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ES-conformant symbol typing #64451

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9853f5f
New RegisteredSymbol<Key> intrinsic
michaelfig Aug 10, 2026
5865d6a
Propagate a narrow `unique symbol` as if `const`
michaelfig Aug 10, 2026
99187cd
Verify symbol-keyed object property access
michaelfig Aug 10, 2026
f42f422
Place symbol compiler tests in active testdata
michaelfig Sep 25, 2026
9d2d9e6
Avoid unique symbol identities for broad registry keys
michaelfig Sep 25, 2026
c6d0ad8
Represent deferred registered symbols with a distinct type flag
michaelfig Sep 26, 2026
d91d6e0
Relate deferred registered symbols through their keys
michaelfig Oct 2, 2026
39605ea
Emit type queries for inaccessible unique symbol aliases
michaelfig Oct 3, 2026
8ed748a
Accept intended symbol behavior baselines
michaelfig Oct 3, 2026
3457127
Emit inferred registered symbol keys as mapped properties
michaelfig Oct 3, 2026
10d6b07
Simplify registered symbol type flag masks
michaelfig Oct 3, 2026
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8 changes: 4 additions & 4 deletions packages/typescript/src/enums/typeFlags.enum.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -33,7 +33,7 @@ export enum TypeFlags {
Intersection = 1 << 28,
Reserved1 = 1 << 29,
Reserved2 = 1 << 30,
Reserved3 = 1 << 31,
RegisteredESSymbol = 1 << 31,
AnyOrUnknown = Any | Unknown,
Nullable = Undefined | Null,
Literal = StringLiteral | NumberLiteral | BigIntLiteral | BooleanLiteral,
Expand All @@ -49,7 +49,7 @@ export enum TypeFlags {
BigIntLike = BigInt | BigIntLiteral,
BooleanLike = Boolean | BooleanLiteral,
EnumLike = Enum | EnumLiteral,
ESSymbolLike = ESSymbol | UniqueESSymbol,
ESSymbolLike = ESSymbol | UniqueESSymbol | RegisteredESSymbol,
VoidLike = Void | Undefined,
Primitive = StringLike | NumberLike | BigIntLike | BooleanLike | EnumLike | ESSymbolLike | VoidLike | Null,
DefinitelyNonNullable = StringLike | NumberLike | BigIntLike | BooleanLike | EnumLike | ESSymbolLike | Object | NonPrimitive,
Expand All @@ -58,13 +58,13 @@ export enum TypeFlags {
StructuredType = Object | Union | Intersection,
TypeVariable = TypeParameter | IndexedAccess,
InstantiableNonPrimitive = TypeVariable | Conditional | Substitution,
InstantiablePrimitive = Index | TemplateLiteral | StringMapping,
InstantiablePrimitive = Index | TemplateLiteral | StringMapping | RegisteredESSymbol,
Instantiable = InstantiableNonPrimitive | InstantiablePrimitive,
StructuredOrInstantiable = StructuredType | Instantiable,
ObjectFlagsType = Any | Nullable | Never | Object | Union | Intersection,
Simplifiable = IndexedAccess | Conditional | Index,
Singleton = Any | Unknown | String | Number | Boolean | BigInt | ESSymbol | Void | Undefined | Null | Never | NonPrimitive,
Narrowable = Any | Unknown | StructuredOrInstantiable | StringLike | NumberLike | BigIntLike | BooleanLike | ESSymbol | UniqueESSymbol | NonPrimitive,
Narrowable = Any | Unknown | StructuredOrInstantiable | StringLike | NumberLike | BigIntLike | BooleanLike | ESSymbolLike | NonPrimitive,
IncludesMask = Any | Unknown | Primitive | Never | Object | Union | Intersection | NonPrimitive | TemplateLiteral | StringMapping,
IncludesMissingType = TypeParameter,
IncludesNonWideningType = Index,
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20 changes: 10 additions & 10 deletions packages/typescript/src/enums/typeFlags.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -33,7 +33,7 @@ export var TypeFlags: any;
TypeFlags[TypeFlags["Intersection"] = 268435456] = "Intersection";
TypeFlags[TypeFlags["Reserved1"] = 536870912] = "Reserved1";
TypeFlags[TypeFlags["Reserved2"] = 1073741824] = "Reserved2";
TypeFlags[TypeFlags["Reserved3"] = -2147483648] = "Reserved3";
TypeFlags[TypeFlags["RegisteredESSymbol"] = -2147483648] = "RegisteredESSymbol";
TypeFlags[TypeFlags["AnyOrUnknown"] = 3] = "AnyOrUnknown";
TypeFlags[TypeFlags["Nullable"] = 12] = "Nullable";
TypeFlags[TypeFlags["Literal"] = 15360] = "Literal";
Expand All @@ -49,23 +49,23 @@ export var TypeFlags: any;
TypeFlags[TypeFlags["BigIntLike"] = 4224] = "BigIntLike";
TypeFlags[TypeFlags["BooleanLike"] = 8448] = "BooleanLike";
TypeFlags[TypeFlags["EnumLike"] = 98304] = "EnumLike";
TypeFlags[TypeFlags["ESSymbolLike"] = 16896] = "ESSymbolLike";
TypeFlags[TypeFlags["ESSymbolLike"] = -2147466752] = "ESSymbolLike";
TypeFlags[TypeFlags["VoidLike"] = 20] = "VoidLike";
TypeFlags[TypeFlags["Primitive"] = 12713980] = "Primitive";
TypeFlags[TypeFlags["DefinitelyNonNullable"] = 13893600] = "DefinitelyNonNullable";
TypeFlags[TypeFlags["DisjointDomains"] = 12812284] = "DisjointDomains";
TypeFlags[TypeFlags["Primitive"] = -2134769668] = "Primitive";
TypeFlags[TypeFlags["DefinitelyNonNullable"] = -2133590048] = "DefinitelyNonNullable";
TypeFlags[TypeFlags["DisjointDomains"] = -2134671364] = "DisjointDomains";
TypeFlags[TypeFlags["UnionOrIntersection"] = 402653184] = "UnionOrIntersection";
TypeFlags[TypeFlags["StructuredType"] = 403701760] = "StructuredType";
TypeFlags[TypeFlags["TypeVariable"] = 34078720] = "TypeVariable";
TypeFlags[TypeFlags["InstantiableNonPrimitive"] = 117964800] = "InstantiableNonPrimitive";
TypeFlags[TypeFlags["InstantiablePrimitive"] = 14680064] = "InstantiablePrimitive";
TypeFlags[TypeFlags["Instantiable"] = 132644864] = "Instantiable";
TypeFlags[TypeFlags["StructuredOrInstantiable"] = 536346624] = "StructuredOrInstantiable";
TypeFlags[TypeFlags["InstantiablePrimitive"] = -2132803584] = "InstantiablePrimitive";
TypeFlags[TypeFlags["Instantiable"] = -2014838784] = "Instantiable";
TypeFlags[TypeFlags["StructuredOrInstantiable"] = -1611137024] = "StructuredOrInstantiable";
TypeFlags[TypeFlags["ObjectFlagsType"] = 403963917] = "ObjectFlagsType";
TypeFlags[TypeFlags["Simplifiable"] = 102760448] = "Simplifiable";
TypeFlags[TypeFlags["Singleton"] = 394239] = "Singleton";
TypeFlags[TypeFlags["Narrowable"] = 536575971] = "Narrowable";
TypeFlags[TypeFlags["IncludesMask"] = 416808959] = "IncludesMask";
TypeFlags[TypeFlags["Narrowable"] = -1610907677] = "Narrowable";
TypeFlags[TypeFlags["IncludesMask"] = -1730674689] = "IncludesMask";
TypeFlags[TypeFlags["IncludesMissingType"] = 524288] = "IncludesMissingType";
TypeFlags[TypeFlags["IncludesNonWideningType"] = 2097152] = "IncludesNonWideningType";
TypeFlags[TypeFlags["IncludesWildcard"] = 33554432] = "IncludesWildcard";
Expand Down
2 changes: 1 addition & 1 deletion tsc/internal/api/enum_values_generated.go
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4 changes: 3 additions & 1 deletion tsc/internal/bundled/libs/lib.es2015.symbol.d.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -31,7 +31,7 @@ interface SymbolConstructor {
* Otherwise, returns a new symbol with this key.
* @param key key to search for.
*/
for(key: string): symbol;
for<Key extends string>(key: Key): RegisteredSymbol<Key>;

/**
* Returns a key from the global symbol registry matching the given Symbol if found.
Expand All @@ -42,3 +42,5 @@ interface SymbolConstructor {
}

declare var Symbol: SymbolConstructor;

type RegisteredSymbol<Key extends string | number> = intrinsic;
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