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Fix unique symbol declaration emit and add baseline test #62379

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422bdb0
Fix unique symbol .d.ts generation and add baseline test
Akshit222 Sep 2, 2025
638c34f
chore: format code
Akshit222 Sep 2, 2025
270aaee
fix(compiler): remove unused export and unnecessary @internal from is…
Akshit222 Sep 2, 2025
dca1f36
fix(compiler): enable declaration emit for uniqueSymbolReassignment t…
Akshit222 Sep 8, 2025
5db0560
Fix formatting for emitter.ts (LF line endings)
Akshit222 Sep 8, 2025
89fd4f0
test(compiler): remove stray baselines and add correct uniqueSymbolRe…
Akshit222 Sep 9, 2025
9e6554f
Delete tests/cases/compiler/uniqueSymbolReassignment.d.ts
Akshit222 Sep 9, 2025
38c02bf
Merge branch 'main' into fix-unique-symbol-dts
Akshit222 Sep 13, 2025
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13 changes: 12 additions & 1 deletion src/compiler/transformers/declarations.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -203,6 +203,7 @@ import {
tryCast,
TypeAliasDeclaration,
TypeNode,
TypeOperatorNode,
TypeParameterDeclaration,
TypeReferenceNode,
unescapeLeadingUnderscores,
Expand Down Expand Up @@ -1479,7 +1480,10 @@ export function transformDeclarations(context: TransformationContext): Transform
exportMappings.push([name, nameStr]);
}
const varDecl = factory.createVariableDeclaration(name, /*exclamationToken*/ undefined, type, /*initializer*/ undefined);
return factory.createVariableStatement(isNonContextualKeywordName ? undefined : [factory.createToken(SyntaxKind.ExportKeyword)], factory.createVariableDeclarationList([varDecl]));
const modifiers = isNonContextualKeywordName ? undefined : [factory.createToken(SyntaxKind.ExportKeyword)];
const isConst = isUniqueSymbolType(type);
const variableDeclarationList = factory.createVariableDeclarationList([varDecl], isConst ? NodeFlags.Const : NodeFlags.None);
return factory.createVariableStatement(modifiers, variableDeclarationList);
});
if (!exportMappings.length) {
declarations = mapDefined(declarations, declaration => factory.replaceModifiers(declaration, ModifierFlags.None));
Expand Down Expand Up @@ -1817,6 +1821,13 @@ export function transformDeclarations(context: TransformationContext): Transform
return isExportAssignment(node) || isExportDeclaration(node);
}

function isUniqueSymbolType(type: TypeNode | undefined): boolean {
return !!type &&
type.kind === SyntaxKind.TypeOperator &&
(type as TypeOperatorNode).operator === SyntaxKind.UniqueKeyword &&
(type as TypeOperatorNode).type.kind === SyntaxKind.SymbolKeyword;
}

function hasScopeMarker(statements: readonly Statement[]) {
return some(statements, isScopeMarker);
}
Expand Down
77 changes: 77 additions & 0 deletions tests/baselines/reference/uniqueSymbolReassignment.js
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@@ -0,0 +1,77 @@
//// [tests/cases/compiler/uniqueSymbolReassignment.ts] ////

//// [uniqueSymbolReassignment.ts]
// This is a unique symbol (const + Symbol())
const mySymbol = Symbol('Symbols.mySymbol');
const Symbols = {
mySymbol
} as const;

const anotherUnique = Symbol('symbols.anotherUnique');
const Symbols2 = {
anotherUnique
} as const;

function myFunction() {}

// Attach the unique ones
myFunction.mySymbol = Symbols.mySymbol;
myFunction.anotherUnique = Symbols2.anotherUnique;

// Non-unique symbols (regular Symbol() without const)
let nonUniqueSymbol1 = Symbol('nonUnique1');
let nonUniqueSymbol2 = Symbol('nonUnique2');

// Plain text variables (not symbols at all)
const normalVar = "not a symbol";
const symbolName = "this contains symbol but is not one";

// Attach those as well
myFunction.nonUnique1 = nonUniqueSymbol1;
myFunction.nonUnique2 = nonUniqueSymbol2;
myFunction.normalVar = normalVar;
myFunction.symbolName = symbolName;

export { myFunction };

//// [uniqueSymbolReassignment.js]
"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.myFunction = myFunction;
// This is a unique symbol (const + Symbol())
var mySymbol = Symbol('Symbols.mySymbol');
var Symbols = {
mySymbol: mySymbol
};
var anotherUnique = Symbol('symbols.anotherUnique');
var Symbols2 = {
anotherUnique: anotherUnique
};
function myFunction() { }
// Attach the unique ones
myFunction.mySymbol = Symbols.mySymbol;
myFunction.anotherUnique = Symbols2.anotherUnique;
// Non-unique symbols (regular Symbol() without const)
var nonUniqueSymbol1 = Symbol('nonUnique1');
var nonUniqueSymbol2 = Symbol('nonUnique2');
// Plain text variables (not symbols at all)
var normalVar = "not a symbol";
var symbolName = "this contains symbol but is not one";
// Attach those as well
myFunction.nonUnique1 = nonUniqueSymbol1;
myFunction.nonUnique2 = nonUniqueSymbol2;
myFunction.normalVar = normalVar;
myFunction.symbolName = symbolName;


//// [uniqueSymbolReassignment.d.ts]
declare function myFunction(): void;
declare namespace myFunction {
const mySymbol: unique symbol;
const anotherUnique: unique symbol;
var nonUnique1: symbol;
var nonUnique2: symbol;
var normalVar: string;
var symbolName: string;
}
export { myFunction };
94 changes: 94 additions & 0 deletions tests/baselines/reference/uniqueSymbolReassignment.symbols
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//// [tests/cases/compiler/uniqueSymbolReassignment.ts] ////

=== uniqueSymbolReassignment.ts ===
// This is a unique symbol (const + Symbol())
const mySymbol = Symbol('Symbols.mySymbol');
>mySymbol : Symbol(mySymbol, Decl(uniqueSymbolReassignment.ts, 1, 5))
>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, --, --))

const Symbols = {
>Symbols : Symbol(Symbols, Decl(uniqueSymbolReassignment.ts, 2, 5))

mySymbol
>mySymbol : Symbol(mySymbol, Decl(uniqueSymbolReassignment.ts, 2, 17))

} as const;
>const : Symbol(const)

const anotherUnique = Symbol('symbols.anotherUnique');
>anotherUnique : Symbol(anotherUnique, Decl(uniqueSymbolReassignment.ts, 6, 5))
>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, --, --))

const Symbols2 = {
>Symbols2 : Symbol(Symbols2, Decl(uniqueSymbolReassignment.ts, 7, 5))

anotherUnique
>anotherUnique : Symbol(anotherUnique, Decl(uniqueSymbolReassignment.ts, 7, 18))

} as const;
>const : Symbol(const)

function myFunction() {}
>myFunction : Symbol(myFunction, Decl(uniqueSymbolReassignment.ts, 9, 11), Decl(uniqueSymbolReassignment.ts, 11, 24), Decl(uniqueSymbolReassignment.ts, 14, 39), Decl(uniqueSymbolReassignment.ts, 23, 57), Decl(uniqueSymbolReassignment.ts, 26, 41) ... and 2 more)

// Attach the unique ones
myFunction.mySymbol = Symbols.mySymbol;
>myFunction.mySymbol : Symbol(myFunction.mySymbol, Decl(uniqueSymbolReassignment.ts, 11, 24))
>myFunction : Symbol(myFunction, Decl(uniqueSymbolReassignment.ts, 9, 11), Decl(uniqueSymbolReassignment.ts, 11, 24), Decl(uniqueSymbolReassignment.ts, 14, 39), Decl(uniqueSymbolReassignment.ts, 23, 57), Decl(uniqueSymbolReassignment.ts, 26, 41) ... and 2 more)
>mySymbol : Symbol(myFunction.mySymbol, Decl(uniqueSymbolReassignment.ts, 11, 24))
>Symbols.mySymbol : Symbol(mySymbol, Decl(uniqueSymbolReassignment.ts, 2, 17))
>Symbols : Symbol(Symbols, Decl(uniqueSymbolReassignment.ts, 2, 5))
>mySymbol : Symbol(mySymbol, Decl(uniqueSymbolReassignment.ts, 2, 17))

myFunction.anotherUnique = Symbols2.anotherUnique;
>myFunction.anotherUnique : Symbol(myFunction.anotherUnique, Decl(uniqueSymbolReassignment.ts, 14, 39))
>myFunction : Symbol(myFunction, Decl(uniqueSymbolReassignment.ts, 9, 11), Decl(uniqueSymbolReassignment.ts, 11, 24), Decl(uniqueSymbolReassignment.ts, 14, 39), Decl(uniqueSymbolReassignment.ts, 23, 57), Decl(uniqueSymbolReassignment.ts, 26, 41) ... and 2 more)
>anotherUnique : Symbol(myFunction.anotherUnique, Decl(uniqueSymbolReassignment.ts, 14, 39))
>Symbols2.anotherUnique : Symbol(anotherUnique, Decl(uniqueSymbolReassignment.ts, 7, 18))
>Symbols2 : Symbol(Symbols2, Decl(uniqueSymbolReassignment.ts, 7, 5))
>anotherUnique : Symbol(anotherUnique, Decl(uniqueSymbolReassignment.ts, 7, 18))

// Non-unique symbols (regular Symbol() without const)
let nonUniqueSymbol1 = Symbol('nonUnique1');
>nonUniqueSymbol1 : Symbol(nonUniqueSymbol1, Decl(uniqueSymbolReassignment.ts, 18, 3))
>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, --, --))

let nonUniqueSymbol2 = Symbol('nonUnique2');
>nonUniqueSymbol2 : Symbol(nonUniqueSymbol2, Decl(uniqueSymbolReassignment.ts, 19, 3))
>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, --, --))

// Plain text variables (not symbols at all)
const normalVar = "not a symbol";
>normalVar : Symbol(normalVar, Decl(uniqueSymbolReassignment.ts, 22, 5))

const symbolName = "this contains symbol but is not one";
>symbolName : Symbol(symbolName, Decl(uniqueSymbolReassignment.ts, 23, 5))

// Attach those as well
myFunction.nonUnique1 = nonUniqueSymbol1;
>myFunction.nonUnique1 : Symbol(myFunction.nonUnique1, Decl(uniqueSymbolReassignment.ts, 23, 57))
>myFunction : Symbol(myFunction, Decl(uniqueSymbolReassignment.ts, 9, 11), Decl(uniqueSymbolReassignment.ts, 11, 24), Decl(uniqueSymbolReassignment.ts, 14, 39), Decl(uniqueSymbolReassignment.ts, 23, 57), Decl(uniqueSymbolReassignment.ts, 26, 41) ... and 2 more)
>nonUnique1 : Symbol(myFunction.nonUnique1, Decl(uniqueSymbolReassignment.ts, 23, 57))
>nonUniqueSymbol1 : Symbol(nonUniqueSymbol1, Decl(uniqueSymbolReassignment.ts, 18, 3))

myFunction.nonUnique2 = nonUniqueSymbol2;
>myFunction.nonUnique2 : Symbol(myFunction.nonUnique2, Decl(uniqueSymbolReassignment.ts, 26, 41))
>myFunction : Symbol(myFunction, Decl(uniqueSymbolReassignment.ts, 9, 11), Decl(uniqueSymbolReassignment.ts, 11, 24), Decl(uniqueSymbolReassignment.ts, 14, 39), Decl(uniqueSymbolReassignment.ts, 23, 57), Decl(uniqueSymbolReassignment.ts, 26, 41) ... and 2 more)
>nonUnique2 : Symbol(myFunction.nonUnique2, Decl(uniqueSymbolReassignment.ts, 26, 41))
>nonUniqueSymbol2 : Symbol(nonUniqueSymbol2, Decl(uniqueSymbolReassignment.ts, 19, 3))

myFunction.normalVar = normalVar;
>myFunction.normalVar : Symbol(myFunction.normalVar, Decl(uniqueSymbolReassignment.ts, 27, 41))
>myFunction : Symbol(myFunction, Decl(uniqueSymbolReassignment.ts, 9, 11), Decl(uniqueSymbolReassignment.ts, 11, 24), Decl(uniqueSymbolReassignment.ts, 14, 39), Decl(uniqueSymbolReassignment.ts, 23, 57), Decl(uniqueSymbolReassignment.ts, 26, 41) ... and 2 more)
>normalVar : Symbol(myFunction.normalVar, Decl(uniqueSymbolReassignment.ts, 27, 41))
>normalVar : Symbol(normalVar, Decl(uniqueSymbolReassignment.ts, 22, 5))

myFunction.symbolName = symbolName;
>myFunction.symbolName : Symbol(myFunction.symbolName, Decl(uniqueSymbolReassignment.ts, 28, 33))
>myFunction : Symbol(myFunction, Decl(uniqueSymbolReassignment.ts, 9, 11), Decl(uniqueSymbolReassignment.ts, 11, 24), Decl(uniqueSymbolReassignment.ts, 14, 39), Decl(uniqueSymbolReassignment.ts, 23, 57), Decl(uniqueSymbolReassignment.ts, 26, 41) ... and 2 more)
>symbolName : Symbol(myFunction.symbolName, Decl(uniqueSymbolReassignment.ts, 28, 33))
>symbolName : Symbol(symbolName, Decl(uniqueSymbolReassignment.ts, 23, 5))

export { myFunction };
>myFunction : Symbol(myFunction, Decl(uniqueSymbolReassignment.ts, 31, 8))

176 changes: 176 additions & 0 deletions tests/baselines/reference/uniqueSymbolReassignment.types
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//// [tests/cases/compiler/uniqueSymbolReassignment.ts] ////

=== uniqueSymbolReassignment.ts ===
// This is a unique symbol (const + Symbol())
const mySymbol = Symbol('Symbols.mySymbol');
>mySymbol : unique symbol
> : ^^^^^^^^^^^^^
>Symbol('Symbols.mySymbol') : unique symbol
> : ^^^^^^^^^^^^^
>Symbol : SymbolConstructor
> : ^^^^^^^^^^^^^^^^^
>'Symbols.mySymbol' : "Symbols.mySymbol"
> : ^^^^^^^^^^^^^^^^^^

const Symbols = {
>Symbols : { readonly mySymbol: unique symbol; }
> : ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>{ mySymbol} as const : { readonly mySymbol: unique symbol; }
> : ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>{ mySymbol} : { readonly mySymbol: unique symbol; }
> : ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

mySymbol
>mySymbol : unique symbol
> : ^^^^^^^^^^^^^

} as const;

const anotherUnique = Symbol('symbols.anotherUnique');
>anotherUnique : unique symbol
> : ^^^^^^^^^^^^^
>Symbol('symbols.anotherUnique') : unique symbol
> : ^^^^^^^^^^^^^
>Symbol : SymbolConstructor
> : ^^^^^^^^^^^^^^^^^
>'symbols.anotherUnique' : "symbols.anotherUnique"
> : ^^^^^^^^^^^^^^^^^^^^^^^

const Symbols2 = {
>Symbols2 : { readonly anotherUnique: unique symbol; }
> : ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>{ anotherUnique} as const : { readonly anotherUnique: unique symbol; }
> : ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>{ anotherUnique} : { readonly anotherUnique: unique symbol; }
> : ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

anotherUnique
>anotherUnique : unique symbol
> : ^^^^^^^^^^^^^

} as const;

function myFunction() {}
>myFunction : typeof myFunction
> : ^^^^^^^^^^^^^^^^^

// Attach the unique ones
myFunction.mySymbol = Symbols.mySymbol;
>myFunction.mySymbol = Symbols.mySymbol : unique symbol
> : ^^^^^^^^^^^^^
>myFunction.mySymbol : unique symbol
> : ^^^^^^^^^^^^^
>myFunction : typeof myFunction
> : ^^^^^^^^^^^^^^^^^
>mySymbol : unique symbol
> : ^^^^^^^^^^^^^
>Symbols.mySymbol : unique symbol
> : ^^^^^^^^^^^^^
>Symbols : { readonly mySymbol: unique symbol; }
> : ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>mySymbol : unique symbol
> : ^^^^^^^^^^^^^

myFunction.anotherUnique = Symbols2.anotherUnique;
>myFunction.anotherUnique = Symbols2.anotherUnique : unique symbol
> : ^^^^^^^^^^^^^
>myFunction.anotherUnique : unique symbol
> : ^^^^^^^^^^^^^
>myFunction : typeof myFunction
> : ^^^^^^^^^^^^^^^^^
>anotherUnique : unique symbol
> : ^^^^^^^^^^^^^
>Symbols2.anotherUnique : unique symbol
> : ^^^^^^^^^^^^^
>Symbols2 : { readonly anotherUnique: unique symbol; }
> : ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>anotherUnique : unique symbol
> : ^^^^^^^^^^^^^

// Non-unique symbols (regular Symbol() without const)
let nonUniqueSymbol1 = Symbol('nonUnique1');
>nonUniqueSymbol1 : symbol
> : ^^^^^^
>Symbol('nonUnique1') : symbol
> : ^^^^^^
>Symbol : SymbolConstructor
> : ^^^^^^^^^^^^^^^^^
>'nonUnique1' : "nonUnique1"
> : ^^^^^^^^^^^^

let nonUniqueSymbol2 = Symbol('nonUnique2');
>nonUniqueSymbol2 : symbol
> : ^^^^^^
>Symbol('nonUnique2') : symbol
> : ^^^^^^
>Symbol : SymbolConstructor
> : ^^^^^^^^^^^^^^^^^
>'nonUnique2' : "nonUnique2"
> : ^^^^^^^^^^^^

// Plain text variables (not symbols at all)
const normalVar = "not a symbol";
>normalVar : "not a symbol"
> : ^^^^^^^^^^^^^^
>"not a symbol" : "not a symbol"
> : ^^^^^^^^^^^^^^

const symbolName = "this contains symbol but is not one";
>symbolName : "this contains symbol but is not one"
> : ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>"this contains symbol but is not one" : "this contains symbol but is not one"
> : ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

// Attach those as well
myFunction.nonUnique1 = nonUniqueSymbol1;
>myFunction.nonUnique1 = nonUniqueSymbol1 : symbol
> : ^^^^^^
>myFunction.nonUnique1 : symbol
> : ^^^^^^
>myFunction : typeof myFunction
> : ^^^^^^^^^^^^^^^^^
>nonUnique1 : symbol
> : ^^^^^^
>nonUniqueSymbol1 : symbol
> : ^^^^^^

myFunction.nonUnique2 = nonUniqueSymbol2;
>myFunction.nonUnique2 = nonUniqueSymbol2 : symbol
> : ^^^^^^
>myFunction.nonUnique2 : symbol
> : ^^^^^^
>myFunction : typeof myFunction
> : ^^^^^^^^^^^^^^^^^
>nonUnique2 : symbol
> : ^^^^^^
>nonUniqueSymbol2 : symbol
> : ^^^^^^

myFunction.normalVar = normalVar;
>myFunction.normalVar = normalVar : "not a symbol"
> : ^^^^^^^^^^^^^^
>myFunction.normalVar : string
> : ^^^^^^
>myFunction : typeof myFunction
> : ^^^^^^^^^^^^^^^^^
>normalVar : string
> : ^^^^^^
>normalVar : "not a symbol"
> : ^^^^^^^^^^^^^^

myFunction.symbolName = symbolName;
>myFunction.symbolName = symbolName : "this contains symbol but is not one"
> : ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>myFunction.symbolName : string
> : ^^^^^^
>myFunction : typeof myFunction
> : ^^^^^^^^^^^^^^^^^
>symbolName : string
> : ^^^^^^
>symbolName : "this contains symbol but is not one"
> : ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

export { myFunction };
>myFunction : typeof myFunction
> : ^^^^^^^^^^^^^^^^^

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