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Let assignability checking of generic mapped types decompose intersections on both the source and the target. #27590

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Let assignability checking of generic mapped types decompose intersections on both the source and the target. #27590

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35 changes: 30 additions & 5 deletions src/compiler/checker.ts
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Expand Up @@ -11817,6 +11817,16 @@ namespace ts {
return relation === definitelyAssignableRelation ? undefined : getConstraintOfType(type);
}

function typeRelatedToMappedTypeTemplateConstituent(source: Type, parameter: TypeParameter, templateConstituent: Type, reportErrors: boolean) {
if (templateConstituent.flags & TypeFlags.IndexedAccess &&
(<IndexedAccessType>templateConstituent).indexType === parameter) {
return isRelatedTo(source, (<IndexedAccessType>templateConstituent).objectType, reportErrors);
}
else {
return Ternary.False;
}
}

function structuredTypeRelatedTo(source: Type, target: Type, reportErrors: boolean): Ternary {
const flags = source.flags & target.flags;
if (relation === identityRelation && !(flags & TypeFlags.Object)) {
Expand Down Expand Up @@ -11853,8 +11863,10 @@ namespace ts {
let originalErrorInfo: DiagnosticMessageChain | undefined;
const saveErrorInfo = errorInfo;
if (target.flags & TypeFlags.TypeParameter) {
// A source type { [P in keyof T]: X } is related to a target type T if X is related to T[P].
if (getObjectFlags(source) & ObjectFlags.Mapped && getConstraintTypeFromMappedType(<MappedType>source) === getIndexType(target)) {
// A source type { [P in K]: X } is related to a target type T if keyof T is related to K
// and X is related to T[P].
if (getObjectFlags(source) & ObjectFlags.Mapped &&
isRelatedTo(getIndexType(target), getConstraintTypeFromMappedType(<MappedType>source))) {
if (!(getMappedTypeModifiers(<MappedType>source) & MappedTypeModifiers.IncludeOptional)) {
const templateType = getTemplateTypeFromMappedType(<MappedType>source);
const indexedAccessType = getIndexedAccessType(target, getTypeParameterFromMappedType(<MappedType>source));
Expand Down Expand Up @@ -11904,9 +11916,22 @@ namespace ts {
const template = getTemplateTypeFromMappedType(target);
const modifiers = getMappedTypeModifiers(target);
if (!(modifiers & MappedTypeModifiers.ExcludeOptional)) {
if (template.flags & TypeFlags.IndexedAccess && (<IndexedAccessType>template).objectType === source &&
(<IndexedAccessType>template).indexType === getTypeParameterFromMappedType(target)) {
return Ternary.True;
const parameter = getTypeParameterFromMappedType(target);
if (template.flags & TypeFlags.Intersection) {
// C.f. typeRelatedToEachType
result = Ternary.True;
for (const templateConstituent of (<IntersectionType>template).types) {
result &= typeRelatedToMappedTypeTemplateConstituent(source, parameter, templateConstituent, reportErrors);
if (!result) {
break;
}
}
}
else {
result = typeRelatedToMappedTypeTemplateConstituent(source, parameter, template, reportErrors);
}
if (result) {
return result;
}
// A source type T is related to a target type { [P in keyof T]: X } if T[P] is related to X.
if (!isGenericMappedType(source) && getConstraintTypeFromMappedType(target) === getIndexType(source)) {
Expand Down
4 changes: 4 additions & 0 deletions tests/baselines/reference/conditionalTypes1.errors.txt
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Expand Up @@ -20,9 +20,11 @@ tests/cases/conformance/types/conditional/conditionalTypes1.ts(106,5): error TS2
Type 'keyof T' is not assignable to type 'never'.
Type 'string | number | symbol' is not assignable to type 'never'.
Type 'string' is not assignable to type 'never'.
Type 'Pick<T, { [K in keyof T]: T[K] extends Function ? never : K; }[keyof T]>' is not assignable to type 'T'.
tests/cases/conformance/types/conditional/conditionalTypes1.ts(108,5): error TS2322: Type 'Pick<T, { [K in keyof T]: T[K] extends Function ? K : never; }[keyof T]>' is not assignable to type 'Pick<T, { [K in keyof T]: T[K] extends Function ? never : K; }[keyof T]>'.
Type 'T[keyof T] extends Function ? never : keyof T' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
Type 'keyof T' is not assignable to type 'never'.
Type 'Pick<T, { [K in keyof T]: T[K] extends Function ? K : never; }[keyof T]>' is not assignable to type 'T'.
tests/cases/conformance/types/conditional/conditionalTypes1.ts(114,5): error TS2322: Type 'keyof T' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
Type 'string | number | symbol' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
Type 'string' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
Expand Down Expand Up @@ -190,12 +192,14 @@ tests/cases/conformance/types/conditional/conditionalTypes1.ts(288,43): error TS
!!! error TS2322: Type 'keyof T' is not assignable to type 'never'.
!!! error TS2322: Type 'string | number | symbol' is not assignable to type 'never'.
!!! error TS2322: Type 'string' is not assignable to type 'never'.
!!! error TS2322: Type 'Pick<T, { [K in keyof T]: T[K] extends Function ? never : K; }[keyof T]>' is not assignable to type 'T'.
z = x;
z = y; // Error
~
!!! error TS2322: Type 'Pick<T, { [K in keyof T]: T[K] extends Function ? K : never; }[keyof T]>' is not assignable to type 'Pick<T, { [K in keyof T]: T[K] extends Function ? never : K; }[keyof T]>'.
!!! error TS2322: Type 'T[keyof T] extends Function ? never : keyof T' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
!!! error TS2322: Type 'keyof T' is not assignable to type 'never'.
!!! error TS2322: Type 'Pick<T, { [K in keyof T]: T[K] extends Function ? K : never; }[keyof T]>' is not assignable to type 'T'.
}

function f8<T>(x: keyof T, y: FunctionPropertyNames<T>, z: NonFunctionPropertyNames<T>) {
Expand Down
14 changes: 14 additions & 0 deletions tests/baselines/reference/genericMappedTypeIntersections.js
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@@ -0,0 +1,14 @@
//// [genericMappedTypeIntersections.ts]
// Repro for #27484
function makePropsForWrappedComponent<PassthroughProps, ExternalProps, InjectedProps>(
outerProps: Readonly<PassthroughProps & ExternalProps>,
injectedProps: Readonly<InjectedProps>): Readonly<PassthroughProps & InjectedProps> {
return Object.assign({}, injectedProps, outerProps);
}


//// [genericMappedTypeIntersections.js]
// Repro for #27484
function makePropsForWrappedComponent(outerProps, injectedProps) {
return Object.assign({}, injectedProps, outerProps);
}
30 changes: 30 additions & 0 deletions tests/baselines/reference/genericMappedTypeIntersections.symbols
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@@ -0,0 +1,30 @@
=== tests/cases/compiler/genericMappedTypeIntersections.ts ===
// Repro for #27484
function makePropsForWrappedComponent<PassthroughProps, ExternalProps, InjectedProps>(
>makePropsForWrappedComponent : Symbol(makePropsForWrappedComponent, Decl(genericMappedTypeIntersections.ts, 0, 0))
>PassthroughProps : Symbol(PassthroughProps, Decl(genericMappedTypeIntersections.ts, 1, 38))
>ExternalProps : Symbol(ExternalProps, Decl(genericMappedTypeIntersections.ts, 1, 55))
>InjectedProps : Symbol(InjectedProps, Decl(genericMappedTypeIntersections.ts, 1, 70))

outerProps: Readonly<PassthroughProps & ExternalProps>,
>outerProps : Symbol(outerProps, Decl(genericMappedTypeIntersections.ts, 1, 86))
>Readonly : Symbol(Readonly, Decl(lib.es5.d.ts, --, --))
>PassthroughProps : Symbol(PassthroughProps, Decl(genericMappedTypeIntersections.ts, 1, 38))
>ExternalProps : Symbol(ExternalProps, Decl(genericMappedTypeIntersections.ts, 1, 55))

injectedProps: Readonly<InjectedProps>): Readonly<PassthroughProps & InjectedProps> {
>injectedProps : Symbol(injectedProps, Decl(genericMappedTypeIntersections.ts, 2, 59))
>Readonly : Symbol(Readonly, Decl(lib.es5.d.ts, --, --))
>InjectedProps : Symbol(InjectedProps, Decl(genericMappedTypeIntersections.ts, 1, 70))
>Readonly : Symbol(Readonly, Decl(lib.es5.d.ts, --, --))
>PassthroughProps : Symbol(PassthroughProps, Decl(genericMappedTypeIntersections.ts, 1, 38))
>InjectedProps : Symbol(InjectedProps, Decl(genericMappedTypeIntersections.ts, 1, 70))

return Object.assign({}, injectedProps, outerProps);
>Object.assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
>assign : Symbol(ObjectConstructor.assign, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
>injectedProps : Symbol(injectedProps, Decl(genericMappedTypeIntersections.ts, 2, 59))
>outerProps : Symbol(outerProps, Decl(genericMappedTypeIntersections.ts, 1, 86))
}

21 changes: 21 additions & 0 deletions tests/baselines/reference/genericMappedTypeIntersections.types
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@@ -0,0 +1,21 @@
=== tests/cases/compiler/genericMappedTypeIntersections.ts ===
// Repro for #27484
function makePropsForWrappedComponent<PassthroughProps, ExternalProps, InjectedProps>(
>makePropsForWrappedComponent : <PassthroughProps, ExternalProps, InjectedProps>(outerProps: Readonly<PassthroughProps & ExternalProps>, injectedProps: Readonly<InjectedProps>) => Readonly<PassthroughProps & InjectedProps>

outerProps: Readonly<PassthroughProps & ExternalProps>,
>outerProps : Readonly<PassthroughProps & ExternalProps>

injectedProps: Readonly<InjectedProps>): Readonly<PassthroughProps & InjectedProps> {
>injectedProps : Readonly<InjectedProps>

return Object.assign({}, injectedProps, outerProps);
>Object.assign({}, injectedProps, outerProps) : Readonly<InjectedProps> & Readonly<PassthroughProps & ExternalProps>
>Object.assign : { <T, U>(target: T, source: U): T & U; <T, U, V>(target: T, source1: U, source2: V): T & U & V; <T, U, V, W>(target: T, source1: U, source2: V, source3: W): T & U & V & W; (target: object, ...sources: any[]): any; }
>Object : ObjectConstructor
>assign : { <T, U>(target: T, source: U): T & U; <T, U, V>(target: T, source1: U, source2: V): T & U & V; <T, U, V, W>(target: T, source1: U, source2: V, source3: W): T & U & V & W; (target: object, ...sources: any[]): any; }
>{} : {}
>injectedProps : Readonly<InjectedProps>
>outerProps : Readonly<PassthroughProps & ExternalProps>
}

16 changes: 16 additions & 0 deletions tests/baselines/reference/mappedTypeRelationships.errors.txt
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Expand Up @@ -35,29 +35,37 @@ tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(66,5): error TS2
tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(72,5): error TS2322: Type 'Partial<T>' is not assignable to type 'T'.
tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(78,5): error TS2322: Type 'Partial<Thing>' is not assignable to type 'Partial<T>'.
tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(88,5): error TS2322: Type 'Readonly<Thing>' is not assignable to type 'Readonly<T>'.
Type 'Readonly<Thing>' is not assignable to type 'T'.
tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(127,5): error TS2322: Type 'Partial<U>' is not assignable to type 'Identity<U>'.
Type 'Partial<U>' is not assignable to type 'U'.
tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(143,5): error TS2322: Type '{ [P in keyof T]: T[P]; }' is not assignable to type '{ [P in keyof T]: U[P]; }'.
Type 'T[P]' is not assignable to type 'U[P]'.
Type 'T' is not assignable to type 'U'.
Type '{ [P in keyof T]: T[P]; }' is not assignable to type 'U'.
tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(148,5): error TS2322: Type '{ [P in keyof T]: T[P]; }' is not assignable to type '{ [P in keyof U]: U[P]; }'.
Type 'keyof U' is not assignable to type 'keyof T'.
Type 'string | number | symbol' is not assignable to type 'keyof T'.
Type 'string' is not assignable to type 'keyof T'.
Type '{ [P in keyof T]: T[P]; }' is not assignable to type 'U'.
tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(153,5): error TS2322: Type '{ [P in K]: T[P]; }' is not assignable to type '{ [P in keyof T]: T[P]; }'.
Type 'keyof T' is not assignable to type 'K'.
Type 'string | number | symbol' is not assignable to type 'K'.
Type 'string' is not assignable to type 'K'.
Type '{ [P in K]: T[P]; }' is not assignable to type 'T'.
tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(158,5): error TS2322: Type '{ [P in K]: T[P]; }' is not assignable to type '{ [P in keyof U]: U[P]; }'.
Type 'keyof U' is not assignable to type 'K'.
Type 'string | number | symbol' is not assignable to type 'K'.
Type 'string' is not assignable to type 'K'.
Type '{ [P in K]: T[P]; }' is not assignable to type 'U'.
tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(163,5): error TS2322: Type '{ [P in K]: T[P]; }' is not assignable to type '{ [P in keyof T]: U[P]; }'.
Type 'keyof T' is not assignable to type 'K'.
Type 'string | number | symbol' is not assignable to type 'K'.
Type 'string' is not assignable to type 'K'.
Type '{ [P in K]: T[P]; }' is not assignable to type 'U'.
tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(168,5): error TS2322: Type '{ [P in K]: T[P]; }' is not assignable to type '{ [P in K]: U[P]; }'.
Type 'T[P]' is not assignable to type 'U[P]'.
Type 'T' is not assignable to type 'U'.
Type '{ [P in K]: T[P]; }' is not assignable to type 'U'.


==== tests/cases/conformance/types/mapped/mappedTypeRelationships.ts (30 errors) ====
Expand Down Expand Up @@ -209,6 +217,7 @@ tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(168,5): error TS
y = x; // Error
~
!!! error TS2322: Type 'Readonly<Thing>' is not assignable to type 'Readonly<T>'.
!!! error TS2322: Type 'Readonly<Thing>' is not assignable to type 'T'.
}

type Item = {
Expand Down Expand Up @@ -250,6 +259,7 @@ tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(168,5): error TS
x = y; // Error
~
!!! error TS2322: Type 'Partial<U>' is not assignable to type 'Identity<U>'.
!!! error TS2322: Type 'Partial<U>' is not assignable to type 'U'.
y = x;
}

Expand All @@ -270,6 +280,7 @@ tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(168,5): error TS
!!! error TS2322: Type '{ [P in keyof T]: T[P]; }' is not assignable to type '{ [P in keyof T]: U[P]; }'.
!!! error TS2322: Type 'T[P]' is not assignable to type 'U[P]'.
!!! error TS2322: Type 'T' is not assignable to type 'U'.
!!! error TS2322: Type '{ [P in keyof T]: T[P]; }' is not assignable to type 'U'.
}

function f72<T, U extends T>(x: { [P in keyof T]: T[P] }, y: { [P in keyof U]: U[P] }) {
Expand All @@ -280,6 +291,7 @@ tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(168,5): error TS
!!! error TS2322: Type 'keyof U' is not assignable to type 'keyof T'.
!!! error TS2322: Type 'string | number | symbol' is not assignable to type 'keyof T'.
!!! error TS2322: Type 'string' is not assignable to type 'keyof T'.
!!! error TS2322: Type '{ [P in keyof T]: T[P]; }' is not assignable to type 'U'.
}

function f73<T, K extends keyof T>(x: { [P in K]: T[P] }, y: { [P in keyof T]: T[P] }) {
Expand All @@ -290,6 +302,7 @@ tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(168,5): error TS
!!! error TS2322: Type 'keyof T' is not assignable to type 'K'.
!!! error TS2322: Type 'string | number | symbol' is not assignable to type 'K'.
!!! error TS2322: Type 'string' is not assignable to type 'K'.
!!! error TS2322: Type '{ [P in K]: T[P]; }' is not assignable to type 'T'.
}

function f74<T, U extends T, K extends keyof T>(x: { [P in K]: T[P] }, y: { [P in keyof U]: U[P] }) {
Expand All @@ -300,6 +313,7 @@ tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(168,5): error TS
!!! error TS2322: Type 'keyof U' is not assignable to type 'K'.
!!! error TS2322: Type 'string | number | symbol' is not assignable to type 'K'.
!!! error TS2322: Type 'string' is not assignable to type 'K'.
!!! error TS2322: Type '{ [P in K]: T[P]; }' is not assignable to type 'U'.
}

function f75<T, U extends T, K extends keyof T>(x: { [P in K]: T[P] }, y: { [P in keyof T]: U[P] }) {
Expand All @@ -310,6 +324,7 @@ tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(168,5): error TS
!!! error TS2322: Type 'keyof T' is not assignable to type 'K'.
!!! error TS2322: Type 'string | number | symbol' is not assignable to type 'K'.
!!! error TS2322: Type 'string' is not assignable to type 'K'.
!!! error TS2322: Type '{ [P in K]: T[P]; }' is not assignable to type 'U'.
}

function f76<T, U extends T, K extends keyof T>(x: { [P in K]: T[P] }, y: { [P in K]: U[P] }) {
Expand All @@ -319,6 +334,7 @@ tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(168,5): error TS
!!! error TS2322: Type '{ [P in K]: T[P]; }' is not assignable to type '{ [P in K]: U[P]; }'.
!!! error TS2322: Type 'T[P]' is not assignable to type 'U[P]'.
!!! error TS2322: Type 'T' is not assignable to type 'U'.
!!! error TS2322: Type '{ [P in K]: T[P]; }' is not assignable to type 'U'.
}

function f80<T>(t: T): Partial<T> {
Expand Down
10 changes: 10 additions & 0 deletions tests/baselines/reference/mappedTypes5.errors.txt
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@@ -1,6 +1,11 @@
tests/cases/conformance/types/mapped/mappedTypes5.ts(6,9): error TS2322: Type 'Partial<T>' is not assignable to type 'Readonly<T>'.
Type 'Partial<T>' is not assignable to type 'T'.
tests/cases/conformance/types/mapped/mappedTypes5.ts(8,9): error TS2322: Type 'Partial<Readonly<T>>' is not assignable to type 'Readonly<T>'.
Type 'Partial<Readonly<T>>' is not assignable to type 'T'.
tests/cases/conformance/types/mapped/mappedTypes5.ts(9,9): error TS2322: Type 'Readonly<Partial<T>>' is not assignable to type 'Readonly<T>'.
Type 'Readonly<Partial<T>>' is not assignable to type 'T'.
Type 'T[P] | undefined' is not assignable to type 'T[P]'.
Type 'undefined' is not assignable to type 'T[P]'.


==== tests/cases/conformance/types/mapped/mappedTypes5.ts (3 errors) ====
Expand All @@ -12,13 +17,18 @@ tests/cases/conformance/types/mapped/mappedTypes5.ts(9,9): error TS2322: Type 'R
let b1: Readonly<T> = p; // Error
~~
!!! error TS2322: Type 'Partial<T>' is not assignable to type 'Readonly<T>'.
!!! error TS2322: Type 'Partial<T>' is not assignable to type 'T'.
let b2: Readonly<T> = r;
let b3: Readonly<T> = pr; // Error
~~
!!! error TS2322: Type 'Partial<Readonly<T>>' is not assignable to type 'Readonly<T>'.
!!! error TS2322: Type 'Partial<Readonly<T>>' is not assignable to type 'T'.
let b4: Readonly<T> = rp; // Error
~~
!!! error TS2322: Type 'Readonly<Partial<T>>' is not assignable to type 'Readonly<T>'.
!!! error TS2322: Type 'Readonly<Partial<T>>' is not assignable to type 'T'.
!!! error TS2322: Type 'T[P] | undefined' is not assignable to type 'T[P]'.
!!! error TS2322: Type 'undefined' is not assignable to type 'T[P]'.
let c1: Partial<Readonly<T>> = p;
let c2: Partial<Readonly<T>> = r;
let c3: Partial<Readonly<T>> = pr;
Expand Down
7 changes: 7 additions & 0 deletions tests/cases/compiler/genericMappedTypeIntersections.ts
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@@ -0,0 +1,7 @@
// Repro for #27484
// @target: es6
function makePropsForWrappedComponent<PassthroughProps, ExternalProps, InjectedProps>(
outerProps: Readonly<PassthroughProps & ExternalProps>,
injectedProps: Readonly<InjectedProps>): Readonly<PassthroughProps & InjectedProps> {
return Object.assign({}, injectedProps, outerProps);
}