Microsoft/TypeScript

Incorrect type declarations for a constant inside a namespace merged with an enum

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#61.944 geöffnet am 25. Juni 2025

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BugDomain: Declaration EmitFix AvailableHelp Wanted

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Beschreibung

🔎 Search Terms

"enum", "namespace", "declaration", "d.ts", "const"

🕗 Version & Regression Information

  • This changed between versions 3.1.0-dev.20180906 and 3.1.0-dev.20180907

⏯ Playground Link

https://www.typescriptlang.org/play/?#code/KYOwrgtgBAYg9nKBvAUFdUBGBDATigXxRGwmAGcAHbAY2FgWTQ2AA9K5cAXKGuEcjxwAvKAF4GcAHQ5cAbkIogA

💻 Code

enum Foo {
    bar
}
namespace Foo {
    export const baz = Foo.bar;
}

🙁 Actual behavior

Typescript generates invalid d.ts for the enum value assigned to the constant (in all versions starting 3.1.0-dev.20180907)

declare enum Foo {
    bar = 0
}
declare namespace Foo {
    const baz = bar; // <-- unknown `bar` identifier, `baz` type is `any`
}

In versions before 3.1.0-dev.20180906 the constant is declared as const baz: Foo;

🙂 Expected behavior

Typescript generates a valid declaration of the constant

declare enum Foo {
    bar = 0
}
declare namespace Foo {
    const baz = Foo.bar;
}

or

declare enum Foo {
    bar = 0
}
declare namespace Foo {
    const baz: Foo;
}

Additional information about the issue

No response

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