Microsoft/TypeScript

tsc with allowJs reports TS9005 error for nested anonymous constructor functions

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#57,523 opened on Feb 24, 2024

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 (6 comments) (0 reactions) (0 assignees)TypeScript (6,726 forks)batch import
Domain: Declaration EmitHelp WantedPossible Improvement

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Description

🔎 Search Terms

TS9005: Declaration emit for this file requires using private name '(Anonymous function)'. An explicit type annotation may unblock declaration emit.

🕗 Version & Regression Information

  • Occurs on versions 3.7.5 - nightly
  • Related to PR #55472

Related to #55172 When 2 separate nested this bindings are used within constructor functions, the following error's returned always at the top of the file (this was really annoying to debug 😅)

Declaration emit for this file requires using private name '(Anonymous function)'. An explicit type annotation may unblock declaration emit.

⏯ Playground Link

https://tsplay.dev/NV57Gw

💻 Code

const a = new function () {
	this.b = new function () {
		this.c = 1
	}
}

🙁 Actual behavior

Complains

🙂 Expected behavior

Shouldn't complain

Additional information about the issue

No response

Contributor guide

Research direction
Investigate the code path for declaration emit when encountering nested anonymous constructor functions with 'new' and 'this' bindings. Look at PR #55472 for context.
Tech stack
typescript
Domain
devtools
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
TypeScriptDeclaration emit
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
50