Cannot auto import namespaces, and unexpectedly import variables inside the namespaces

[otomad]

Describe the bug

When you declare a TypeScript namespace, and export it by named export, it cannot be auto imported. However, export the namespace by default export works fine.

Not only that, it can also accidentally export variables and types that are inside the namespace, which cannot be accessed directly. This causes these auto imported variables to point to non-existent variables and cannot be used normally.

Example

Source code:

// src/utils/test.ts

export namespace NamedNS {
	export const foo = "foo";
	export type Foo = string;
}

namespace DefaultNS {
	export const bar = "bar";
	export type Bar = string;
}

export default DefaultNS;

Actual result dts file:

// auto-imports.d.ts

export {}
declare global {
  const bar: typeof import('./src/utils/test')['bar']
  const foo: typeof import('./src/utils/test')['foo']
  const test: typeof import('./src/utils/test')['default']
}
// for type re-export
declare global {
  export type { Foo, Bar } from './src/utils/test'
  import('./src/utils/test')
}

Expected result dts file:

// auto-imports.d.ts

export {}
declare global {
  const NamedNS: typeof import('./src/utils/test')['NamedNS']
  const test: typeof import('./src/utils/test')['default']
}
// for type re-export
declare global {
  export type { NamedNS, default as test } from './src/utils/test'
  import('./src/utils/test')
}

Reproduction

https://stackblitz.com/edit/vitejs-vite-eyr3zatt?file=src%2Futils%2Ftest.ts,auto-imports.d.ts

System Info

System:
    OS: Windows 11 10.0.26100
    CPU: (16) x64 12th Gen Intel(R) Core(TM) i5-12600KF
    Memory: 16.77 GB / 31.82 GB
  Binaries:
    Node: 23.6.1 - D:\Program Files\nodejs\node.EXE
    npm: 10.9.2 - D:\Program Files\nodejs\npm.CMD
    pnpm: 10.14.0 - D:\pnpm\pnpm.CMD
  Browsers:
    Edge: Chromium (139.0.3405.119)
    Internet Explorer: 11.0.26100.1882

Used Package Manager

pnpm

Validations

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• Read the Contributing Guide.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Check that this is a concrete bug. For Q&A, please open a GitHub Discussion instead.
• The provided reproduction is a minimal reproducible of the bug.

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• vitejs-vite-eyr3zatt (Open reproduction)