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Prevent readonly symbols widening #54778

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78fe4f4
Prevent readonly unique symbols from widening
Andarist Jun 26, 2023
203ba19
Widen symbols in mutable locations early
Andarist Jun 26, 2023
1994e6c
Bring back symbol widening if the type is not accessible
Andarist Jun 26, 2023
16456d7
Use `type.symbol.valueDeclaration` to compute visibility
Andarist Jun 26, 2023
87dbb90
Add a new test case for the fixed case
Andarist Jun 26, 2023
d7dc3f9
Remove a redundant check
Andarist Jun 26, 2023
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6 changes: 3 additions & 3 deletions src/compiler/checker.ts
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Expand Up @@ -11055,8 +11055,8 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
reportErrorsFromWidening(declaration, type);
}

// always widen a 'unique symbol' type if the type was created for a different declaration.
if (type.flags & TypeFlags.UniqueESSymbol && (isBindingElement(declaration) || !declaration.type) && type.symbol !== getSymbolOfDeclaration(declaration)) {
// always widen a 'unique symbol' type if the type was created for a different declaration and if it isn't accessible
if (type.flags & TypeFlags.UniqueESSymbol && !declaration.type && type.symbol !== getSymbolOfDeclaration(declaration) && !isValueSymbolAccessible(type.symbol, type.symbol.valueDeclaration)) {
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I have a feeling that passing type.symbol.valueDeclaration to isValueSymbolAccessible here might not be 100% correct but so far I wasn't able to write a test that would fail with this

type = esSymbolType;
}

Expand Down Expand Up @@ -37570,7 +37570,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
}

function widenTypeInferredFromInitializer(declaration: HasExpressionInitializer, type: Type) {
const widened = getCombinedNodeFlagsCached(declaration) & NodeFlags.Constant || isDeclarationReadonly(declaration) ? type : getWidenedLiteralType(type);
const widened = getCombinedNodeFlagsCached(declaration) & NodeFlags.Constant || isDeclarationReadonly(declaration) ? type : getWidenedUniqueESSymbolType(getWidenedLiteralType(type));
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I think that perhaps as const should preserve the uniqueness of symbols created in object literals but that's not strictly related to this issue so I think it should be fine to tackle this separately if that's something that you think should be done.

if (isInJSFile(declaration)) {
if (isEmptyLiteralType(widened)) {
reportImplicitAny(declaration, anyType);
Expand Down
36 changes: 36 additions & 0 deletions tests/baselines/reference/indirectUniqueSymbolDeclarationEmit2.js
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@@ -0,0 +1,36 @@
//// [tests/cases/compiler/indirectUniqueSymbolDeclarationEmit2.ts] ////

//// [indirectUniqueSymbolDeclarationEmit2.ts]
// repro from https://github.com/microsoft/TypeScript/issues/53276

export const a = Symbol.toStringTag;

export class F {
[a](){ return "" }
}

export const b = (new F())[a];


//// [indirectUniqueSymbolDeclarationEmit2.js]
"use strict";
// repro from https://github.com/microsoft/TypeScript/issues/53276
Object.defineProperty(exports, "__esModule", { value: true });
exports.b = exports.F = exports.a = void 0;
exports.a = Symbol.toStringTag;
var F = /** @class */ (function () {
function F() {
}
F.prototype[exports.a] = function () { return ""; };
return F;
}());
exports.F = F;
exports.b = (new F())[exports.a];


//// [indirectUniqueSymbolDeclarationEmit2.d.ts]
export declare const a: typeof Symbol.toStringTag;
export declare class F {
[a](): string;
}
export declare const b: () => string;
24 changes: 24 additions & 0 deletions tests/baselines/reference/indirectUniqueSymbolDeclarationEmit2.symbols
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@@ -0,0 +1,24 @@
//// [tests/cases/compiler/indirectUniqueSymbolDeclarationEmit2.ts] ////

=== indirectUniqueSymbolDeclarationEmit2.ts ===
// repro from https://github.com/microsoft/TypeScript/issues/53276

export const a = Symbol.toStringTag;
>a : Symbol(a, Decl(indirectUniqueSymbolDeclarationEmit2.ts, 2, 12))
>Symbol.toStringTag : Symbol(SymbolConstructor.toStringTag, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
>Symbol : Symbol(Symbol, Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2019.symbol.d.ts, --, --))
>toStringTag : Symbol(SymbolConstructor.toStringTag, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))

export class F {
>F : Symbol(F, Decl(indirectUniqueSymbolDeclarationEmit2.ts, 2, 36))

[a](){ return "" }
>[a] : Symbol(F[a], Decl(indirectUniqueSymbolDeclarationEmit2.ts, 4, 16))
>a : Symbol(a, Decl(indirectUniqueSymbolDeclarationEmit2.ts, 2, 12))
}

export const b = (new F())[a];
>b : Symbol(b, Decl(indirectUniqueSymbolDeclarationEmit2.ts, 8, 12))
>F : Symbol(F, Decl(indirectUniqueSymbolDeclarationEmit2.ts, 2, 36))
>a : Symbol(a, Decl(indirectUniqueSymbolDeclarationEmit2.ts, 2, 12))

28 changes: 28 additions & 0 deletions tests/baselines/reference/indirectUniqueSymbolDeclarationEmit2.types
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@@ -0,0 +1,28 @@
//// [tests/cases/compiler/indirectUniqueSymbolDeclarationEmit2.ts] ////

=== indirectUniqueSymbolDeclarationEmit2.ts ===
// repro from https://github.com/microsoft/TypeScript/issues/53276

export const a = Symbol.toStringTag;
>a : unique symbol
>Symbol.toStringTag : unique symbol
>Symbol : SymbolConstructor
>toStringTag : unique symbol

export class F {
>F : F

[a](){ return "" }
>[a] : () => string
>a : unique symbol
>"" : ""
}

export const b = (new F())[a];
>b : () => string
>(new F())[a] : () => string
>(new F()) : F
>new F() : F
>F : typeof F
>a : unique symbol

24 changes: 12 additions & 12 deletions tests/baselines/reference/uniqueSymbols.types
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Expand Up @@ -29,7 +29,7 @@ const constTypeAndCall: unique symbol = Symbol();

// declaration from initializer
const constInitToConstCall = constCall;
>constInitToConstCall : symbol
>constInitToConstCall : unique symbol
>constCall : unique symbol

const constInitToLetCall = letCall;
Expand All @@ -41,7 +41,7 @@ const constInitToVarCall = varCall;
>varCall : symbol

const constInitToConstDeclAmbient = constType;
>constInitToConstDeclAmbient : symbol
>constInitToConstDeclAmbient : unique symbol
>constType : unique symbol

let letInitToConstCall = constCall;
Expand Down Expand Up @@ -201,19 +201,19 @@ declare const c: C;
>c : C

const constInitToCReadonlyStaticCall = C.readonlyStaticCall;
>constInitToCReadonlyStaticCall : symbol
>constInitToCReadonlyStaticCall : unique symbol
>C.readonlyStaticCall : unique symbol
>C : typeof C
>readonlyStaticCall : unique symbol

const constInitToCReadonlyStaticType = C.readonlyStaticType;
>constInitToCReadonlyStaticType : symbol
>constInitToCReadonlyStaticType : unique symbol
>C.readonlyStaticType : unique symbol
>C : typeof C
>readonlyStaticType : unique symbol

const constInitToCReadonlyStaticTypeAndCall = C.readonlyStaticTypeAndCall;
>constInitToCReadonlyStaticTypeAndCall : symbol
>constInitToCReadonlyStaticTypeAndCall : unique symbol
>C.readonlyStaticTypeAndCall : unique symbol
>C : typeof C
>readonlyStaticTypeAndCall : unique symbol
Expand Down Expand Up @@ -311,7 +311,7 @@ declare const i: I;
>i : I

const constInitToIReadonlyType = i.readonlyType;
>constInitToIReadonlyType : symbol
>constInitToIReadonlyType : unique symbol
>i.readonlyType : unique symbol
>i : I
>readonlyType : unique symbol
Expand Down Expand Up @@ -536,17 +536,17 @@ class C0 {
>C0 : C0

static readonly a = s;
>a : symbol
>a : unique symbol
>s : unique symbol

static readonly b = N.s;
>b : symbol
>b : unique symbol
>N.s : unique symbol
>N : typeof N
>s : unique symbol

static readonly c = N["s"];
>c : symbol
>c : unique symbol
>N["s"] : unique symbol
>N : typeof N
>"s" : "s"
Expand All @@ -568,17 +568,17 @@ class C0 {
>"s" : "s"

readonly a = s;
>a : symbol
>a : unique symbol
>s : unique symbol

readonly b = N.s;
>b : symbol
>b : unique symbol
>N.s : unique symbol
>N : typeof N
>s : unique symbol

readonly c = N["s"];
>c : symbol
>c : unique symbol
>N["s"] : unique symbol
>N : typeof N
>"s" : "s"
Expand Down
24 changes: 12 additions & 12 deletions tests/baselines/reference/uniqueSymbolsDeclarations.js
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Expand Up @@ -414,10 +414,10 @@ declare let letCall: symbol;
declare var varCall: symbol;
declare const constType: unique symbol;
declare const constTypeAndCall: unique symbol;
declare const constInitToConstCall: symbol;
declare const constInitToConstCall: typeof constCall;
declare const constInitToLetCall: symbol;
declare const constInitToVarCall: symbol;
declare const constInitToConstDeclAmbient: symbol;
declare const constInitToConstDeclAmbient: typeof constType;
declare let letInitToConstCall: symbol;
declare let letInitToLetCall: symbol;
declare let letInitToVarCall: symbol;
Expand Down Expand Up @@ -451,9 +451,9 @@ declare class C {
readwriteCall: symbol;
}
declare const c: C;
declare const constInitToCReadonlyStaticCall: symbol;
declare const constInitToCReadonlyStaticType: symbol;
declare const constInitToCReadonlyStaticTypeAndCall: symbol;
declare const constInitToCReadonlyStaticCall: typeof C.readonlyStaticCall;
declare const constInitToCReadonlyStaticType: typeof C.readonlyStaticType;
declare const constInitToCReadonlyStaticTypeAndCall: typeof C.readonlyStaticTypeAndCall;
declare const constInitToCReadwriteStaticCall: symbol;
declare const constInitToCReadonlyStaticCallWithTypeQuery: typeof C.readonlyStaticCall;
declare const constInitToCReadonlyStaticTypeWithTypeQuery: typeof C.readonlyStaticType;
Expand All @@ -469,7 +469,7 @@ interface I {
readonly readonlyType: unique symbol;
}
declare const i: I;
declare const constInitToIReadonlyType: symbol;
declare const constInitToIReadonlyType: typeof i.readonlyType;
declare const constInitToIReadonlyTypeWithTypeQuery: typeof i.readonlyType;
declare const constInitToIReadonlyTypeWithIndexedAccess: I["readonlyType"];
type L = {
Expand Down Expand Up @@ -509,15 +509,15 @@ declare const o2: {
method5(p?: symbol): symbol;
};
declare class C0 {
static readonly a: symbol;
static readonly b: symbol;
static readonly c: symbol;
static readonly a: typeof s;
static readonly b: typeof N.s;
static readonly c: typeof N.s;
static d: symbol;
static e: symbol;
static f: symbol;
readonly a: symbol;
readonly b: symbol;
readonly c: symbol;
readonly a: typeof s;
readonly b: typeof N.s;
readonly c: typeof N.s;
d: symbol;
e: symbol;
f: symbol;
Expand Down
24 changes: 12 additions & 12 deletions tests/baselines/reference/uniqueSymbolsDeclarations.types
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Expand Up @@ -29,7 +29,7 @@ const constTypeAndCall: unique symbol = Symbol();

// declaration from initializer
const constInitToConstCall = constCall;
>constInitToConstCall : symbol
>constInitToConstCall : unique symbol
>constCall : unique symbol

const constInitToLetCall = letCall;
Expand All @@ -41,7 +41,7 @@ const constInitToVarCall = varCall;
>varCall : symbol

const constInitToConstDeclAmbient = constType;
>constInitToConstDeclAmbient : symbol
>constInitToConstDeclAmbient : unique symbol
>constType : unique symbol

let letInitToConstCall = constCall;
Expand Down Expand Up @@ -194,19 +194,19 @@ declare const c: C;
>c : C

const constInitToCReadonlyStaticCall = C.readonlyStaticCall;
>constInitToCReadonlyStaticCall : symbol
>constInitToCReadonlyStaticCall : unique symbol
>C.readonlyStaticCall : unique symbol
>C : typeof C
>readonlyStaticCall : unique symbol

const constInitToCReadonlyStaticType = C.readonlyStaticType;
>constInitToCReadonlyStaticType : symbol
>constInitToCReadonlyStaticType : unique symbol
>C.readonlyStaticType : unique symbol
>C : typeof C
>readonlyStaticType : unique symbol

const constInitToCReadonlyStaticTypeAndCall = C.readonlyStaticTypeAndCall;
>constInitToCReadonlyStaticTypeAndCall : symbol
>constInitToCReadonlyStaticTypeAndCall : unique symbol
>C.readonlyStaticTypeAndCall : unique symbol
>C : typeof C
>readonlyStaticTypeAndCall : unique symbol
Expand Down Expand Up @@ -304,7 +304,7 @@ declare const i: I;
>i : I

const constInitToIReadonlyType = i.readonlyType;
>constInitToIReadonlyType : symbol
>constInitToIReadonlyType : unique symbol
>i.readonlyType : unique symbol
>i : I
>readonlyType : unique symbol
Expand Down Expand Up @@ -529,17 +529,17 @@ class C0 {
>C0 : C0

static readonly a = s;
>a : symbol
>a : unique symbol
>s : unique symbol

static readonly b = N.s;
>b : symbol
>b : unique symbol
>N.s : unique symbol
>N : typeof N
>s : unique symbol

static readonly c = N["s"];
>c : symbol
>c : unique symbol
>N["s"] : unique symbol
>N : typeof N
>"s" : "s"
Expand All @@ -561,17 +561,17 @@ class C0 {
>"s" : "s"

readonly a = s;
>a : symbol
>a : unique symbol
>s : unique symbol

readonly b = N.s;
>b : symbol
>b : unique symbol
>N.s : unique symbol
>N : typeof N
>s : unique symbol

readonly c = N["s"];
>c : symbol
>c : unique symbol
>N["s"] : unique symbol
>N : typeof N
>"s" : "s"
Expand Down
13 changes: 13 additions & 0 deletions tests/cases/compiler/indirectUniqueSymbolDeclarationEmit2.ts
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@@ -0,0 +1,13 @@
// @strict: true
// @lib: esnext
// @declaration: true

// repro from https://github.com/microsoft/TypeScript/issues/53276

export const a = Symbol.toStringTag;

export class F {
[a](){ return "" }
}

export const b = (new F())[a];