>x : { y: { z?: { w: boolean; } | undefined; }; }
+>y : { z?: { w: boolean; } | undefined; }
 >z : { w: boolean; }
 >w : true
 
     o5.x?.y.z?.w; // true
 >o5.x?.y.z?.w : true
 >o5.x?.y.z : { w: boolean; }
->o5.x?.y : { z?: { w: boolean; }; }
->o5.x : { y: { z?: { w: boolean; }; }; }
->o5 : { x?: { y: { z?: { w: boolean; }; }; }; }
->x : { y: { z?: { w: boolean; }; }; }
->y : { z?: { w: boolean; }; }
+>o5.x?.y : { z?: { w: boolean; } | undefined; }
+>o5.x : { y: { z?: { w: boolean; } | undefined; }; }
+>o5 : { x?: { y: { z?: { w: boolean; } | undefined; }; } | undefined; }
+>x : { y: { z?: { w: boolean; } | undefined; }; }
+>y : { z?: { w: boolean; } | undefined; }
 >z : { w: boolean; }
 >w : true
 }
 else {
     o5.x;
->o5.x : { y: { z?: { w: boolean; }; }; } | undefined
->o5 : { x?: { y: { z?: { w: boolean; }; }; }; }
->x : { y: { z?: { w: boolean; }; }; } | undefined
+>o5.x : { y: { z?: { w: boolean; } | undefined; }; } | undefined
+>o5 : { x?: { y: { z?: { w: boolean; } | undefined; }; } | undefined; }
+>x : { y: { z?: { w: boolean; } | undefined; }; } | undefined
 
     o5.x?.y;
->o5.x?.y : { z?: { w: boolean; }; } | undefined
->o5.x : { y: { z?: { w: boolean; }; }; } | undefined
->o5 : { x?: { y: { z?: { w: boolean; }; }; }; }
->x : { y: { z?: { w: boolean; }; }; } | undefined
->y : { z?: { w: boolean; }; } | undefined
+>o5.x?.y : { z?: { w: boolean; } | undefined; } | undefined
+>o5.x : { y: { z?: { w: boolean; } | undefined; }; } | undefined
+>o5 : { x?: { y: { z?: { w: boolean; } | undefined; }; } | undefined; }
+>x : { y: { z?: { w: boolean; } | undefined; }; } | undefined
+>y : { z?: { w: boolean; } | undefined; } | undefined
 
     o5.x?.y.z;
 >o5.x?.y.z : { w: boolean; } | undefined
->o5.x?.y : { z?: { w: boolean; }; } | undefined
->o5.x : { y: { z?: { w: boolean; }; }; } | undefined
->o5 : { x?: { y: { z?: { w: boolean; }; }; }; }
->x : { y: { z?: { w: boolean; }; }; } | undefined
->y : { z?: { w: boolean; }; } | undefined
+>o5.x?.y : { z?: { w: boolean; } | undefined; } | undefined
+>o5.x : { y: { z?: { w: boolean; } | undefined; }; } | undefined
+>o5 : { x?: { y: { z?: { w: boolean; } | undefined; }; } | undefined; }
+>x : { y: { z?: { w: boolean; } | undefined; }; } | undefined
+>y : { z?: { w: boolean; } | undefined; } | undefined
 >z : { w: boolean; } | undefined
 
     o5.x?.y.z?.w;
 >o5.x?.y.z?.w : boolean | undefined
 >o5.x?.y.z : { w: boolean; } | undefined
->o5.x?.y : { z?: { w: boolean; }; } | undefined
->o5.x : { y: { z?: { w: boolean; }; }; } | undefined
->o5 : { x?: { y: { z?: { w: boolean; }; }; }; }
->x : { y: { z?: { w: boolean; }; }; } | undefined
->y : { z?: { w: boolean; }; } | undefined
+>o5.x?.y : { z?: { w: boolean; } | undefined; } | undefined
+>o5.x : { y: { z?: { w: boolean; } | undefined; }; } | undefined
+>o5 : { x?: { y: { z?: { w: boolean; } | undefined; }; } | undefined; }
+>x : { y: { z?: { w: boolean; } | undefined; }; } | undefined
+>y : { z?: { w: boolean; } | undefined; } | undefined
 >z : { w: boolean; } | undefined
 >w : boolean | undefined
 
     o5.x.y;
->o5.x.y : { z?: { w: boolean; }; }
->o5.x : { y: { z?: { w: boolean; }; }; } | undefined
->o5 : { x?: { y: { z?: { w: boolean; }; }; }; }
->x : { y: { z?: { w: boolean; }; }; } | undefined
->y : { z?: { w: boolean; }; }
+>o5.x.y : { z?: { w: boolean; } | undefined; }
+>o5.x : { y: { z?: { w: boolean; } | undefined; }; } | undefined
+>o5 : { x?: { y: { z?: { w: boolean; } | undefined; }; } | undefined; }
+>x : { y: { z?: { w: boolean; } | undefined; }; } | undefined
+>y : { z?: { w: boolean; } | undefined; }
 
     o5.x.y.z.w;
 >o5.x.y.z.w : boolean
 >o5.x.y.z : { w: boolean; } | undefined
->o5.x.y : { z?: { w: boolean; }; }
->o5.x : { y: { z?: { w: boolean; }; }; } | undefined
->o5 : { x?: { y: { z?: { w: boolean; }; }; }; }
->x : { y: { z?: { w: boolean; }; }; } | undefined
->y : { z?: { w: boolean; }; }
+>o5.x.y : { z?: { w: boolean; } | undefined; }
+>o5.x : { y: { z?: { w: boolean; } | undefined; }; } | undefined
+>o5 : { x?: { y: { z?: { w: boolean; } | undefined; }; } | undefined; }
+>x : { y: { z?: { w: boolean; } | undefined; }; } | undefined
+>y : { z?: { w: boolean; } | undefined; }
 >z : { w: boolean; } | undefined
 >w : boolean
 }
 o5.x;
->o5.x : { y: { z?: { w: boolean; }; }; } | undefined
->o5 : { x?: { y: { z?: { w: boolean; }; }; }; }
->x : { y: { z?: { w: boolean; }; }; } | undefined
+>o5.x : { y: { z?: { w: boolean; } | undefined; }; } | undefined
+>o5 : { x?: { y: { z?: { w: boolean; } | undefined; }; } | undefined; }
+>x : { y: { z?: { w: boolean; } | undefined; }; } | undefined
 
 o5.x?.y;
->o5.x?.y : { z?: { w: boolean; }; } | undefined
->o5.x : { y: { z?: { w: boolean; }; }; } | undefined
->o5 : { x?: { y: { z?: { w: boolean; }; }; }; }
->x : { y: { z?: { w: boolean; }; }; } | undefined
->y : { z?: { w: boolean; }; } | undefined
+>o5.x?.y : { z?: { w: boolean; } | undefined; } | undefined
+>o5.x : { y: { z?: { w: boolean; } | undefined; }; } | undefined
+>o5 : { x?: { y: { z?: { w: boolean; } | undefined; }; } | undefined; }
+>x : { y: { z?: { w: boolean; } | undefined; }; } | undefined
+>y : { z?: { w: boolean; } | undefined; } | undefined
 
 o5.x?.y.z;
 >o5.x?.y.z : { w: boolean; } | undefined
->o5.x?.y : { z?: { w: boolean; }; } | undefined
->o5.x : { y: { z?: { w: boolean; }; }; } | undefined
->o5 : { x?: { y: { z?: { w: boolean; }; }; }; }
->x : { y: { z?: { w: boolean; }; }; } | undefined
->y : { z?: { w: boolean; }; } | undefined
+>o5.x?.y : { z?: { w: boolean; } | undefined; } | undefined
+>o5.x : { y: { z?: { w: boolean; } | undefined; }; } | undefined
+>o5 : { x?: { y: { z?: { w: boolean; } | undefined; }; } | undefined; }
+>x : { y: { z?: { w: boolean; } | undefined; }; } | undefined
+>y : { z?: { w: boolean; } | undefined; } | undefined
 >z : { w: boolean; } | undefined
 
 o5.x?.y.z?.w;
 >o5.x?.y.z?.w : boolean | undefined
 >o5.x?.y.z : { w: boolean; } | undefined
->o5.x?.y : { z?: { w: boolean; }; } | undefined
->o5.x : { y: { z?: { w: boolean; }; }; } | undefined
->o5 : { x?: { y: { z?: { w: boolean; }; }; }; }
->x : { y: { z?: { w: boolean; }; }; } | undefined
->y : { z?: { w: boolean; }; } | undefined
+>o5.x?.y : { z?: { w: boolean; } | undefined; } | undefined
+>o5.x : { y: { z?: { w: boolean; } | undefined; }; } | undefined
+>o5 : { x?: { y: { z?: { w: boolean; } | undefined; }; } | undefined; }
+>x : { y: { z?: { w: boolean; } | undefined; }; } | undefined
+>y : { z?: { w: boolean; } | undefined; } | undefined
 >z : { w: boolean; } | undefined
 >w : boolean | undefined
 
 o5.x.y;
->o5.x.y : { z?: { w: boolean; }; }
->o5.x : { y: { z?: { w: boolean; }; }; } | undefined
->o5 : { x?: { y: { z?: { w: boolean; }; }; }; }
->x : { y: { z?: { w: boolean; }; }; } | undefined
->y : { z?: { w: boolean; }; }
+>o5.x.y : { z?: { w: boolean; } | undefined; }
+>o5.x : { y: { z?: { w: boolean; } | undefined; }; } | undefined
+>o5 : { x?: { y: { z?: { w: boolean; } | undefined; }; } | undefined; }
+>x : { y: { z?: { w: boolean; } | undefined; }; } | undefined
+>y : { z?: { w: boolean; } | undefined; }
 
 o5.x.y.z.w;
 >o5.x.y.z.w : boolean
 >o5.x.y.z : { w: boolean; } | undefined
->o5.x.y : { z?: { w: boolean; }; }
->o5.x : { y: { z?: { w: boolean; }; }; } | undefined
->o5 : { x?: { y: { z?: { w: boolean; }; }; }; }
->x : { y: { z?: { w: boolean; }; }; } | undefined
->y : { z?: { w: boolean; }; }
+>o5.x.y : { z?: { w: boolean; } | undefined; }
+>o5.x : { y: { z?: { w: boolean; } | undefined; }; } | undefined
+>o5 : { x?: { y: { z?: { w: boolean; } | undefined; }; } | undefined; }
+>x : { y: { z?: { w: boolean; } | undefined; }; } | undefined
+>y : { z?: { w: boolean; } | undefined; }
 >z : { w: boolean; } | undefined
 >w : boolean
 

tests/baselines/reference/deleteChain.types

@@ -61,9 +61,9 @@ delete (o3.b?.c);
 >c : string | undefined
 
 declare const o4: { b?: { c: { d?: { e: string } } } };
->o4 : { b?: {    c: {        d?: {            e: string;        };    };}; }
+>o4 : { b?: { c: {    d?: {        e: string;    };}; } | undefined; }
 >b : { c: {    d?: {        e: string;    };}; } | undefined
->c : { d?: {    e: string;}; }
+>c : { d?: { e: string; } | undefined; }
 >d : { e: string; } | undefined
 >e : string
 
@@ -71,11 +71,11 @@ delete o4.b?.c.d?.e;
 >delete o4.b?.c.d?.e : boolean
 >o4.b?.c.d?.e : string | undefined
 >o4.b?.c.d : { e: string; } | undefined
->o4.b?.c : { d?: { e: string; }; } | undefined
->o4.b : { c: { d?: { e: string; }; }; } | undefined
->o4 : { b?: { c: { d?: { e: string; }; }; }; }
->b : { c: { d?: { e: string; }; }; } | undefined
->c : { d?: { e: string; }; } | undefined
+>o4.b?.c : { d?: { e: string; } | undefined; } | undefined
+>o4.b : { c: { d?: { e: string; } | undefined; }; } | undefined
+>o4 : { b?: { c: { d?: { e: string; } | undefined; }; } | undefined; }
+>b : { c: { d?: { e: string; } | undefined; }; } | undefined
+>c : { d?: { e: string; } | undefined; } | undefined
 >d : { e: string; } | undefined
 >e : string | undefined
 
@@ -84,11 +84,11 @@ delete (o4.b?.c.d)?.e;
 >(o4.b?.c.d)?.e : string | undefined
 >(o4.b?.c.d) : { e: string; } | undefined
 >o4.b?.c.d : { e: string; } | undefined
->o4.b?.c : { d?: { e: string; }; } | undefined
->o4.b : { c: { d?: { e: string; }; }; } | undefined
->o4 : { b?: { c: { d?: { e: string; }; }; }; }
->b : { c: { d?: { e: string; }; }; } | undefined
->c : { d?: { e: string; }; } | undefined
+>o4.b?.c : { d?: { e: string; } | undefined; } | undefined
+>o4.b : { c: { d?: { e: string; } | undefined; }; } | undefined
+>o4 : { b?: { c: { d?: { e: string; } | undefined; }; } | undefined; }
+>b : { c: { d?: { e: string; } | undefined; }; } | undefined
+>c : { d?: { e: string; } | undefined; } | undefined
 >d : { e: string; } | undefined
 >e : string | undefined
 
@@ -97,18 +97,18 @@ delete (o4.b?.c.d?.e);
 >(o4.b?.c.d?.e) : string | undefined
 >o4.b?.c.d?.e : string | undefined
 >o4.b?.c.d : { e: string; } | undefined
->o4.b?.c : { d?: { e: string; }; } | undefined
->o4.b : { c: { d?: { e: string; }; }; } | undefined
->o4 : { b?: { c: { d?: { e: string; }; }; }; }
->b : { c: { d?: { e: string; }; }; } | undefined
->c : { d?: { e: string; }; } | undefined
+>o4.b?.c : { d?: { e: string; } | undefined; } | undefined
+>o4.b : { c: { d?: { e: string; } | undefined; }; } | undefined
+>o4 : { b?: { c: { d?: { e: string; } | undefined; }; } | undefined; }
+>b : { c: { d?: { e: string; } | undefined; }; } | undefined
+>c : { d?: { e: string; } | undefined; } | undefined
 >d : { e: string; } | undefined
 >e : string | undefined
 
 declare const o5: { b?(): { c: { d?: { e: string } } } };
 >o5 : { b?(): {    c: {        d?: {            e: string;        };    };}; }
 >b : (() => {    c: {        d?: {            e: string;        };    };}) | undefined
->c : { d?: {    e: string;}; }
+>c : { d?: { e: string; } | undefined; }
 >d : { e: string; } | undefined
 >e : string
 
@@ -116,12 +116,12 @@ delete o5.b?.().c.d?.e;
 >delete o5.b?.().c.d?.e : boolean
 >o5.b?.().c.d?.e : string | undefined
 >o5.b?.().c.d : { e: string; } | undefined
->o5.b?.().c : { d?: { e: string; }; } | undefined
->o5.b?.() : { c: { d?: { e: string; }; }; } | undefined
->o5.b : (() => { c: { d?: { e: string; }; }; }) | undefined
->o5 : { b?(): { c: { d?: { e: string; }; }; }; }
->b : (() => { c: { d?: { e: string; }; }; }) | undefined
->c : { d?: { e: string; }; } | undefined
+>o5.b?.().c : { d?: { e: string; } | undefined; } | undefined
+>o5.b?.() : { c: { d?: { e: string; } | undefined; }; } | undefined
+>o5.b : (() => { c: { d?: { e: string; } | undefined; }; }) | undefined
+>o5 : { b?(): { c: { d?: { e: string; } | undefined; }; }; }
+>b : (() => { c: { d?: { e: string; } | undefined; }; }) | undefined
+>c : { d?: { e: string; } | undefined; } | undefined
 >d : { e: string; } | undefined
 >e : string | undefined
 
@@ -130,19 +130,19 @@ delete (o5.b?.().c.d?.e);
 >(o5.b?.().c.d?.e) : string | undefined
 >o5.b?.().c.d?.e : string | undefined
 >o5.b?.().c.d : { e: string; } | undefined
->o5.b?.().c : { d?: { e: string; }; } | undefined
->o5.b?.() : { c: { d?: { e: string; }; }; } | undefined
->o5.b : (() => { c: { d?: { e: string; }; }; }) | undefined
->o5 : { b?(): { c: { d?: { e: string; }; }; }; }
->b : (() => { c: { d?: { e: string; }; }; }) | undefined
->c : { d?: { e: string; }; } | undefined
+>o5.b?.().c : { d?: { e: string; } | undefined; } | undefined
+>o5.b?.() : { c: { d?: { e: string; } | undefined; }; } | undefined
+>o5.b : (() => { c: { d?: { e: string; } | undefined; }; }) | undefined
+>o5 : { b?(): { c: { d?: { e: string; } | undefined; }; }; }
+>b : (() => { c: { d?: { e: string; } | undefined; }; }) | undefined
+>c : { d?: { e: string; } | undefined; } | undefined
 >d : { e: string; } | undefined
 >e : string | undefined
 
 declare const o6: { b?: { c: { d?: { e: string } } } };
->o6 : { b?: {    c: {        d?: {            e: string;        };    };}; }
+>o6 : { b?: { c: {    d?: {        e: string;    };}; } | undefined; }
 >b : { c: {    d?: {        e: string;    };}; } | undefined
->c : { d?: {    e: string;}; }
+>c : { d?: { e: string; } | undefined; }
 >d : { e: string; } | undefined
 >e : string
 
@@ -150,10 +150,10 @@ delete o6.b?.['c'].d?.['e'];
 >delete o6.b?.['c'].d?.['e'] : boolean
 >o6.b?.['c'].d?.['e'] : string | undefined
 >o6.b?.['c'].d : { e: string; } | undefined
->o6.b?.['c'] : { d?: { e: string; }; } | undefined
->o6.b : { c: { d?: { e: string; }; }; } | undefined
->o6 : { b?: { c: { d?: { e: string; }; }; }; }
->b : { c: { d?: { e: string; }; }; } | undefined
+>o6.b?.['c'] : { d?: { e: string; } | undefined; } | undefined
+>o6.b : { c: { d?: { e: string; } | undefined; }; } | undefined
+>o6 : { b?: { c: { d?: { e: string; } | undefined; }; } | undefined; }
+>b : { c: { d?: { e: string; } | undefined; }; } | undefined
 >'c' : "c"
 >d : { e: string; } | undefined
 >'e' : "e"
@@ -163,10 +163,10 @@ delete (o6.b?.['c'].d?.['e']);
 >(o6.b?.['c'].d?.['e']) : string | undefined
 >o6.b?.['c'].d?.['e'] : string | undefined
 >o6.b?.['c'].d : { e: string; } | undefined
->o6.b?.['c'] : { d?: { e: string; }; } | undefined
->o6.b : { c: { d?: { e: string; }; }; } | undefined
->o6 : { b?: { c: { d?: { e: string; }; }; }; }
->b : { c: { d?: { e: string; }; }; } | undefined
+>o6.b?.['c'] : { d?: { e: string; } | undefined; } | undefined
+>o6.b : { c: { d?: { e: string; } | undefined; }; } | undefined
+>o6 : { b?: { c: { d?: { e: string; } | undefined; }; } | undefined; }
+>b : { c: { d?: { e: string; } | undefined; }; } | undefined
 >'c' : "c"
 >d : { e: string; } | undefined
 >'e' : "e"

tests/baselines/reference/destructuringControlFlow.types

@@ -1,29 +1,29 @@
 === tests/cases/conformance/es6/destructuring/destructuringControlFlow.ts ===
 function f1(obj: { a?: string }) {
 >f1 : (obj: {    a?: string;}) => void
->obj : { a?: string; }
+>obj : { a?: string | undefined; }
 >a : string | undefined
 
     if (obj.a) {
 >obj.a : string | undefined
->obj : { a?: string; }
+>obj : { a?: string | undefined; }
 >a : string | undefined
 
         obj = {};
 >obj = {} : {}
->obj : { a?: string; }
+>obj : { a?: string | undefined; }
 >{} : {}
 
         let a1 = obj["a"];  // string | undefined
 >a1 : string | undefined
 >obj["a"] : string | undefined
->obj : { a?: string; }
+>obj : { a?: string | undefined; }
 >"a" : "a"
 
         let a2 = obj.a;  // string | undefined
 >a2 : string | undefined
 >obj.a : string | undefined
->obj : { a?: string; }
+>obj : { a?: string | undefined; }
 >a : string | undefined
     }
 }
@@ -96,31 +96,31 @@ function f2(obj: [number, string] | null[]) {
 
 function f3(obj: { a?: number, b?: string }) {
 >f3 : (obj: {    a?: number;    b?: string;}) => void
->obj : { a?: number; b?: string; }
+>obj : { a?: number | undefined; b?: string | undefined; }
 >a : number | undefined
 >b : string | undefined
 
     if (obj.a && obj.b) {
 >obj.a && obj.b : string | 0 | undefined
 >obj.a : number | undefined
->obj : { a?: number; b?: string; }
+>obj : { a?: number | undefined; b?: string | undefined; }
 >a : number | undefined
 >obj.b : string | undefined
->obj : { a?: number; b?: string; }
+>obj : { a?: number | undefined; b?: string | undefined; }
 >b : string | undefined
 
         let { a, b } = obj;  // number, string
 >a : number
 >b : string
->obj : { a?: number; b?: string; }
+>obj : { a?: number | undefined; b?: string | undefined; }
 
         ({ a, b } = obj);
->({ a, b } = obj) : { a?: number; b?: string; }
->{ a, b } = obj : { a?: number; b?: string; }
+>({ a, b } = obj) : { a?: number | undefined; b?: string | undefined; }
+>{ a, b } = obj : { a?: number | undefined; b?: string | undefined; }
 >{ a, b } : { a: number; b: string; }
 >a : number
 >b : string
->obj : { a?: number; b?: string; }
+>obj : { a?: number | undefined; b?: string | undefined; }
     }
 }
 

tests/baselines/reference/elementAccessChain.types

@@ -47,19 +47,19 @@ o3.b?.["c"];
 >"c" : "c"
 
 declare const o4: { b?: { c: { d?: { e: string } } } };
->o4 : { b?: {    c: {        d?: {            e: string;        };    };}; }
+>o4 : { b?: { c: {    d?: {        e: string;    };}; } | undefined; }
 >b : { c: {    d?: {        e: string;    };}; } | undefined
->c : { d?: {    e: string;}; }
+>c : { d?: { e: string; } | undefined; }
 >d : { e: string; } | undefined
 >e : string
 
 o4.b?.["c"].d?.e;
 >o4.b?.["c"].d?.e : string | undefined
 >o4.b?.["c"].d : { e: string; } | undefined
->o4.b?.["c"] : { d?: { e: string; }; } | undefined
->o4.b : { c: { d?: { e: string; }; }; } | undefined
->o4 : { b?: { c: { d?: { e: string; }; }; }; }
->b : { c: { d?: { e: string; }; }; } | undefined
+>o4.b?.["c"] : { d?: { e: string; } | undefined; } | undefined
+>o4.b : { c: { d?: { e: string; } | undefined; }; } | undefined
+>o4 : { b?: { c: { d?: { e: string; } | undefined; }; } | undefined; }
+>b : { c: { d?: { e: string; } | undefined; }; } | undefined
 >"c" : "c"
 >d : { e: string; } | undefined
 >e : string | undefined
@@ -67,10 +67,10 @@ o4.b?.["c"].d?.e;
 o4.b?.["c"].d?.["e"];
 >o4.b?.["c"].d?.["e"] : string | undefined
 >o4.b?.["c"].d : { e: string; } | undefined
->o4.b?.["c"] : { d?: { e: string; }; } | undefined
->o4.b : { c: { d?: { e: string; }; }; } | undefined
->o4 : { b?: { c: { d?: { e: string; }; }; }; }
->b : { c: { d?: { e: string; }; }; } | undefined
+>o4.b?.["c"] : { d?: { e: string; } | undefined; } | undefined
+>o4.b : { c: { d?: { e: string; } | undefined; }; } | undefined
+>o4 : { b?: { c: { d?: { e: string; } | undefined; }; } | undefined; }
+>b : { c: { d?: { e: string; } | undefined; }; } | undefined
 >"c" : "c"
 >d : { e: string; } | undefined
 >"e" : "e"
@@ -78,18 +78,18 @@ o4.b?.["c"].d?.["e"];
 declare const o5: { b?(): { c: { d?: { e: string } } } };
 >o5 : { b?(): {    c: {        d?: {            e: string;        };    };}; }
 >b : (() => {    c: {        d?: {            e: string;        };    };}) | undefined
->c : { d?: {    e: string;}; }
+>c : { d?: { e: string; } | undefined; }
 >d : { e: string; } | undefined
 >e : string
 
 o5.b?.()["c"].d?.e;
 >o5.b?.()["c"].d?.e : string | undefined
 >o5.b?.()["c"].d : { e: string; } | undefined
->o5.b?.()["c"] : { d?: { e: string; }; } | undefined
->o5.b?.() : { c: { d?: { e: string; }; }; } | undefined
->o5.b : (() => { c: { d?: { e: string; }; }; }) | undefined
->o5 : { b?(): { c: { d?: { e: string; }; }; }; }
->b : (() => { c: { d?: { e: string; }; }; }) | undefined
+>o5.b?.()["c"] : { d?: { e: string; } | undefined; } | undefined
+>o5.b?.() : { c: { d?: { e: string; } | undefined; }; } | undefined
+>o5.b : (() => { c: { d?: { e: string; } | undefined; }; }) | undefined
+>o5 : { b?(): { c: { d?: { e: string; } | undefined; }; }; }
+>b : (() => { c: { d?: { e: string; } | undefined; }; }) | undefined
 >"c" : "c"
 >d : { e: string; } | undefined
 >e : string | undefined
@@ -97,11 +97,11 @@ o5.b?.()["c"].d?.e;
 o5.b?.()["c"].d?.["e"];
 >o5.b?.()["c"].d?.["e"] : string | undefined
 >o5.b?.()["c"].d : { e: string; } | undefined
->o5.b?.()["c"] : { d?: { e: string; }; } | undefined
->o5.b?.() : { c: { d?: { e: string; }; }; } | undefined
->o5.b : (() => { c: { d?: { e: string; }; }; }) | undefined
->o5 : { b?(): { c: { d?: { e: string; }; }; }; }
->b : (() => { c: { d?: { e: string; }; }; }) | undefined
+>o5.b?.()["c"] : { d?: { e: string; } | undefined; } | undefined
+>o5.b?.() : { c: { d?: { e: string; } | undefined; }; } | undefined
+>o5.b : (() => { c: { d?: { e: string; } | undefined; }; }) | undefined
+>o5 : { b?(): { c: { d?: { e: string; } | undefined; }; }; }
+>b : (() => { c: { d?: { e: string; } | undefined; }; }) | undefined
 >"c" : "c"
 >d : { e: string; } | undefined
 >"e" : "e"
@@ -109,10 +109,10 @@ o5.b?.()["c"].d?.["e"];
 o5["b"]?.()["c"].d?.e;
 >o5["b"]?.()["c"].d?.e : string | undefined
 >o5["b"]?.()["c"].d : { e: string; } | undefined
->o5["b"]?.()["c"] : { d?: { e: string; }; } | undefined
->o5["b"]?.() : { c: { d?: { e: string; }; }; } | undefined
->o5["b"] : (() => { c: { d?: { e: string; }; }; }) | undefined
->o5 : { b?(): { c: { d?: { e: string; }; }; }; }
+>o5["b"]?.()["c"] : { d?: { e: string; } | undefined; } | undefined
+>o5["b"]?.() : { c: { d?: { e: string; } | undefined; }; } | undefined
+>o5["b"] : (() => { c: { d?: { e: string; } | undefined; }; }) | undefined
+>o5 : { b?(): { c: { d?: { e: string; } | undefined; }; }; }
 >"b" : "b"
 >"c" : "c"
 >d : { e: string; } | undefined
@@ -121,10 +121,10 @@ o5["b"]?.()["c"].d?.e;
 o5["b"]?.()["c"].d?.["e"];
 >o5["b"]?.()["c"].d?.["e"] : string | undefined
 >o5["b"]?.()["c"].d : { e: string; } | undefined
->o5["b"]?.()["c"] : { d?: { e: string; }; } | undefined
->o5["b"]?.() : { c: { d?: { e: string; }; }; } | undefined
->o5["b"] : (() => { c: { d?: { e: string; }; }; }) | undefined
->o5 : { b?(): { c: { d?: { e: string; }; }; }; }
+>o5["b"]?.()["c"] : { d?: { e: string; } | undefined; } | undefined
+>o5["b"]?.() : { c: { d?: { e: string; } | undefined; }; } | undefined
+>o5["b"] : (() => { c: { d?: { e: string; } | undefined; }; }) | undefined
+>o5 : { b?(): { c: { d?: { e: string; } | undefined; }; }; }
 >"b" : "b"
 >"c" : "c"
 >d : { e: string; } | undefined

tests/baselines/reference/homomorphicMappedTypeIntersectionAssignability.types

@@ -3,7 +3,7 @@ function f<TType>(
 >f : <TType>(a: {    weak?: string;} & Readonly<TType> & {    name: "ok";}, b: Readonly<TType & {    name: string;}>, c: Readonly<TType> & {    name: string;}) => void
 
     a: { weak?: string } & Readonly<TType> & { name: "ok" },
->a : { weak?: string; } & Readonly<TType> & { name: "ok"; }
+>a : { weak?: string | undefined; } & Readonly<TType> & { name: "ok"; }
 >weak : string | undefined
 >name : "ok"
 
@@ -16,13 +16,13 @@ function f<TType>(
 >name : string
 
     c = a; // Works
->c = a : { weak?: string; } & Readonly<TType> & { name: "ok"; }
+>c = a : { weak?: string | undefined; } & Readonly<TType> & { name: "ok"; }
 >c : Readonly<TType> & { name: string; }
->a : { weak?: string; } & Readonly<TType> & { name: "ok"; }
+>a : { weak?: string | undefined; } & Readonly<TType> & { name: "ok"; }
 
     b = a; // Should also work
->b = a : { weak?: string; } & Readonly<TType> & { name: "ok"; }
+>b = a : { weak?: string | undefined; } & Readonly<TType> & { name: "ok"; }
 >b : Readonly<TType & { name: string; }>
->a : { weak?: string; } & Readonly<TType> & { name: "ok"; }
+>a : { weak?: string | undefined; } & Readonly<TType> & { name: "ok"; }
 }
 

tests/baselines/reference/inferenceOptionalPropertiesToIndexSignatures.types

@@ -15,7 +15,7 @@ declare const x2: { a: string, b: number | undefined };
 >b : number | undefined
 
 declare const x3: { a: string, b?: number };
->x3 : { a: string; b?: number; }
+>x3 : { a: string; b?: number | undefined; }
 >a : string
 >b : number | undefined
 
@@ -40,11 +40,11 @@ let a3 = foo(x3);  // string | number
 >a3 : string | number
 >foo(x3) : string | number
 >foo : <T>(obj: { [x: string]: T; }) => T
->x3 : { a: string; b?: number; }
+>x3 : { a: string; b?: number | undefined; }
 
 let a4 = foo(x4);  // string | number
->a4 : string | number | undefined
->foo(x4) : string | number | undefined
+>a4 : string | number
+>foo(x4) : string | number
 >foo : <T>(obj: { [x: string]: T; }) => T
 >x4 : { a: string; b?: number | undefined; }
 
@@ -63,8 +63,8 @@ const param2 = Math.random() < 0.5 ? 'value2' : null;
 >null : null
 
 const obj = {
->obj : { param2?: string; param1: string; }
->{    param1: 'value1',    ...(param2 ? {param2} : {})} : { param2?: string; param1: string; }
+>obj : { param2?: string | undefined; param1: string; }
+>{    param1: 'value1',    ...(param2 ? {param2} : {})} : { param2?: string | undefined; param1: string; }
 
     param1: 'value1',
 >param1 : string
@@ -90,7 +90,7 @@ const query = Object.entries(obj).map(
 >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][]; }
->obj : { param2?: string; param1: string; }
+>obj : { param2?: string | undefined; param1: string; }
 >map : <U>(callbackfn: (value: [string, string], index: number, array: [string, string][]) => U, thisArg?: any) => U[]
 
     ([k, v]) => `${k}=${encodeURIComponent(v)}`

tests/baselines/reference/initializedParameterBeforeNonoptionalNotOptional.types

@@ -1,6 +1,6 @@
 === tests/cases/compiler/index.d.ts ===
 export declare function foo({a}?: {
->foo : ({ a }?: { a?: string; } | undefined) => void
+>foo : ({ a }?: { a?: string | undefined; } | undefined) => void
 >a : string | undefined
 
     a?: string;

tests/baselines/reference/instantiateContextualTypes.types

@@ -221,7 +221,7 @@ interface ComponentClass<P = {}> {
 }
 
 type CreateElementChildren<P> =
->CreateElementChildren : P extends { children?: infer C; } ? C extends any[] ? C : C[] : unknown
+>CreateElementChildren : P extends { children?: infer C | undefined; } ? C extends any[] ? C : C[] : unknown
 
   P extends { children?: infer C }
 >children : C | undefined
@@ -232,24 +232,24 @@ type CreateElementChildren<P> =
   : unknown;
 
 declare function createElement<P extends {}>(
->createElement : <P extends {}>(type: ComponentClass<P>, ...children: P extends { children?: infer C; } ? C extends any[] ? C : C[] : unknown) => any
+>createElement : <P extends {}>(type: ComponentClass<P>, ...children: P extends { children?: infer C | undefined; } ? C extends any[] ? C : C[] : unknown) => any
 
   type: ComponentClass<P>,
 >type : ComponentClass<P>
 
   ...children: CreateElementChildren<P>
->children : P extends { children?: infer C; } ? C extends any[] ? C : C[] : unknown
+>children : P extends { children?: infer C | undefined; } ? C extends any[] ? C : C[] : unknown
 
 ): any;
 
 declare function createElement2<P extends {}>(
->createElement2 : <P extends {}>(type: ComponentClass<P>, child: P extends { children?: infer C; } ? C extends any[] ? C : C[] : unknown) => any
+>createElement2 : <P extends {}>(type: ComponentClass<P>, child: P extends { children?: infer C | undefined; } ? C extends any[] ? C : C[] : unknown) => any
 
   type: ComponentClass<P>,
 >type : ComponentClass<P>
 
   child: CreateElementChildren<P>
->child : P extends { children?: infer C; } ? C extends any[] ? C : C[] : unknown
+>child : P extends { children?: infer C | undefined; } ? C extends any[] ? C : C[] : unknown
 
 ): any;
 
@@ -261,7 +261,7 @@ class InferFunctionTypes extends Component<{children: (foo: number) => string}>
 
 createElement(InferFunctionTypes, (foo) => "" + foo);
 >createElement(InferFunctionTypes, (foo) => "" + foo) : any
->createElement : <P extends {}>(type: ComponentClass<P>, ...children: P extends { children?: infer C; } ? C extends any[] ? C : C[] : unknown) => any
+>createElement : <P extends {}>(type: ComponentClass<P>, ...children: P extends { children?: infer C | undefined; } ? C extends any[] ? C : C[] : unknown) => any
 >InferFunctionTypes : typeof InferFunctionTypes
 >(foo) => "" + foo : (foo: number) => string
 >foo : number
@@ -271,7 +271,7 @@ createElement(InferFunctionTypes, (foo) => "" + foo);
 
 createElement2(InferFunctionTypes, [(foo) => "" + foo]);
 >createElement2(InferFunctionTypes, [(foo) => "" + foo]) : any
->createElement2 : <P extends {}>(type: ComponentClass<P>, child: P extends { children?: infer C; } ? C extends any[] ? C : C[] : unknown) => any
+>createElement2 : <P extends {}>(type: ComponentClass<P>, child: P extends { children?: infer C | undefined; } ? C extends any[] ? C : C[] : unknown) => any
 >InferFunctionTypes : typeof InferFunctionTypes
 >[(foo) => "" + foo] : ((foo: number) => string)[]
 >(foo) => "" + foo : (foo: number) => string

tests/baselines/reference/intersectionPropertyCheck.errors.txt

@@ -1,12 +1,12 @@
 tests/cases/compiler/intersectionPropertyCheck.ts(1,68): error TS2322: Type '{ x: string; y: number; }' is not assignable to type '{ x: string; }'.
   Object literal may only specify known properties, and 'y' does not exist in type '{ x: string; }'.
-tests/cases/compiler/intersectionPropertyCheck.ts(4,5): error TS2322: Type '{ a: { y: string; }; }' is not assignable to type '{ a?: { x?: number; }; } & { c?: string; }'.
+tests/cases/compiler/intersectionPropertyCheck.ts(4,5): error TS2322: Type '{ a: { y: string; }; }' is not assignable to type '{ a?: { x?: number | undefined; } | undefined; } & { c?: string | undefined; }'.
   Types of property 'a' are incompatible.
-    Type '{ y: string; }' has no properties in common with type '{ x?: number; }'.
-tests/cases/compiler/intersectionPropertyCheck.ts(7,3): error TS2322: Type 'T & { a: boolean; }' is not assignable to type '{ a?: string; }'.
+    Type '{ y: string; }' has no properties in common with type '{ x?: number | undefined; }'.
+tests/cases/compiler/intersectionPropertyCheck.ts(7,3): error TS2322: Type 'T & { a: boolean; }' is not assignable to type '{ a?: string | undefined; }'.
   Types of property 'a' are incompatible.
-    Type 'boolean' is not assignable to type 'string'.
-tests/cases/compiler/intersectionPropertyCheck.ts(17,22): error TS2322: Type 'boolean' is not assignable to type 'string[]'.
+    Type 'boolean' is not assignable to type 'string | undefined'.
+tests/cases/compiler/intersectionPropertyCheck.ts(17,22): error TS2322: Type 'true' is not assignable to type 'string[] | undefined'.
 
 
 ==== tests/cases/compiler/intersectionPropertyCheck.ts (4 errors) ====
@@ -19,16 +19,16 @@ tests/cases/compiler/intersectionPropertyCheck.ts(17,22): error TS2322: Type 'bo
     declare let wrong: { a: { y: string } };
     let weak: { a?: { x?: number } } & { c?: string } = wrong;  // Nested weak object type
         ~~~~
-!!! error TS2322: Type '{ a: { y: string; }; }' is not assignable to type '{ a?: { x?: number; }; } & { c?: string; }'.
+!!! error TS2322: Type '{ a: { y: string; }; }' is not assignable to type '{ a?: { x?: number | undefined; } | undefined; } & { c?: string | undefined; }'.
 !!! error TS2322:   Types of property 'a' are incompatible.
-!!! error TS2322:     Type '{ y: string; }' has no properties in common with type '{ x?: number; }'.
+!!! error TS2322:     Type '{ y: string; }' has no properties in common with type '{ x?: number | undefined; }'.
     
     function foo<T extends object>(x: { a?: string }, y: T & { a: boolean }) {
       x = y;  // Mismatched property in source intersection
       ~
-!!! error TS2322: Type 'T & { a: boolean; }' is not assignable to type '{ a?: string; }'.
+!!! error TS2322: Type 'T & { a: boolean; }' is not assignable to type '{ a?: string | undefined; }'.
 !!! error TS2322:   Types of property 'a' are incompatible.
-!!! error TS2322:     Type 'boolean' is not assignable to type 'string'.
+!!! error TS2322:     Type 'boolean' is not assignable to type 'string | undefined'.
     }
     
     // Repro from #36637
@@ -40,7 +40,7 @@ tests/cases/compiler/intersectionPropertyCheck.ts(17,22): error TS2322: Type 'bo
     function test<T extends object>(value: T): Test {
       return { ...value, hi: true }
                          ~~
-!!! error TS2322: Type 'boolean' is not assignable to type 'string[]'.
+!!! error TS2322: Type 'true' is not assignable to type 'string[] | undefined'.
 !!! related TS6500 tests/cases/compiler/intersectionPropertyCheck.ts:13:12: The expected type comes from property 'hi' which is declared here on type 'Test'
     }
     

tests/baselines/reference/intersectionPropertyCheck.types

@@ -20,22 +20,22 @@ declare let wrong: { a: { y: string } };
 >y : string
 
 let weak: { a?: { x?: number } } & { c?: string } = wrong;  // Nested weak object type
->weak : { a?: {    x?: number;}; } & { c?: string; }
->a : { x?: number; } | undefined
+>weak : { a?: { x?: number | undefined; } | undefined; } & { c?: string | undefined; }
+>a : { x?: number | undefined; } | undefined
 >x : number | undefined
 >c : string | undefined
 >wrong : { a: { y: string; }; }
 
 function foo<T extends object>(x: { a?: string }, y: T & { a: boolean }) {
 >foo : <T extends object>(x: {    a?: string;}, y: T & {    a: boolean;}) => void
->x : { a?: string; }
+>x : { a?: string | undefined; }
 >a : string | undefined
 >y : T & { a: boolean; }
 >a : boolean
 
   x = y;  // Mismatched property in source intersection
 >x = y : T & { a: boolean; }
->x : { a?: string; }
+>x : { a?: string | undefined; }
 >y : T & { a: boolean; }
 }
 

tests/baselines/reference/intersectionsAndOptionalProperties.errors.txt

@@ -1,13 +1,13 @@
-tests/cases/compiler/intersectionsAndOptionalProperties.ts(5,1): error TS2322: Type '{ a: null; b: string; }' is not assignable to type '{ a?: number; b: string; }'.
+tests/cases/compiler/intersectionsAndOptionalProperties.ts(5,1): error TS2322: Type '{ a: null; b: string; }' is not assignable to type '{ a?: number | undefined; b: string; }'.
   Types of property 'a' are incompatible.
-    Type 'null' is not assignable to type 'number'.
-tests/cases/compiler/intersectionsAndOptionalProperties.ts(6,1): error TS2322: Type '{ a: null; } & { b: string; }' is not assignable to type '{ a?: number; b: string; }'.
+    Type 'null' is not assignable to type 'number | undefined'.
+tests/cases/compiler/intersectionsAndOptionalProperties.ts(6,1): error TS2322: Type '{ a: null; } & { b: string; }' is not assignable to type '{ a?: number | undefined; b: string; }'.
   Types of property 'a' are incompatible.
-    Type 'null' is not assignable to type 'number'.
+    Type 'null' is not assignable to type 'number | undefined'.
 tests/cases/compiler/intersectionsAndOptionalProperties.ts(19,5): error TS2322: Type 'From' is not assignable to type 'To'.
   Types of property 'field' are incompatible.
-    Type 'null' is not assignable to type 'number'.
-tests/cases/compiler/intersectionsAndOptionalProperties.ts(20,5): error TS2322: Type 'null' is not assignable to type 'number'.
+    Type 'null' is not assignable to type 'number | undefined'.
+tests/cases/compiler/intersectionsAndOptionalProperties.ts(20,5): error TS2322: Type 'null' is not assignable to type 'number | undefined'.
 
 
 ==== tests/cases/compiler/intersectionsAndOptionalProperties.ts (4 errors) ====
@@ -17,14 +17,14 @@ tests/cases/compiler/intersectionsAndOptionalProperties.ts(20,5): error TS2322:
     
     x = y;  // Error
     ~
-!!! error TS2322: Type '{ a: null; b: string; }' is not assignable to type '{ a?: number; b: string; }'.
+!!! error TS2322: Type '{ a: null; b: string; }' is not assignable to type '{ a?: number | undefined; b: string; }'.
 !!! error TS2322:   Types of property 'a' are incompatible.
-!!! error TS2322:     Type 'null' is not assignable to type 'number'.
+!!! error TS2322:     Type 'null' is not assignable to type 'number | undefined'.
     x = z;  // Error
     ~
-!!! error TS2322: Type '{ a: null; } & { b: string; }' is not assignable to type '{ a?: number; b: string; }'.
+!!! error TS2322: Type '{ a: null; } & { b: string; }' is not assignable to type '{ a?: number | undefined; b: string; }'.
 !!! error TS2322:   Types of property 'a' are incompatible.
-!!! error TS2322:     Type 'null' is not assignable to type 'number'.
+!!! error TS2322:     Type 'null' is not assignable to type 'number | undefined'.
     
     // Repro from #36604
     
@@ -41,10 +41,10 @@ tests/cases/compiler/intersectionsAndOptionalProperties.ts(20,5): error TS2322:
         ~
 !!! error TS2322: Type 'From' is not assignable to type 'To'.
 !!! error TS2322:   Types of property 'field' are incompatible.
-!!! error TS2322:     Type 'null' is not assignable to type 'number'.
+!!! error TS2322:     Type 'null' is not assignable to type 'number | undefined'.
         x.field = v.field; // Error
         ~~~~~~~
-!!! error TS2322: Type 'null' is not assignable to type 'number'.
+!!! error TS2322: Type 'null' is not assignable to type 'number | undefined'.
     }
     
     // Repro from #38348

tests/baselines/reference/intersectionsAndOptionalProperties.types

@@ -1,6 +1,6 @@
 === tests/cases/compiler/intersectionsAndOptionalProperties.ts ===
 declare let x: { a?: number, b: string };
->x : { a?: number; b: string; }
+>x : { a?: number | undefined; b: string; }
 >a : number | undefined
 >b : string
 
@@ -18,12 +18,12 @@ declare let z: { a: null } & { b: string };
 
 x = y;  // Error
 >x = y : { a: null; b: string; }
->x : { a?: number; b: string; }
+>x : { a?: number | undefined; b: string; }
 >y : { a: null; b: string; }
 
 x = z;  // Error
 >x = z : { a: null; } & { b: string; }
->x : { a?: number; b: string; }
+>x : { a?: number | undefined; b: string; }
 >z : { a: null; } & { b: string; }
 
 // Repro from #36604
@@ -55,9 +55,9 @@ function foo(v: From) {
 
     x.field = v.field; // Error
 >x.field = v.field : null
->x.field : number
+>x.field : number | undefined
 >x : To
->field : number
+>field : number | undefined
 >v.field : null
 >v : From
 >field : null

tests/baselines/reference/jsDeclarationsReactComponents.types

@@ -61,7 +61,7 @@ import React from "react";
  */
 const TabbedShowLayout = () => {
 >TabbedShowLayout : React.SFC<{}>
->() => {    return (        <div className="" key="">            ok        </div>    );} : { (): JSX.Element; defaultProps: Partial<{}>; }
+>() => {    return (        <div className="" key="">            ok        </div>    );} : { (): JSX.Element; defaultProps: Partial<{}> | undefined; }
 
     return (
 >(        <div className="" key="">            ok        </div>    ) : JSX.Element
@@ -81,9 +81,9 @@ const TabbedShowLayout = () => {
 
 TabbedShowLayout.defaultProps = {
 >TabbedShowLayout.defaultProps = {    tabs: "default value"} : { tabs: string; }
->TabbedShowLayout.defaultProps : Partial<{}>
+>TabbedShowLayout.defaultProps : Partial<{}> | undefined
 >TabbedShowLayout : React.SFC<{}>
->defaultProps : Partial<{}>
+>defaultProps : Partial<{}> | undefined
 >{    tabs: "default value"} : { tabs: string; }
 
     tabs: "default value"

tests/baselines/reference/jsxComplexSignatureHasApplicabilityError.errors.txt

@@ -1,626 +0,0 @@
-tests/cases/compiler/jsxComplexSignatureHasApplicabilityError.tsx(31,17): error TS2769: No overload matches this call.
-  Overload 1 of 2, '(props: Readonly<ReactSelectProps<ExtractValueType<WrappedProps>>>): ReactSelectClass<ExtractValueType<WrappedProps>>', gave the following error.
-    Type 'ExtractValueType<WrappedProps> | Option<ExtractValueType<WrappedProps>> | undefined' is not assignable to type 'string | number | boolean | string[] | number[] | Option<ExtractValueType<WrappedProps>> | Options<ExtractValueType<WrappedProps>>'.
-      Type 'undefined' is not assignable to type 'string | number | boolean | string[] | number[] | Option<ExtractValueType<WrappedProps>> | Options<ExtractValueType<WrappedProps>>'.
-  Overload 2 of 2, '(props: ReactSelectProps<ExtractValueType<WrappedProps>>, context?: any): ReactSelectClass<ExtractValueType<WrappedProps>>', gave the following error.
-    Type 'ExtractValueType<WrappedProps> | Option<ExtractValueType<WrappedProps>> | undefined' is not assignable to type 'string | number | boolean | string[] | number[] | Option<ExtractValueType<WrappedProps>> | Options<ExtractValueType<WrappedProps>>'.
-
-
-==== tests/cases/compiler/jsxComplexSignatureHasApplicabilityError.tsx (1 errors) ====
-    /// <reference path="/.lib/react16.d.ts" />
-    
-    import * as React from "react";
-    
-    
-    interface Props<T extends OptionValues> {
-        value?: Option<T> | T;
-        onChange?(value: Option<T> | undefined): void;
-    }
-    
-    type ExtractValueType<T> = T extends ReactSelectProps<infer U> ? U : never;
-    
-    export type ReactSingleSelectProps<
-        WrappedProps extends ReactSelectProps<any>
-    > = Overwrite<
-        Omit<WrappedProps, "multi">,
-        Props<ExtractValueType<WrappedProps>>
-    >;
-    
-    export function createReactSingleSelect<
-        WrappedProps extends ReactSelectProps<any>
-    >(
-        WrappedComponent: React.ComponentType<WrappedProps>
-    ): React.ComponentType<ReactSingleSelectProps<WrappedProps>> {
-        return (props) => {
-            return (
-                <ReactSelectClass<ExtractValueType<WrappedProps>>
-                    {...props}
-                    multi={false}
-                    autosize={false}
-                    value={props.value}
-                    ~~~~~
-!!! error TS2769: No overload matches this call.
-!!! error TS2769:   Overload 1 of 2, '(props: Readonly<ReactSelectProps<ExtractValueType<WrappedProps>>>): ReactSelectClass<ExtractValueType<WrappedProps>>', gave the following error.
-!!! error TS2769:     Type 'ExtractValueType<WrappedProps> | Option<ExtractValueType<WrappedProps>> | undefined' is not assignable to type 'string | number | boolean | string[] | number[] | Option<ExtractValueType<WrappedProps>> | Options<ExtractValueType<WrappedProps>>'.
-!!! error TS2769:       Type 'undefined' is not assignable to type 'string | number | boolean | string[] | number[] | Option<ExtractValueType<WrappedProps>> | Options<ExtractValueType<WrappedProps>>'.
-!!! error TS2769:   Overload 2 of 2, '(props: ReactSelectProps<ExtractValueType<WrappedProps>>, context?: any): ReactSelectClass<ExtractValueType<WrappedProps>>', gave the following error.
-!!! error TS2769:     Type 'ExtractValueType<WrappedProps> | Option<ExtractValueType<WrappedProps>> | undefined' is not assignable to type 'string | number | boolean | string[] | number[] | Option<ExtractValueType<WrappedProps>> | Options<ExtractValueType<WrappedProps>>'.
-!!! related TS6500 tests/cases/compiler/jsxComplexSignatureHasApplicabilityError.tsx:567:5: The expected type comes from property 'value' which is declared here on type 'IntrinsicAttributes & IntrinsicClassAttributes<ReactSelectClass<ExtractValueType<WrappedProps>>> & Readonly<{ children?: ReactNode; }> & Readonly<ReactSelectProps<ExtractValueType<WrappedProps>>>'
-!!! related TS6500 tests/cases/compiler/jsxComplexSignatureHasApplicabilityError.tsx:567:5: The expected type comes from property 'value' which is declared here on type 'IntrinsicAttributes & IntrinsicClassAttributes<ReactSelectClass<ExtractValueType<WrappedProps>>> & Readonly<{ children?: ReactNode; }> & Readonly<ReactSelectProps<ExtractValueType<WrappedProps>>>'
-                    onChange={(value) => {
-                        if (props.onChange) {
-                            props.onChange(value === null ? undefined : value);
-                        }
-                    }}
-                />
-            );
-        };
-    }
-    
-    
-    // Copied from "type-zoo" version 3.4.0
-    export type Omit<T, K extends keyof any> = T extends any ? Pick<T, Exclude<keyof T, K>> : never;
-    export type Overwrite<T, U> = Omit<T, keyof T & keyof U> & U;
-    
-    // Everything below here copied from "@types/react-select" version 1.3.4
-    declare class ReactSelectClass<TValue = OptionValues> extends React.Component<ReactSelectProps<TValue>> {
-        focus(): void;
-        setValue(value: Option<TValue>): void;
-    }
-    
-    export type OptionComponentType<TValue = OptionValues> = React.ComponentType<OptionComponentProps<TValue>>;
-    export type ValueComponentType<TValue = OptionValues> =  React.ComponentType<ValueComponentProps<TValue>>;
-    
-    export type HandlerRendererResult = JSX.Element | null | false;
-    
-    // Handlers
-    export type FocusOptionHandler<TValue = OptionValues> = (option: Option<TValue>) => void;
-    export type SelectValueHandler<TValue = OptionValues> = (option: Option<TValue>) => void;
-    export type ArrowRendererHandler = (props: ArrowRendererProps) => HandlerRendererResult;
-    export type ClearRendererHandler = () => HandlerRendererResult;
-    export type FilterOptionHandler<TValue = OptionValues> = (option: Option<TValue>, filter: string) => boolean;
-    export type FilterOptionsHandler<TValue = OptionValues> = (options: Options<TValue>, filter: string, currentValues: Options<TValue>) => Options<TValue>;
-    export type InputRendererHandler = (props: { [key: string]: any }) => HandlerRendererResult;
-    export type MenuRendererHandler<TValue = OptionValues> = (props: MenuRendererProps<TValue>) => HandlerRendererResult;
-    export type OnCloseHandler = () => void;
-    export type OnInputChangeHandler = (inputValue: string) => string;
-    export type OnInputKeyDownHandler = React.KeyboardEventHandler<HTMLDivElement | HTMLInputElement>;
-    export type OnMenuScrollToBottomHandler = () => void;
-    export type OnOpenHandler = () => void;
-    export type OnFocusHandler = React.FocusEventHandler<HTMLDivElement | HTMLInputElement>;
-    export type OnBlurHandler = React.FocusEventHandler<HTMLDivElement | HTMLInputElement>;
-    export type OptionRendererHandler<TValue = OptionValues> = (option: Option<TValue>) => HandlerRendererResult;
-    export type ValueRendererHandler<TValue = OptionValues> = (option: Option<TValue>, index?: number) => HandlerRendererResult;
-    export type OnValueClickHandler<TValue = OptionValues> = (option: Option<TValue>, event: React.MouseEvent<HTMLAnchorElement>) => void;
-    export type IsOptionUniqueHandler<TValue = OptionValues> = (arg: { option: Option<TValue>, options: Options<TValue>, labelKey: string, valueKey: string }) => boolean;
-    export type IsValidNewOptionHandler = (arg: { label: string }) => boolean;
-    export type NewOptionCreatorHandler<TValue = OptionValues> = (arg: { label: string, labelKey: string, valueKey: string }) => Option<TValue>;
-    export type PromptTextCreatorHandler = (filterText: string) => string;
-    export type ShouldKeyDownEventCreateNewOptionHandler = (arg: { keyCode: number }) => boolean;
-    
-    export type OnChangeSingleHandler<TValue = OptionValues> = OnChangeHandler<TValue, Option<TValue>>;
-    export type OnChangeMultipleHandler<TValue = OptionValues> = OnChangeHandler<TValue, Options<TValue>>;
-    export type OnChangeHandler<TValue = OptionValues, TOption = Option<TValue> | Options<TValue>> = (newValue: TOption | null) => void;
-    export type OnNewOptionClickHandler<TValue = OptionValues> = (option: Option<TValue>) => void;
-    
-    export type LoadOptionsHandler<TValue = OptionValues> = LoadOptionsAsyncHandler<TValue> | LoadOptionsLegacyHandler<TValue>;
-    export type LoadOptionsAsyncHandler<TValue = OptionValues> = (input: string) => Promise<AutocompleteResult<TValue>>;
-    export type LoadOptionsLegacyHandler<TValue = OptionValues> = (input: string, callback: (err: any, result: AutocompleteResult<TValue>) => void) => void;
-    
-    export interface AutocompleteResult<TValue = OptionValues> {
-        /** The search-results to be displayed  */
-        options: Options<TValue>;
-        /**
-         * Should be set to true, if and only if a longer query with the same prefix
-         * would return a subset of the results
-         * If set to true, more specific queries will not be sent to the server.
-         */
-        complete: boolean;
-    }
-    
-    export type Options<TValue = OptionValues> = Array<Option<TValue>>;
-    
-    export interface Option<TValue = OptionValues> {
-        /** Text for rendering */
-        label?: string;
-        /** Value for searching */
-        value?: TValue;
-        /**
-         * Allow this option to be cleared
-         * @default true
-         */
-        clearableValue?: boolean;
-        /**
-         * Do not allow this option to be selected
-         * @default false
-         */
-        disabled?: boolean;
-        /**
-         * In the event that a custom menuRenderer is provided, Option should be able
-         * to accept arbitrary key-value pairs. See react-virtualized-select.
-         */
-        [property: string]: any;
-    }
-    
-    export type OptionValues = string | number | boolean;
-    
-    export interface MenuRendererProps<TValue = OptionValues> {
-        /**
-         * The currently focused option; should be visible in the menu by default.
-         * default {}
-         */
-        focusedOption: Option<TValue>;
-    
-        /**
-         * Callback to focus a new option; receives the option as a parameter.
-         */
-        focusOption: FocusOptionHandler<TValue>;
-    
-        /**
-         * Option labels are accessible with this string key.
-         */
-        labelKey: string;
-    
-        /**
-         * Ordered array of options to render.
-         */
-        options: Options<TValue>;
-    
-        /**
-         * Callback to select a new option; receives the option as a parameter.
-         */
-        selectValue: SelectValueHandler<TValue>;
-    
-        /**
-         * Array of currently selected options.
-         */
-        valueArray: Options<TValue>;
-    
-        /**
-         * Callback to remove selection from option; receives the option as a parameter.
-         */
-        removeValue: SelectValueHandler<TValue>;
-    
-        /**
-         * function which returns a custom way to render the options in the menu
-         */
-        optionRenderer: OptionRendererHandler<TValue>;
-    }
-    
-    export interface OptionComponentProps<TValue = OptionValues> {
-        /**
-         * Classname(s) to apply to the option component.
-         */
-        className?: string;
-    
-        /**
-         * Currently focused option.
-         */
-        focusOption?: Option<TValue>;
-    
-        inputValue?: string;
-        instancePrefix?: string;
-    
-        /**
-         * True if this option is disabled.
-         */
-        isDisabled?: boolean;
-    
-        /**
-         * True if this option is focused.
-         */
-        isFocused?: boolean;
-    
-        /**
-         * True if this option is selected.
-         */
-        isSelected?: boolean;
-    
-        /**
-         * Callback to be invoked when this option is focused.
-         */
-        onFocus?: (option: Option<TValue>, event: any) => void;
-    
-        /**
-         * Callback to be invoked when this option is selected.
-         */
-        onSelect?: (option: Option<TValue>, event: any) => void;
-    
-        /**
-         * Option to be rendered by this component.
-         */
-        option: Option<TValue>;
-    
-        /**
-         * Index of the option being rendered in the list
-         */
-        optionIndex?: number;
-    
-        /**
-         * Callback to invoke when removing an option from a multi-selection. (Not necessarily the one
-         * being rendered)
-         */
-        removeValue?: (value: TValue | TValue[]) => void;
-    
-        /**
-         * Callback to invoke to select an option. (Not necessarily the one being rendered)
-         */
-        selectValue?: (value: TValue | TValue[]) => void;
-    }
-    
-    export interface ArrowRendererProps {
-        /**
-         * Arrow mouse down event handler.
-         */
-        onMouseDown: React.MouseEventHandler<any>;
-    
-        /**
-         * whether the Select is open or not.
-         */
-        isOpen: boolean;
-    }
-    
-    export interface ValueComponentProps<TValue = OptionValues> {
-        disabled: ReactSelectProps<TValue>['disabled'];
-        id: string;
-        instancePrefix: string;
-        onClick: OnValueClickHandler<TValue> | null;
-        onRemove?: SelectValueHandler<TValue>;
-        placeholder: ReactSelectProps<TValue>['placeholder'];
-        value: Option<TValue>;
-        values?: Array<Option<TValue>>;
-    }
-    
-    export interface ReactSelectProps<TValue = OptionValues> extends React.Props<ReactSelectClass<TValue>> {
-        /**
-         * text to display when `allowCreate` is true.
-         * @default 'Add "{label}"?'
-         */
-        addLabelText?: string;
-        /**
-         * renders a custom drop-down arrow to be shown in the right-hand side of the select.
-         * @default undefined
-         */
-        arrowRenderer?: ArrowRendererHandler | null;
-        /**
-         * blurs the input element after a selection has been made. Handy for lowering the keyboard on mobile devices.
-         * @default false
-         */
-        autoBlur?: boolean;
-        /**
-         * autofocus the component on mount
-         * @deprecated. Use autoFocus instead
-         * @default false
-         */
-        autofocus?: boolean;
-        /**
-         * autofocus the component on mount
-         * @default false
-         */
-        autoFocus?: boolean;
-        /**
-         *  If enabled, the input will expand as the length of its value increases
-         */
-        autosize?: boolean;
-        /**
-         * whether pressing backspace removes the last item when there is no input value
-         * @default true
-         */
-        backspaceRemoves?: boolean;
-        /**
-         * Message to use for screenreaders to press backspace to remove the current item
-         * {label} is replaced with the item label
-         * @default "Press backspace to remove..."
-         */
-        backspaceToRemoveMessage?: string;
-        /**
-         * CSS className for the outer element
-         */
-        className?: string;
-        /**
-         * Prefix prepended to element default className if no className is defined
-         */
-        classNamePrefix?: string;
-        /**
-         * title for the "clear" control when `multi` is true
-         * @default "Clear all"
-         */
-        clearAllText?: string;
-        /**
-         * Renders a custom clear to be shown in the right-hand side of the select when clearable true
-         * @default undefined
-         */
-        clearRenderer?: ClearRendererHandler;
-        /**
-         * title for the "clear" control
-         * @default "Clear value"
-         */
-        clearValueText?: string;
-        /**
-         * whether to close the menu when a value is selected
-         * @default true
-         */
-        closeOnSelect?: boolean;
-        /**
-         * whether it is possible to reset value. if enabled, an X button will appear at the right side.
-         * @default true
-         */
-        clearable?: boolean;
-        /**
-         * whether backspace removes an item if there is no text input
-         * @default true
-         */
-        deleteRemoves?: boolean;
-        /**
-         * delimiter to use to join multiple values
-         * @default ","
-         */
-        delimiter?: string;
-        /**
-         * whether the Select is disabled or not
-         * @default false
-         */
-        disabled?: boolean;
-        /**
-         * whether escape clears the value when the menu is closed
-         * @default true
-         */
-        escapeClearsValue?: boolean;
-        /**
-         * method to filter a single option
-         */
-        filterOption?: FilterOptionHandler<TValue>;
-        /**
-         * method to filter the options array
-         */
-        filterOptions?: FilterOptionsHandler<TValue>;
-        /**
-         * id for the underlying HTML input element
-         * @default undefined
-         */
-        id?: string;
-        /**
-         * whether to strip diacritics when filtering
-         * @default true
-         */
-        ignoreAccents?: boolean;
-        /**
-         * whether to perform case-insensitive filtering
-         * @default true
-         */
-        ignoreCase?: boolean;
-        /**
-         * custom attributes for the Input (in the Select-control) e.g: {'data-foo': 'bar'}
-         * @default {}
-         */
-        inputProps?: { [key: string]: any };
-        /**
-         * renders a custom input
-         */
-        inputRenderer?: InputRendererHandler;
-        /**
-         * allows for synchronization of component id's on server and client.
-         * @see https://github.com/JedWatson/react-select/pull/1105
-         */
-        instanceId?: string;
-        /**
-         * whether the Select is loading externally or not (such as options being loaded).
-         * if true, a loading spinner will be shown at the right side.
-         * @default false
-         */
-        isLoading?: boolean;
-        /**
-         * (legacy mode) joins multiple values into a single form field with the delimiter
-         * @default false
-         */
-        joinValues?: boolean;
-        /**
-         * the option property to use for the label
-         * @default "label"
-         */
-        labelKey?: string;
-        /**
-         * (any, start) match the start or entire string when filtering
-         * @default "any"
-         */
-        matchPos?: string;
-        /**
-         * (any, label, value) which option property to filter on
-         * @default "any"
-         */
-        matchProp?: string;
-        /**
-         * buffer of px between the base of the dropdown and the viewport to shift if menu doesnt fit in viewport
-         * @default 0
-         */
-        menuBuffer?: number;
-        /**
-         * optional style to apply to the menu container
-         */
-        menuContainerStyle?: React.CSSProperties;
-        /**
-         * renders a custom menu with options
-         */
-        menuRenderer?: MenuRendererHandler<TValue>;
-        /**
-         * optional style to apply to the menu
-         */
-        menuStyle?: React.CSSProperties;
-        /**
-         * multi-value input
-         * @default false
-         */
-        multi?: boolean;
-        /**
-         * field name, for hidden `<input>` tag
-         */
-        name?: string;
-        /**
-         * placeholder displayed when there are no matching search results or a falsy value to hide it
-         * @default "No results found"
-         */
-        noResultsText?: string | JSX.Element;
-        /**
-         * onBlur handler: function (event) {}
-         */
-        onBlur?: OnBlurHandler;
-        /**
-         * whether to clear input on blur or not
-         * @default true
-         */
-        onBlurResetsInput?: boolean;
-        /**
-         * whether the input value should be reset when options are selected.
-         * Also input value will be set to empty if 'onSelectResetsInput=true' and
-         * Select will get new value that not equal previous value.
-         * @default true
-         */
-        onSelectResetsInput?: boolean;
-        /**
-         * whether to clear input when closing the menu through the arrow
-         * @default true
-         */
-        onCloseResetsInput?: boolean;
-        /**
-         * onChange handler: function (newValue) {}
-         */
-        onChange?: OnChangeHandler<TValue>;
-        /**
-         * fires when the menu is closed
-         */
-        onClose?: OnCloseHandler;
-        /**
-         * onFocus handler: function (event) {}
-         */
-        onFocus?: OnFocusHandler;
-        /**
-         * onInputChange handler: function (inputValue) {}
-         */
-        onInputChange?: OnInputChangeHandler;
-        /**
-         * onInputKeyDown handler: function (keyboardEvent) {}
-         */
-        onInputKeyDown?: OnInputKeyDownHandler;
-        /**
-         * fires when the menu is scrolled to the bottom; can be used to paginate options
-         */
-        onMenuScrollToBottom?: OnMenuScrollToBottomHandler;
-        /**
-         * fires when the menu is opened
-         */
-        onOpen?: OnOpenHandler;
-        /**
-         * boolean to enable opening dropdown when focused
-         * @default false
-         */
-        openOnClick?: boolean;
-        /**
-         * open the options menu when the input gets focus (requires searchable = true)
-         * @default true
-         */
-        openOnFocus?: boolean;
-        /**
-         * className to add to each option component
-         */
-        optionClassName?: string;
-        /**
-         * option component to render in dropdown
-         */
-        optionComponent?: OptionComponentType<TValue>;
-        /**
-         * function which returns a custom way to render the options in the menu
-         */
-        optionRenderer?: OptionRendererHandler<TValue>;
-        /**
-         * array of Select options
-         * @default false
-         */
-        options?: Options<TValue>;
-        /**
-         * number of options to jump when using page up/down keys
-         * @default 5
-         */
-        pageSize?: number;
-        /**
-         * field placeholder, displayed when there's no value
-         * @default "Select..."
-         */
-        placeholder?: string | JSX.Element;
-        /**
-         * whether the selected option is removed from the dropdown on multi selects
-         * @default true
-         */
-        removeSelected?: boolean;
-        /**
-         * applies HTML5 required attribute when needed
-         * @default false
-         */
-        required?: boolean;
-        /**
-         * value to use when you clear the control
-         */
-        resetValue?: any;
-        /**
-         * use react-select in right-to-left direction
-         * @default false
-         */
-        rtl?: boolean;
-        /**
-         * whether the viewport will shift to display the entire menu when engaged
-         * @default true
-         */
-        scrollMenuIntoView?: boolean;
-        /**
-         * whether to enable searching feature or not
-         * @default true;
-         */
-        searchable?: boolean;
-        /**
-         * whether to select the currently focused value when the  [tab]  key is pressed
-         */
-        tabSelectsValue?: boolean;
-        /**
-         * initial field value
-         */
-        value?: Option<TValue> | Options<TValue> | string | string[] | number | number[] | boolean;
-        /**
-         * the option property to use for the value
-         * @default "value"
-         */
-        valueKey?: string;
-        /**
-         * function which returns a custom way to render the value selected
-         * @default false
-         */
-        valueRenderer?: ValueRendererHandler<TValue>;
-        /**
-         *  optional style to apply to the control
-         */
-        style?: React.CSSProperties;
-    
-        /**
-         *  optional tab index of the control
-         */
-        tabIndex?: string | number;
-    
-        /**
-         *  value component to render
-         */
-        valueComponent?: ValueComponentType<TValue>;
-    
-        /**
-         *  optional style to apply to the component wrapper
-         */
-        wrapperStyle?: React.CSSProperties;
-    
-        /**
-         * onClick handler for value labels: function (value, event) {}
-         */
-        onValueClick?: OnValueClickHandler<TValue>;
-    
-        /**
-         *  pass the value to onChange as a simple value (legacy pre 1.0 mode), defaults to false
-         */
-        simpleValue?: boolean;
-    }
-    

tests/baselines/reference/jsxNamespaceGlobalReexport.types

@@ -90,13 +90,13 @@ import { JSXInternal } from '..';
 >JSXInternal : any
 
 export function jsx(
->jsx : { (type: string, props: JSXInternal.HTMLAttributes & JSXInternal.SVGAttributes & Record<string, any> & {    children?: ComponentChild;}, key?: string | undefined): VNode<any>; <P>(type: ComponentType<P>, props: P & { children?: ComponentChild; }, key?: string | undefined): VNode<any>; }
+>jsx : { (type: string, props: JSXInternal.HTMLAttributes & JSXInternal.SVGAttributes & Record<string, any> & {    children?: ComponentChild;}, key?: string | undefined): VNode<any>; <P>(type: ComponentType<P>, props: P & { children?: ComponentChild | undefined; }, key?: string | undefined): VNode<any>; }
 
     type: string,
 >type : string
 
     props: JSXInternal.HTMLAttributes &
->props : JSXInternal.HTMLAttributes<{}> & JSXInternal.SVGAttributes<{}> & Record<string, any> & { children?: ComponentChild; }
+>props : JSXInternal.HTMLAttributes<{}> & JSXInternal.SVGAttributes<{}> & Record<string, any> & { children?: ComponentChild | undefined; }
 >JSXInternal : any
 
         JSXInternal.SVGAttributes &
@@ -110,13 +110,13 @@ export function jsx(
 
 ): VNode<any>;
 export function jsx<P>(
->jsx : { (type: string, props: JSXInternal.HTMLAttributes<{}> & JSXInternal.SVGAttributes<{}> & Record<string, any> & { children?: ComponentChild; }, key?: string | undefined): VNode<any>; <P>(type: ComponentType<P>, props: Attributes & P & {    children?: ComponentChild;}, key?: string | undefined): VNode<any>; }
+>jsx : { (type: string, props: JSXInternal.HTMLAttributes<{}> & JSXInternal.SVGAttributes<{}> & Record<string, any> & { children?: ComponentChild | undefined; }, key?: string | undefined): VNode<any>; <P>(type: ComponentType<P>, props: Attributes & P & {    children?: ComponentChild;}, key?: string | undefined): VNode<any>; }
 
     type: ComponentType<P>,
 >type : ComponentType<P>
 
     props: Attributes & P & { children?: ComponentChild },
->props : P & { children?: ComponentChild; }
+>props : P & { children?: ComponentChild | undefined; }
 >children : ComponentChild | undefined
 
     key?: string
@@ -125,13 +125,13 @@ export function jsx<P>(
 ): VNode<any>;
 
 export function jsxs(
->jsxs : { (type: string, props: JSXInternal.HTMLAttributes & JSXInternal.SVGAttributes & Record<string, any> & {    children?: ComponentChild[];}, key?: string | undefined): VNode<any>; <P>(type: ComponentType<P>, props: P & { children?: ComponentChild[]; }, key?: string | undefined): VNode<any>; }
+>jsxs : { (type: string, props: JSXInternal.HTMLAttributes & JSXInternal.SVGAttributes & Record<string, any> & {    children?: ComponentChild[];}, key?: string | undefined): VNode<any>; <P>(type: ComponentType<P>, props: P & { children?: ComponentChild[] | undefined; }, key?: string | undefined): VNode<any>; }
 
     type: string,
 >type : string
 
     props: JSXInternal.HTMLAttributes &
->props : JSXInternal.HTMLAttributes<{}> & JSXInternal.SVGAttributes<{}> & Record<string, any> & { children?: ComponentChild[]; }
+>props : JSXInternal.HTMLAttributes<{}> & JSXInternal.SVGAttributes<{}> & Record<string, any> & { children?: ComponentChild[] | undefined; }
 >JSXInternal : any
 
         JSXInternal.SVGAttributes &
@@ -145,13 +145,13 @@ export function jsxs(
 
 ): VNode<any>;
 export function jsxs<P>(
->jsxs : { (type: string, props: JSXInternal.HTMLAttributes<{}> & JSXInternal.SVGAttributes<{}> & Record<string, any> & { children?: ComponentChild[]; }, key?: string | undefined): VNode<any>; <P>(type: ComponentType<P>, props: Attributes & P & {    children?: ComponentChild[];}, key?: string | undefined): VNode<any>; }
+>jsxs : { (type: string, props: JSXInternal.HTMLAttributes<{}> & JSXInternal.SVGAttributes<{}> & Record<string, any> & { children?: ComponentChild[] | undefined; }, key?: string | undefined): VNode<any>; <P>(type: ComponentType<P>, props: Attributes & P & {    children?: ComponentChild[];}, key?: string | undefined): VNode<any>; }
 
     type: ComponentType<P>,
 >type : ComponentType<P>
 
     props: Attributes & P & { children?: ComponentChild[] },
->props : P & { children?: ComponentChild[]; }
+>props : P & { children?: ComponentChild[] | undefined; }
 >children : ComponentChild[] | undefined
 
     key?: string
@@ -160,13 +160,13 @@ export function jsxs<P>(
 ): VNode<any>;
 
 export function jsxDEV(
->jsxDEV : { (type: string, props: JSXInternal.HTMLAttributes & JSXInternal.SVGAttributes & Record<string, any> & {    children?: ComponentChildren;}, key?: string | undefined): VNode<any>; <P>(type: ComponentType<P>, props: P & { children?: ComponentChildren; }, key?: string | undefined): VNode<any>; }
+>jsxDEV : { (type: string, props: JSXInternal.HTMLAttributes & JSXInternal.SVGAttributes & Record<string, any> & {    children?: ComponentChildren;}, key?: string | undefined): VNode<any>; <P>(type: ComponentType<P>, props: P & { children?: ComponentChildren | undefined; }, key?: string | undefined): VNode<any>; }
 
     type: string,
 >type : string
 
     props: JSXInternal.HTMLAttributes &
->props : JSXInternal.HTMLAttributes<{}> & JSXInternal.SVGAttributes<{}> & Record<string, any> & { children?: ComponentChildren; }
+>props : JSXInternal.HTMLAttributes<{}> & JSXInternal.SVGAttributes<{}> & Record<string, any> & { children?: ComponentChildren | undefined; }
 >JSXInternal : any
 
         JSXInternal.SVGAttributes &
@@ -180,13 +180,13 @@ export function jsxDEV(
 
 ): VNode<any>;
 export function jsxDEV<P>(
->jsxDEV : { (type: string, props: JSXInternal.HTMLAttributes<{}> & JSXInternal.SVGAttributes<{}> & Record<string, any> & { children?: ComponentChildren; }, key?: string | undefined): VNode<any>; <P>(type: ComponentType<P>, props: Attributes & P & {    children?: ComponentChildren;}, key?: string | undefined): VNode<any>; }
+>jsxDEV : { (type: string, props: JSXInternal.HTMLAttributes<{}> & JSXInternal.SVGAttributes<{}> & Record<string, any> & { children?: ComponentChildren | undefined; }, key?: string | undefined): VNode<any>; <P>(type: ComponentType<P>, props: Attributes & P & {    children?: ComponentChildren;}, key?: string | undefined): VNode<any>; }
 
     type: ComponentType<P>,
 >type : ComponentType<P>
 
     props: Attributes & P & { children?: ComponentChildren },
->props : P & { children?: ComponentChildren; }
+>props : P & { children?: ComponentChildren | undefined; }
 >children : ComponentChildren | undefined
 
     key?: string

tests/baselines/reference/jsxNamespaceGlobalReexportMissingAliasTarget.types

@@ -90,13 +90,13 @@ import { JSXInternal } from '..';
 >JSXInternal : any
 
 export function jsx(
->jsx : { (type: string, props: JSXInternal.HTMLAttributes & JSXInternal.SVGAttributes & Record<string, any> & {    children?: ComponentChild;}, key?: string | undefined): VNode<any>; <P>(type: ComponentType<P>, props: P & { children?: ComponentChild; }, key?: string | undefined): VNode<any>; }
+>jsx : { (type: string, props: JSXInternal.HTMLAttributes & JSXInternal.SVGAttributes & Record<string, any> & {    children?: ComponentChild;}, key?: string | undefined): VNode<any>; <P>(type: ComponentType<P>, props: P & { children?: ComponentChild | undefined; }, key?: string | undefined): VNode<any>; }
 
     type: string,
 >type : string
 
     props: JSXInternal.HTMLAttributes &
->props : JSXInternal.HTMLAttributes<{}> & JSXInternal.SVGAttributes<{}> & Record<string, any> & { children?: ComponentChild; }
+>props : JSXInternal.HTMLAttributes<{}> & JSXInternal.SVGAttributes<{}> & Record<string, any> & { children?: ComponentChild | undefined; }
 >JSXInternal : any
 
         JSXInternal.SVGAttributes &
@@ -110,13 +110,13 @@ export function jsx(
 
 ): VNode<any>;
 export function jsx<P>(
->jsx : { (type: string, props: JSXInternal.HTMLAttributes<{}> & JSXInternal.SVGAttributes<{}> & Record<string, any> & { children?: ComponentChild; }, key?: string | undefined): VNode<any>; <P>(type: ComponentType<P>, props: Attributes & P & {    children?: ComponentChild;}, key?: string | undefined): VNode<any>; }
+>jsx : { (type: string, props: JSXInternal.HTMLAttributes<{}> & JSXInternal.SVGAttributes<{}> & Record<string, any> & { children?: ComponentChild | undefined; }, key?: string | undefined): VNode<any>; <P>(type: ComponentType<P>, props: Attributes & P & {    children?: ComponentChild;}, key?: string | undefined): VNode<any>; }
 
     type: ComponentType<P>,
 >type : ComponentType<P>
 
     props: Attributes & P & { children?: ComponentChild },
->props : P & { children?: ComponentChild; }
+>props : P & { children?: ComponentChild | undefined; }
 >children : ComponentChild | undefined
 
     key?: string
@@ -125,13 +125,13 @@ export function jsx<P>(
 ): VNode<any>;
 
 export function jsxs(
->jsxs : { (type: string, props: JSXInternal.HTMLAttributes & JSXInternal.SVGAttributes & Record<string, any> & {    children?: ComponentChild[];}, key?: string | undefined): VNode<any>; <P>(type: ComponentType<P>, props: P & { children?: ComponentChild[]; }, key?: string | undefined): VNode<any>; }
+>jsxs : { (type: string, props: JSXInternal.HTMLAttributes & JSXInternal.SVGAttributes & Record<string, any> & {    children?: ComponentChild[];}, key?: string | undefined): VNode<any>; <P>(type: ComponentType<P>, props: P & { children?: ComponentChild[] | undefined; }, key?: string | undefined): VNode<any>; }
 
     type: string,
 >type : string
 
     props: JSXInternal.HTMLAttributes &
->props : JSXInternal.HTMLAttributes<{}> & JSXInternal.SVGAttributes<{}> & Record<string, any> & { children?: ComponentChild[]; }
+>props : JSXInternal.HTMLAttributes<{}> & JSXInternal.SVGAttributes<{}> & Record<string, any> & { children?: ComponentChild[] | undefined; }
 >JSXInternal : any
 
         JSXInternal.SVGAttributes &
@@ -145,13 +145,13 @@ export function jsxs(
 
 ): VNode<any>;
 export function jsxs<P>(
->jsxs : { (type: string, props: JSXInternal.HTMLAttributes<{}> & JSXInternal.SVGAttributes<{}> & Record<string, any> & { children?: ComponentChild[]; }, key?: string | undefined): VNode<any>; <P>(type: ComponentType<P>, props: Attributes & P & {    children?: ComponentChild[];}, key?: string | undefined): VNode<any>; }
+>jsxs : { (type: string, props: JSXInternal.HTMLAttributes<{}> & JSXInternal.SVGAttributes<{}> & Record<string, any> & { children?: ComponentChild[] | undefined; }, key?: string | undefined): VNode<any>; <P>(type: ComponentType<P>, props: Attributes & P & {    children?: ComponentChild[];}, key?: string | undefined): VNode<any>; }
 
     type: ComponentType<P>,
 >type : ComponentType<P>
 
     props: Attributes & P & { children?: ComponentChild[] },
->props : P & { children?: ComponentChild[]; }
+>props : P & { children?: ComponentChild[] | undefined; }
 >children : ComponentChild[] | undefined
 
     key?: string
@@ -160,13 +160,13 @@ export function jsxs<P>(
 ): VNode<any>;
 
 export function jsxDEV(
->jsxDEV : { (type: string, props: JSXInternal.HTMLAttributes & JSXInternal.SVGAttributes & Record<string, any> & {    children?: ComponentChildren;}, key?: string | undefined): VNode<any>; <P>(type: ComponentType<P>, props: P & { children?: ComponentChildren; }, key?: string | undefined): VNode<any>; }
+>jsxDEV : { (type: string, props: JSXInternal.HTMLAttributes & JSXInternal.SVGAttributes & Record<string, any> & {    children?: ComponentChildren;}, key?: string | undefined): VNode<any>; <P>(type: ComponentType<P>, props: P & { children?: ComponentChildren | undefined; }, key?: string | undefined): VNode<any>; }
 
     type: string,
 >type : string
 
     props: JSXInternal.HTMLAttributes &
->props : JSXInternal.HTMLAttributes<{}> & JSXInternal.SVGAttributes<{}> & Record<string, any> & { children?: ComponentChildren; }
+>props : JSXInternal.HTMLAttributes<{}> & JSXInternal.SVGAttributes<{}> & Record<string, any> & { children?: ComponentChildren | undefined; }
 >JSXInternal : any
 
         JSXInternal.SVGAttributes &
@@ -180,13 +180,13 @@ export function jsxDEV(
 
 ): VNode<any>;
 export function jsxDEV<P>(
->jsxDEV : { (type: string, props: JSXInternal.HTMLAttributes<{}> & JSXInternal.SVGAttributes<{}> & Record<string, any> & { children?: ComponentChildren; }, key?: string | undefined): VNode<any>; <P>(type: ComponentType<P>, props: Attributes & P & {    children?: ComponentChildren;}, key?: string | undefined): VNode<any>; }
+>jsxDEV : { (type: string, props: JSXInternal.HTMLAttributes<{}> & JSXInternal.SVGAttributes<{}> & Record<string, any> & { children?: ComponentChildren | undefined; }, key?: string | undefined): VNode<any>; <P>(type: ComponentType<P>, props: Attributes & P & {    children?: ComponentChildren;}, key?: string | undefined): VNode<any>; }
 
     type: ComponentType<P>,
 >type : ComponentType<P>
 
     props: Attributes & P & { children?: ComponentChildren },
->props : P & { children?: ComponentChildren; }
+>props : P & { children?: ComponentChildren | undefined; }
 >children : ComponentChildren | undefined
 
     key?: string

tests/baselines/reference/jsxNamespaceImplicitImportJSXNamespace.types

@@ -90,13 +90,13 @@ import { JSXInternal } from '..';
 >JSXInternal : any
 
 export function jsx(
->jsx : { (type: string, props: JSXInternal.HTMLAttributes & JSXInternal.SVGAttributes & Record<string, any> & {    children?: ComponentChild;}, key?: string | undefined): VNode<any>; <P>(type: ComponentType<P>, props: P & { children?: ComponentChild; }, key?: string | undefined): VNode<any>; }
+>jsx : { (type: string, props: JSXInternal.HTMLAttributes & JSXInternal.SVGAttributes & Record<string, any> & {    children?: ComponentChild;}, key?: string | undefined): VNode<any>; <P>(type: ComponentType<P>, props: P & { children?: ComponentChild | undefined; }, key?: string | undefined): VNode<any>; }
 
     type: string,
 >type : string
 
     props: JSXInternal.HTMLAttributes &
->props : JSXInternal.HTMLAttributes<{}> & JSXInternal.SVGAttributes<{}> & Record<string, any> & { children?: ComponentChild; }
+>props : JSXInternal.HTMLAttributes<{}> & JSXInternal.SVGAttributes<{}> & Record<string, any> & { children?: ComponentChild | undefined; }
 >JSXInternal : any
 
         JSXInternal.SVGAttributes &
@@ -110,13 +110,13 @@ export function jsx(
 
 ): VNode<any>;
 export function jsx<P>(
->jsx : { (type: string, props: JSXInternal.HTMLAttributes<{}> & JSXInternal.SVGAttributes<{}> & Record<string, any> & { children?: ComponentChild; }, key?: string | undefined): VNode<any>; <P>(type: ComponentType<P>, props: Attributes & P & {    children?: ComponentChild;}, key?: string | undefined): VNode<any>; }
+>jsx : { (type: string, props: JSXInternal.HTMLAttributes<{}> & JSXInternal.SVGAttributes<{}> & Record<string, any> & { children?: ComponentChild | undefined; }, key?: string | undefined): VNode<any>; <P>(type: ComponentType<P>, props: Attributes & P & {    children?: ComponentChild;}, key?: string | undefined): VNode<any>; }
 
     type: ComponentType<P>,
 >type : ComponentType<P>
 
     props: Attributes & P & { children?: ComponentChild },
->props : P & { children?: ComponentChild; }
+>props : P & { children?: ComponentChild | undefined; }
 >children : ComponentChild | undefined
 
     key?: string
@@ -126,13 +126,13 @@ export function jsx<P>(
 
 
 export function jsxs(
->jsxs : { (type: string, props: JSXInternal.HTMLAttributes & JSXInternal.SVGAttributes & Record<string, any> & {    children?: ComponentChild[];}, key?: string | undefined): VNode<any>; <P>(type: ComponentType<P>, props: P & { children?: ComponentChild[]; }, key?: string | undefined): VNode<any>; }
+>jsxs : { (type: string, props: JSXInternal.HTMLAttributes & JSXInternal.SVGAttributes & Record<string, any> & {    children?: ComponentChild[];}, key?: string | undefined): VNode<any>; <P>(type: ComponentType<P>, props: P & { children?: ComponentChild[] | undefined; }, key?: string | undefined): VNode<any>; }
 
     type: string,
 >type : string
 
     props: JSXInternal.HTMLAttributes &
->props : JSXInternal.HTMLAttributes<{}> & JSXInternal.SVGAttributes<{}> & Record<string, any> & { children?: ComponentChild[]; }
+>props : JSXInternal.HTMLAttributes<{}> & JSXInternal.SVGAttributes<{}> & Record<string, any> & { children?: ComponentChild[] | undefined; }
 >JSXInternal : any
 
         JSXInternal.SVGAttributes &
@@ -146,13 +146,13 @@ export function jsxs(
 
 ): VNode<any>;
 export function jsxs<P>(
->jsxs : { (type: string, props: JSXInternal.HTMLAttributes<{}> & JSXInternal.SVGAttributes<{}> & Record<string, any> & { children?: ComponentChild[]; }, key?: string | undefined): VNode<any>; <P>(type: ComponentType<P>, props: Attributes & P & {    children?: ComponentChild[];}, key?: string | undefined): VNode<any>; }
+>jsxs : { (type: string, props: JSXInternal.HTMLAttributes<{}> & JSXInternal.SVGAttributes<{}> & Record<string, any> & { children?: ComponentChild[] | undefined; }, key?: string | undefined): VNode<any>; <P>(type: ComponentType<P>, props: Attributes & P & {    children?: ComponentChild[];}, key?: string | undefined): VNode<any>; }
 
     type: ComponentType<P>,
 >type : ComponentType<P>
 
     props: Attributes & P & { children?: ComponentChild[] },
->props : P & { children?: ComponentChild[]; }
+>props : P & { children?: ComponentChild[] | undefined; }
 >children : ComponentChild[] | undefined
 
     key?: string
@@ -162,13 +162,13 @@ export function jsxs<P>(
 
 
 export function jsxDEV(
->jsxDEV : { (type: string, props: JSXInternal.HTMLAttributes & JSXInternal.SVGAttributes & Record<string, any> & {    children?: ComponentChildren;}, key?: string | undefined): VNode<any>; <P>(type: ComponentType<P>, props: P & { children?: ComponentChildren; }, key?: string | undefined): VNode<any>; }
+>jsxDEV : { (type: string, props: JSXInternal.HTMLAttributes & JSXInternal.SVGAttributes & Record<string, any> & {    children?: ComponentChildren;}, key?: string | undefined): VNode<any>; <P>(type: ComponentType<P>, props: P & { children?: ComponentChildren | undefined; }, key?: string | undefined): VNode<any>; }
 
     type: string,
 >type : string
 
     props: JSXInternal.HTMLAttributes &
->props : JSXInternal.HTMLAttributes<{}> & JSXInternal.SVGAttributes<{}> & Record<string, any> & { children?: ComponentChildren; }
+>props : JSXInternal.HTMLAttributes<{}> & JSXInternal.SVGAttributes<{}> & Record<string, any> & { children?: ComponentChildren | undefined; }
 >JSXInternal : any
 
         JSXInternal.SVGAttributes &
@@ -182,13 +182,13 @@ export function jsxDEV(
 
 ): VNode<any>;
 export function jsxDEV<P>(
->jsxDEV : { (type: string, props: JSXInternal.HTMLAttributes<{}> & JSXInternal.SVGAttributes<{}> & Record<string, any> & { children?: ComponentChildren; }, key?: string | undefined): VNode<any>; <P>(type: ComponentType<P>, props: Attributes & P & {    children?: ComponentChildren;}, key?: string | undefined): VNode<any>; }
+>jsxDEV : { (type: string, props: JSXInternal.HTMLAttributes<{}> & JSXInternal.SVGAttributes<{}> & Record<string, any> & { children?: ComponentChildren | undefined; }, key?: string | undefined): VNode<any>; <P>(type: ComponentType<P>, props: Attributes & P & {    children?: ComponentChildren;}, key?: string | undefined): VNode<any>; }
 
     type: ComponentType<P>,
 >type : ComponentType<P>
 
     props: Attributes & P & { children?: ComponentChildren },
->props : P & { children?: ComponentChildren; }
+>props : P & { children?: ComponentChildren | undefined; }
 >children : ComponentChildren | undefined
 
     key?: string

tests/baselines/reference/logicalAssignment8(target=es2015).types

@@ -1,6 +1,6 @@
 === tests/cases/conformance/es2021/logicalAssignment/logicalAssignment8.ts ===
 declare const bar: { value?: number[] } | undefined
->bar : { value?: number[]; } | undefined
+>bar : { value?: number[] | undefined; } | undefined
 >value : number[] | undefined
 
 function foo1(results: number[] | undefined) {
@@ -15,7 +15,7 @@ function foo1(results: number[] | undefined) {
 >results : number[] | undefined
 >bar?.value ?? [] : number[]
 >bar?.value : number[] | undefined
->bar : { value?: number[]; } | undefined
+>bar : { value?: number[] | undefined; } | undefined
 >value : number[] | undefined
 >[] : never[]
 >push : (...items: number[]) => number
@@ -34,7 +34,7 @@ function foo2(results: number[] | undefined) {
 >results : number[] | undefined
 >bar?.value ?? [] : number[]
 >bar?.value : number[] | undefined
->bar : { value?: number[]; } | undefined
+>bar : { value?: number[] | undefined; } | undefined
 >value : number[] | undefined
 >[] : never[]
 >push : (...items: number[]) => number
@@ -53,7 +53,7 @@ function foo3(results: number[] | undefined) {
 >results : number[] | undefined
 >bar?.value ?? [] : number[]
 >bar?.value : number[] | undefined
->bar : { value?: number[]; } | undefined
+>bar : { value?: number[] | undefined; } | undefined
 >value : number[] | undefined
 >[] : never[]
 >push : (...items: number[]) => number

tests/baselines/reference/logicalAssignment8(target=es2020).types

@@ -1,6 +1,6 @@
 === tests/cases/conformance/es2021/logicalAssignment/logicalAssignment8.ts ===
 declare const bar: { value?: number[] } | undefined
->bar : { value?: number[]; } | undefined
+>bar : { value?: number[] | undefined; } | undefined
 >value : number[] | undefined
 
 function foo1(results: number[] | undefined) {
@@ -15,7 +15,7 @@ function foo1(results: number[] | undefined) {
 >results : number[] | undefined
 >bar?.value ?? [] : number[]
 >bar?.value : number[] | undefined
->bar : { value?: number[]; } | undefined
+>bar : { value?: number[] | undefined; } | undefined
 >value : number[] | undefined
 >[] : never[]
 >push : (...items: number[]) => number
@@ -34,7 +34,7 @@ function foo2(results: number[] | undefined) {
 >results : number[] | undefined
 >bar?.value ?? [] : number[]
 >bar?.value : number[] | undefined
->bar : { value?: number[]; } | undefined
+>bar : { value?: number[] | undefined; } | undefined
 >value : number[] | undefined
 >[] : never[]
 >push : (...items: number[]) => number
@@ -53,7 +53,7 @@ function foo3(results: number[] | undefined) {
 >results : number[] | undefined
 >bar?.value ?? [] : number[]
 >bar?.value : number[] | undefined
->bar : { value?: number[]; } | undefined
+>bar : { value?: number[] | undefined; } | undefined
 >value : number[] | undefined
 >[] : never[]
 >push : (...items: number[]) => number

tests/baselines/reference/logicalAssignment8(target=es2021).types

@@ -1,6 +1,6 @@
 === tests/cases/conformance/es2021/logicalAssignment/logicalAssignment8.ts ===
 declare const bar: { value?: number[] } | undefined
->bar : { value?: number[]; } | undefined
+>bar : { value?: number[] | undefined; } | undefined
 >value : number[] | undefined
 
 function foo1(results: number[] | undefined) {
@@ -15,7 +15,7 @@ function foo1(results: number[] | undefined) {
 >results : number[] | undefined
 >bar?.value ?? [] : number[]
 >bar?.value : number[] | undefined
->bar : { value?: number[]; } | undefined
+>bar : { value?: number[] | undefined; } | undefined
 >value : number[] | undefined
 >[] : never[]
 >push : (...items: number[]) => number
@@ -34,7 +34,7 @@ function foo2(results: number[] | undefined) {
 >results : number[] | undefined
 >bar?.value ?? [] : number[]
 >bar?.value : number[] | undefined
->bar : { value?: number[]; } | undefined
+>bar : { value?: number[] | undefined; } | undefined
 >value : number[] | undefined
 >[] : never[]
 >push : (...items: number[]) => number
@@ -53,7 +53,7 @@ function foo3(results: number[] | undefined) {
 >results : number[] | undefined
 >bar?.value ?? [] : number[]
 >bar?.value : number[] | undefined
->bar : { value?: number[]; } | undefined
+>bar : { value?: number[] | undefined; } | undefined
 >value : number[] | undefined
 >[] : never[]
 >push : (...items: number[]) => number

tests/baselines/reference/logicalAssignment8(target=esnext).types

@@ -1,6 +1,6 @@
 === tests/cases/conformance/es2021/logicalAssignment/logicalAssignment8.ts ===
 declare const bar: { value?: number[] } | undefined
->bar : { value?: number[]; } | undefined
+>bar : { value?: number[] | undefined; } | undefined
 >value : number[] | undefined
 
 function foo1(results: number[] | undefined) {
@@ -15,7 +15,7 @@ function foo1(results: number[] | undefined) {
 >results : number[] | undefined
 >bar?.value ?? [] : number[]
 >bar?.value : number[] | undefined
->bar : { value?: number[]; } | undefined
+>bar : { value?: number[] | undefined; } | undefined
 >value : number[] | undefined
 >[] : never[]
 >push : (...items: number[]) => number
@@ -34,7 +34,7 @@ function foo2(results: number[] | undefined) {
 >results : number[] | undefined
 >bar?.value ?? [] : number[]
 >bar?.value : number[] | undefined
->bar : { value?: number[]; } | undefined
+>bar : { value?: number[] | undefined; } | undefined
 >value : number[] | undefined
 >[] : never[]
 >push : (...items: number[]) => number
@@ -53,7 +53,7 @@ function foo3(results: number[] | undefined) {
 >results : number[] | undefined
 >bar?.value ?? [] : number[]
 >bar?.value : number[] | undefined
->bar : { value?: number[]; } | undefined
+>bar : { value?: number[] | undefined; } | undefined
 >value : number[] | undefined
 >[] : never[]
 >push : (...items: number[]) => number

tests/baselines/reference/logicalAssignment9.types

@@ -1,19 +1,19 @@
 === tests/cases/conformance/es2021/logicalAssignment/logicalAssignment9.ts ===
 declare let x: { a?: boolean };
->x : { a?: boolean; }
+>x : { a?: boolean | undefined; }
 >a : boolean | undefined
 
 x.a ??= true;
 >x.a ??= true : boolean
->x.a : boolean
->x : { a?: boolean; }
->a : boolean
+>x.a : boolean | undefined
+>x : { a?: boolean | undefined; }
+>a : boolean | undefined
 >true : true
 
 x.a &&= false;
->x.a &&= false : false
->x.a : boolean
->x : { a?: boolean; }
->a : boolean
+>x.a &&= false : false | undefined
+>x.a : boolean | undefined
+>x : { a?: boolean | undefined; }
+>a : boolean | undefined
 >false : false
 

tests/baselines/reference/mappedTypesArraysTuples.js

@@ -178,15 +178,15 @@ declare let y12: {
 };
 declare function nonpartial<T>(x: Partial<T>): T;
 declare let x20: [number | undefined, string?, ...boolean[]];
-declare let y20: [number | undefined, string, ...boolean[]];
+declare let y20: [number, string, ...boolean[]];
 declare let x21: (number | undefined)[];
-declare let y21: (number | undefined)[];
+declare let y21: number[];
 declare let x22: {
     a: number | undefined;
     b?: string[];
 };
 declare let y22: {
-    a: number | undefined;
+    a: number;
     b: string[];
 };
 declare type Awaited<T> = T extends PromiseLike<infer U> ? U : T;

tests/baselines/reference/mappedTypesArraysTuples.types

@@ -10,7 +10,7 @@ type T00 = Boxified<[number, string?, ...boolean[]]>;
 >T00 : [Box<number>, Box<string | undefined>?, ...Box<boolean>[]]
 
 type T01 = Partial<[number, string?, ...boolean[]]>;
->T01 : [number?, string?, ...(boolean | undefined)[]]
+>T01 : [(number | undefined)?, (string | undefined)?, ...(boolean | undefined)[]]
 
 type T02 = Required<[number, string?, ...boolean[]]>;
 >T02 : [number, string, ...boolean[]]
@@ -124,33 +124,33 @@ declare function nonpartial<T>(x: Partial<T>): T;
 >x : Partial<T>
 
 declare let x20: [number | undefined, string?, ...boolean[]];
->x20 : [number | undefined, string?, ...boolean[]]
+>x20 : [number | undefined, (string | undefined)?, ...boolean[]]
 
 let y20 = nonpartial(x20);
->y20 : [number | undefined, string, ...boolean[]]
->nonpartial(x20) : [number | undefined, string, ...boolean[]]
+>y20 : [number, string, ...boolean[]]
+>nonpartial(x20) : [number, string, ...boolean[]]
 >nonpartial : <T>(x: Partial<T>) => T
->x20 : [number | undefined, string?, ...boolean[]]
+>x20 : [number | undefined, (string | undefined)?, ...boolean[]]
 
 declare let x21: (number | undefined)[];
 >x21 : (number | undefined)[]
 
 let y21 = nonpartial(x21);
->y21 : (number | undefined)[]
->nonpartial(x21) : (number | undefined)[]
+>y21 : number[]
+>nonpartial(x21) : number[]
 >nonpartial : <T>(x: Partial<T>) => T
 >x21 : (number | undefined)[]
 
 declare let x22: { a: number | undefined, b?: string[] };
->x22 : { a: number | undefined; b?: string[]; }
+>x22 : { a: number | undefined; b?: string[] | undefined; }
 >a : number | undefined
 >b : string[] | undefined
 
 let y22 = nonpartial(x22);
->y22 : { a: number | undefined; b: string[]; }
->nonpartial(x22) : { a: number | undefined; b: string[]; }
+>y22 : { a: number; b: string[]; }
+>nonpartial(x22) : { a: number; b: string[]; }
 >nonpartial : <T>(x: Partial<T>) => T
->x22 : { a: number | undefined; b?: string[]; }
+>x22 : { a: number | undefined; b?: string[] | undefined; }
 
 type Awaited<T> = T extends PromiseLike<infer U> ? U : T;
 >Awaited : Awaited<T>

tests/baselines/reference/narrowingOfQualifiedNames.types

@@ -56,10 +56,10 @@ function init(properties: IProperties) {
 
 interface DeepOptional {
     a?: {
->a : { b?: {    c?: string;}; } | undefined
+>a : { b?: { c?: string | undefined; } | undefined; } | undefined
 
         b?: {
->b : { c?: string; } | undefined
+>b : { c?: string | undefined; } | undefined
 
             c?: string
 >c : string | undefined
@@ -72,32 +72,32 @@ function init2(foo: DeepOptional) {
 >foo : DeepOptional
 
     if (foo.a) {
->foo.a : { b?: { c?: string; }; } | undefined
+>foo.a : { b?: { c?: string | undefined; } | undefined; } | undefined
 >foo : DeepOptional
->a : { b?: { c?: string; }; } | undefined
+>a : { b?: { c?: string | undefined; } | undefined; } | undefined
 
         type A = typeof foo.a;
->A : { b?: { c?: string; }; }
->foo.a : { b?: { c?: string; }; }
+>A : { b?: { c?: string | undefined; } | undefined; }
+>foo.a : { b?: { c?: string | undefined; } | undefined; }
 >foo : DeepOptional
->a : { b?: { c?: string; }; }
+>a : { b?: { c?: string | undefined; } | undefined; }
 
         type B = typeof foo.a.b;
->B : { c?: string; } | undefined
->foo.a.b : { c?: string; } | undefined
->foo.a : { b?: { c?: string; }; }
+>B : { c?: string | undefined; } | undefined
+>foo.a.b : { c?: string | undefined; } | undefined
+>foo.a : { b?: { c?: string | undefined; } | undefined; }
 >foo : DeepOptional
->a : { b?: { c?: string; }; }
->b : { c?: string; } | undefined
+>a : { b?: { c?: string | undefined; } | undefined; }
+>b : { c?: string | undefined; } | undefined
 
         type C = typeof foo.a.b.c;
 >C : string | undefined
 >foo.a.b.c : string | undefined
->foo.a.b : { c?: string; } | undefined
->foo.a : { b?: { c?: string; }; }
+>foo.a.b : { c?: string | undefined; } | undefined
+>foo.a : { b?: { c?: string | undefined; } | undefined; }
 >foo : DeepOptional
->a : { b?: { c?: string; }; }
->b : { c?: string; } | undefined
+>a : { b?: { c?: string | undefined; } | undefined; }
+>b : { c?: string | undefined; } | undefined
 >c : string | undefined
 
         for(const _ of [1]) {
@@ -106,58 +106,58 @@ function init2(foo: DeepOptional) {
 >1 : 1
 
             type A = typeof foo.a;
->A : { b?: { c?: string; }; }
->foo.a : { b?: { c?: string; }; }
+>A : { b?: { c?: string | undefined; } | undefined; }
+>foo.a : { b?: { c?: string | undefined; } | undefined; }
 >foo : DeepOptional
->a : { b?: { c?: string; }; }
+>a : { b?: { c?: string | undefined; } | undefined; }
 
             type B = typeof foo.a.b;
->B : { c?: string; } | undefined
->foo.a.b : { c?: string; } | undefined
->foo.a : { b?: { c?: string; }; }
+>B : { c?: string | undefined; } | undefined
+>foo.a.b : { c?: string | undefined; } | undefined
+>foo.a : { b?: { c?: string | undefined; } | undefined; }
 >foo : DeepOptional
->a : { b?: { c?: string; }; }
->b : { c?: string; } | undefined
+>a : { b?: { c?: string | undefined; } | undefined; }
+>b : { c?: string | undefined; } | undefined
 
             type C = typeof foo.a.b.c;
 >C : string | undefined
 >foo.a.b.c : string | undefined
->foo.a.b : { c?: string; } | undefined
->foo.a : { b?: { c?: string; }; }
+>foo.a.b : { c?: string | undefined; } | undefined
+>foo.a : { b?: { c?: string | undefined; } | undefined; }
 >foo : DeepOptional
->a : { b?: { c?: string; }; }
->b : { c?: string; } | undefined
+>a : { b?: { c?: string | undefined; } | undefined; }
+>b : { c?: string | undefined; } | undefined
 >c : string | undefined
 
             if (foo.a.b) {
->foo.a.b : { c?: string; } | undefined
->foo.a : { b?: { c?: string; }; }
+>foo.a.b : { c?: string | undefined; } | undefined
+>foo.a : { b?: { c?: string | undefined; } | undefined; }
 >foo : DeepOptional
->a : { b?: { c?: string; }; }
->b : { c?: string; } | undefined
+>a : { b?: { c?: string | undefined; } | undefined; }
+>b : { c?: string | undefined; } | undefined
 
                 type A = typeof foo.a;
->A : { b?: { c?: string; }; }
->foo.a : { b?: { c?: string; }; }
+>A : { b?: { c?: string | undefined; } | undefined; }
+>foo.a : { b?: { c?: string | undefined; } | undefined; }
 >foo : DeepOptional
->a : { b?: { c?: string; }; }
+>a : { b?: { c?: string | undefined; } | undefined; }
 
                 type B = typeof foo.a.b;
->B : { c?: string; }
->foo.a.b : { c?: string; }
->foo.a : { b?: { c?: string; }; }
+>B : { c?: string | undefined; }
+>foo.a.b : { c?: string | undefined; }
+>foo.a : { b?: { c?: string | undefined; } | undefined; }
 >foo : DeepOptional
->a : { b?: { c?: string; }; }
->b : { c?: string; }
+>a : { b?: { c?: string | undefined; } | undefined; }
+>b : { c?: string | undefined; }
 
                 type C = typeof foo.a.b.c;
 >C : string | undefined
 >foo.a.b.c : string | undefined
->foo.a.b : { c?: string; }
->foo.a : { b?: { c?: string; }; }
+>foo.a.b : { c?: string | undefined; }
+>foo.a : { b?: { c?: string | undefined; } | undefined; }
 >foo : DeepOptional
->a : { b?: { c?: string; }; }
->b : { c?: string; }
+>a : { b?: { c?: string | undefined; } | undefined; }
+>b : { c?: string | undefined; }
 >c : string | undefined
 
                 for(const _ of [1]) {
@@ -166,60 +166,60 @@ function init2(foo: DeepOptional) {
 >1 : 1
 
                     type A = typeof foo.a;
->A : { b?: { c?: string; }; }
->foo.a : { b?: { c?: string; }; }
+>A : { b?: { c?: string | undefined; } | undefined; }
+>foo.a : { b?: { c?: string | undefined; } | undefined; }
 >foo : DeepOptional
->a : { b?: { c?: string; }; }
+>a : { b?: { c?: string | undefined; } | undefined; }
 
                     type B = typeof foo.a.b;
->B : { c?: string; }
->foo.a.b : { c?: string; }
->foo.a : { b?: { c?: string; }; }
+>B : { c?: string | undefined; }
+>foo.a.b : { c?: string | undefined; }
+>foo.a : { b?: { c?: string | undefined; } | undefined; }
 >foo : DeepOptional
->a : { b?: { c?: string; }; }
->b : { c?: string; }
+>a : { b?: { c?: string | undefined; } | undefined; }
+>b : { c?: string | undefined; }
 
                     type C = typeof foo.a.b.c;
 >C : string | undefined
 >foo.a.b.c : string | undefined
->foo.a.b : { c?: string; }
->foo.a : { b?: { c?: string; }; }
+>foo.a.b : { c?: string | undefined; }
+>foo.a : { b?: { c?: string | undefined; } | undefined; }
 >foo : DeepOptional
->a : { b?: { c?: string; }; }
->b : { c?: string; }
+>a : { b?: { c?: string | undefined; } | undefined; }
+>b : { c?: string | undefined; }
 >c : string | undefined
 
                     if (foo.a.b.c) {
 >foo.a.b.c : string | undefined
->foo.a.b : { c?: string; }
->foo.a : { b?: { c?: string; }; }
+>foo.a.b : { c?: string | undefined; }
+>foo.a : { b?: { c?: string | undefined; } | undefined; }
 >foo : DeepOptional
->a : { b?: { c?: string; }; }
->b : { c?: string; }
+>a : { b?: { c?: string | undefined; } | undefined; }
+>b : { c?: string | undefined; }
 >c : string | undefined
 
                         type A = typeof foo.a;
->A : { b?: { c?: string; }; }
->foo.a : { b?: { c?: string; }; }
+>A : { b?: { c?: string | undefined; } | undefined; }
+>foo.a : { b?: { c?: string | undefined; } | undefined; }
 >foo : DeepOptional
->a : { b?: { c?: string; }; }
+>a : { b?: { c?: string | undefined; } | undefined; }
 
                         type B = typeof foo.a.b;
->B : { c?: string; }
->foo.a.b : { c?: string; }
->foo.a : { b?: { c?: string; }; }
+>B : { c?: string | undefined; }
+>foo.a.b : { c?: string | undefined; }
+>foo.a : { b?: { c?: string | undefined; } | undefined; }
 >foo : DeepOptional
->a : { b?: { c?: string; }; }
->b : { c?: string; }
+>a : { b?: { c?: string | undefined; } | undefined; }
+>b : { c?: string | undefined; }
 
                         type C = typeof foo.a.b.c;
 >C : string
 >foo.a.b.c : string
->foo.a.b : { c?: string; }
->foo.a : { b?: { c?: string; }; }
+>foo.a.b : { c?: string | undefined; }
+>foo.a : { b?: { c?: string | undefined; } | undefined; }
 >foo : DeepOptional
->a : { b?: { c?: string; }; }
->b : { c?: string; }
+>a : { b?: { c?: string | undefined; } | undefined; }
+>b : { c?: string | undefined; }
 >c : string
 
                         for(const _ of [1]) {
@@ -228,27 +228,27 @@ function init2(foo: DeepOptional) {
 >1 : 1
 
                             type A = typeof foo.a;
->A : { b?: { c?: string; }; }
->foo.a : { b?: { c?: string; }; }
+>A : { b?: { c?: string | undefined; } | undefined; }
+>foo.a : { b?: { c?: string | undefined; } | undefined; }
 >foo : DeepOptional
->a : { b?: { c?: string; }; }
+>a : { b?: { c?: string | undefined; } | undefined; }
 
                             type B = typeof foo.a.b;
->B : { c?: string; }
->foo.a.b : { c?: string; }
->foo.a : { b?: { c?: string; }; }
+>B : { c?: string | undefined; }
+>foo.a.b : { c?: string | undefined; }
+>foo.a : { b?: { c?: string | undefined; } | undefined; }
 >foo : DeepOptional
->a : { b?: { c?: string; }; }
->b : { c?: string; }
+>a : { b?: { c?: string | undefined; } | undefined; }
+>b : { c?: string | undefined; }
 
                             type C = typeof foo.a.b.c;
 >C : string
 >foo.a.b.c : string
->foo.a.b : { c?: string; }
->foo.a : { b?: { c?: string; }; }
+>foo.a.b : { c?: string | undefined; }
+>foo.a : { b?: { c?: string | undefined; } | undefined; }
 >foo : DeepOptional
->a : { b?: { c?: string; }; }
->b : { c?: string; }
+>a : { b?: { c?: string | undefined; } | undefined; }
+>b : { c?: string | undefined; }
 >c : string
                         }
                     }

tests/baselines/reference/noUncheckedIndexedAccessDestructuring.types

@@ -158,7 +158,7 @@ declare let target_string_arr: string[];
 
 [,,, ...target_string_arr] = strArray; // Should OK
 >[,,, ...target_string_arr] = strArray : string[]
->[,,, ...target_string_arr] : [never?, never?, never?, ...string[]]
+>[,,, ...target_string_arr] : [undefined, undefined, undefined, ...string[]]
 > : undefined
 > : undefined
 > : undefined

tests/baselines/reference/normalizedIntersectionTooComplex.types

@@ -20,112 +20,112 @@ type CtorOf<T> = (arg: UnionToIntersection<T>) => T;
 
 interface Big {
     "0": { common?: string; "0"?: number, ref?: Obj<Big["0"]> | Func<Big["0"]>; }
->"0" : { common?: string; "0"?: number; ref?: Obj<Big["0"]> | Func<Big["0"]>; }
+>"0" : { common?: string | undefined; "0"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }
 >common : string | undefined
 >"0" : number | undefined
->ref : Obj<{ common?: string; "0"?: number; ref?: Obj<Big["0"]> | Func<Big["0"]>; }> | Func<{ common?: string; "0"?: number; ref?: Obj<Big["0"]> | Func<Big["0"]>; }> | undefined
+>ref : Obj<{ common?: string | undefined; "0"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }> | Func<{ common?: string | undefined; "0"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }> | undefined
 
     "1": { common?: string; "1"?: number, ref?: Obj<Big["1"]> | Func<Big["1"]>; }
->"1" : { common?: string; "1"?: number; ref?: Obj<Big["1"]> | Func<Big["1"]>; }
+>"1" : { common?: string | undefined; "1"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }
 >common : string | undefined
 >"1" : number | undefined
->ref : Obj<{ common?: string; "1"?: number; ref?: Obj<Big["1"]> | Func<Big["1"]>; }> | Func<{ common?: string; "1"?: number; ref?: Obj<Big["1"]> | Func<Big["1"]>; }> | undefined
+>ref : Obj<{ common?: string | undefined; "1"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }> | Func<{ common?: string | undefined; "1"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }> | undefined
 
     "2": { common?: string; "2"?: number, ref?: Obj<Big["2"]> | Func<Big["2"]>; }
->"2" : { common?: string; "2"?: number; ref?: Obj<Big["2"]> | Func<Big["2"]>; }
+>"2" : { common?: string | undefined; "2"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }
 >common : string | undefined
 >"2" : number | undefined
->ref : Obj<{ common?: string; "2"?: number; ref?: Obj<Big["2"]> | Func<Big["2"]>; }> | Func<{ common?: string; "2"?: number; ref?: Obj<Big["2"]> | Func<Big["2"]>; }> | undefined
+>ref : Obj<{ common?: string | undefined; "2"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }> | Func<{ common?: string | undefined; "2"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }> | undefined
 
     "3": { common?: string; "3"?: number, ref?: Obj<Big["3"]> | Func<Big["3"]>; }
->"3" : { common?: string; "3"?: number; ref?: Obj<Big["3"]> | Func<Big["3"]>; }
+>"3" : { common?: string | undefined; "3"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }
 >common : string | undefined
 >"3" : number | undefined
->ref : Obj<{ common?: string; "3"?: number; ref?: Obj<Big["3"]> | Func<Big["3"]>; }> | Func<{ common?: string; "3"?: number; ref?: Obj<Big["3"]> | Func<Big["3"]>; }> | undefined
+>ref : Obj<{ common?: string | undefined; "3"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }> | Func<{ common?: string | undefined; "3"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }> | undefined
 
     "4": { common?: string; "4"?: number, ref?: Obj<Big["4"]> | Func<Big["4"]>; }
->"4" : { common?: string; "4"?: number; ref?: Obj<Big["4"]> | Func<Big["4"]>; }
+>"4" : { common?: string | undefined; "4"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }
 >common : string | undefined
 >"4" : number | undefined
->ref : Obj<{ common?: string; "4"?: number; ref?: Obj<Big["4"]> | Func<Big["4"]>; }> | Func<{ common?: string; "4"?: number; ref?: Obj<Big["4"]> | Func<Big["4"]>; }> | undefined
+>ref : Obj<{ common?: string | undefined; "4"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }> | Func<{ common?: string | undefined; "4"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }> | undefined
 
     "5": { common?: string; "5"?: number, ref?: Obj<Big["5"]> | Func<Big["5"]>; }
->"5" : { common?: string; "5"?: number; ref?: Obj<Big["5"]> | Func<Big["5"]>; }
+>"5" : { common?: string | undefined; "5"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }
 >common : string | undefined
 >"5" : number | undefined
->ref : Obj<{ common?: string; "5"?: number; ref?: Obj<Big["5"]> | Func<Big["5"]>; }> | Func<{ common?: string; "5"?: number; ref?: Obj<Big["5"]> | Func<Big["5"]>; }> | undefined
+>ref : Obj<{ common?: string | undefined; "5"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }> | Func<{ common?: string | undefined; "5"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }> | undefined
 
     "6": { common?: string; "6"?: number, ref?: Obj<Big["6"]> | Func<Big["6"]>; }
->"6" : { common?: string; "6"?: number; ref?: Obj<Big["6"]> | Func<Big["6"]>; }
+>"6" : { common?: string | undefined; "6"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }
 >common : string | undefined
 >"6" : number | undefined
->ref : Obj<{ common?: string; "6"?: number; ref?: Obj<Big["6"]> | Func<Big["6"]>; }> | Func<{ common?: string; "6"?: number; ref?: Obj<Big["6"]> | Func<Big["6"]>; }> | undefined
+>ref : Obj<{ common?: string | undefined; "6"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }> | Func<{ common?: string | undefined; "6"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }> | undefined
 
     "7": { common?: string; "7"?: number, ref?: Obj<Big["7"]> | Func<Big["7"]>; }
->"7" : { common?: string; "7"?: number; ref?: Obj<Big["7"]> | Func<Big["7"]>; }
+>"7" : { common?: string | undefined; "7"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }
 >common : string | undefined
 >"7" : number | undefined
->ref : Obj<{ common?: string; "7"?: number; ref?: Obj<Big["7"]> | Func<Big["7"]>; }> | Func<{ common?: string; "7"?: number; ref?: Obj<Big["7"]> | Func<Big["7"]>; }> | undefined
+>ref : Obj<{ common?: string | undefined; "7"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }> | Func<{ common?: string | undefined; "7"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }> | undefined
 
     "8": { common?: string; "8"?: number, ref?: Obj<Big["8"]> | Func<Big["8"]>; }
->"8" : { common?: string; "8"?: number; ref?: Obj<Big["8"]> | Func<Big["8"]>; }
+>"8" : { common?: string | undefined; "8"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }
 >common : string | undefined
 >"8" : number | undefined
->ref : Obj<{ common?: string; "8"?: number; ref?: Obj<Big["8"]> | Func<Big["8"]>; }> | Func<{ common?: string; "8"?: number; ref?: Obj<Big["8"]> | Func<Big["8"]>; }> | undefined
+>ref : Obj<{ common?: string | undefined; "8"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }> | Func<{ common?: string | undefined; "8"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }> | undefined
 
     "9": { common?: string; "9"?: number, ref?: Obj<Big["9"]> | Func<Big["9"]>; }
->"9" : { common?: string; "9"?: number; ref?: Obj<Big["9"]> | Func<Big["9"]>; }
+>"9" : { common?: string | undefined; "9"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }
 >common : string | undefined
 >"9" : number | undefined
->ref : Obj<{ common?: string; "9"?: number; ref?: Obj<Big["9"]> | Func<Big["9"]>; }> | Func<{ common?: string; "9"?: number; ref?: Obj<Big["9"]> | Func<Big["9"]>; }> | undefined
+>ref : Obj<{ common?: string | undefined; "9"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }> | Func<{ common?: string | undefined; "9"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }> | undefined
 
     "10": { common?: string; "10"?: number, ref?: Obj<Big["10"]> | Func<Big["10"]>; }
->"10" : { common?: string; "10"?: number; ref?: Obj<Big["10"]> | Func<Big["10"]>; }
+>"10" : { common?: string | undefined; "10"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }
 >common : string | undefined
 >"10" : number | undefined
->ref : Obj<{ common?: string; "10"?: number; ref?: Obj<Big["10"]> | Func<Big["10"]>; }> | Func<{ common?: string; "10"?: number; ref?: Obj<Big["10"]> | Func<Big["10"]>; }> | undefined
+>ref : Obj<{ common?: string | undefined; "10"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }> | Func<{ common?: string | undefined; "10"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }> | undefined
 
     "11": { common?: string; "11"?: number, ref?: Obj<Big["11"]> | Func<Big["11"]>; }
->"11" : { common?: string; "11"?: number; ref?: Obj<Big["11"]> | Func<Big["11"]>; }
+>"11" : { common?: string | undefined; "11"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }
 >common : string | undefined
 >"11" : number | undefined
->ref : Obj<{ common?: string; "11"?: number; ref?: Obj<Big["11"]> | Func<Big["11"]>; }> | Func<{ common?: string; "11"?: number; ref?: Obj<Big["11"]> | Func<Big["11"]>; }> | undefined
+>ref : Obj<{ common?: string | undefined; "11"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }> | Func<{ common?: string | undefined; "11"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }> | undefined
 
     "12": { common?: string; "12"?: number, ref?: Obj<Big["12"]> | Func<Big["12"]>; }
->"12" : { common?: string; "12"?: number; ref?: Obj<Big["12"]> | Func<Big["12"]>; }
+>"12" : { common?: string | undefined; "12"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }
 >common : string | undefined
 >"12" : number | undefined
->ref : Obj<{ common?: string; "12"?: number; ref?: Obj<Big["12"]> | Func<Big["12"]>; }> | Func<{ common?: string; "12"?: number; ref?: Obj<Big["12"]> | Func<Big["12"]>; }> | undefined
+>ref : Obj<{ common?: string | undefined; "12"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }> | Func<{ common?: string | undefined; "12"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }> | undefined
 
     "13": { common?: string; "13"?: number, ref?: Obj<Big["13"]> | Func<Big["13"]>; }
->"13" : { common?: string; "13"?: number; ref?: Obj<Big["13"]> | Func<Big["13"]>; }
+>"13" : { common?: string | undefined; "13"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }
 >common : string | undefined
 >"13" : number | undefined
->ref : Obj<{ common?: string; "13"?: number; ref?: Obj<Big["13"]> | Func<Big["13"]>; }> | Func<{ common?: string; "13"?: number; ref?: Obj<Big["13"]> | Func<Big["13"]>; }> | undefined
+>ref : Obj<{ common?: string | undefined; "13"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }> | Func<{ common?: string | undefined; "13"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }> | undefined
 
     "14": { common?: string; "14"?: number, ref?: Obj<Big["14"]> | Func<Big["14"]>; }
->"14" : { common?: string; "14"?: number; ref?: Obj<Big["14"]> | Func<Big["14"]>; }
+>"14" : { common?: string | undefined; "14"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }
 >common : string | undefined
 >"14" : number | undefined
->ref : Obj<{ common?: string; "14"?: number; ref?: Obj<Big["14"]> | Func<Big["14"]>; }> | Func<{ common?: string; "14"?: number; ref?: Obj<Big["14"]> | Func<Big["14"]>; }> | undefined
+>ref : Obj<{ common?: string | undefined; "14"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }> | Func<{ common?: string | undefined; "14"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }> | undefined
 
     "15": { common?: string; "15"?: number, ref?: Obj<Big["15"]> | Func<Big["15"]>; }
->"15" : { common?: string; "15"?: number; ref?: Obj<Big["15"]> | Func<Big["15"]>; }
+>"15" : { common?: string | undefined; "15"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }
 >common : string | undefined
 >"15" : number | undefined
->ref : Obj<{ common?: string; "15"?: number; ref?: Obj<Big["15"]> | Func<Big["15"]>; }> | Func<{ common?: string; "15"?: number; ref?: Obj<Big["15"]> | Func<Big["15"]>; }> | undefined
+>ref : Obj<{ common?: string | undefined; "15"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }> | Func<{ common?: string | undefined; "15"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }> | undefined
 
     "16": { common?: string; "16"?: number, ref?: Obj<Big["16"]> | Func<Big["16"]>; }
->"16" : { common?: string; "16"?: number; ref?: Obj<Big["16"]> | Func<Big["16"]>; }
+>"16" : { common?: string | undefined; "16"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }
 >common : string | undefined
 >"16" : number | undefined
->ref : Obj<{ common?: string; "16"?: number; ref?: Obj<Big["16"]> | Func<Big["16"]>; }> | Func<{ common?: string; "16"?: number; ref?: Obj<Big["16"]> | Func<Big["16"]>; }> | undefined
+>ref : Obj<{ common?: string | undefined; "16"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }> | Func<{ common?: string | undefined; "16"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }> | undefined
 
     "17": { common?: string; "17"?: number, ref?: Obj<Big["17"]> | Func<Big["17"]>; }
->"17" : { common?: string; "17"?: number; ref?: Obj<Big["17"]> | Func<Big["17"]>; }
+>"17" : { common?: string | undefined; "17"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }
 >common : string | undefined
 >"17" : number | undefined
->ref : Obj<{ common?: string; "17"?: number; ref?: Obj<Big["17"]> | Func<Big["17"]>; }> | Func<{ common?: string; "17"?: number; ref?: Obj<Big["17"]> | Func<Big["17"]>; }> | undefined
+>ref : Obj<{ common?: string | undefined; "17"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }> | Func<{ common?: string | undefined; "17"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }> | undefined
 }
 declare function getCtor<T extends keyof Big>(comp: T): CtorOf<Big[T]>
 >getCtor : <T extends keyof Big>(comp: T) => CtorOf<Big[T]>
@@ -135,15 +135,15 @@ declare var all: keyof Big;
 >all : keyof Big
 
 const ctor = getCtor(all);
->ctor : CtorOf<{ common?: string; "0"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "1"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "2"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "3"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "4"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "5"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "6"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "7"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "8"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "9"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "10"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "11"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "12"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "13"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "14"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "15"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "16"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "17"?: number; ref?: Obj<any> | Func<any>; }>
->getCtor(all) : CtorOf<{ common?: string; "0"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "1"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "2"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "3"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "4"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "5"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "6"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "7"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "8"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "9"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "10"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "11"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "12"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "13"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "14"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "15"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "16"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "17"?: number; ref?: Obj<any> | Func<any>; }>
+>ctor : CtorOf<{ common?: string | undefined; "0"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "1"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "2"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "3"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "4"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "5"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "6"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "7"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "8"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "9"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "10"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "11"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "12"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "13"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "14"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "15"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "16"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "17"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }>
+>getCtor(all) : CtorOf<{ common?: string | undefined; "0"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "1"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "2"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "3"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "4"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "5"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "6"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "7"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "8"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "9"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "10"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "11"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "12"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "13"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "14"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "15"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "16"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "17"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }>
 >getCtor : <T extends keyof Big>(comp: T) => CtorOf<Big[T]>
 >all : keyof Big
 
 const comp = ctor({ common: "ok", ref: x => console.log(x) });
->comp : { common?: string; "0"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "1"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "2"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "3"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "4"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "5"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "6"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "7"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "8"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "9"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "10"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "11"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "12"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "13"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "14"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "15"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "16"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "17"?: number; ref?: Obj<any> | Func<any>; }
->ctor({ common: "ok", ref: x => console.log(x) }) : { common?: string; "0"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "1"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "2"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "3"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "4"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "5"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "6"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "7"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "8"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "9"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "10"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "11"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "12"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "13"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "14"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "15"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "16"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "17"?: number; ref?: Obj<any> | Func<any>; }
->ctor : CtorOf<{ common?: string; "0"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "1"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "2"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "3"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "4"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "5"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "6"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "7"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "8"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "9"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "10"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "11"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "12"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "13"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "14"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "15"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "16"?: number; ref?: Obj<any> | Func<any>; } | { common?: string; "17"?: number; ref?: Obj<any> | Func<any>; }>
+>comp : { common?: string | undefined; "0"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "1"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "2"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "3"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "4"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "5"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "6"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "7"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "8"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "9"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "10"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "11"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "12"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "13"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "14"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "15"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "16"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "17"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }
+>ctor({ common: "ok", ref: x => console.log(x) }) : { common?: string | undefined; "0"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "1"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "2"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "3"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "4"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "5"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "6"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "7"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "8"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "9"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "10"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "11"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "12"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "13"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "14"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "15"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "16"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "17"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }
+>ctor : CtorOf<{ common?: string | undefined; "0"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "1"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "2"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "3"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "4"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "5"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "6"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "7"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "8"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "9"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "10"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "11"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "12"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "13"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "14"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "15"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "16"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; } | { common?: string | undefined; "17"?: number | undefined; ref?: Obj<any> | Func<any> | undefined; }>
 >{ common: "ok", ref: x => console.log(x) } : { common: string; ref: (x: any) => void; }
 >common : string
 >"ok" : "ok"

tests/baselines/reference/numericEnumMappedType.types

@@ -41,14 +41,14 @@ const e2: E2 = E2.ONE;
 
 b1[1] = "a";
 >b1[1] = "a" : "a"
->b1[1] : string
+>b1[1] : string | undefined
 >b1 : Bins1
 >1 : 1
 >"a" : "a"
 
 b1[e1] = "b";
 >b1[e1] = "b" : "b"
->b1[e1] : string
+>b1[e1] : string | undefined
 >b1 : Bins1
 >e1 : E1.ONE
 >"b" : "b"

tests/baselines/reference/objectLiteralNormalization.errors.txt

@@ -1,13 +1,13 @@
-tests/cases/conformance/expressions/objectLiterals/objectLiteralNormalization.ts(7,14): error TS2322: Type 'number' is not assignable to type 'string'.
-tests/cases/conformance/expressions/objectLiterals/objectLiteralNormalization.ts(8,1): error TS2322: Type '{ b: string; }' is not assignable to type '{ a: number; b?: never; c?: never; } | { a: number; b: string; c?: never; } | { a: number; b: string; c: boolean; }'.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralNormalization.ts(7,14): error TS2322: Type 'number' is not assignable to type 'string | undefined'.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralNormalization.ts(8,1): error TS2322: Type '{ b: string; }' is not assignable to type '{ a: number; b?: undefined; c?: undefined; } | { a: number; b: string; c?: undefined; } | { a: number; b: string; c: boolean; }'.
   Type '{ b: string; }' is missing the following properties from type '{ a: number; b: string; c: boolean; }': a, c
-tests/cases/conformance/expressions/objectLiterals/objectLiteralNormalization.ts(9,1): error TS2322: Type '{ c: true; }' is not assignable to type '{ a: number; b?: never; c?: never; } | { a: number; b: string; c?: never; } | { a: number; b: string; c: boolean; }'.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralNormalization.ts(9,1): error TS2322: Type '{ c: true; }' is not assignable to type '{ a: number; b?: undefined; c?: undefined; } | { a: number; b: string; c?: undefined; } | { a: number; b: string; c: boolean; }'.
   Type '{ c: true; }' is missing the following properties from type '{ a: number; b: string; c: boolean; }': a, b
-tests/cases/conformance/expressions/objectLiterals/objectLiteralNormalization.ts(17,1): error TS2322: Type '{ a: string; b: number; }' is not assignable to type '{ a: number; b: number; } | { a: string; b?: never; } | { a?: never; b?: never; }'.
-  Type '{ a: string; b: number; }' is not assignable to type '{ a?: never; b?: never; }'.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralNormalization.ts(17,1): error TS2322: Type '{ a: string; b: number; }' is not assignable to type '{ a: number; b: number; } | { a: string; b?: undefined; } | { a?: undefined; b?: undefined; }'.
+  Type '{ a: string; b: number; }' is not assignable to type '{ a?: undefined; b?: undefined; }'.
     Types of property 'a' are incompatible.
-      Type 'string' is not assignable to type 'never'.
-tests/cases/conformance/expressions/objectLiterals/objectLiteralNormalization.ts(18,1): error TS2322: Type '{ a: number; }' is not assignable to type '{ a: number; b: number; } | { a: string; b?: never; } | { a?: never; b?: never; }'.
+      Type 'string' is not assignable to type 'undefined'.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralNormalization.ts(18,1): error TS2322: Type '{ a: number; }' is not assignable to type '{ a: number; b: number; } | { a: string; b?: undefined; } | { a?: undefined; b?: undefined; }'.
   Property 'b' is missing in type '{ a: number; }' but required in type '{ a: number; b: number; }'.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralNormalization.ts(48,20): error TS2322: Type '2' is not assignable to type '1'.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralNormalization.ts(49,14): error TS2322: Type '2' is not assignable to type '1'.
@@ -22,15 +22,15 @@ tests/cases/conformance/expressions/objectLiterals/objectLiteralNormalization.ts
     a1 = { a: 1 };
     a1 = { a: 0, b: 0 };  // Error
                  ~
-!!! error TS2322: Type 'number' is not assignable to type 'string'.
-!!! related TS6500 tests/cases/conformance/expressions/objectLiterals/objectLiteralNormalization.ts:2:47: The expected type comes from property 'b' which is declared here on type '{ a: number; b?: never; c?: never; } | { a: number; b: string; c?: never; } | { a: number; b: string; c: boolean; }'
+!!! error TS2322: Type 'number' is not assignable to type 'string | undefined'.
+!!! related TS6500 tests/cases/conformance/expressions/objectLiterals/objectLiteralNormalization.ts:2:47: The expected type comes from property 'b' which is declared here on type '{ a: number; b?: undefined; c?: undefined; } | { a: number; b: string; c?: undefined; } | { a: number; b: string; c: boolean; }'
     a1 = { b: "y" };  // Error
     ~~
-!!! error TS2322: Type '{ b: string; }' is not assignable to type '{ a: number; b?: never; c?: never; } | { a: number; b: string; c?: never; } | { a: number; b: string; c: boolean; }'.
+!!! error TS2322: Type '{ b: string; }' is not assignable to type '{ a: number; b?: undefined; c?: undefined; } | { a: number; b: string; c?: undefined; } | { a: number; b: string; c: boolean; }'.
 !!! error TS2322:   Type '{ b: string; }' is missing the following properties from type '{ a: number; b: string; c: boolean; }': a, c
     a1 = { c: true };  // Error
     ~~
-!!! error TS2322: Type '{ c: true; }' is not assignable to type '{ a: number; b?: never; c?: never; } | { a: number; b: string; c?: never; } | { a: number; b: string; c: boolean; }'.
+!!! error TS2322: Type '{ c: true; }' is not assignable to type '{ a: number; b?: undefined; c?: undefined; } | { a: number; b: string; c?: undefined; } | { a: number; b: string; c: boolean; }'.
 !!! error TS2322:   Type '{ c: true; }' is missing the following properties from type '{ a: number; b: string; c: boolean; }': a, b
     
     let a2 = [{ a: 1, b: 2 }, { a: "abc" }, {}][0];
@@ -41,13 +41,13 @@ tests/cases/conformance/expressions/objectLiterals/objectLiteralNormalization.ts
     a2 = {};
     a2 = { a: "def", b: 20 };  // Error
     ~~
-!!! error TS2322: Type '{ a: string; b: number; }' is not assignable to type '{ a: number; b: number; } | { a: string; b?: never; } | { a?: never; b?: never; }'.
-!!! error TS2322:   Type '{ a: string; b: number; }' is not assignable to type '{ a?: never; b?: never; }'.
+!!! error TS2322: Type '{ a: string; b: number; }' is not assignable to type '{ a: number; b: number; } | { a: string; b?: undefined; } | { a?: undefined; b?: undefined; }'.
+!!! error TS2322:   Type '{ a: string; b: number; }' is not assignable to type '{ a?: undefined; b?: undefined; }'.
 !!! error TS2322:     Types of property 'a' are incompatible.
-!!! error TS2322:       Type 'string' is not assignable to type 'never'.
+!!! error TS2322:       Type 'string' is not assignable to type 'undefined'.
     a2 = { a: 1 };  // Error
     ~~
-!!! error TS2322: Type '{ a: number; }' is not assignable to type '{ a: number; b: number; } | { a: string; b?: never; } | { a?: never; b?: never; }'.
+!!! error TS2322: Type '{ a: number; }' is not assignable to type '{ a: number; b: number; } | { a: string; b?: undefined; } | { a?: undefined; b?: undefined; }'.
 !!! error TS2322:   Property 'b' is missing in type '{ a: number; }' but required in type '{ a: number; b: number; }'.
 !!! related TS2728 tests/cases/conformance/expressions/objectLiterals/objectLiteralNormalization.ts:11:19: 'b' is declared here.
     

tests/baselines/reference/objectLiteralNormalization.js

@@ -104,12 +104,12 @@ var e4 = f({ a: 2 }, data);
 //// [objectLiteralNormalization.d.ts]
 declare let a1: {
     a: number;
-    b?: never;
-    c?: never;
+    b?: undefined;
+    c?: undefined;
 } | {
     a: number;
     b: string;
-    c?: never;
+    c?: undefined;
 } | {
     a: number;
     b: string;
@@ -120,10 +120,10 @@ declare let a2: {
     b: number;
 } | {
     a: string;
-    b?: never;
+    b?: undefined;
 } | {
-    a?: never;
-    b?: never;
+    a?: undefined;
+    b?: undefined;
 };
 declare let b1: {
     a: string;
@@ -156,25 +156,25 @@ declare let opts: {
     baz?: boolean;
 };
 declare let c1: {
-    foo?: string;
-    bar?: string;
-    baz?: boolean;
+    foo?: string | undefined;
+    bar?: string | undefined;
+    baz?: boolean | undefined;
 };
 declare let c2: {
-    foo?: string;
-    bar?: string;
-    baz?: boolean;
+    foo?: string | undefined;
+    bar?: string | undefined;
+    baz?: boolean | undefined;
 };
 declare let c3: {
     a: number;
     b: number;
 } | {
-    a?: never;
-    b?: never;
+    a?: undefined;
+    b?: undefined;
 };
 declare let c4: {
-    a?: never;
-    b?: never;
+    a?: undefined;
+    b?: undefined;
 } | {
     a: number;
     b: number;
@@ -184,21 +184,21 @@ declare let d1: {
     pos: {
         x: number;
         y: number;
-        a?: never;
-        b?: never;
+        a?: undefined;
+        b?: undefined;
     };
 } | {
     kind: string;
     pos: {
         a: string;
-        x?: never;
-        y?: never;
-        b?: never;
+        x?: undefined;
+        y?: undefined;
+        b?: undefined;
     } | {
         b: number;
-        x?: never;
-        y?: never;
-        a?: never;
+        x?: undefined;
+        y?: undefined;
+        a?: undefined;
     };
 };
 declare function f<T>(...items: T[]): T;
@@ -212,17 +212,17 @@ declare let e1: {
     b: number;
 } | {
     a: string;
-    b?: never;
+    b?: undefined;
 } | {
-    a?: never;
-    b?: never;
+    a?: undefined;
+    b?: undefined;
 };
 declare let e2: {
-    a?: never;
-    b?: never;
+    a?: undefined;
+    b?: undefined;
 } | {
     a: string;
-    b?: never;
+    b?: undefined;
 } | {
     a: number;
     b: number;

tests/baselines/reference/objectLiteralNormalization.types

@@ -1,7 +1,7 @@
 === tests/cases/conformance/expressions/objectLiterals/objectLiteralNormalization.ts ===
 // Object literals in unions are normalized upon widening
 let a1 = [{ a: 0 }, { a: 1, b: "x" }, { a: 2, b: "y", c: true }][0];
->a1 : { a: number; b?: never; c?: never; } | { a: number; b: string; c?: never; } | { a: number; b: string; c: boolean; }
+>a1 : { a: number; b?: undefined; c?: undefined; } | { a: number; b: string; c?: undefined; } | { a: number; b: string; c: boolean; }
 >[{ a: 0 }, { a: 1, b: "x" }, { a: 2, b: "y", c: true }][0] : { a: number; } | { a: number; b: string; } | { a: number; b: string; c: boolean; }
 >[{ a: 0 }, { a: 1, b: "x" }, { a: 2, b: "y", c: true }] : ({ a: number; } | { a: number; b: string; } | { a: number; b: string; c: boolean; })[]
 >{ a: 0 } : { a: number; }
@@ -23,29 +23,29 @@ let a1 = [{ a: 0 }, { a: 1, b: "x" }, { a: 2, b: "y", c: true }][0];
 
 a1.a;  // number
 >a1.a : number
->a1 : { a: number; b?: never; c?: never; } | { a: number; b: string; c?: never; } | { a: number; b: string; c: boolean; }
+>a1 : { a: number; b?: undefined; c?: undefined; } | { a: number; b: string; c?: undefined; } | { a: number; b: string; c: boolean; }
 >a : number
 
 a1.b;  // string | undefined
 >a1.b : string | undefined
->a1 : { a: number; b?: never; c?: never; } | { a: number; b: string; c?: never; } | { a: number; b: string; c: boolean; }
+>a1 : { a: number; b?: undefined; c?: undefined; } | { a: number; b: string; c?: undefined; } | { a: number; b: string; c: boolean; }
 >b : string | undefined
 
 a1.c;  // boolean | undefined
 >a1.c : boolean | undefined
->a1 : { a: number; b?: never; c?: never; } | { a: number; b: string; c?: never; } | { a: number; b: string; c: boolean; }
+>a1 : { a: number; b?: undefined; c?: undefined; } | { a: number; b: string; c?: undefined; } | { a: number; b: string; c: boolean; }
 >c : boolean | undefined
 
 a1 = { a: 1 };
 >a1 = { a: 1 } : { a: number; }
->a1 : { a: number; b?: never; c?: never; } | { a: number; b: string; c?: never; } | { a: number; b: string; c: boolean; }
+>a1 : { a: number; b?: undefined; c?: undefined; } | { a: number; b: string; c?: undefined; } | { a: number; b: string; c: boolean; }
 >{ a: 1 } : { a: number; }
 >a : number
 >1 : 1
 
 a1 = { a: 0, b: 0 };  // Error
 >a1 = { a: 0, b: 0 } : { a: number; b: number; }
->a1 : { a: number; b?: never; c?: never; } | { a: number; b: string; c?: never; } | { a: number; b: string; c: boolean; }
+>a1 : { a: number; b?: undefined; c?: undefined; } | { a: number; b: string; c?: undefined; } | { a: number; b: string; c: boolean; }
 >{ a: 0, b: 0 } : { a: number; b: number; }
 >a : number
 >0 : 0
@@ -54,20 +54,20 @@ a1 = { a: 0, b: 0 };  // Error
 
 a1 = { b: "y" };  // Error
 >a1 = { b: "y" } : { b: string; }
->a1 : { a: number; b?: never; c?: never; } | { a: number; b: string; c?: never; } | { a: number; b: string; c: boolean; }
+>a1 : { a: number; b?: undefined; c?: undefined; } | { a: number; b: string; c?: undefined; } | { a: number; b: string; c: boolean; }
 >{ b: "y" } : { b: string; }
 >b : string
 >"y" : "y"
 
 a1 = { c: true };  // Error
 >a1 = { c: true } : { c: true; }
->a1 : { a: number; b?: never; c?: never; } | { a: number; b: string; c?: never; } | { a: number; b: string; c: boolean; }
+>a1 : { a: number; b?: undefined; c?: undefined; } | { a: number; b: string; c?: undefined; } | { a: number; b: string; c: boolean; }
 >{ c: true } : { c: true; }
 >c : true
 >true : true
 
 let a2 = [{ a: 1, b: 2 }, { a: "abc" }, {}][0];
->a2 : { a: number; b: number; } | { a: string; b?: never; } | { a?: never; b?: never; }
+>a2 : { a: number; b: number; } | { a: string; b?: undefined; } | { a?: undefined; b?: undefined; }
 >[{ a: 1, b: 2 }, { a: "abc" }, {}][0] : { a: number; b: number; } | { a: string; } | {}
 >[{ a: 1, b: 2 }, { a: "abc" }, {}] : ({ a: number; b: number; } | { a: string; } | {})[]
 >{ a: 1, b: 2 } : { a: number; b: number; }
@@ -83,17 +83,17 @@ let a2 = [{ a: 1, b: 2 }, { a: "abc" }, {}][0];
 
 a2.a;  // string | number | undefined
 >a2.a : string | number | undefined
->a2 : { a: number; b: number; } | { a: string; b?: never; } | { a?: never; b?: never; }
+>a2 : { a: number; b: number; } | { a: string; b?: undefined; } | { a?: undefined; b?: undefined; }
 >a : string | number | undefined
 
 a2.b;  // number | undefined
 >a2.b : number | undefined
->a2 : { a: number; b: number; } | { a: string; b?: never; } | { a?: never; b?: never; }
+>a2 : { a: number; b: number; } | { a: string; b?: undefined; } | { a?: undefined; b?: undefined; }
 >b : number | undefined
 
 a2 = { a: 10, b: 20 };
 >a2 = { a: 10, b: 20 } : { a: number; b: number; }
->a2 : { a: number; b: number; } | { a: string; b?: never; } | { a?: never; b?: never; }
+>a2 : { a: number; b: number; } | { a: string; b?: undefined; } | { a?: undefined; b?: undefined; }
 >{ a: 10, b: 20 } : { a: number; b: number; }
 >a : number
 >10 : 10
@@ -102,19 +102,19 @@ a2 = { a: 10, b: 20 };
 
 a2 = { a: "def" };
 >a2 = { a: "def" } : { a: string; }
->a2 : { a: number; b: number; } | { a: string; b?: never; } | { a?: never; b?: never; }
+>a2 : { a: number; b: number; } | { a: string; b?: undefined; } | { a?: undefined; b?: undefined; }
 >{ a: "def" } : { a: string; }
 >a : string
 >"def" : "def"
 
 a2 = {};
 >a2 = {} : {}
->a2 : { a: number; b: number; } | { a: string; b?: never; } | { a?: never; b?: never; }
+>a2 : { a: number; b: number; } | { a: string; b?: undefined; } | { a?: undefined; b?: undefined; }
 >{} : {}
 
 a2 = { a: "def", b: 20 };  // Error
 >a2 = { a: "def", b: 20 } : { a: string; b: number; }
->a2 : { a: number; b: number; } | { a: string; b?: never; } | { a?: never; b?: never; }
+>a2 : { a: number; b: number; } | { a: string; b?: undefined; } | { a?: undefined; b?: undefined; }
 >{ a: "def", b: 20 } : { a: string; b: number; }
 >a : string
 >"def" : "def"
@@ -123,7 +123,7 @@ a2 = { a: "def", b: 20 };  // Error
 
 a2 = { a: 1 };  // Error
 >a2 = { a: 1 } : { a: number; }
->a2 : { a: number; b: number; } | { a: string; b?: never; } | { a?: never; b?: never; }
+>a2 : { a: number; b: number; } | { a: string; b?: undefined; } | { a?: undefined; b?: undefined; }
 >{ a: 1 } : { a: number; }
 >a : number
 >1 : 1
@@ -151,29 +151,29 @@ let b3 = { ...b2 };
 // Before widening {} acts like { [x: string]: undefined }, which is a
 // subtype of types with all optional properties
 declare let opts: { foo?: string, bar?: string, baz?: boolean };
->opts : { foo?: string; bar?: string; baz?: boolean; }
+>opts : { foo?: string | undefined; bar?: string | undefined; baz?: boolean | undefined; }
 >foo : string | undefined
 >bar : string | undefined
 >baz : boolean | undefined
 
 let c1 = !true ? {} : opts;
->c1 : { foo?: string; bar?: string; baz?: boolean; }
->!true ? {} : opts : { foo?: string; bar?: string; baz?: boolean; }
+>c1 : { foo?: string | undefined; bar?: string | undefined; baz?: boolean | undefined; }
+>!true ? {} : opts : { foo?: string | undefined; bar?: string | undefined; baz?: boolean | undefined; }
 >!true : false
 >true : true
 >{} : {}
->opts : { foo?: string; bar?: string; baz?: boolean; }
+>opts : { foo?: string | undefined; bar?: string | undefined; baz?: boolean | undefined; }
 
 let c2 = !true ? opts : {};
->c2 : { foo?: string; bar?: string; baz?: boolean; }
->!true ? opts : {} : { foo?: string; bar?: string; baz?: boolean; }
+>c2 : { foo?: string | undefined; bar?: string | undefined; baz?: boolean | undefined; }
+>!true ? opts : {} : { foo?: string | undefined; bar?: string | undefined; baz?: boolean | undefined; }
 >!true : false
 >true : true
->opts : { foo?: string; bar?: string; baz?: boolean; }
+>opts : { foo?: string | undefined; bar?: string | undefined; baz?: boolean | undefined; }
 >{} : {}
 
 let c3 = !true ? { a: 0, b: 0 } : {};
->c3 : { a: number; b: number; } | { a?: never; b?: never; }
+>c3 : { a: number; b: number; } | { a?: undefined; b?: undefined; }
 >!true ? { a: 0, b: 0 } : {} : { a: number; b: number; } | {}
 >!true : false
 >true : true
@@ -185,7 +185,7 @@ let c3 = !true ? { a: 0, b: 0 } : {};
 >{} : {}
 
 let c4 = !true ? {} : { a: 0, b: 0 };
->c4 : { a?: never; b?: never; } | { a: number; b: number; }
+>c4 : { a?: undefined; b?: undefined; } | { a: number; b: number; }
 >!true ? {} : { a: 0, b: 0 } : {} | { a: number; b: number; }
 >!true : false
 >true : true
@@ -198,7 +198,7 @@ let c4 = !true ? {} : { a: 0, b: 0 };
 
 // Normalization applies to nested properties
 let d1 = [{ kind: 'a', pos: { x: 0, y: 0 } }, { kind: 'b', pos: !true ? { a: "x" } : { b: 0 } }][0];
->d1 : { kind: string; pos: { x: number; y: number; a?: never; b?: never; }; } | { kind: string; pos: { a: string; x?: never; y?: never; b?: never; } | { b: number; x?: never; y?: never; a?: never; }; }
+>d1 : { kind: string; pos: { x: number; y: number; a?: undefined; b?: undefined; }; } | { kind: string; pos: { a: string; x?: undefined; y?: undefined; b?: undefined; } | { b: number; x?: undefined; y?: undefined; a?: undefined; }; }
 >[{ kind: 'a', pos: { x: 0, y: 0 } }, { kind: 'b', pos: !true ? { a: "x" } : { b: 0 } }][0] : { kind: string; pos: { x: number; y: number; }; } | { kind: string; pos: { a: string; } | { b: number; }; }
 >[{ kind: 'a', pos: { x: 0, y: 0 } }, { kind: 'b', pos: !true ? { a: "x" } : { b: 0 } }] : ({ kind: string; pos: { x: number; y: number; }; } | { kind: string; pos: { a: string; } | { b: number; }; })[]
 >{ kind: 'a', pos: { x: 0, y: 0 } } : { kind: string; pos: { x: number; y: number; }; }
@@ -227,40 +227,40 @@ let d1 = [{ kind: 'a', pos: { x: 0, y: 0 } }, { kind: 'b', pos: !true ? { a: "x"
 
 d1.kind;
 >d1.kind : string
->d1 : { kind: string; pos: { x: number; y: number; a?: never; b?: never; }; } | { kind: string; pos: { a: string; x?: never; y?: never; b?: never; } | { b: number; x?: never; y?: never; a?: never; }; }
+>d1 : { kind: string; pos: { x: number; y: number; a?: undefined; b?: undefined; }; } | { kind: string; pos: { a: string; x?: undefined; y?: undefined; b?: undefined; } | { b: number; x?: undefined; y?: undefined; a?: undefined; }; }
 >kind : string
 
 d1.pos;
->d1.pos : { x: number; y: number; a?: never; b?: never; } | { a: string; x?: never; y?: never; b?: never; } | { b: number; x?: never; y?: never; a?: never; }
->d1 : { kind: string; pos: { x: number; y: number; a?: never; b?: never; }; } | { kind: string; pos: { a: string; x?: never; y?: never; b?: never; } | { b: number; x?: never; y?: never; a?: never; }; }
->pos : { x: number; y: number; a?: never; b?: never; } | { a: string; x?: never; y?: never; b?: never; } | { b: number; x?: never; y?: never; a?: never; }
+>d1.pos : { x: number; y: number; a?: undefined; b?: undefined; } | { a: string; x?: undefined; y?: undefined; b?: undefined; } | { b: number; x?: undefined; y?: undefined; a?: undefined; }
+>d1 : { kind: string; pos: { x: number; y: number; a?: undefined; b?: undefined; }; } | { kind: string; pos: { a: string; x?: undefined; y?: undefined; b?: undefined; } | { b: number; x?: undefined; y?: undefined; a?: undefined; }; }
+>pos : { x: number; y: number; a?: undefined; b?: undefined; } | { a: string; x?: undefined; y?: undefined; b?: undefined; } | { b: number; x?: undefined; y?: undefined; a?: undefined; }
 
 d1.pos.x;
 >d1.pos.x : number | undefined
->d1.pos : { x: number; y: number; a?: never; b?: never; } | { a: string; x?: never; y?: never; b?: never; } | { b: number; x?: never; y?: never; a?: never; }
->d1 : { kind: string; pos: { x: number; y: number; a?: never; b?: never; }; } | { kind: string; pos: { a: string; x?: never; y?: never; b?: never; } | { b: number; x?: never; y?: never; a?: never; }; }
->pos : { x: number; y: number; a?: never; b?: never; } | { a: string; x?: never; y?: never; b?: never; } | { b: number; x?: never; y?: never; a?: never; }
+>d1.pos : { x: number; y: number; a?: undefined; b?: undefined; } | { a: string; x?: undefined; y?: undefined; b?: undefined; } | { b: number; x?: undefined; y?: undefined; a?: undefined; }
+>d1 : { kind: string; pos: { x: number; y: number; a?: undefined; b?: undefined; }; } | { kind: string; pos: { a: string; x?: undefined; y?: undefined; b?: undefined; } | { b: number; x?: undefined; y?: undefined; a?: undefined; }; }
+>pos : { x: number; y: number; a?: undefined; b?: undefined; } | { a: string; x?: undefined; y?: undefined; b?: undefined; } | { b: number; x?: undefined; y?: undefined; a?: undefined; }
 >x : number | undefined
 
 d1.pos.y;
 >d1.pos.y : number | undefined
->d1.pos : { x: number; y: number; a?: never; b?: never; } | { a: string; x?: never; y?: never; b?: never; } | { b: number; x?: never; y?: never; a?: never; }
->d1 : { kind: string; pos: { x: number; y: number; a?: never; b?: never; }; } | { kind: string; pos: { a: string; x?: never; y?: never; b?: never; } | { b: number; x?: never; y?: never; a?: never; }; }
->pos : { x: number; y: number; a?: never; b?: never; } | { a: string; x?: never; y?: never; b?: never; } | { b: number; x?: never; y?: never; a?: never; }
+>d1.pos : { x: number; y: number; a?: undefined; b?: undefined; } | { a: string; x?: undefined; y?: undefined; b?: undefined; } | { b: number; x?: undefined; y?: undefined; a?: undefined; }
+>d1 : { kind: string; pos: { x: number; y: number; a?: undefined; b?: undefined; }; } | { kind: string; pos: { a: string; x?: undefined; y?: undefined; b?: undefined; } | { b: number; x?: undefined; y?: undefined; a?: undefined; }; }
+>pos : { x: number; y: number; a?: undefined; b?: undefined; } | { a: string; x?: undefined; y?: undefined; b?: undefined; } | { b: number; x?: undefined; y?: undefined; a?: undefined; }
 >y : number | undefined
 
 d1.pos.a;
 >d1.pos.a : string | undefined
->d1.pos : { x: number; y: number; a?: never; b?: never; } | { a: string; x?: never; y?: never; b?: never; } | { b: number; x?: never; y?: never; a?: never; }
->d1 : { kind: string; pos: { x: number; y: number; a?: never; b?: never; }; } | { kind: string; pos: { a: string; x?: never; y?: never; b?: never; } | { b: number; x?: never; y?: never; a?: never; }; }
->pos : { x: number; y: number; a?: never; b?: never; } | { a: string; x?: never; y?: never; b?: never; } | { b: number; x?: never; y?: never; a?: never; }
+>d1.pos : { x: number; y: number; a?: undefined; b?: undefined; } | { a: string; x?: undefined; y?: undefined; b?: undefined; } | { b: number; x?: undefined; y?: undefined; a?: undefined; }
+>d1 : { kind: string; pos: { x: number; y: number; a?: undefined; b?: undefined; }; } | { kind: string; pos: { a: string; x?: undefined; y?: undefined; b?: undefined; } | { b: number; x?: undefined; y?: undefined; a?: undefined; }; }
+>pos : { x: number; y: number; a?: undefined; b?: undefined; } | { a: string; x?: undefined; y?: undefined; b?: undefined; } | { b: number; x?: undefined; y?: undefined; a?: undefined; }
 >a : string | undefined
 
 d1.pos.b;
 >d1.pos.b : number | undefined
->d1.pos : { x: number; y: number; a?: never; b?: never; } | { a: string; x?: never; y?: never; b?: never; } | { b: number; x?: never; y?: never; a?: never; }
->d1 : { kind: string; pos: { x: number; y: number; a?: never; b?: never; }; } | { kind: string; pos: { a: string; x?: never; y?: never; b?: never; } | { b: number; x?: never; y?: never; a?: never; }; }
->pos : { x: number; y: number; a?: never; b?: never; } | { a: string; x?: never; y?: never; b?: never; } | { b: number; x?: never; y?: never; a?: never; }
+>d1.pos : { x: number; y: number; a?: undefined; b?: undefined; } | { a: string; x?: undefined; y?: undefined; b?: undefined; } | { b: number; x?: undefined; y?: undefined; a?: undefined; }
+>d1 : { kind: string; pos: { x: number; y: number; a?: undefined; b?: undefined; }; } | { kind: string; pos: { a: string; x?: undefined; y?: undefined; b?: undefined; } | { b: number; x?: undefined; y?: undefined; a?: undefined; }; }
+>pos : { x: number; y: number; a?: undefined; b?: undefined; } | { a: string; x?: undefined; y?: undefined; b?: undefined; } | { b: number; x?: undefined; y?: undefined; a?: undefined; }
 >b : number | undefined
 
 declare function f<T>(...items: T[]): T;
@@ -276,8 +276,8 @@ declare let data: { a: 1, b: "abc", c: true };
 
 // Object literals are inferred as a single normalized union type
 let e1 = f({ a: 1, b: 2 }, { a: "abc" }, {});
->e1 : { a: number; b: number; } | { a: string; b?: never; } | { a?: never; b?: never; }
->f({ a: 1, b: 2 }, { a: "abc" }, {}) : { a: number; b: number; } | { a: string; b?: never; } | { a?: never; b?: never; }
+>e1 : { a: number; b: number; } | { a: string; b?: undefined; } | { a?: undefined; b?: undefined; }
+>f({ a: 1, b: 2 }, { a: "abc" }, {}) : { a: number; b: number; } | { a: string; b?: undefined; } | { a?: undefined; b?: undefined; }
 >f : <T>(...items: T[]) => T
 >{ a: 1, b: 2 } : { a: number; b: number; }
 >a : number
@@ -290,8 +290,8 @@ let e1 = f({ a: 1, b: 2 }, { a: "abc" }, {});
 >{} : {}
 
 let e2 = f({}, { a: "abc" }, { a: 1, b: 2 });
->e2 : { a?: never; b?: never; } | { a: string; b?: never; } | { a: number; b: number; }
->f({}, { a: "abc" }, { a: 1, b: 2 }) : { a?: never; b?: never; } | { a: string; b?: never; } | { a: number; b: number; }
+>e2 : { a?: undefined; b?: undefined; } | { a: string; b?: undefined; } | { a: number; b: number; }
+>f({}, { a: "abc" }, { a: 1, b: 2 }) : { a?: undefined; b?: undefined; } | { a: string; b?: undefined; } | { a: number; b: number; }
 >f : <T>(...items: T[]) => T
 >{} : {}
 >{ a: "abc" } : { a: string; }

tests/baselines/reference/objectSpreadRepeatedComplexity.types

@@ -1,11 +1,11 @@
 === tests/cases/conformance/types/spread/objectSpreadRepeatedComplexity.ts ===
 function f(cnd: Record<number, boolean>){
->f : (cnd: Record<number, boolean>) => { prop20a?: number; prop20b?: number; prop19a?: number; prop19b?: number; prop18a?: number; prop18b?: number; prop17a?: number; prop17b?: number; prop16a?: number; prop16b?: number; prop15a?: number; prop15b?: number; prop14a?: number; prop14b?: number; prop13a?: number; prop13b?: number; prop12a?: number; prop12b?: number; prop11a?: number; prop11b?: number; prop10a?: number; prop10b?: number; prop9a?: number; prop9b?: number; prop8a?: number; prop8b?: number; prop7a?: number; prop7b?: number; prop6a?: number; prop6b?: number; prop5a?: number; prop5b?: number; prop4a?: number; prop4b?: number; prop3a?: number; prop3b?: number; prop0?: number; }
+>f : (cnd: Record<number, boolean>) => { prop20a?: number | undefined; prop20b?: number | undefined; prop19a?: number | undefined; prop19b?: number | undefined; prop18a?: number | undefined; prop18b?: number | undefined; prop17a?: number | undefined; prop17b?: number | undefined; prop16a?: number | undefined; prop16b?: number | undefined; prop15a?: number | undefined; prop15b?: number | undefined; prop14a?: number | undefined; prop14b?: number | undefined; prop13a?: number | undefined; prop13b?: number | undefined; prop12a?: number | undefined; prop12b?: number | undefined; prop11a?: number | undefined; prop11b?: number | undefined; prop10a?: number | undefined; prop10b?: number | undefined; prop9a?: number | undefined; prop9b?: number | undefined; prop8a?: number | undefined; prop8b?: number | undefined; prop7a?: number | undefined; prop7b?: number | undefined; prop6a?: number | undefined; prop6b?: number | undefined; prop5a?: number | undefined; prop5b?: number | undefined; prop4a?: number | undefined; prop4b?: number | undefined; prop3a?: number | undefined; prop3b?: number | undefined; prop0?: number | undefined; }
 >cnd : Record<number, boolean>
 
     // Type is a union of 2^(n-1) members, where n is the number of spread objects
     return {
->{        // Without this one, it collapses to {} ?        ...(cnd[1] &&            cnd[2] && {            prop0: 0,        }),        // With one prop each, it collapses to a single object (#34853?)        ...(cnd[3] && {            prop3a: 1,            prop3b: 1,        }),        ...(cnd[4] && {            prop4a: 1,            prop4b: 1,        }),        ...(cnd[5] && {            prop5a: 1,            prop5b: 1,        }),        ...(cnd[6] && {            prop6a: 1,            prop6b: 1,        }),        ...(cnd[7] && {            prop7a: 1,            prop7b: 1,        }),        ...(cnd[8] && {            prop8a: 1,            prop8b: 1,        }),        ...(cnd[9] && {            prop9a: 1,            prop9b: 1,        }),        ...(cnd[10] && {            prop10a: 1,            prop10b: 1,        }),        ...(cnd[11] && {            prop11a: 1,            prop11b: 1,        }),        ...(cnd[12] && {            prop12a: 1,            prop12b: 1,        }),        ...(cnd[13] && {            prop13a: 1,            prop13b: 1,        }),        ...(cnd[14] && {            prop14a: 1,            prop14b: 1,        }),        ...(cnd[15] && {            prop15a: 1,            prop15b: 1,        }),        ...(cnd[16] && {            prop16a: 1,            prop16b: 1,        }),        ...(cnd[17] && {            prop17a: 1,            prop17b: 1,        }),        ...(cnd[18] && {            prop18a: 1,            prop18b: 1,        }),        ...(cnd[19] && {            prop19a: 1,            prop19b: 1,        }),        ...(cnd[20] && {            prop20a: 1,            prop20b: 1,        }),    } : { prop20a?: number; prop20b?: number; prop19a?: number; prop19b?: number; prop18a?: number; prop18b?: number; prop17a?: number; prop17b?: number; prop16a?: number; prop16b?: number; prop15a?: number; prop15b?: number; prop14a?: number; prop14b?: number; prop13a?: number; prop13b?: number; prop12a?: number; prop12b?: number; prop11a?: number; prop11b?: number; prop10a?: number; prop10b?: number; prop9a?: number; prop9b?: number; prop8a?: number; prop8b?: number; prop7a?: number; prop7b?: number; prop6a?: number; prop6b?: number; prop5a?: number; prop5b?: number; prop4a?: number; prop4b?: number; prop3a?: number; prop3b?: number; prop0?: number; }
+>{        // Without this one, it collapses to {} ?        ...(cnd[1] &&            cnd[2] && {            prop0: 0,        }),        // With one prop each, it collapses to a single object (#34853?)        ...(cnd[3] && {            prop3a: 1,            prop3b: 1,        }),        ...(cnd[4] && {            prop4a: 1,            prop4b: 1,        }),        ...(cnd[5] && {            prop5a: 1,            prop5b: 1,        }),        ...(cnd[6] && {            prop6a: 1,            prop6b: 1,        }),        ...(cnd[7] && {            prop7a: 1,            prop7b: 1,        }),        ...(cnd[8] && {            prop8a: 1,            prop8b: 1,        }),        ...(cnd[9] && {            prop9a: 1,            prop9b: 1,        }),        ...(cnd[10] && {            prop10a: 1,            prop10b: 1,        }),        ...(cnd[11] && {            prop11a: 1,            prop11b: 1,        }),        ...(cnd[12] && {            prop12a: 1,            prop12b: 1,        }),        ...(cnd[13] && {            prop13a: 1,            prop13b: 1,        }),        ...(cnd[14] && {            prop14a: 1,            prop14b: 1,        }),        ...(cnd[15] && {            prop15a: 1,            prop15b: 1,        }),        ...(cnd[16] && {            prop16a: 1,            prop16b: 1,        }),        ...(cnd[17] && {            prop17a: 1,            prop17b: 1,        }),        ...(cnd[18] && {            prop18a: 1,            prop18b: 1,        }),        ...(cnd[19] && {            prop19a: 1,            prop19b: 1,        }),        ...(cnd[20] && {            prop20a: 1,            prop20b: 1,        }),    } : { prop20a?: number | undefined; prop20b?: number | undefined; prop19a?: number | undefined; prop19b?: number | undefined; prop18a?: number | undefined; prop18b?: number | undefined; prop17a?: number | undefined; prop17b?: number | undefined; prop16a?: number | undefined; prop16b?: number | undefined; prop15a?: number | undefined; prop15b?: number | undefined; prop14a?: number | undefined; prop14b?: number | undefined; prop13a?: number | undefined; prop13b?: number | undefined; prop12a?: number | undefined; prop12b?: number | undefined; prop11a?: number | undefined; prop11b?: number | undefined; prop10a?: number | undefined; prop10b?: number | undefined; prop9a?: number | undefined; prop9b?: number | undefined; prop8a?: number | undefined; prop8b?: number | undefined; prop7a?: number | undefined; prop7b?: number | undefined; prop6a?: number | undefined; prop6b?: number | undefined; prop5a?: number | undefined; prop5b?: number | undefined; prop4a?: number | undefined; prop4b?: number | undefined; prop3a?: number | undefined; prop3b?: number | undefined; prop0?: number | undefined; }
 
         // Without this one, it collapses to {} ?
         ...(cnd[1] &&

tests/baselines/reference/objectSpreadRepeatedNullCheckPerf.types

@@ -84,7 +84,7 @@ function parseWithSpread(config: Record<string, number>): Props {
 >config : Record<string, number>
 
     return {
->{        ...config.a !== undefined && { a: config.a.toString() },        ...config.b !== undefined && { b: config.b.toString() },        ...config.c !== undefined && { c: config.c.toString() },        ...config.d !== undefined && { d: config.d.toString() },        ...config.e !== undefined && { e: config.e.toString() },        ...config.f !== undefined && { f: config.f.toString() },        ...config.g !== undefined && { g: config.g.toString() },        ...config.h !== undefined && { h: config.h.toString() },        ...config.i !== undefined && { i: config.i.toString() },        ...config.j !== undefined && { j: config.j.toString() },        ...config.k !== undefined && { k: config.k.toString() },        ...config.l !== undefined && { l: config.l.toString() },        ...config.m !== undefined && { m: config.m.toString() },        ...config.n !== undefined && { n: config.n.toString() },        ...config.o !== undefined && { o: config.o.toString() },        ...config.p !== undefined && { p: config.p.toString() },        ...config.q !== undefined && { q: config.q.toString() },        ...config.r !== undefined && { r: config.r.toString() },        ...config.s !== undefined && { s: config.s.toString() },        ...config.t !== undefined && { t: config.t.toString() },        ...config.u !== undefined && { u: config.u.toString() },        ...config.v !== undefined && { v: config.v.toString() },        ...config.w !== undefined && { w: config.w.toString() },        ...config.x !== undefined && { x: config.x.toString() },        ...config.y !== undefined && { y: config.y.toString() },        ...config.z !== undefined && { z: config.z.toString() }    } : { z?: string; y?: string; x?: string; w?: string; v?: string; u?: string; t?: string; s?: string; r?: string; q?: string; p?: string; o?: string; n?: string; m?: string; l?: string; k?: string; j?: string; i?: string; h?: string; g?: string; f?: string; e?: string; d?: string; c?: string; b?: string; a?: string; }
+>{        ...config.a !== undefined && { a: config.a.toString() },        ...config.b !== undefined && { b: config.b.toString() },        ...config.c !== undefined && { c: config.c.toString() },        ...config.d !== undefined && { d: config.d.toString() },        ...config.e !== undefined && { e: config.e.toString() },        ...config.f !== undefined && { f: config.f.toString() },        ...config.g !== undefined && { g: config.g.toString() },        ...config.h !== undefined && { h: config.h.toString() },        ...config.i !== undefined && { i: config.i.toString() },        ...config.j !== undefined && { j: config.j.toString() },        ...config.k !== undefined && { k: config.k.toString() },        ...config.l !== undefined && { l: config.l.toString() },        ...config.m !== undefined && { m: config.m.toString() },        ...config.n !== undefined && { n: config.n.toString() },        ...config.o !== undefined && { o: config.o.toString() },        ...config.p !== undefined && { p: config.p.toString() },        ...config.q !== undefined && { q: config.q.toString() },        ...config.r !== undefined && { r: config.r.toString() },        ...config.s !== undefined && { s: config.s.toString() },        ...config.t !== undefined && { t: config.t.toString() },        ...config.u !== undefined && { u: config.u.toString() },        ...config.v !== undefined && { v: config.v.toString() },        ...config.w !== undefined && { w: config.w.toString() },        ...config.x !== undefined && { x: config.x.toString() },        ...config.y !== undefined && { y: config.y.toString() },        ...config.z !== undefined && { z: config.z.toString() }    } : { z?: string | undefined; y?: string | undefined; x?: string | undefined; w?: string | undefined; v?: string | undefined; u?: string | undefined; t?: string | undefined; s?: string | undefined; r?: string | undefined; q?: string | undefined; p?: string | undefined; o?: string | undefined; n?: string | undefined; m?: string | undefined; l?: string | undefined; k?: string | undefined; j?: string | undefined; i?: string | undefined; h?: string | undefined; g?: string | undefined; f?: string | undefined; e?: string | undefined; d?: string | undefined; c?: string | undefined; b?: string | undefined; a?: string | undefined; }
 
         ...config.a !== undefined && { a: config.a.toString() },
 >config.a !== undefined && { a: config.a.toString() } : false | { a: string; }

tests/baselines/reference/omitTypeHelperModifiers01.errors.txt

@@ -1,8 +1,7 @@
-tests/cases/compiler/omitTypeHelperModifiers01.ts(13,5): error TS2322: Type 'undefined' is not assignable to type 'string'.
 tests/cases/compiler/omitTypeHelperModifiers01.ts(16,7): error TS2540: Cannot assign to 'c' because it is a read-only property.
 
 
-==== tests/cases/compiler/omitTypeHelperModifiers01.ts (2 errors) ====
+==== tests/cases/compiler/omitTypeHelperModifiers01.ts (1 errors) ====
     type A = {
         a: number;
         b?: string;
@@ -16,8 +15,6 @@ tests/cases/compiler/omitTypeHelperModifiers01.ts(16,7): error TS2540: Cannot as
         const b = x.b;
         x.b = "hello";
         x.b = undefined;
-        ~~~
-!!! error TS2322: Type 'undefined' is not assignable to type 'string'.
     
         const c = x.c;
         x.c = true;

tests/baselines/reference/omitTypeHelperModifiers01.types

@@ -31,16 +31,16 @@ function f(x: B) {
 
     x.b = "hello";
 >x.b = "hello" : "hello"
->x.b : string
+>x.b : string | undefined
 >x : B
->b : string
+>b : string | undefined
 >"hello" : "hello"
 
     x.b = undefined;
 >x.b = undefined : undefined
->x.b : string
+>x.b : string | undefined
 >x : B
->b : string
+>b : string | undefined
 >undefined : undefined
 
     const c = x.c;

tests/baselines/reference/optionalPropertyAssignableToStringIndexSignature.errors.txt

@@ -2,7 +2,7 @@ tests/cases/conformance/types/typeRelationships/assignmentCompatibility/optional
   Property 'k1' is incompatible with index signature.
     Type 'string | undefined' is not assignable to type 'string'.
       Type 'undefined' is not assignable to type 'string'.
-tests/cases/conformance/types/typeRelationships/assignmentCompatibility/optionalPropertyAssignableToStringIndexSignature.ts(10,1): error TS2322: Type '{ 1?: string; }' is not assignable to type '{ [key: number]: string; }'.
+tests/cases/conformance/types/typeRelationships/assignmentCompatibility/optionalPropertyAssignableToStringIndexSignature.ts(10,1): error TS2322: Type '{ 1?: string | undefined; }' is not assignable to type '{ [key: number]: string; }'.
   Property '1' is incompatible with index signature.
     Type 'string | undefined' is not assignable to type 'string'.
       Type 'undefined' is not assignable to type 'string'.
@@ -28,7 +28,7 @@ tests/cases/conformance/types/typeRelationships/assignmentCompatibility/optional
     declare let numberLiteralKeys: { 1?: string };
     probablyArray = numberLiteralKeys;  // error
     ~~~~~~~~~~~~~
-!!! error TS2322: Type '{ 1?: string; }' is not assignable to type '{ [key: number]: string; }'.
+!!! error TS2322: Type '{ 1?: string | undefined; }' is not assignable to type '{ [key: number]: string; }'.
 !!! error TS2322:   Property '1' is incompatible with index signature.
 !!! error TS2322:     Type 'string | undefined' is not assignable to type 'string'.
 !!! error TS2322:       Type 'undefined' is not assignable to type 'string'.

tests/baselines/reference/optionalPropertyAssignableToStringIndexSignature.types

@@ -1,6 +1,6 @@
 === tests/cases/conformance/types/typeRelationships/assignmentCompatibility/optionalPropertyAssignableToStringIndexSignature.ts ===
 declare let optionalProperties: { k1?: string };
->optionalProperties : { k1?: string; }
+>optionalProperties : { k1?: string | undefined; }
 >k1 : string | undefined
 
 declare let undefinedProperties: { k1: string | undefined };
@@ -12,9 +12,9 @@ declare let stringDictionary: { [key: string]: string };
 >key : string
 
 stringDictionary = optionalProperties;  // ok
->stringDictionary = optionalProperties : { k1?: string; }
+>stringDictionary = optionalProperties : { k1?: string | undefined; }
 >stringDictionary : { [key: string]: string; }
->optionalProperties : { k1?: string; }
+>optionalProperties : { k1?: string | undefined; }
 
 stringDictionary = undefinedProperties; // error
 >stringDictionary = undefinedProperties : { k1: string | undefined; }
@@ -26,13 +26,13 @@ declare let probablyArray: { [key: number]: string };
 >key : number
 
 declare let numberLiteralKeys: { 1?: string };
->numberLiteralKeys : { 1?: string; }
+>numberLiteralKeys : { 1?: string | undefined; }
 >1 : string | undefined
 
 probablyArray = numberLiteralKeys;  // error
->probablyArray = numberLiteralKeys : { 1?: string; }
+>probablyArray = numberLiteralKeys : { 1?: string | undefined; }
 >probablyArray : { [key: number]: string; }
->numberLiteralKeys : { 1?: string; }
+>numberLiteralKeys : { 1?: string | undefined; }
 
 declare let optionalUndefined: { k1?: undefined };
 >optionalUndefined : { k1?: undefined; }
@@ -47,7 +47,7 @@ function f<T>() {
 >f : <T>() => void
 
 	let optional: { k1?: T } = undefined!;
->optional : { k1?: T; }
+>optional : { k1?: T | undefined; }
 >k1 : T | undefined
 >undefined! : never
 >undefined : undefined
@@ -55,6 +55,6 @@ function f<T>() {
 	let dict: { [key: string]: T | number } = optional; // ok
 >dict : { [key: string]: number | T; }
 >key : string
->optional : { k1?: T; }
+>optional : { k1?: T | undefined; }
 }
 

tests/baselines/reference/optionalTupleElements1.types

@@ -138,9 +138,9 @@ t3 = [42, "hello"];
 >"hello" : "hello"
 
 t3 = [42,,true]
->t3 = [42,,true] : [number, never?, true?]
+>t3 = [42,,true] : [number, undefined, true]
 >t3 : T3
->[42,,true] : [number, never?, true?]
+>[42,,true] : [number, undefined, true]
 >42 : 42
 > : undefined
 >true : true
@@ -159,25 +159,25 @@ t4 = [42, "hello"];
 >"hello" : "hello"
 
 t4 = [42,,true];
->t4 = [42,,true] : [number, never?, true?]
+>t4 = [42,,true] : [number, undefined, true]
 >t4 : T4
->[42,,true] : [number, never?, true?]
+>[42,,true] : [number, undefined, true]
 >42 : 42
 > : undefined
 >true : true
 
 t4 = [,"hello", true];
->t4 = [,"hello", true] : [never?, string?, true?]
+>t4 = [,"hello", true] : [undefined, string, true]
 >t4 : T4
->[,"hello", true] : [never?, string?, true?]
+>[,"hello", true] : [undefined, string, true]
 > : undefined
 >"hello" : "hello"
 >true : true
 
 t4 = [,,true];
->t4 = [,,true] : [never?, never?, true?]
+>t4 = [,,true] : [undefined, undefined, true]
 >t4 : T4
->[,,true] : [never?, never?, true?]
+>[,,true] : [undefined, undefined, true]
 > : undefined
 > : undefined
 >true : true

tests/baselines/reference/paramsOnlyHaveLiteralTypesWhenAppropriatelyContextualized.errors.txt

@@ -1,11 +1,13 @@
-tests/cases/compiler/paramsOnlyHaveLiteralTypesWhenAppropriatelyContextualized.ts(27,23): error TS2345: Argument of type '{ x?: number[]; y?: string[]; }' is not assignable to parameter of type '{ y?: number[]; }'.
+tests/cases/compiler/paramsOnlyHaveLiteralTypesWhenAppropriatelyContextualized.ts(27,23): error TS2345: Argument of type '{ x?: number[] | undefined; y?: string[] | undefined; }' is not assignable to parameter of type '{ y?: number[] | undefined; }'.
   Types of property 'y' are incompatible.
-    Type 'string[]' is not assignable to type 'number[]'.
-      Type 'string' is not assignable to type 'number'.
-tests/cases/compiler/paramsOnlyHaveLiteralTypesWhenAppropriatelyContextualized.ts(28,23): error TS2345: Argument of type '{ x?: number[]; y?: string[]; }' is not assignable to parameter of type '{ x?: string[]; }'.
+    Type 'string[] | undefined' is not assignable to type 'number[] | undefined'.
+      Type 'string[]' is not assignable to type 'number[]'.
+        Type 'string' is not assignable to type 'number'.
+tests/cases/compiler/paramsOnlyHaveLiteralTypesWhenAppropriatelyContextualized.ts(28,23): error TS2345: Argument of type '{ x?: number[] | undefined; y?: string[] | undefined; }' is not assignable to parameter of type '{ x?: string[] | undefined; }'.
   Types of property 'x' are incompatible.
-    Type 'number[]' is not assignable to type 'string[]'.
-      Type 'number' is not assignable to type 'string'.
+    Type 'number[] | undefined' is not assignable to type 'string[] | undefined'.
+      Type 'number[]' is not assignable to type 'string[]'.
+        Type 'number' is not assignable to type 'string'.
 
 
 ==== tests/cases/compiler/paramsOnlyHaveLiteralTypesWhenAppropriatelyContextualized.ts (2 errors) ====
@@ -37,13 +39,15 @@ tests/cases/compiler/paramsOnlyHaveLiteralTypesWhenAppropriatelyContextualized.t
     appendToOptionalArray(foo, 'y', 'bar'); // ok
     appendToOptionalArray(foo, 'y', 12);    // should fail
                           ~~~
-!!! error TS2345: Argument of type '{ x?: number[]; y?: string[]; }' is not assignable to parameter of type '{ y?: number[]; }'.
+!!! error TS2345: Argument of type '{ x?: number[] | undefined; y?: string[] | undefined; }' is not assignable to parameter of type '{ y?: number[] | undefined; }'.
 !!! error TS2345:   Types of property 'y' are incompatible.
-!!! error TS2345:     Type 'string[]' is not assignable to type 'number[]'.
-!!! error TS2345:       Type 'string' is not assignable to type 'number'.
+!!! error TS2345:     Type 'string[] | undefined' is not assignable to type 'number[] | undefined'.
+!!! error TS2345:       Type 'string[]' is not assignable to type 'number[]'.
+!!! error TS2345:         Type 'string' is not assignable to type 'number'.
     appendToOptionalArray(foo, 'x', "no");  // should fail
                           ~~~
-!!! error TS2345: Argument of type '{ x?: number[]; y?: string[]; }' is not assignable to parameter of type '{ x?: string[]; }'.
+!!! error TS2345: Argument of type '{ x?: number[] | undefined; y?: string[] | undefined; }' is not assignable to parameter of type '{ x?: string[] | undefined; }'.
 !!! error TS2345:   Types of property 'x' are incompatible.
-!!! error TS2345:     Type 'number[]' is not assignable to type 'string[]'.
-!!! error TS2345:       Type 'number' is not assignable to type 'string'.
+!!! error TS2345:     Type 'number[] | undefined' is not assignable to type 'string[] | undefined'.
+!!! error TS2345:       Type 'number[]' is not assignable to type 'string[]'.
+!!! error TS2345:         Type 'number' is not assignable to type 'string'.

tests/baselines/reference/paramsOnlyHaveLiteralTypesWhenAppropriatelyContextualized.types

@@ -7,13 +7,13 @@ type Lower<T> = { [K in keyof T]: T[K] };
 >Lower : Lower<T>
 
 export function appendToOptionalArray<
->appendToOptionalArray : <K extends string | number | symbol, T>(object: { [x in K]?: Lower<T>[]; }, key: K, value: T) => void
+>appendToOptionalArray : <K extends string | number | symbol, T>(object: { [x in K]?: Lower<T>[] | undefined; }, key: K, value: T) => void
 
   K extends string | number | symbol,
   T
 >(
   object: { [x in K]?: Lower<T>[] },
->object : { [x in K]?: Lower<T>[]; }
+>object : { [x in K]?: Lower<T>[] | undefined; }
 
   key: K,
 >key : K
@@ -23,13 +23,13 @@ export function appendToOptionalArray<
 
 ) {
   const array = object[key];
->array : { [x in K]?: Lower<T>[]; }[K]
->object[key] : { [x in K]?: Lower<T>[]; }[K]
->object : { [x in K]?: Lower<T>[]; }
+>array : { [x in K]?: Lower<T>[] | undefined; }[K]
+>object[key] : { [x in K]?: Lower<T>[] | undefined; }[K]
+>object : { [x in K]?: Lower<T>[] | undefined; }
 >key : K
 
   if (array) {
->array : { [x in K]?: Lower<T>[]; }[K]
+>array : { [x in K]?: Lower<T>[] | undefined; }[K]
 
     array.push(value);
 >array.push(value) : number
@@ -41,8 +41,8 @@ export function appendToOptionalArray<
   } else {
     object[key] = [value];
 >object[key] = [value] : T[]
->object[key] : { [x in K]?: Lower<T>[]; }[K]
->object : { [x in K]?: Lower<T>[]; }
+>object[key] : { [x in K]?: Lower<T>[] | undefined; }[K]
+>object : { [x in K]?: Lower<T>[] | undefined; }
 >key : K
 >[value] : T[]
 >value : T
@@ -51,36 +51,36 @@ export function appendToOptionalArray<
 
 // e.g.
 const foo: {x?: number[]; y?: string[]; } = {};
->foo : { x?: number[]; y?: string[]; }
+>foo : { x?: number[] | undefined; y?: string[] | undefined; }
 >x : number[] | undefined
 >y : string[] | undefined
 >{} : {}
 
 appendToOptionalArray(foo, 'x', 123);   // ok
 >appendToOptionalArray(foo, 'x', 123) : void
->appendToOptionalArray : <K extends string | number | symbol, T>(object: { [x in K]?: Lower<T>[]; }, key: K, value: T) => void
->foo : { x?: number[]; y?: string[]; }
+>appendToOptionalArray : <K extends string | number | symbol, T>(object: { [x in K]?: Lower<T>[] | undefined; }, key: K, value: T) => void
+>foo : { x?: number[] | undefined; y?: string[] | undefined; }
 >'x' : "x"
 >123 : 123
 
 appendToOptionalArray(foo, 'y', 'bar'); // ok
 >appendToOptionalArray(foo, 'y', 'bar') : void
->appendToOptionalArray : <K extends string | number | symbol, T>(object: { [x in K]?: Lower<T>[]; }, key: K, value: T) => void
->foo : { x?: number[]; y?: string[]; }
+>appendToOptionalArray : <K extends string | number | symbol, T>(object: { [x in K]?: Lower<T>[] | undefined; }, key: K, value: T) => void
+>foo : { x?: number[] | undefined; y?: string[] | undefined; }
 >'y' : "y"
 >'bar' : "bar"
 
 appendToOptionalArray(foo, 'y', 12);    // should fail
 >appendToOptionalArray(foo, 'y', 12) : void
->appendToOptionalArray : <K extends string | number | symbol, T>(object: { [x in K]?: Lower<T>[]; }, key: K, value: T) => void
->foo : { x?: number[]; y?: string[]; }
+>appendToOptionalArray : <K extends string | number | symbol, T>(object: { [x in K]?: Lower<T>[] | undefined; }, key: K, value: T) => void
+>foo : { x?: number[] | undefined; y?: string[] | undefined; }
 >'y' : "y"
 >12 : 12
 
 appendToOptionalArray(foo, 'x', "no");  // should fail
 >appendToOptionalArray(foo, 'x', "no") : void
->appendToOptionalArray : <K extends string | number | symbol, T>(object: { [x in K]?: Lower<T>[]; }, key: K, value: T) => void
->foo : { x?: number[]; y?: string[]; }
+>appendToOptionalArray : <K extends string | number | symbol, T>(object: { [x in K]?: Lower<T>[] | undefined; }, key: K, value: T) => void
+>foo : { x?: number[] | undefined; y?: string[] | undefined; }
 >'x' : "x"
 >"no" : "no"
 

tests/baselines/reference/propTypeValidatorInference.types

@@ -91,7 +91,7 @@ interface Props {
 >bool : boolean
 
     shape: {
->shape : { foo: string; bar?: boolean; baz?: any; }
+>shape : { foo: string; bar?: boolean | undefined; baz?: any; }
 
         foo: string;
 >foo : string
@@ -104,7 +104,7 @@ interface Props {
 
     };
     oneOfType: string | boolean | {
->oneOfType : string | boolean | { foo?: string; bar: number; }
+>oneOfType : string | boolean | { foo?: string | undefined; bar: number; }
 
         foo?: string;
 >foo : string | undefined

tests/baselines/reference/propertyAccessChain.types

@@ -33,39 +33,39 @@ o3.b?.c;
 >c : string | undefined
 
 declare const o4: { b?: { c: { d?: { e: string } } } };
->o4 : { b?: {    c: {        d?: {            e: string;        };    };}; }
+>o4 : { b?: { c: {    d?: {        e: string;    };}; } | undefined; }
 >b : { c: {    d?: {        e: string;    };}; } | undefined
->c : { d?: {    e: string;}; }
+>c : { d?: { e: string; } | undefined; }
 >d : { e: string; } | undefined
 >e : string
 
 o4.b?.c.d?.e;
 >o4.b?.c.d?.e : string | undefined
 >o4.b?.c.d : { e: string; } | undefined
->o4.b?.c : { d?: { e: string; }; } | undefined
->o4.b : { c: { d?: { e: string; }; }; } | undefined
->o4 : { b?: { c: { d?: { e: string; }; }; }; }
->b : { c: { d?: { e: string; }; }; } | undefined
->c : { d?: { e: string; }; } | undefined
+>o4.b?.c : { d?: { e: string; } | undefined; } | undefined
+>o4.b : { c: { d?: { e: string; } | undefined; }; } | undefined
+>o4 : { b?: { c: { d?: { e: string; } | undefined; }; } | undefined; }
+>b : { c: { d?: { e: string; } | undefined; }; } | undefined
+>c : { d?: { e: string; } | undefined; } | undefined
 >d : { e: string; } | undefined
 >e : string | undefined
 
 declare const o5: { b?(): { c: { d?: { e: string } } } };
 >o5 : { b?(): {    c: {        d?: {            e: string;        };    };}; }
 >b : (() => {    c: {        d?: {            e: string;        };    };}) | undefined
->c : { d?: {    e: string;}; }
+>c : { d?: { e: string; } | undefined; }
 >d : { e: string; } | undefined
 >e : string
 
 o5.b?.().c.d?.e;
 >o5.b?.().c.d?.e : string | undefined
 >o5.b?.().c.d : { e: string; } | undefined
->o5.b?.().c : { d?: { e: string; }; } | undefined
->o5.b?.() : { c: { d?: { e: string; }; }; } | undefined
->o5.b : (() => { c: { d?: { e: string; }; }; }) | undefined
->o5 : { b?(): { c: { d?: { e: string; }; }; }; }
->b : (() => { c: { d?: { e: string; }; }; }) | undefined
->c : { d?: { e: string; }; } | undefined
+>o5.b?.().c : { d?: { e: string; } | undefined; } | undefined
+>o5.b?.() : { c: { d?: { e: string; } | undefined; }; } | undefined
+>o5.b : (() => { c: { d?: { e: string; } | undefined; }; }) | undefined
+>o5 : { b?(): { c: { d?: { e: string; } | undefined; }; }; }
+>b : (() => { c: { d?: { e: string; } | undefined; }; }) | undefined
+>c : { d?: { e: string; } | undefined; } | undefined
 >d : { e: string; } | undefined
 >e : string | undefined
 

tests/baselines/reference/reactDefaultPropsInferenceSuccess.errors.txt

@@ -1,24 +1,23 @@
 tests/cases/compiler/reactDefaultPropsInferenceSuccess.tsx(27,36): error TS2769: No overload matches this call.
   Overload 1 of 2, '(props: Readonly<Props>): FieldFeedback<Props>', gave the following error.
-    Type '(value: string) => void' is not assignable to type '"a" | "b" | ((value: string) => boolean)'.
+    Type '(value: string) => void' is not assignable to type '"a" | "b" | ((value: string) => boolean) | undefined'.
       Type '(value: string) => void' is not assignable to type '(value: string) => boolean'.
         Type 'void' is not assignable to type 'boolean'.
   Overload 2 of 2, '(props: Props, context?: any): FieldFeedback<Props>', gave the following error.
-    Type '(value: string) => void' is not assignable to type '"a" | "b" | ((value: string) => boolean)'.
-      Type '(value: string) => void' is not assignable to type '(value: string) => boolean'.
+    Type '(value: string) => void' is not assignable to type '"a" | "b" | ((value: string) => boolean) | undefined'.
 tests/cases/compiler/reactDefaultPropsInferenceSuccess.tsx(43,41): error TS2769: No overload matches this call.
   Overload 1 of 2, '(props: Readonly<Props>): FieldFeedbackBeta<Props>', gave the following error.
-    Type '(value: string) => void' is not assignable to type '"a" | "b" | ((value: string) => boolean)'.
+    Type '(value: string) => void' is not assignable to type '"a" | "b" | ((value: string) => boolean) | undefined'.
       Type '(value: string) => void' is not assignable to type '(value: string) => boolean'.
         Type 'void' is not assignable to type 'boolean'.
   Overload 2 of 2, '(props: Props, context?: any): FieldFeedbackBeta<Props>', gave the following error.
-    Type '(value: string) => void' is not assignable to type '"a" | "b" | ((value: string) => boolean)'.
-      Type '(value: string) => void' is not assignable to type '(value: string) => boolean'.
-tests/cases/compiler/reactDefaultPropsInferenceSuccess.tsx(64,52): error TS2769: No overload matches this call.
+    Type '(value: string) => void' is not assignable to type '"a" | "b" | ((value: string) => boolean) | undefined'.
+tests/cases/compiler/reactDefaultPropsInferenceSuccess.tsx(64,37): error TS2769: No overload matches this call.
   Overload 1 of 2, '(props: Readonly<MyPropsProps>): FieldFeedback2<MyPropsProps>', gave the following error.
-    Type 'void' is not assignable to type 'boolean'.
+    Type '(value: string) => void' is not assignable to type '(value: string) => boolean'.
+      Type 'void' is not assignable to type 'boolean'.
   Overload 2 of 2, '(props: MyPropsProps, context?: any): FieldFeedback2<MyPropsProps>', gave the following error.
-    Type 'void' is not assignable to type 'boolean'.
+    Type '(value: string) => void' is not assignable to type '(value: string) => boolean'.
 
 
 ==== tests/cases/compiler/reactDefaultPropsInferenceSuccess.tsx (3 errors) ====
@@ -52,12 +51,11 @@ tests/cases/compiler/reactDefaultPropsInferenceSuccess.tsx(64,52): error TS2769:
                                        ~~~~
 !!! error TS2769: No overload matches this call.
 !!! error TS2769:   Overload 1 of 2, '(props: Readonly<Props>): FieldFeedback<Props>', gave the following error.
-!!! error TS2769:     Type '(value: string) => void' is not assignable to type '"a" | "b" | ((value: string) => boolean)'.
+!!! error TS2769:     Type '(value: string) => void' is not assignable to type '"a" | "b" | ((value: string) => boolean) | undefined'.
 !!! error TS2769:       Type '(value: string) => void' is not assignable to type '(value: string) => boolean'.
 !!! error TS2769:         Type 'void' is not assignable to type 'boolean'.
 !!! error TS2769:   Overload 2 of 2, '(props: Props, context?: any): FieldFeedback<Props>', gave the following error.
-!!! error TS2769:     Type '(value: string) => void' is not assignable to type '"a" | "b" | ((value: string) => boolean)'.
-!!! error TS2769:       Type '(value: string) => void' is not assignable to type '(value: string) => boolean'.
+!!! error TS2769:     Type '(value: string) => void' is not assignable to type '"a" | "b" | ((value: string) => boolean) | undefined'.
 !!! related TS6500 tests/cases/compiler/reactDefaultPropsInferenceSuccess.tsx:6:3: The expected type comes from property 'when' which is declared here on type 'IntrinsicAttributes & IntrinsicClassAttributes<FieldFeedback<Props>> & Pick<Readonly<{ children?: ReactNode; }> & Readonly<Props>, "children" | "error"> & Partial<Pick<Readonly<{ children?: ReactNode; }> & Readonly<Props>, "when">> & Partial<Pick<{ when: () => boolean; }, never>>'
 !!! related TS6500 tests/cases/compiler/reactDefaultPropsInferenceSuccess.tsx:6:3: The expected type comes from property 'when' which is declared here on type 'IntrinsicAttributes & IntrinsicClassAttributes<FieldFeedback<Props>> & Pick<Readonly<{ children?: ReactNode; }> & Readonly<Props>, "children" | "error"> & Partial<Pick<Readonly<{ children?: ReactNode; }> & Readonly<Props>, "when">> & Partial<Pick<{ when: () => boolean; }, never>>'
     
@@ -79,12 +77,11 @@ tests/cases/compiler/reactDefaultPropsInferenceSuccess.tsx(64,52): error TS2769:
                                             ~~~~
 !!! error TS2769: No overload matches this call.
 !!! error TS2769:   Overload 1 of 2, '(props: Readonly<Props>): FieldFeedbackBeta<Props>', gave the following error.
-!!! error TS2769:     Type '(value: string) => void' is not assignable to type '"a" | "b" | ((value: string) => boolean)'.
+!!! error TS2769:     Type '(value: string) => void' is not assignable to type '"a" | "b" | ((value: string) => boolean) | undefined'.
 !!! error TS2769:       Type '(value: string) => void' is not assignable to type '(value: string) => boolean'.
 !!! error TS2769:         Type 'void' is not assignable to type 'boolean'.
 !!! error TS2769:   Overload 2 of 2, '(props: Props, context?: any): FieldFeedbackBeta<Props>', gave the following error.
-!!! error TS2769:     Type '(value: string) => void' is not assignable to type '"a" | "b" | ((value: string) => boolean)'.
-!!! error TS2769:       Type '(value: string) => void' is not assignable to type '(value: string) => boolean'.
+!!! error TS2769:     Type '(value: string) => void' is not assignable to type '"a" | "b" | ((value: string) => boolean) | undefined'.
 !!! related TS6500 tests/cases/compiler/reactDefaultPropsInferenceSuccess.tsx:6:3: The expected type comes from property 'when' which is declared here on type 'IntrinsicAttributes & IntrinsicClassAttributes<FieldFeedbackBeta<Props>> & Pick<Readonly<{ children?: ReactNode; }> & Readonly<Props>, "children"> & Partial<Pick<Readonly<{ children?: ReactNode; }> & Readonly<Props>, keyof Props>> & Partial<Pick<BaseProps, never>>'
 !!! related TS6500 tests/cases/compiler/reactDefaultPropsInferenceSuccess.tsx:6:3: The expected type comes from property 'when' which is declared here on type 'IntrinsicAttributes & IntrinsicClassAttributes<FieldFeedbackBeta<Props>> & Pick<Readonly<{ children?: ReactNode; }> & Readonly<Props>, "children"> & Partial<Pick<Readonly<{ children?: ReactNode; }> & Readonly<Props>, keyof Props>> & Partial<Pick<BaseProps, never>>'
     
@@ -108,14 +105,15 @@ tests/cases/compiler/reactDefaultPropsInferenceSuccess.tsx(64,52): error TS2769:
     
     // Error: Void not assignable to boolean
     const Test4 = () => <FieldFeedback2 when={value => console.log(value)} />;
-                                                       ~~~~~~~~~~~~~~~~~~
+                                        ~~~~
 !!! error TS2769: No overload matches this call.
 !!! error TS2769:   Overload 1 of 2, '(props: Readonly<MyPropsProps>): FieldFeedback2<MyPropsProps>', gave the following error.
-!!! error TS2769:     Type 'void' is not assignable to type 'boolean'.
+!!! error TS2769:     Type '(value: string) => void' is not assignable to type '(value: string) => boolean'.
+!!! error TS2769:       Type 'void' is not assignable to type 'boolean'.
 !!! error TS2769:   Overload 2 of 2, '(props: MyPropsProps, context?: any): FieldFeedback2<MyPropsProps>', gave the following error.
-!!! error TS2769:     Type 'void' is not assignable to type 'boolean'.
-!!! related TS6502 tests/cases/compiler/reactDefaultPropsInferenceSuccess.tsx:46:9: The expected type comes from the return type of this signature.
-!!! related TS6502 tests/cases/compiler/reactDefaultPropsInferenceSuccess.tsx:46:9: The expected type comes from the return type of this signature.
+!!! error TS2769:     Type '(value: string) => void' is not assignable to type '(value: string) => boolean'.
+!!! related TS6500 tests/cases/compiler/reactDefaultPropsInferenceSuccess.tsx:46:3: The expected type comes from property 'when' which is declared here on type 'IntrinsicAttributes & IntrinsicClassAttributes<FieldFeedback2<MyPropsProps>> & Pick<Readonly<{ children?: ReactNode; }> & Readonly<MyPropsProps>, "children" | "error"> & Partial<Pick<Readonly<{ children?: ReactNode; }> & Readonly<MyPropsProps>, "when">> & Partial<Pick<{ when: () => boolean; }, never>>'
+!!! related TS6500 tests/cases/compiler/reactDefaultPropsInferenceSuccess.tsx:46:3: The expected type comes from property 'when' which is declared here on type 'IntrinsicAttributes & IntrinsicClassAttributes<FieldFeedback2<MyPropsProps>> & Pick<Readonly<{ children?: ReactNode; }> & Readonly<MyPropsProps>, "children" | "error"> & Partial<Pick<Readonly<{ children?: ReactNode; }> & Readonly<MyPropsProps>, "when">> & Partial<Pick<{ when: () => boolean; }, never>>'
     
     // OK
     const Test5 = () => <FieldFeedback2 />;

tests/baselines/reference/reactReduxLikeDeferredInferenceAllowsAssignment.types

@@ -10,7 +10,7 @@ declare class Component<P> {
 >context : any
 
   readonly props: Readonly<P> & Readonly<{ children?: {} }>;
->props : Readonly<P> & Readonly<{ children?: {}; }>
+>props : Readonly<P> & Readonly<{ children?: {} | undefined; }>
 >children : {} | undefined
 }
 interface ComponentClass<P = {}> {
@@ -29,7 +29,7 @@ interface ComponentClass<P = {}> {
 }
 interface FunctionComponent<P = {}> {
   (props: P & { children?: {} }, context?: any): {} | null;
->props : P & { children?: {}; }
+>props : P & { children?: {} | undefined; }
 >children : {} | undefined
 >context : any
 >null : null

tests/baselines/reference/showConfig/Shows tsconfig for single option/exactOptionalPropertyTypes/tsconfig.json

@@ -0,0 +1,5 @@
+{
+    "compilerOptions": {
+        "exactOptionalPropertyTypes": true
+    }
+}

tests/baselines/reference/spreadIdenticalTypesRemoved.types

@@ -17,12 +17,12 @@ interface Animal {
 }
 
 function clonePet(pet: Animal, fullCopy?: boolean) {
->clonePet : (pet: Animal, fullCopy?: boolean | undefined) => { name: string; kind: string; age?: number; location?: string; owner?: object; }
+>clonePet : (pet: Animal, fullCopy?: boolean | undefined) => { name: string; kind: string; age?: number | undefined; location?: string | undefined; owner?: object | undefined; }
 >pet : Animal
 >fullCopy : boolean | undefined
 
     return {
->{        name: pet.name,        kind: pet.kind,        ...(fullCopy && pet),    } : { name: string; kind: string; age?: number; location?: string; owner?: object; }
+>{        name: pet.name,        kind: pet.kind,        ...(fullCopy && pet),    } : { name: string; kind: string; age?: number | undefined; location?: string | undefined; owner?: object | undefined; }
 
         name: pet.name,
 >name : string
@@ -52,11 +52,11 @@ interface Animal2 {
 >owner : string | undefined
 }
 function billOwner(pet: Animal2) {
->billOwner : (pet: Animal2) => { paid: boolean; name?: string; owner?: string; }
+>billOwner : (pet: Animal2) => { paid: boolean; name?: string | undefined; owner?: string | undefined; }
 >pet : Animal2
 
     return {
->{        ...(pet.owner && pet),        paid: false    } : { paid: boolean; name?: string; owner?: string; }
+>{        ...(pet.owner && pet),        paid: false    } : { paid: boolean; name?: string | undefined; owner?: string | undefined; }
 
         ...(pet.owner && pet),
 >(pet.owner && pet) : "" | Animal2 | undefined

tests/baselines/reference/spreadOfObjectLiteralAssignableToIndexSignature.types

@@ -9,11 +9,11 @@ const recordOfRecords: RecordOfRecords = {}
 >{} : {}
 
 recordOfRecords.propA = {...(foo !== undefined ? {foo} : {})} // OK
->recordOfRecords.propA = {...(foo !== undefined ? {foo} : {})} : { foo?: Record<never, never>; }
+>recordOfRecords.propA = {...(foo !== undefined ? {foo} : {})} : { foo?: Record<never, never> | undefined; }
 >recordOfRecords.propA : RecordOfRecords
 >recordOfRecords : RecordOfRecords
 >propA : RecordOfRecords
->{...(foo !== undefined ? {foo} : {})} : { foo?: Record<never, never>; }
+>{...(foo !== undefined ? {foo} : {})} : { foo?: Record<never, never> | undefined; }
 >(foo !== undefined ? {foo} : {}) : { foo: Record<never, never>; } | {}
 >foo !== undefined ? {foo} : {} : { foo: Record<never, never>; } | {}
 >foo !== undefined : boolean
@@ -36,11 +36,11 @@ recordOfRecords.propB = {...(foo && {foo})} // OK
 >foo : Record<never, never>
 
 recordOfRecords.propC = {...(foo !== undefined && {foo})} // error'd in 3.7 beta, should be OK
->recordOfRecords.propC = {...(foo !== undefined && {foo})} : { foo?: Record<never, never>; }
+>recordOfRecords.propC = {...(foo !== undefined && {foo})} : { foo?: Record<never, never> | undefined; }
 >recordOfRecords.propC : RecordOfRecords
 >recordOfRecords : RecordOfRecords
 >propC : RecordOfRecords
->{...(foo !== undefined && {foo})} : { foo?: Record<never, never>; }
+>{...(foo !== undefined && {foo})} : { foo?: Record<never, never> | undefined; }
 >(foo !== undefined && {foo}) : false | { foo: Record<never, never>; }
 >foo !== undefined && {foo} : false | { foo: Record<never, never>; }
 >foo !== undefined : boolean
@@ -55,11 +55,11 @@ const recordsOfRecordsOrEmpty: RecordOfRecordsOrEmpty = {}
 >{} : {}
 
 recordsOfRecordsOrEmpty.propA = {...(foo !== undefined ? {foo} : {})} // OK
->recordsOfRecordsOrEmpty.propA = {...(foo !== undefined ? {foo} : {})} : { foo?: Record<never, never>; }
+>recordsOfRecordsOrEmpty.propA = {...(foo !== undefined ? {foo} : {})} : { foo?: Record<never, never> | undefined; }
 >recordsOfRecordsOrEmpty.propA : {} | RecordOfRecordsOrEmpty
 >recordsOfRecordsOrEmpty : RecordOfRecordsOrEmpty
 >propA : {} | RecordOfRecordsOrEmpty
->{...(foo !== undefined ? {foo} : {})} : { foo?: Record<never, never>; }
+>{...(foo !== undefined ? {foo} : {})} : { foo?: Record<never, never> | undefined; }
 >(foo !== undefined ? {foo} : {}) : { foo: Record<never, never>; } | {}
 >foo !== undefined ? {foo} : {} : { foo: Record<never, never>; } | {}
 >foo !== undefined : boolean
@@ -82,11 +82,11 @@ recordsOfRecordsOrEmpty.propB = {...(foo && {foo})} // OK
 >foo : Record<never, never>
 
 recordsOfRecordsOrEmpty.propC = {...(foo !== undefined && {foo})} // OK
->recordsOfRecordsOrEmpty.propC = {...(foo !== undefined && {foo})} : { foo?: Record<never, never>; }
+>recordsOfRecordsOrEmpty.propC = {...(foo !== undefined && {foo})} : { foo?: Record<never, never> | undefined; }
 >recordsOfRecordsOrEmpty.propC : {} | RecordOfRecordsOrEmpty
 >recordsOfRecordsOrEmpty : RecordOfRecordsOrEmpty
 >propC : {} | RecordOfRecordsOrEmpty
->{...(foo !== undefined && {foo})} : { foo?: Record<never, never>; }
+>{...(foo !== undefined && {foo})} : { foo?: Record<never, never> | undefined; }
 >(foo !== undefined && {foo}) : false | { foo: Record<never, never>; }
 >foo !== undefined && {foo} : false | { foo: Record<never, never>; }
 >foo !== undefined : boolean

tests/baselines/reference/spreadOverwritesPropertyStrict.types

@@ -5,7 +5,7 @@ declare var ab: { a: number, b: number };
 >b : number
 
 declare var abq: { a: number, b?: number };
->abq : { a: number; b?: number; }
+>abq : { a: number; b?: number | undefined; }
 >a : number
 >b : number | undefined
 
@@ -27,7 +27,7 @@ var unused3 = { b: 1, ...abq } // ok, abq might have b: undefined
 >{ b: 1, ...abq } : { a: number; b: number; }
 >b : number
 >1 : 1
->abq : { a: number; b?: number; }
+>abq : { a: number; b?: number | undefined; }
 
 var unused4 = { ...ab, b: 1 } // ok, we don't care that b in ab is overwritten
 >unused4 : { b: number; a: number; }
@@ -39,7 +39,7 @@ var unused4 = { ...ab, b: 1 } // ok, we don't care that b in ab is overwritten
 var unused5 = { ...abq, b: 1 } // ok
 >unused5 : { b: number; a: number; }
 >{ ...abq, b: 1 } : { b: number; a: number; }
->abq : { a: number; b?: number; }
+>abq : { a: number; b?: number | undefined; }
 >b : number
 >1 : 1
 
@@ -78,14 +78,14 @@ function h(obj: { x: number } | { x: string }) {
 >obj : { x: number; } | { x: string; }
 }
 function i(b: boolean, t: { command: string, ok: string }) {
->i : (b: boolean, t: {    command: string;    ok: string;}) => { command: string; ok?: string; }
+>i : (b: boolean, t: {    command: string;    ok: string;}) => { command: string; ok?: string | undefined; }
 >b : boolean
 >t : { command: string; ok: string; }
 >command : string
 >ok : string
 
     return { command: "hi", ...(b ? t : {}) } // ok
->{ command: "hi", ...(b ? t : {}) } : { command: string; ok?: string; }
+>{ command: "hi", ...(b ? t : {}) } : { command: string; ok?: string | undefined; }
 >command : string
 >"hi" : "hi"
 >(b ? t : {}) : { command: string; ok: string; } | {}

tests/baselines/reference/tsConfig/Default initialized TSConfig/tsconfig.json

@@ -79,12 +79,12 @@
     // "strictFunctionTypes": true,                      /* When assigning functions, check to ensure parameters and the return values are subtype-compatible. */
     // "strictBindCallApply": true,                      /* Check that the arguments for `bind`, `call`, and `apply` methods match the original function. */
     // "strictPropertyInitialization": true,             /* Check for class properties that are declared but not set in the constructor. */
-    // "strictOptionalProperties": true,                 /* Enable strict checking of optional properties. */
     // "noImplicitThis": true,                           /* Enable error reporting when `this` is given the type `any`. */
     // "useUnknownInCatchVariables": true,               /* Type catch clause variables as 'unknown' instead of 'any'. */
     // "alwaysStrict": true,                             /* Ensure 'use strict' is always emitted. */
     // "noUnusedLocals": true,                           /* Enable error reporting when a local variables aren't read. */
     // "noUnusedParameters": true,                       /* Raise an error when a function parameter isn't read */
+    // "exactOptionalPropertyTypes": true,               /* Interpret optional property types as written, rather than adding 'undefined'. */
     // "noImplicitReturns": true,                        /* Enable error reporting for codepaths that do not explicitly return in a function. */
     // "noFallthroughCasesInSwitch": true,               /* Enable error reporting for fallthrough cases in switch statements. */
     // "noUncheckedIndexedAccess": true,                 /* Include 'undefined' in index signature results */

tests/baselines/reference/tsConfig/Initialized TSConfig with advanced options/tsconfig.json

@@ -79,12 +79,12 @@
     // "strictFunctionTypes": true,                      /* When assigning functions, check to ensure parameters and the return values are subtype-compatible. */
     // "strictBindCallApply": true,                      /* Check that the arguments for `bind`, `call`, and `apply` methods match the original function. */
     // "strictPropertyInitialization": true,             /* Check for class properties that are declared but not set in the constructor. */
-    // "strictOptionalProperties": true,                 /* Enable strict checking of optional properties. */
     // "noImplicitThis": true,                           /* Enable error reporting when `this` is given the type `any`. */
     // "useUnknownInCatchVariables": true,               /* Type catch clause variables as 'unknown' instead of 'any'. */
     // "alwaysStrict": true,                             /* Ensure 'use strict' is always emitted. */
     // "noUnusedLocals": true,                           /* Enable error reporting when a local variables aren't read. */
     // "noUnusedParameters": true,                       /* Raise an error when a function parameter isn't read */
+    // "exactOptionalPropertyTypes": true,               /* Interpret optional property types as written, rather than adding 'undefined'. */
     // "noImplicitReturns": true,                        /* Enable error reporting for codepaths that do not explicitly return in a function. */
     // "noFallthroughCasesInSwitch": true,               /* Enable error reporting for fallthrough cases in switch statements. */
     // "noUncheckedIndexedAccess": true,                 /* Include 'undefined' in index signature results */

tests/baselines/reference/tsConfig/Initialized TSConfig with boolean value compiler options/tsconfig.json

@@ -79,12 +79,12 @@
     // "strictFunctionTypes": true,                      /* When assigning functions, check to ensure parameters and the return values are subtype-compatible. */
     // "strictBindCallApply": true,                      /* Check that the arguments for `bind`, `call`, and `apply` methods match the original function. */
     // "strictPropertyInitialization": true,             /* Check for class properties that are declared but not set in the constructor. */
-    // "strictOptionalProperties": true,                 /* Enable strict checking of optional properties. */
     // "noImplicitThis": true,                           /* Enable error reporting when `this` is given the type `any`. */
     // "useUnknownInCatchVariables": true,               /* Type catch clause variables as 'unknown' instead of 'any'. */
     // "alwaysStrict": true,                             /* Ensure 'use strict' is always emitted. */
     "noUnusedLocals": true,                              /* Enable error reporting when a local variables aren't read. */
     // "noUnusedParameters": true,                       /* Raise an error when a function parameter isn't read */
+    // "exactOptionalPropertyTypes": true,               /* Interpret optional property types as written, rather than adding 'undefined'. */
     // "noImplicitReturns": true,                        /* Enable error reporting for codepaths that do not explicitly return in a function. */
     // "noFallthroughCasesInSwitch": true,               /* Enable error reporting for fallthrough cases in switch statements. */
     // "noUncheckedIndexedAccess": true,                 /* Include 'undefined' in index signature results */

tests/baselines/reference/tsConfig/Initialized TSConfig with enum value compiler options/tsconfig.json

@@ -79,12 +79,12 @@
     // "strictFunctionTypes": true,                      /* When assigning functions, check to ensure parameters and the return values are subtype-compatible. */
     // "strictBindCallApply": true,                      /* Check that the arguments for `bind`, `call`, and `apply` methods match the original function. */
     // "strictPropertyInitialization": true,             /* Check for class properties that are declared but not set in the constructor. */
-    // "strictOptionalProperties": true,                 /* Enable strict checking of optional properties. */
     // "noImplicitThis": true,                           /* Enable error reporting when `this` is given the type `any`. */
     // "useUnknownInCatchVariables": true,               /* Type catch clause variables as 'unknown' instead of 'any'. */
     // "alwaysStrict": true,                             /* Ensure 'use strict' is always emitted. */
     // "noUnusedLocals": true,                           /* Enable error reporting when a local variables aren't read. */
     // "noUnusedParameters": true,                       /* Raise an error when a function parameter isn't read */
+    // "exactOptionalPropertyTypes": true,               /* Interpret optional property types as written, rather than adding 'undefined'. */
     // "noImplicitReturns": true,                        /* Enable error reporting for codepaths that do not explicitly return in a function. */
     // "noFallthroughCasesInSwitch": true,               /* Enable error reporting for fallthrough cases in switch statements. */
     // "noUncheckedIndexedAccess": true,                 /* Include 'undefined' in index signature results */

tests/baselines/reference/tsConfig/Initialized TSConfig with files options/tsconfig.json

@@ -79,12 +79,12 @@
     // "strictFunctionTypes": true,                      /* When assigning functions, check to ensure parameters and the return values are subtype-compatible. */
     // "strictBindCallApply": true,                      /* Check that the arguments for `bind`, `call`, and `apply` methods match the original function. */
     // "strictPropertyInitialization": true,             /* Check for class properties that are declared but not set in the constructor. */
-    // "strictOptionalProperties": true,                 /* Enable strict checking of optional properties. */
     // "noImplicitThis": true,                           /* Enable error reporting when `this` is given the type `any`. */
     // "useUnknownInCatchVariables": true,               /* Type catch clause variables as 'unknown' instead of 'any'. */
     // "alwaysStrict": true,                             /* Ensure 'use strict' is always emitted. */
     // "noUnusedLocals": true,                           /* Enable error reporting when a local variables aren't read. */
     // "noUnusedParameters": true,                       /* Raise an error when a function parameter isn't read */
+    // "exactOptionalPropertyTypes": true,               /* Interpret optional property types as written, rather than adding 'undefined'. */
     // "noImplicitReturns": true,                        /* Enable error reporting for codepaths that do not explicitly return in a function. */
     // "noFallthroughCasesInSwitch": true,               /* Enable error reporting for fallthrough cases in switch statements. */
     // "noUncheckedIndexedAccess": true,                 /* Include 'undefined' in index signature results */

tests/baselines/reference/tsConfig/Initialized TSConfig with incorrect compiler option value/tsconfig.json

@@ -79,12 +79,12 @@
     // "strictFunctionTypes": true,                      /* When assigning functions, check to ensure parameters and the return values are subtype-compatible. */
     // "strictBindCallApply": true,                      /* Check that the arguments for `bind`, `call`, and `apply` methods match the original function. */
     // "strictPropertyInitialization": true,             /* Check for class properties that are declared but not set in the constructor. */
-    // "strictOptionalProperties": true,                 /* Enable strict checking of optional properties. */
     // "noImplicitThis": true,                           /* Enable error reporting when `this` is given the type `any`. */
     // "useUnknownInCatchVariables": true,               /* Type catch clause variables as 'unknown' instead of 'any'. */
     // "alwaysStrict": true,                             /* Ensure 'use strict' is always emitted. */
     // "noUnusedLocals": true,                           /* Enable error reporting when a local variables aren't read. */
     // "noUnusedParameters": true,                       /* Raise an error when a function parameter isn't read */
+    // "exactOptionalPropertyTypes": true,               /* Interpret optional property types as written, rather than adding 'undefined'. */
     // "noImplicitReturns": true,                        /* Enable error reporting for codepaths that do not explicitly return in a function. */
     // "noFallthroughCasesInSwitch": true,               /* Enable error reporting for fallthrough cases in switch statements. */
     // "noUncheckedIndexedAccess": true,                 /* Include 'undefined' in index signature results */

tests/baselines/reference/tsConfig/Initialized TSConfig with incorrect compiler option/tsconfig.json

@@ -79,12 +79,12 @@
     // "strictFunctionTypes": true,                      /* When assigning functions, check to ensure parameters and the return values are subtype-compatible. */
     // "strictBindCallApply": true,                      /* Check that the arguments for `bind`, `call`, and `apply` methods match the original function. */
     // "strictPropertyInitialization": true,             /* Check for class properties that are declared but not set in the constructor. */
-    // "strictOptionalProperties": true,                 /* Enable strict checking of optional properties. */
     // "noImplicitThis": true,                           /* Enable error reporting when `this` is given the type `any`. */
     // "useUnknownInCatchVariables": true,               /* Type catch clause variables as 'unknown' instead of 'any'. */
     // "alwaysStrict": true,                             /* Ensure 'use strict' is always emitted. */
     // "noUnusedLocals": true,                           /* Enable error reporting when a local variables aren't read. */
     // "noUnusedParameters": true,                       /* Raise an error when a function parameter isn't read */
+    // "exactOptionalPropertyTypes": true,               /* Interpret optional property types as written, rather than adding 'undefined'. */
     // "noImplicitReturns": true,                        /* Enable error reporting for codepaths that do not explicitly return in a function. */
     // "noFallthroughCasesInSwitch": true,               /* Enable error reporting for fallthrough cases in switch statements. */
     // "noUncheckedIndexedAccess": true,                 /* Include 'undefined' in index signature results */

tests/baselines/reference/tsConfig/Initialized TSConfig with list compiler options with enum value/tsconfig.json

@@ -79,12 +79,12 @@
     // "strictFunctionTypes": true,                      /* When assigning functions, check to ensure parameters and the return values are subtype-compatible. */
     // "strictBindCallApply": true,                      /* Check that the arguments for `bind`, `call`, and `apply` methods match the original function. */
     // "strictPropertyInitialization": true,             /* Check for class properties that are declared but not set in the constructor. */
-    // "strictOptionalProperties": true,                 /* Enable strict checking of optional properties. */
     // "noImplicitThis": true,                           /* Enable error reporting when `this` is given the type `any`. */
     // "useUnknownInCatchVariables": true,               /* Type catch clause variables as 'unknown' instead of 'any'. */
     // "alwaysStrict": true,                             /* Ensure 'use strict' is always emitted. */
     // "noUnusedLocals": true,                           /* Enable error reporting when a local variables aren't read. */
     // "noUnusedParameters": true,                       /* Raise an error when a function parameter isn't read */
+    // "exactOptionalPropertyTypes": true,               /* Interpret optional property types as written, rather than adding 'undefined'. */
     // "noImplicitReturns": true,                        /* Enable error reporting for codepaths that do not explicitly return in a function. */
     // "noFallthroughCasesInSwitch": true,               /* Enable error reporting for fallthrough cases in switch statements. */
     // "noUncheckedIndexedAccess": true,                 /* Include 'undefined' in index signature results */

tests/baselines/reference/tsConfig/Initialized TSConfig with list compiler options/tsconfig.json

@@ -79,12 +79,12 @@
     // "strictFunctionTypes": true,                      /* When assigning functions, check to ensure parameters and the return values are subtype-compatible. */
     // "strictBindCallApply": true,                      /* Check that the arguments for `bind`, `call`, and `apply` methods match the original function. */
     // "strictPropertyInitialization": true,             /* Check for class properties that are declared but not set in the constructor. */
-    // "strictOptionalProperties": true,                 /* Enable strict checking of optional properties. */
     // "noImplicitThis": true,                           /* Enable error reporting when `this` is given the type `any`. */
     // "useUnknownInCatchVariables": true,               /* Type catch clause variables as 'unknown' instead of 'any'. */
     // "alwaysStrict": true,                             /* Ensure 'use strict' is always emitted. */
     // "noUnusedLocals": true,                           /* Enable error reporting when a local variables aren't read. */
     // "noUnusedParameters": true,                       /* Raise an error when a function parameter isn't read */
+    // "exactOptionalPropertyTypes": true,               /* Interpret optional property types as written, rather than adding 'undefined'. */
     // "noImplicitReturns": true,                        /* Enable error reporting for codepaths that do not explicitly return in a function. */
     // "noFallthroughCasesInSwitch": true,               /* Enable error reporting for fallthrough cases in switch statements. */
     // "noUncheckedIndexedAccess": true,                 /* Include 'undefined' in index signature results */

tests/baselines/reference/tscWatch/programUpdates/should-not-trigger-recompilation-because-of-program-emit/declarationDir-is-specified.js

@@ -100,12 +100,12 @@ interface Array<T> { length: number; [n: number]: T; }
     // "strictFunctionTypes": true,                      /* When assigning functions, check to ensure parameters and the return values are subtype-compatible. */
     // "strictBindCallApply": true,                      /* Check that the arguments for `bind`, `call`, and `apply` methods match the original function. */
     // "strictPropertyInitialization": true,             /* Check for class properties that are declared but not set in the constructor. */
-    // "strictOptionalProperties": true,                 /* Enable strict checking of optional properties. */
     // "noImplicitThis": true,                           /* Enable error reporting when `this` is given the type `any`. */
     // "useUnknownInCatchVariables": true,               /* Type catch clause variables as 'unknown' instead of 'any'. */
     // "alwaysStrict": true,                             /* Ensure 'use strict' is always emitted. */
     // "noUnusedLocals": true,                           /* Enable error reporting when a local variables aren't read. */
     // "noUnusedParameters": true,                       /* Raise an error when a function parameter isn't read */
+    // "exactOptionalPropertyTypes": true,               /* Interpret optional property types as written, rather than adding 'undefined'. */
     // "noImplicitReturns": true,                        /* Enable error reporting for codepaths that do not explicitly return in a function. */
     // "noFallthroughCasesInSwitch": true,               /* Enable error reporting for fallthrough cases in switch statements. */
     // "noUncheckedIndexedAccess": true,                 /* Include 'undefined' in index signature results */

tests/baselines/reference/tscWatch/programUpdates/should-not-trigger-recompilation-because-of-program-emit/when-outDir-and-declarationDir-is-specified.js

@@ -100,12 +100,12 @@ interface Array<T> { length: number; [n: number]: T; }
     // "strictFunctionTypes": true,                      /* When assigning functions, check to ensure parameters and the return values are subtype-compatible. */
     // "strictBindCallApply": true,                      /* Check that the arguments for `bind`, `call`, and `apply` methods match the original function. */
     // "strictPropertyInitialization": true,             /* Check for class properties that are declared but not set in the constructor. */
-    // "strictOptionalProperties": true,                 /* Enable strict checking of optional properties. */
     // "noImplicitThis": true,                           /* Enable error reporting when `this` is given the type `any`. */
     // "useUnknownInCatchVariables": true,               /* Type catch clause variables as 'unknown' instead of 'any'. */
     // "alwaysStrict": true,                             /* Ensure 'use strict' is always emitted. */
     // "noUnusedLocals": true,                           /* Enable error reporting when a local variables aren't read. */
     // "noUnusedParameters": true,                       /* Raise an error when a function parameter isn't read */
+    // "exactOptionalPropertyTypes": true,               /* Interpret optional property types as written, rather than adding 'undefined'. */
     // "noImplicitReturns": true,                        /* Enable error reporting for codepaths that do not explicitly return in a function. */
     // "noFallthroughCasesInSwitch": true,               /* Enable error reporting for fallthrough cases in switch statements. */
     // "noUncheckedIndexedAccess": true,                 /* Include 'undefined' in index signature results */

tests/baselines/reference/tscWatch/programUpdates/should-not-trigger-recompilation-because-of-program-emit/when-outDir-is-specified.js

@@ -100,12 +100,12 @@ interface Array<T> { length: number; [n: number]: T; }
     // "strictFunctionTypes": true,                      /* When assigning functions, check to ensure parameters and the return values are subtype-compatible. */
     // "strictBindCallApply": true,                      /* Check that the arguments for `bind`, `call`, and `apply` methods match the original function. */
     // "strictPropertyInitialization": true,             /* Check for class properties that are declared but not set in the constructor. */
-    // "strictOptionalProperties": true,                 /* Enable strict checking of optional properties. */
     // "noImplicitThis": true,                           /* Enable error reporting when `this` is given the type `any`. */
     // "useUnknownInCatchVariables": true,               /* Type catch clause variables as 'unknown' instead of 'any'. */
     // "alwaysStrict": true,                             /* Ensure 'use strict' is always emitted. */
     // "noUnusedLocals": true,                           /* Enable error reporting when a local variables aren't read. */
     // "noUnusedParameters": true,                       /* Raise an error when a function parameter isn't read */
+    // "exactOptionalPropertyTypes": true,               /* Interpret optional property types as written, rather than adding 'undefined'. */
     // "noImplicitReturns": true,                        /* Enable error reporting for codepaths that do not explicitly return in a function. */
     // "noFallthroughCasesInSwitch": true,               /* Enable error reporting for fallthrough cases in switch statements. */
     // "noUncheckedIndexedAccess": true,                 /* Include 'undefined' in index signature results */

tests/baselines/reference/tscWatch/programUpdates/should-not-trigger-recompilation-because-of-program-emit/with-outFile.js

@@ -100,12 +100,12 @@ interface Array<T> { length: number; [n: number]: T; }
     // "strictFunctionTypes": true,                      /* When assigning functions, check to ensure parameters and the return values are subtype-compatible. */
     // "strictBindCallApply": true,                      /* Check that the arguments for `bind`, `call`, and `apply` methods match the original function. */
     // "strictPropertyInitialization": true,             /* Check for class properties that are declared but not set in the constructor. */
-    // "strictOptionalProperties": true,                 /* Enable strict checking of optional properties. */
     // "noImplicitThis": true,                           /* Enable error reporting when `this` is given the type `any`. */
     // "useUnknownInCatchVariables": true,               /* Type catch clause variables as 'unknown' instead of 'any'. */
     // "alwaysStrict": true,                             /* Ensure 'use strict' is always emitted. */
     // "noUnusedLocals": true,                           /* Enable error reporting when a local variables aren't read. */
     // "noUnusedParameters": true,                       /* Raise an error when a function parameter isn't read */
+    // "exactOptionalPropertyTypes": true,               /* Interpret optional property types as written, rather than adding 'undefined'. */
     // "noImplicitReturns": true,                        /* Enable error reporting for codepaths that do not explicitly return in a function. */
     // "noFallthroughCasesInSwitch": true,               /* Enable error reporting for fallthrough cases in switch statements. */
     // "noUncheckedIndexedAccess": true,                 /* Include 'undefined' in index signature results */

tests/baselines/reference/tscWatch/programUpdates/should-not-trigger-recompilation-because-of-program-emit/without-outDir-or-outFile-is-specified-with-declaration-enabled.js

@@ -100,12 +100,12 @@ interface Array<T> { length: number; [n: number]: T; }
     // "strictFunctionTypes": true,                      /* When assigning functions, check to ensure parameters and the return values are subtype-compatible. */
     // "strictBindCallApply": true,                      /* Check that the arguments for `bind`, `call`, and `apply` methods match the original function. */
     // "strictPropertyInitialization": true,             /* Check for class properties that are declared but not set in the constructor. */
-    // "strictOptionalProperties": true,                 /* Enable strict checking of optional properties. */
     // "noImplicitThis": true,                           /* Enable error reporting when `this` is given the type `any`. */
     // "useUnknownInCatchVariables": true,               /* Type catch clause variables as 'unknown' instead of 'any'. */
     // "alwaysStrict": true,                             /* Ensure 'use strict' is always emitted. */
     // "noUnusedLocals": true,                           /* Enable error reporting when a local variables aren't read. */
     // "noUnusedParameters": true,                       /* Raise an error when a function parameter isn't read */
+    // "exactOptionalPropertyTypes": true,               /* Interpret optional property types as written, rather than adding 'undefined'. */
     // "noImplicitReturns": true,                        /* Enable error reporting for codepaths that do not explicitly return in a function. */
     // "noFallthroughCasesInSwitch": true,               /* Enable error reporting for fallthrough cases in switch statements. */
     // "noUncheckedIndexedAccess": true,                 /* Include 'undefined' in index signature results */

tests/baselines/reference/tscWatch/programUpdates/should-not-trigger-recompilation-because-of-program-emit/without-outDir-or-outFile-is-specified.js

@@ -100,12 +100,12 @@ interface Array<T> { length: number; [n: number]: T; }
     // "strictFunctionTypes": true,                      /* When assigning functions, check to ensure parameters and the return values are subtype-compatible. */
     // "strictBindCallApply": true,                      /* Check that the arguments for `bind`, `call`, and `apply` methods match the original function. */
     // "strictPropertyInitialization": true,             /* Check for class properties that are declared but not set in the constructor. */
-    // "strictOptionalProperties": true,                 /* Enable strict checking of optional properties. */
     // "noImplicitThis": true,                           /* Enable error reporting when `this` is given the type `any`. */
     // "useUnknownInCatchVariables": true,               /* Type catch clause variables as 'unknown' instead of 'any'. */
     // "alwaysStrict": true,                             /* Ensure 'use strict' is always emitted. */
     // "noUnusedLocals": true,                           /* Enable error reporting when a local variables aren't read. */
     // "noUnusedParameters": true,                       /* Raise an error when a function parameter isn't read */
+    // "exactOptionalPropertyTypes": true,               /* Interpret optional property types as written, rather than adding 'undefined'. */
     // "noImplicitReturns": true,                        /* Enable error reporting for codepaths that do not explicitly return in a function. */
     // "noFallthroughCasesInSwitch": true,               /* Enable error reporting for fallthrough cases in switch statements. */
     // "noUncheckedIndexedAccess": true,                 /* Include 'undefined' in index signature results */

tests/baselines/reference/tsxInvokeComponentType.types

@@ -20,12 +20,12 @@ const good = <Elem someKey="ok" />;
 >someKey : string
 
 declare const Elem2: ComponentType<{ opt?: number }>;
->Elem2 : React.ComponentType<{ opt?: number; }>
+>Elem2 : React.ComponentType<{ opt?: number | undefined; }>
 >opt : number | undefined
 
 const alsoOk = <Elem2>text</Elem2>;
 >alsoOk : JSX.Element
 ><Elem2>text</Elem2> : JSX.Element
->Elem2 : React.ComponentType<{ opt?: number; }>
->Elem2 : React.ComponentType<{ opt?: number; }>
+>Elem2 : React.ComponentType<{ opt?: number | undefined; }>
+>Elem2 : React.ComponentType<{ opt?: number | undefined; }>
 

tests/baselines/reference/tsxLibraryManagedAttributes.errors.txt

@@ -7,7 +7,7 @@ tests/cases/conformance/jsx/tsxLibraryManagedAttributes.tsx(69,26): error TS2322
 tests/cases/conformance/jsx/tsxLibraryManagedAttributes.tsx(71,35): error TS2322: Type 'null' is not assignable to type 'ReactNode'.
 tests/cases/conformance/jsx/tsxLibraryManagedAttributes.tsx(80,38): error TS2322: Type '{ foo: number; bar: string; }' is not assignable to type 'Defaultize<{}, { foo: number; }>'.
   Property 'bar' does not exist on type 'Defaultize<{}, { foo: number; }>'.
-tests/cases/conformance/jsx/tsxLibraryManagedAttributes.tsx(81,29): error TS2322: Type 'string' is not assignable to type 'number'.
+tests/cases/conformance/jsx/tsxLibraryManagedAttributes.tsx(81,29): error TS2322: Type 'string' is not assignable to type 'number | undefined'.
 tests/cases/conformance/jsx/tsxLibraryManagedAttributes.tsx(98,12): error TS2322: Type '{ foo: string; }' is not assignable to type 'Defaultize<FooProps & InferredPropTypes<{ foo: PropTypeChecker<string, false>; bar: PropTypeChecker<ReactNode, false>; baz: PropTypeChecker<number, true>; }>, { foo: string; }>'.
   Type '{ foo: string; }' is missing the following properties from type '{ bar: ReactNode | null | undefined; baz: number; }': bar, baz
 tests/cases/conformance/jsx/tsxLibraryManagedAttributes.tsx(100,56): error TS2322: Type '{ bar: string; baz: number; bat: string; }' is not assignable to type 'Defaultize<FooProps & InferredPropTypes<{ foo: PropTypeChecker<string, false>; bar: PropTypeChecker<ReactNode, false>; baz: PropTypeChecker<number, true>; }>, { foo: string; }>'.
@@ -18,7 +18,7 @@ tests/cases/conformance/jsx/tsxLibraryManagedAttributes.tsx(112,46): error TS232
 tests/cases/conformance/jsx/tsxLibraryManagedAttributes.tsx(113,57): error TS2322: Type 'null' is not assignable to type 'ReactNode'.
 tests/cases/conformance/jsx/tsxLibraryManagedAttributes.tsx(122,58): error TS2322: Type '{ foo: string; bar: string; }' is not assignable to type 'Defaultize<FooProps, { foo: string; }>'.
   Property 'bar' does not exist on type 'Defaultize<FooProps, { foo: string; }>'.
-tests/cases/conformance/jsx/tsxLibraryManagedAttributes.tsx(123,49): error TS2322: Type 'number' is not assignable to type 'string'.
+tests/cases/conformance/jsx/tsxLibraryManagedAttributes.tsx(123,49): error TS2322: Type 'number' is not assignable to type 'string | undefined'.
 
 
 ==== tests/cases/conformance/jsx/tsxLibraryManagedAttributes.tsx (15 errors) ====
@@ -121,7 +121,7 @@ tests/cases/conformance/jsx/tsxLibraryManagedAttributes.tsx(123,49): error TS232
 !!! error TS2322:   Property 'bar' does not exist on type 'Defaultize<{}, { foo: number; }>'.
     const m = <JustDefaultProps foo="no" />; // error, wrong type
                                 ~~~
-!!! error TS2322: Type 'string' is not assignable to type 'number'.
+!!! error TS2322: Type 'string' is not assignable to type 'number | undefined'.
 !!! related TS6500 tests/cases/conformance/jsx/tsxLibraryManagedAttributes.tsx:75:9: The expected type comes from property 'foo' which is declared here on type 'Defaultize<{}, { foo: number; }>'
     
     interface FooProps {
@@ -186,7 +186,7 @@ tests/cases/conformance/jsx/tsxLibraryManagedAttributes.tsx(123,49): error TS232
 !!! error TS2322:   Property 'bar' does not exist on type 'Defaultize<FooProps, { foo: string; }>'.
     const z = <JustDefaultPropsWithSpecifiedGeneric foo={12} />; // error, wrong type
                                                     ~~~
-!!! error TS2322: Type 'number' is not assignable to type 'string'.
+!!! error TS2322: Type 'number' is not assignable to type 'string | undefined'.
 !!! related TS6500 tests/cases/conformance/jsx/tsxLibraryManagedAttributes.tsx:117:9: The expected type comes from property 'foo' which is declared here on type 'Defaultize<FooProps, { foo: string; }>'
     const aa = <JustDefaultPropsWithSpecifiedGeneric />;
     

tests/baselines/reference/typeFromContextualThisType.types

@@ -20,7 +20,7 @@ const o1 = {
 
 /** @type {{ d(): void; e?(n: number): number; f?(n: number): number; g?: number }} */
 const o2 = {
->o2 : { d(): void; e?(n: number): number; f?(n: number): number; g?: number; }
+>o2 : { d(): void; e?(n: number): number; f?(n: number): number; g?: number | undefined; }
 >{    d() {        this.e = this.f = m => this.g || m;    }} : { d(): void; }
 
     d() {
@@ -29,17 +29,17 @@ const o2 = {
         this.e = this.f = m => this.g || m;
 >this.e = this.f = m => this.g || m : (m: number) => number
 >this.e : ((n: number) => number) | undefined
->this : { d(): void; e?(n: number): number; f?(n: number): number; g?: number; }
+>this : { d(): void; e?(n: number): number; f?(n: number): number; g?: number | undefined; }
 >e : ((n: number) => number) | undefined
 >this.f = m => this.g || m : (m: number) => number
 >this.f : ((n: number) => number) | undefined
->this : { d(): void; e?(n: number): number; f?(n: number): number; g?: number; }
+>this : { d(): void; e?(n: number): number; f?(n: number): number; g?: number | undefined; }
 >f : ((n: number) => number) | undefined
 >m => this.g || m : (m: number) => number
 >m : number
 >this.g || m : number
 >this.g : number | undefined
->this : { d(): void; e?(n: number): number; f?(n: number): number; g?: number; }
+>this : { d(): void; e?(n: number): number; f?(n: number): number; g?: number | undefined; }
 >g : number | undefined
 >m : number
     }

tests/baselines/reference/typeGuardNarrowsIndexedAccessOfKnownProperty.types

@@ -290,15 +290,15 @@ function check(z: Z, c: C) {
 
 export function g(pair: [number, string?]): string {
 >g : (pair: [number, string?]) => string
->pair : [number, string?]
+>pair : [number, (string | undefined)?]
 
     return pair[1] ? pair[1] : 'nope';
 >pair[1] ? pair[1] : 'nope' : string
 >pair[1] : string | undefined
->pair : [number, string?]
+>pair : [number, (string | undefined)?]
 >1 : 1
 >pair[1] : string
->pair : [number, string?]
+>pair : [number, (string | undefined)?]
 >1 : 1
 >'nope' : "nope"
 }

tests/baselines/reference/unionExcessPropsWithPartialMember.types

@@ -22,9 +22,9 @@ declare var a: A;
 >a : A
 
 ab = {...a, y: (null as any as string | undefined)}; // Should be allowed, since `y` is missing on `A`
->ab = {...a, y: (null as any as string | undefined)} : { y: string | undefined; unused?: string; x: string; }
+>ab = {...a, y: (null as any as string | undefined)} : { y: string | undefined; unused?: string | undefined; x: string; }
 >ab : A | B
->{...a, y: (null as any as string | undefined)} : { y: string | undefined; unused?: string; x: string; }
+>{...a, y: (null as any as string | undefined)} : { y: string | undefined; unused?: string | undefined; x: string; }
 >a : A
 >y : string | undefined
 >(null as any as string | undefined) : string | undefined

tests/baselines/reference/unionTypeInference.types

@@ -213,26 +213,26 @@ async function fun<T>(deepPromised: DeepPromised<T>) {
 >deepPromised : DeepPromised<T>
 
     for (const value of Object.values(deepPromisedWithIndexer)) {
->value : {} | ({ [containsPromises]?: true; } & {}) | Promise<{ [containsPromises]?: true; } & {}> | null | undefined
->Object.values(deepPromisedWithIndexer) : ({} | ({ [containsPromises]?: true; } & {}) | Promise<{ [containsPromises]?: true; } & {}> | null | undefined)[]
+>value : {} | ({ [containsPromises]?: true | undefined; } & {}) | Promise<{ [containsPromises]?: true | undefined; } & {}> | null | undefined
+>Object.values(deepPromisedWithIndexer) : ({} | ({ [containsPromises]?: true | undefined; } & {}) | Promise<{ [containsPromises]?: true | undefined; } & {}> | null | undefined)[]
 >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[]; }
 >deepPromisedWithIndexer : DeepPromised<{ [name: string]: {} | null | undefined; }>
 
         const awaitedValue = await value;
->awaitedValue : {} | ({ [containsPromises]?: true; } & {}) | null | undefined
->await value : {} | ({ [containsPromises]?: true; } & {}) | null | undefined
->value : {} | ({ [containsPromises]?: true; } & {}) | Promise<{ [containsPromises]?: true; } & {}> | null | undefined
+>awaitedValue : {} | ({ [containsPromises]?: true | undefined; } & {}) | null | undefined
+>await value : {} | ({ [containsPromises]?: true | undefined; } & {}) | null | undefined
+>value : {} | ({ [containsPromises]?: true | undefined; } & {}) | Promise<{ [containsPromises]?: true | undefined; } & {}> | null | undefined
 
         if (awaitedValue)
->awaitedValue : {} | ({ [containsPromises]?: true; } & {}) | null | undefined
+>awaitedValue : {} | ({ [containsPromises]?: true | undefined; } & {}) | null | undefined
 
             await fun(awaitedValue);
 >await fun(awaitedValue) : void
 >fun(awaitedValue) : Promise<void>
 >fun : <T>(deepPromised: DeepPromised<T>) => Promise<void>
->awaitedValue : {} | ({ [containsPromises]?: true; } & {})
+>awaitedValue : {} | ({ [containsPromises]?: true | undefined; } & {})
     }
 }
 

tests/baselines/reference/uniqueSymbolAssignmentOnGlobalAugmentationSuceeds.types

@@ -21,7 +21,7 @@ export function foo<T>(p: Promise<T>) {
 
     p[FOO_SYMBOL] = 3;
 >p[FOO_SYMBOL] = 3 : 3
->p[FOO_SYMBOL] : number
+>p[FOO_SYMBOL] : number | undefined
 >p : Promise<T>
 >FOO_SYMBOL : unique symbol
 >3 : 3

tests/baselines/reference/variadicTuples1.errors.txt

@@ -35,7 +35,7 @@ tests/cases/conformance/types/tuple/variadicTuples1.ts(191,5): error TS2322: Typ
     'T' is assignable to the constraint of type 'U', but 'U' could be instantiated with a different subtype of constraint 'readonly string[]'.
 tests/cases/conformance/types/tuple/variadicTuples1.ts(203,5): error TS2322: Type 'string' is not assignable to type 'keyof [1, 2, ...T]'.
   Type '"2"' is not assignable to type 'number | "0" | keyof T[] | "1"'.
-tests/cases/conformance/types/tuple/variadicTuples1.ts(357,26): error TS2322: Type 'string' is not assignable to type 'number'.
+tests/cases/conformance/types/tuple/variadicTuples1.ts(357,26): error TS2322: Type 'string' is not assignable to type 'number | undefined'.
 tests/cases/conformance/types/tuple/variadicTuples1.ts(397,7): error TS2322: Type '[false, false]' is not assignable to type '[...number[], boolean]'.
   Type at position 0 in source is not compatible with type at position 0 in target.
     Type 'boolean' is not assignable to type 'number'.
@@ -456,7 +456,7 @@ tests/cases/conformance/types/tuple/variadicTuples1.ts(397,7): error TS2322: Typ
         let v1 = f20(args);  // U
         let v2 = f20(["foo", "bar"]);  // [string]
                              ~~~~~
-!!! error TS2322: Type 'string' is not assignable to type 'number'.
+!!! error TS2322: Type 'string' is not assignable to type 'number | undefined'.
         let v3 = f20(["foo", 42]);  // [string]
     }
     

tests/baselines/reference/variadicTuples1.types

@@ -412,10 +412,10 @@ type TM1<U extends unknown[]> = Arrayify<readonly [string, number?, ...U, ...boo
 >TM1 : readonly [string[], (number | undefined)[]?, ...Arrayify<U>, ...boolean[][]]
 
 type TP1<T extends unknown[]> = Partial<[string, ...T, number]>;  // [string?, Partial<T>, number?]
->TP1 : [string?, ...Partial<T>, number?]
+>TP1 : [(string | undefined)?, ...Partial<T>, (number | undefined)?]
 
 type TP2<T extends unknown[]> = Partial<[string, ...T, ...number[]]>;  // [string?, Partial<T>, ...(number | undefined)[]]
->TP2 : [string?, ...Partial<T>, ...(number | undefined)[]]
+>TP2 : [(string | undefined)?, ...Partial<T>, ...(number | undefined)[]]
 
 // Reverse mapping through mapped type applied to variadic tuple type
 
@@ -897,7 +897,7 @@ type T34 = DropLast<[symbol, ...string[]]>;
 >T34 : [symbol, ...string[]]
 
 type T35 = DropLast<[string?]>;
->T35 : [string?]
+>T35 : [(string | undefined)?]
 
 type T36 = DropLast<string[]>;
 >T36 : string[]
@@ -1181,11 +1181,11 @@ curry2(fn10, ['hello'], [42, true]);
 declare function ft<T extends unknown[]>(t1: [...T], t2: [...T, number?]): T;
 >ft : <T extends unknown[]>(t1: [...T], t2: [...T, number?]) => T
 >t1 : [...T]
->t2 : [...T, number?]
+>t2 : [...T, (number | undefined)?]
 
 ft([1, 2, 3], [1, 2, 3]);
 >ft([1, 2, 3], [1, 2, 3]) : [number, number, number]
->ft : <T extends unknown[]>(t1: [...T], t2: [...T, number?]) => T
+>ft : <T extends unknown[]>(t1: [...T], t2: [...T, (number | undefined)?]) => T
 >[1, 2, 3] : [number, number, number]
 >1 : 1
 >2 : 2
@@ -1197,7 +1197,7 @@ ft([1, 2, 3], [1, 2, 3]);
 
 ft([1, 2], [1, 2, 3]);
 >ft([1, 2], [1, 2, 3]) : [number, number]
->ft : <T extends unknown[]>(t1: [...T], t2: [...T, number?]) => T
+>ft : <T extends unknown[]>(t1: [...T], t2: [...T, (number | undefined)?]) => T
 >[1, 2] : [number, number]
 >1 : 1
 >2 : 2
@@ -1208,7 +1208,7 @@ ft([1, 2], [1, 2, 3]);
 
 ft(['a', 'b'], ['c', 'd'])
 >ft(['a', 'b'], ['c', 'd']) : [string, string]
->ft : <T extends unknown[]>(t1: [...T], t2: [...T, number?]) => T
+>ft : <T extends unknown[]>(t1: [...T], t2: [...T, (number | undefined)?]) => T
 >['a', 'b'] : [string, string]
 >'a' : "a"
 >'b' : "b"
@@ -1218,7 +1218,7 @@ ft(['a', 'b'], ['c', 'd'])
 
 ft(['a', 'b'], ['c', 'd', 42])
 >ft(['a', 'b'], ['c', 'd', 42]) : [string, string]
->ft : <T extends unknown[]>(t1: [...T], t2: [...T, number?]) => T
+>ft : <T extends unknown[]>(t1: [...T], t2: [...T, (number | undefined)?]) => T
 >['a', 'b'] : [string, string]
 >'a' : "a"
 >'b' : "b"
@@ -1257,22 +1257,22 @@ call(...sa, (...x) => 42);
 
 declare function f20<T extends unknown[] = []>(args: [...T, number?]): T;
 >f20 : <T extends unknown[] = []>(args: [...T, number?]) => T
->args : [...T, number?]
+>args : [...T, (number | undefined)?]
 
 function f21<U extends string[]>(args: [...U, number?]) {
 >f21 : <U extends string[]>(args: [...U, number?]) => void
->args : [...U, number?]
+>args : [...U, (number | undefined)?]
 
     let v1 = f20(args);  // U
 >v1 : U
 >f20(args) : U
->f20 : <T extends unknown[] = []>(args: [...T, number?]) => T
->args : [...U, number?]
+>f20 : <T extends unknown[] = []>(args: [...T, (number | undefined)?]) => T
+>args : [...U, (number | undefined)?]
 
     let v2 = f20(["foo", "bar"]);  // [string]
 >v2 : [string]
 >f20(["foo", "bar"]) : [string]
->f20 : <T extends unknown[] = []>(args: [...T, number?]) => T
+>f20 : <T extends unknown[] = []>(args: [...T, (number | undefined)?]) => T
 >["foo", "bar"] : [string, string]
 >"foo" : "foo"
 >"bar" : "bar"
@@ -1280,7 +1280,7 @@ function f21<U extends string[]>(args: [...U, number?]) {
     let v3 = f20(["foo", 42]);  // [string]
 >v3 : [string]
 >f20(["foo", 42]) : [string]
->f20 : <T extends unknown[] = []>(args: [...T, number?]) => T
+>f20 : <T extends unknown[] = []>(args: [...T, (number | undefined)?]) => T
 >["foo", 42] : [string, number]
 >"foo" : "foo"
 >42 : 42
@@ -1349,16 +1349,16 @@ const b = a.bind("", 1);  // Desc<[boolean], object>
 // Repro from #39607
 
 declare function getUser(id: string, options?: { x?: string }): string;
->getUser : (id: string, options?: { x?: string; } | undefined) => string
+>getUser : (id: string, options?: { x?: string | undefined; } | undefined) => string
 >id : string
->options : { x?: string; } | undefined
+>options : { x?: string | undefined; } | undefined
 >x : string | undefined
 
 declare function getOrgUser(id: string, orgId: number, options?: { y?: number, z?: boolean }): void;
->getOrgUser : (id: string, orgId: number, options?: { y?: number; z?: boolean; } | undefined) => void
+>getOrgUser : (id: string, orgId: number, options?: { y?: number | undefined; z?: boolean | undefined; } | undefined) => void
 >id : string
 >orgId : number
->options : { y?: number; z?: boolean; } | undefined
+>options : { y?: number | undefined; z?: boolean | undefined; } | undefined
 >y : number | undefined
 >z : boolean | undefined
 
@@ -1380,12 +1380,12 @@ function callApi<T extends unknown[] = [], U = void>(method: (...args: [...T, ob
 callApi(getUser);
 >callApi(getUser) : (id: string) => string
 >callApi : <T extends unknown[] = [], U = void>(method: (...args: [...T, object]) => U) => (...args_0: T) => U
->getUser : (id: string, options?: { x?: string; } | undefined) => string
+>getUser : (id: string, options?: { x?: string | undefined; } | undefined) => string
 
 callApi(getOrgUser);
 >callApi(getOrgUser) : (id: string, orgId: number) => void
 >callApi : <T extends unknown[] = [], U = void>(method: (...args: [...T, object]) => U) => (...args_0: T) => U
->getOrgUser : (id: string, orgId: number, options?: { y?: number; z?: boolean; } | undefined) => void
+>getOrgUser : (id: string, orgId: number, options?: { y?: number | undefined; z?: boolean | undefined; } | undefined) => void
 
 // Repro from #40235
 

tests/baselines/reference/variadicTuples2.types

@@ -37,7 +37,7 @@ type V23 = Tup3<[number], string[], [boolean?]>;  // [number, (string | boolean
 >V23 : [number, ...(string | boolean | undefined)[]]
 
 type V24 = Tup3<[number], [boolean?], string[]>;  // [number, boolean?, ...string[]]
->V24 : [number, boolean?, ...string[]]
+>V24 : [number, (boolean | undefined)?, ...string[]]
 
 type V25 = Tup3<string[], number[], boolean[]>;  // (string | number | boolean)[]
 >V25 : (string | number | boolean)[]
@@ -46,7 +46,7 @@ type V26 = Tup3<string[], number[], [boolean]>;  // [...(string | number)[], boo
 >V26 : [...(string | number)[], boolean]
 
 type V27 = Tup3<[number?], [string], [boolean?]>;  // [number | undefined, string, boolean?]
->V27 : [number | undefined, string, boolean?]
+>V27 : [number | undefined, string, (boolean | undefined)?]
 
 type V30<A extends unknown[]> = Tup3<A, string[], number[]>;  // [...A, ...(string | number)[]]
 >V30 : [...A, ...(string | number)[]]
@@ -58,13 +58,13 @@ type V32<A extends unknown[]> = Tup3<string[], number[], A>;  // [...(string | n
 >V32 : [...(string | number)[], ...A]
 
 type V40<A extends unknown[]> = Tup3<A, [string?], number[]>;  // [...A, string?, ...number[]]
->V40 : [...A, string?, ...number[]]
+>V40 : [...A, (string | undefined)?, ...number[]]
 
 type V41<A extends unknown[]> = Tup3<[string?], A, number[]>;  // [string?, ...A, ...number[]]
->V41 : [string?, ...A, ...number[]]
+>V41 : [(string | undefined)?, ...A, ...number[]]
 
 type V42<A extends unknown[]> = Tup3<[string?], number[], A>;  // [string?, ...number[], ...A]
->V42 : [string?, ...number[], ...A]
+>V42 : [(string | undefined)?, ...number[], ...A]
 
 type V50<A extends unknown[]> = Tup3<A, string[], [number?]>;  // [...A, ...(string | number | undefined)[]]
 >V50 : [...A, ...(string | number | undefined)[]]

tests/cases/compiler/inferenceOptionalProperties.ts

@@ -1,5 +1,5 @@
 // @strict: true
-// @strictOptionalProperties: true
+// @exactOptionalPropertyTypes: true
 // @declaration: true
 
 declare function test<T>(x: { [key: string]: T }): T;

tests/cases/compiler/inferenceOptionalPropertiesStrict.ts

@@ -1,5 +1,5 @@
 // @strict: true
-// @strictOptionalProperties: true
+// @exactOptionalPropertyTypes: true
 // @declaration: true
 
 declare function test<T>(x: { [key: string]: T }): T;

tests/cases/compiler/strictOptionalProperties1.ts

@@ -1,4 +1,5 @@
 // @strict: true
+// @exactOptionalPropertyTypes: true
 // @declaration: true
 
 function f1(obj: { a?: string, b?: string | undefined }) {

tests/cases/compiler/strictOptionalProperties2.ts

@@ -1,4 +1,5 @@
 // @strict: true
+// @exactOptionalPropertyTypes: true
 // @declaration: true
 
 // Repro from #44567