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Strip literal freshness when contextually typed by instantiable type that has return mapper constraint inferences #50759

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Strip literal freshness when contextually typed by instantiable type that has return mapper constraint inferences #50759

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410d2f7
Strip literal freshness when contextually typed by instantiable type …
andrewbranch Sep 13, 2022
5d4e489
Apply same fix to checkExpressionForMutableLocation
andrewbranch Sep 19, 2022
e12b99d
Run test varying by strictNullChecks
andrewbranch Sep 19, 2022
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15 changes: 10 additions & 5 deletions src/compiler/checker.ts
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Expand Up @@ -21533,9 +21533,12 @@ namespace ts {
type;
}

function getWidenedLiteralLikeTypeForContextualType(type: Type, contextualType: Type | undefined) {
function getWidenedLiteralLikeTypeForContextualType(type: Type, contextualType: Type | undefined, node?: Node | undefined) {
if (!isLiteralOfContextualType(type, contextualType)) {
type = getWidenedUniqueESSymbolType(getWidenedLiteralType(type));
const instantiatedContextualType = node && instantiateContextualType(contextualType, node, /*contextFlags*/ undefined);
if (!instantiatedContextualType || instantiatedContextualType === contextualType || !isLiteralOfContextualType(type, instantiatedContextualType)) {
type = getWidenedUniqueESSymbolType(getWidenedLiteralType(type));
}
}
return getRegularTypeOfLiteralType(type);
}
Expand Down Expand Up @@ -30340,7 +30343,7 @@ namespace ts {
// A return type inference from a binding pattern can be used in instantiating the contextual
// type of an argument later in inference, but cannot stand on its own as the final return type.
// It is incorporated into `context.returnMapper` which is used in `instantiateContextualType`,
// but doesn't need to go into `context.inferences`. This allows a an array binding pattern to
// but doesn't need to go into `context.inferences`. This allows an array binding pattern to
// produce a tuple for `T` in
// declare function f<T>(cb: () => T): T;
// const [e1, e2, e3] = f(() => [1, "hi", true]);
Expand Down Expand Up @@ -34796,7 +34799,9 @@ namespace ts {
// We strip literal freshness when an appropriate contextual type is present such that contextually typed
// literals always preserve their literal types (otherwise they might widen during type inference). An alternative
// here would be to not mark contextually typed literals as fresh in the first place.
const result = maybeTypeOfKind(type, TypeFlags.Literal) && isLiteralOfContextualType(type, instantiateContextualType(contextualType, node, /*contextFlags*/ undefined)) ?
const result = maybeTypeOfKind(type, TypeFlags.Literal) && (
isLiteralOfContextualType(type, instantiateContextualType(contextualType, node, /*contextFlags*/ undefined)) ||
isLiteralOfContextualType(type, contextualType)) ?
getRegularTypeOfLiteralType(type) : type;
return result;
}
Expand Down Expand Up @@ -34923,7 +34928,7 @@ namespace ts {
const type = checkExpression(node, checkMode, forceTuple);
return isConstContext(node) || isCommonJsExportedExpression(node) ? getRegularTypeOfLiteralType(type) :
isTypeAssertion(node) ? type :
getWidenedLiteralLikeTypeForContextualType(type, instantiateContextualType(arguments.length === 2 ? getContextualType(node, /*contextFlags*/ undefined) : contextualType, node, /*contextFlags*/ undefined));
getWidenedLiteralLikeTypeForContextualType(type, arguments.length === 2 ? getContextualType(node, /*contextFlags*/ undefined) : contextualType, node);
}

function checkPropertyAssignment(node: PropertyAssignment, checkMode?: CheckMode): Type {
Expand Down
33 changes: 33 additions & 0 deletions tests/baselines/reference/stringLiteralFreshnessContextuallyTypedByGeneric1.js
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@@ -0,0 +1,33 @@
//// [stringLiteralFreshnessContextuallyTypedByGeneric1.ts]
interface Guard<T> {
(val: unknown): val is T;
}

type ObjectGuard<T> = {
[key in keyof T]: Guard<T[key]>;
};

function isObject(val: unknown): val is Record<string, unknown> {
return val !== undefined && val !== null && typeof val === 'object' && !Array.isArray(val);
}

declare function createObjectGuard<T>(guard: ObjectGuard<T>): (val: unknown) => val is T;

declare function asLiteral<T extends (string | boolean | number)[]>(...literals: T): (val: unknown) => val is T[number]

// See type of `isWorking` - should include the type key as a union of strings
const isWorking = createObjectGuard({
// ^?
type: asLiteral('these', 'should', 'be', 'a', 'union'),
});


//// [stringLiteralFreshnessContextuallyTypedByGeneric1.js]
function isObject(val) {
return val !== undefined && val !== null && typeof val === 'object' && !Array.isArray(val);
}
// See type of `isWorking` - should include the type key as a union of strings
var isWorking = createObjectGuard({
// ^?
type: asLiteral('these', 'should', 'be', 'a', 'union')
});
72 changes: 72 additions & 0 deletions tests/baselines/reference/stringLiteralFreshnessContextuallyTypedByGeneric1.symbols
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=== tests/cases/compiler/stringLiteralFreshnessContextuallyTypedByGeneric1.ts ===
interface Guard<T> {
>Guard : Symbol(Guard, Decl(stringLiteralFreshnessContextuallyTypedByGeneric1.ts, 0, 0))
>T : Symbol(T, Decl(stringLiteralFreshnessContextuallyTypedByGeneric1.ts, 0, 16))

(val: unknown): val is T;
>val : Symbol(val, Decl(stringLiteralFreshnessContextuallyTypedByGeneric1.ts, 1, 3))
>val : Symbol(val, Decl(stringLiteralFreshnessContextuallyTypedByGeneric1.ts, 1, 3))
>T : Symbol(T, Decl(stringLiteralFreshnessContextuallyTypedByGeneric1.ts, 0, 16))
}

type ObjectGuard<T> = {
>ObjectGuard : Symbol(ObjectGuard, Decl(stringLiteralFreshnessContextuallyTypedByGeneric1.ts, 2, 1))
>T : Symbol(T, Decl(stringLiteralFreshnessContextuallyTypedByGeneric1.ts, 4, 17))

[key in keyof T]: Guard<T[key]>;
>key : Symbol(key, Decl(stringLiteralFreshnessContextuallyTypedByGeneric1.ts, 5, 3))
>T : Symbol(T, Decl(stringLiteralFreshnessContextuallyTypedByGeneric1.ts, 4, 17))
>Guard : Symbol(Guard, Decl(stringLiteralFreshnessContextuallyTypedByGeneric1.ts, 0, 0))
>T : Symbol(T, Decl(stringLiteralFreshnessContextuallyTypedByGeneric1.ts, 4, 17))
>key : Symbol(key, Decl(stringLiteralFreshnessContextuallyTypedByGeneric1.ts, 5, 3))

};

function isObject(val: unknown): val is Record<string, unknown> {
>isObject : Symbol(isObject, Decl(stringLiteralFreshnessContextuallyTypedByGeneric1.ts, 6, 2))
>val : Symbol(val, Decl(stringLiteralFreshnessContextuallyTypedByGeneric1.ts, 8, 18))
>val : Symbol(val, Decl(stringLiteralFreshnessContextuallyTypedByGeneric1.ts, 8, 18))
>Record : Symbol(Record, Decl(lib.es5.d.ts, --, --))

return val !== undefined && val !== null && typeof val === 'object' && !Array.isArray(val);
>val : Symbol(val, Decl(stringLiteralFreshnessContextuallyTypedByGeneric1.ts, 8, 18))
>undefined : Symbol(undefined)
>val : Symbol(val, Decl(stringLiteralFreshnessContextuallyTypedByGeneric1.ts, 8, 18))
>val : Symbol(val, Decl(stringLiteralFreshnessContextuallyTypedByGeneric1.ts, 8, 18))
>Array.isArray : Symbol(ArrayConstructor.isArray, Decl(lib.es5.d.ts, --, --))
>Array : Symbol(Array, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
>isArray : Symbol(ArrayConstructor.isArray, Decl(lib.es5.d.ts, --, --))
>val : Symbol(val, Decl(stringLiteralFreshnessContextuallyTypedByGeneric1.ts, 8, 18))
}

declare function createObjectGuard<T>(guard: ObjectGuard<T>): (val: unknown) => val is T;
>createObjectGuard : Symbol(createObjectGuard, Decl(stringLiteralFreshnessContextuallyTypedByGeneric1.ts, 10, 1))
>T : Symbol(T, Decl(stringLiteralFreshnessContextuallyTypedByGeneric1.ts, 12, 35))
>guard : Symbol(guard, Decl(stringLiteralFreshnessContextuallyTypedByGeneric1.ts, 12, 38))
>ObjectGuard : Symbol(ObjectGuard, Decl(stringLiteralFreshnessContextuallyTypedByGeneric1.ts, 2, 1))
>T : Symbol(T, Decl(stringLiteralFreshnessContextuallyTypedByGeneric1.ts, 12, 35))
>val : Symbol(val, Decl(stringLiteralFreshnessContextuallyTypedByGeneric1.ts, 12, 63))
>val : Symbol(val, Decl(stringLiteralFreshnessContextuallyTypedByGeneric1.ts, 12, 63))
>T : Symbol(T, Decl(stringLiteralFreshnessContextuallyTypedByGeneric1.ts, 12, 35))

declare function asLiteral<T extends (string | boolean | number)[]>(...literals: T): (val: unknown) => val is T[number]
>asLiteral : Symbol(asLiteral, Decl(stringLiteralFreshnessContextuallyTypedByGeneric1.ts, 12, 89))
>T : Symbol(T, Decl(stringLiteralFreshnessContextuallyTypedByGeneric1.ts, 14, 27))
>literals : Symbol(literals, Decl(stringLiteralFreshnessContextuallyTypedByGeneric1.ts, 14, 68))
>T : Symbol(T, Decl(stringLiteralFreshnessContextuallyTypedByGeneric1.ts, 14, 27))
>val : Symbol(val, Decl(stringLiteralFreshnessContextuallyTypedByGeneric1.ts, 14, 86))
>val : Symbol(val, Decl(stringLiteralFreshnessContextuallyTypedByGeneric1.ts, 14, 86))
>T : Symbol(T, Decl(stringLiteralFreshnessContextuallyTypedByGeneric1.ts, 14, 27))

// See type of `isWorking` - should include the type key as a union of strings
const isWorking = createObjectGuard({
>isWorking : Symbol(isWorking, Decl(stringLiteralFreshnessContextuallyTypedByGeneric1.ts, 17, 5))
>createObjectGuard : Symbol(createObjectGuard, Decl(stringLiteralFreshnessContextuallyTypedByGeneric1.ts, 10, 1))

// ^?
type: asLiteral('these', 'should', 'be', 'a', 'union'),
>type : Symbol(type, Decl(stringLiteralFreshnessContextuallyTypedByGeneric1.ts, 17, 37))
>asLiteral : Symbol(asLiteral, Decl(stringLiteralFreshnessContextuallyTypedByGeneric1.ts, 12, 89))

});

68 changes: 68 additions & 0 deletions tests/baselines/reference/stringLiteralFreshnessContextuallyTypedByGeneric1.types
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=== tests/cases/compiler/stringLiteralFreshnessContextuallyTypedByGeneric1.ts ===
interface Guard<T> {
(val: unknown): val is T;
>val : unknown
}

type ObjectGuard<T> = {
>ObjectGuard : ObjectGuard<T>

[key in keyof T]: Guard<T[key]>;
};

function isObject(val: unknown): val is Record<string, unknown> {
>isObject : (val: unknown) => val is Record<string, unknown>
>val : unknown

return val !== undefined && val !== null && typeof val === 'object' && !Array.isArray(val);
>val !== undefined && val !== null && typeof val === 'object' && !Array.isArray(val) : boolean
>val !== undefined && val !== null && typeof val === 'object' : boolean
>val !== undefined && val !== null : boolean
>val !== undefined : boolean
>val : unknown
>undefined : undefined
>val !== null : boolean
>val : unknown
>null : null
>typeof val === 'object' : boolean
>typeof val : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
>val : unknown
>'object' : "object"
>!Array.isArray(val) : boolean
>Array.isArray(val) : boolean
>Array.isArray : (arg: any) => arg is any[]
>Array : ArrayConstructor
>isArray : (arg: any) => arg is any[]
>val : object
}

declare function createObjectGuard<T>(guard: ObjectGuard<T>): (val: unknown) => val is T;
>createObjectGuard : <T>(guard: ObjectGuard<T>) => (val: unknown) => val is T
>guard : ObjectGuard<T>
>val : unknown

declare function asLiteral<T extends (string | boolean | number)[]>(...literals: T): (val: unknown) => val is T[number]
>asLiteral : <T extends (string | number | boolean)[]>(...literals: T) => (val: unknown) => val is T[number]
>literals : T
>val : unknown

// See type of `isWorking` - should include the type key as a union of strings
const isWorking = createObjectGuard({
>isWorking : (val: unknown) => val is { type: "these" | "should" | "be" | "a" | "union"; }
>createObjectGuard({// ^? type: asLiteral('these', 'should', 'be', 'a', 'union'),}) : (val: unknown) => val is { type: "these" | "should" | "be" | "a" | "union"; }
>createObjectGuard : <T>(guard: ObjectGuard<T>) => (val: unknown) => val is T
>{// ^? type: asLiteral('these', 'should', 'be', 'a', 'union'),} : { type: (val: unknown) => val is "these" | "should" | "be" | "a" | "union"; }

// ^?
type: asLiteral('these', 'should', 'be', 'a', 'union'),
>type : (val: unknown) => val is "these" | "should" | "be" | "a" | "union"
>asLiteral('these', 'should', 'be', 'a', 'union') : (val: unknown) => val is "these" | "should" | "be" | "a" | "union"
>asLiteral : <T extends (string | number | boolean)[]>(...literals: T) => (val: unknown) => val is T[number]
>'these' : "these"
>'should' : "should"
>'be' : "be"
>'a' : "a"
>'union' : "union"

});

18 changes: 18 additions & 0 deletions ...es/reference/stringLiteralFreshnessContextuallyTypedByGeneric2(strictnullchecks=false).js
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//// [stringLiteralFreshnessContextuallyTypedByGeneric2.ts]
type Model = { s: string; b: boolean }
declare let pick: <Keys extends keyof Model>(properties: readonly Keys[]) => Pick<Model, Keys>
declare let transform1: <T>(obj: T) => T
declare let transform2: <T extends {}>(obj: T) => T

const result1 = transform1(pick(["s"]))
const result2 = transform2(pick(["s"]))

const intermediate = pick(["s"])
const result3 = transform1(intermediate)


//// [stringLiteralFreshnessContextuallyTypedByGeneric2.js]
var result1 = transform1(pick(["s"]));
var result2 = transform2(pick(["s"]));
var intermediate = pick(["s"]);
var result3 = transform1(intermediate);
49 changes: 49 additions & 0 deletions ...ference/stringLiteralFreshnessContextuallyTypedByGeneric2(strictnullchecks=false).symbols
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=== tests/cases/compiler/stringLiteralFreshnessContextuallyTypedByGeneric2.ts ===
type Model = { s: string; b: boolean }
>Model : Symbol(Model, Decl(stringLiteralFreshnessContextuallyTypedByGeneric2.ts, 0, 0))
>s : Symbol(s, Decl(stringLiteralFreshnessContextuallyTypedByGeneric2.ts, 0, 14))
>b : Symbol(b, Decl(stringLiteralFreshnessContextuallyTypedByGeneric2.ts, 0, 25))

declare let pick: <Keys extends keyof Model>(properties: readonly Keys[]) => Pick<Model, Keys>
>pick : Symbol(pick, Decl(stringLiteralFreshnessContextuallyTypedByGeneric2.ts, 1, 11))
>Keys : Symbol(Keys, Decl(stringLiteralFreshnessContextuallyTypedByGeneric2.ts, 1, 19))
>Model : Symbol(Model, Decl(stringLiteralFreshnessContextuallyTypedByGeneric2.ts, 0, 0))
>properties : Symbol(properties, Decl(stringLiteralFreshnessContextuallyTypedByGeneric2.ts, 1, 45))
>Keys : Symbol(Keys, Decl(stringLiteralFreshnessContextuallyTypedByGeneric2.ts, 1, 19))
>Pick : Symbol(Pick, Decl(lib.es5.d.ts, --, --))
>Model : Symbol(Model, Decl(stringLiteralFreshnessContextuallyTypedByGeneric2.ts, 0, 0))
>Keys : Symbol(Keys, Decl(stringLiteralFreshnessContextuallyTypedByGeneric2.ts, 1, 19))

declare let transform1: <T>(obj: T) => T
>transform1 : Symbol(transform1, Decl(stringLiteralFreshnessContextuallyTypedByGeneric2.ts, 2, 11))
>T : Symbol(T, Decl(stringLiteralFreshnessContextuallyTypedByGeneric2.ts, 2, 25))
>obj : Symbol(obj, Decl(stringLiteralFreshnessContextuallyTypedByGeneric2.ts, 2, 28))
>T : Symbol(T, Decl(stringLiteralFreshnessContextuallyTypedByGeneric2.ts, 2, 25))
>T : Symbol(T, Decl(stringLiteralFreshnessContextuallyTypedByGeneric2.ts, 2, 25))

declare let transform2: <T extends {}>(obj: T) => T
>transform2 : Symbol(transform2, Decl(stringLiteralFreshnessContextuallyTypedByGeneric2.ts, 3, 11))
>T : Symbol(T, Decl(stringLiteralFreshnessContextuallyTypedByGeneric2.ts, 3, 25))
>obj : Symbol(obj, Decl(stringLiteralFreshnessContextuallyTypedByGeneric2.ts, 3, 39))
>T : Symbol(T, Decl(stringLiteralFreshnessContextuallyTypedByGeneric2.ts, 3, 25))
>T : Symbol(T, Decl(stringLiteralFreshnessContextuallyTypedByGeneric2.ts, 3, 25))

const result1 = transform1(pick(["s"]))
>result1 : Symbol(result1, Decl(stringLiteralFreshnessContextuallyTypedByGeneric2.ts, 5, 5))
>transform1 : Symbol(transform1, Decl(stringLiteralFreshnessContextuallyTypedByGeneric2.ts, 2, 11))
>pick : Symbol(pick, Decl(stringLiteralFreshnessContextuallyTypedByGeneric2.ts, 1, 11))

const result2 = transform2(pick(["s"]))
>result2 : Symbol(result2, Decl(stringLiteralFreshnessContextuallyTypedByGeneric2.ts, 6, 5))
>transform2 : Symbol(transform2, Decl(stringLiteralFreshnessContextuallyTypedByGeneric2.ts, 3, 11))
>pick : Symbol(pick, Decl(stringLiteralFreshnessContextuallyTypedByGeneric2.ts, 1, 11))

const intermediate = pick(["s"])
>intermediate : Symbol(intermediate, Decl(stringLiteralFreshnessContextuallyTypedByGeneric2.ts, 8, 5))
>pick : Symbol(pick, Decl(stringLiteralFreshnessContextuallyTypedByGeneric2.ts, 1, 11))

const result3 = transform1(intermediate)
>result3 : Symbol(result3, Decl(stringLiteralFreshnessContextuallyTypedByGeneric2.ts, 9, 5))
>transform1 : Symbol(transform1, Decl(stringLiteralFreshnessContextuallyTypedByGeneric2.ts, 2, 11))
>intermediate : Symbol(intermediate, Decl(stringLiteralFreshnessContextuallyTypedByGeneric2.ts, 8, 5))

49 changes: 49 additions & 0 deletions ...reference/stringLiteralFreshnessContextuallyTypedByGeneric2(strictnullchecks=false).types
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=== tests/cases/compiler/stringLiteralFreshnessContextuallyTypedByGeneric2.ts ===
type Model = { s: string; b: boolean }
>Model : { s: string; b: boolean; }
>s : string
>b : boolean

declare let pick: <Keys extends keyof Model>(properties: readonly Keys[]) => Pick<Model, Keys>
>pick : <Keys extends keyof Model>(properties: readonly Keys[]) => Pick<Model, Keys>
>properties : readonly Keys[]

declare let transform1: <T>(obj: T) => T
>transform1 : <T>(obj: T) => T
>obj : T

declare let transform2: <T extends {}>(obj: T) => T
>transform2 : <T extends {}>(obj: T) => T
>obj : T

const result1 = transform1(pick(["s"]))
>result1 : Pick<Model, "s">
>transform1(pick(["s"])) : Pick<Model, "s">
>transform1 : <T>(obj: T) => T
>pick(["s"]) : Pick<Model, "s">
>pick : <Keys extends keyof Model>(properties: readonly Keys[]) => Pick<Model, Keys>
>["s"] : "s"[]
>"s" : "s"

const result2 = transform2(pick(["s"]))
>result2 : Pick<Model, "s">
>transform2(pick(["s"])) : Pick<Model, "s">
>transform2 : <T extends {}>(obj: T) => T
>pick(["s"]) : Pick<Model, "s">
>pick : <Keys extends keyof Model>(properties: readonly Keys[]) => Pick<Model, Keys>
>["s"] : "s"[]
>"s" : "s"

const intermediate = pick(["s"])
>intermediate : Pick<Model, "s">
>pick(["s"]) : Pick<Model, "s">
>pick : <Keys extends keyof Model>(properties: readonly Keys[]) => Pick<Model, Keys>
>["s"] : "s"[]
>"s" : "s"

const result3 = transform1(intermediate)
>result3 : Pick<Model, "s">
>transform1(intermediate) : Pick<Model, "s">
>transform1 : <T>(obj: T) => T
>intermediate : Pick<Model, "s">

18 changes: 18 additions & 0 deletions ...nes/reference/stringLiteralFreshnessContextuallyTypedByGeneric2(strictnullchecks=true).js
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//// [stringLiteralFreshnessContextuallyTypedByGeneric2.ts]
type Model = { s: string; b: boolean }
declare let pick: <Keys extends keyof Model>(properties: readonly Keys[]) => Pick<Model, Keys>
declare let transform1: <T>(obj: T) => T
declare let transform2: <T extends {}>(obj: T) => T

const result1 = transform1(pick(["s"]))
const result2 = transform2(pick(["s"]))

const intermediate = pick(["s"])
const result3 = transform1(intermediate)


//// [stringLiteralFreshnessContextuallyTypedByGeneric2.js]
var result1 = transform1(pick(["s"]));
var result2 = transform2(pick(["s"]));
var intermediate = pick(["s"]);
var result3 = transform1(intermediate);
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