microsoft / microsoft/TypeScript
'never' (and probably 'void') shouldn't be silently indexable types
Open
Nobody has claimed this yet.
Bug
Domain: Indexed Access Types
Rescheduled
- Dominant language
- Go
- Stars
- 111k
- Forks
- 14.3k
- Avg merge
- 2d 4h
- Merged PRs (30d)
- 132
Description
let x = [1, 2, 3, 4].forEach(x => { console.log(x));
x["hello"] = 123;
Expected: an error that x is possibly void or something
Actual: no errors
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by reproducing the provided TypeScript snippet and compare the checker’s treatment of the forEach result with the expected diagnostic. Done means the example reports that x may be void or never before allowing the indexed assignment, with coverage for the affected 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