microsoft / microsoft/TypeScript

Error when accessing properties on `globalThis` with the same name of a global variable

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Bug Domain: Something Else Help Wanted
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Description

🔎 Search Terms

globalThis redefined error script property does not exist

🕗 Version & Regression Information
  • This is the behavior in every version I tried
⏯ Playground Link

https://www.typescriptlang.org/play/?noImplicitAny=false&ts=5.5.0-beta#code/DYUwLgBAlgdgbgQ2FAJgRggXggc2AewCMkAVACygGcA6WRZdAbgChRIBPLXA44cq2vCSo0LNhABeXPEVIUadYSgBMLIA

💻 Code
let invalid1 = globalThis.invalid1;
let y = globalThis.invalid1;
let z = globalThis.invalid2;
🙁 Actual behavior

Property 'invalid1' does not exist on type 'typeof globalThis'.

🙂 Expected behavior

It should either complain about both invalid1 and invalid2, or neither

Additional information about the issue

It only happens in scripts and not in modules (if I add export {}, there are no reported errors).

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start with the linked TypeScript Playground repro and compare diagnostics for the script and module versions. Trace how the type checker handles globalThis property access when a same-named global variable is declared; done means invalid1 and invalid2 receive consistent diagnostics without changing the documented module behavior.

Written by the indexing model from the issue text.

Assessment

Tech stack
typescript
Domain
compilers
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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