microsoft / microsoft/TypeScript

No report of implicit any type in a generator when destructuring

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Bug Domain: check: Type Inference Help Wanted
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Description

Bug Report

🔎 Search Terms

no implicit any, generator, yield, destructure
#41348 - Report implicit any error for 'yield' result with no contextual type

🕗 Version & Regression Information

TypeScript 4.2.3

⏯ Playground Link

Playground link with relevant code

💻 Code
function* sample() {
    const a = yield 1 // error, as expected, a is implicitly any
    const { b } = yield 1 // no error, but expected, b is implicitly any
    const [c] = yield 1 // no error, but expected, c is implicitly any
}
🙁 Actual behavior

b, c implicitly have type any, but no error reported

🙂 Expected behavior

Errors reported

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 example and trace how the checker handles implicit-any diagnostics for destructuring assignments from a generator yield. Done means the sample reports errors for both destructured variables b and c, while preserving the existing diagnostic for a.

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
Clearly specified
Newbie friendliness
45/100

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