microsoft / microsoft/TypeScript
In JS, typedef tags are not bound on non-expression statements
Open
Nobody has claimed this yet.
Awaiting More Feedback
Domain: JavaScript
Suggestion
- Dominant language
- Go
- Stars
- 111k
- Forks
- 14.3k
- Avg merge
- 2d 4h
- Merged PRs (30d)
- 132
Description
/** @typedef {number} A */
var ok;
/** @typedef {number} B */
ok = 1; // also ok
/** @typedef {number} C not ok */
;
/** @typedef {number} D not ok */
if (ok) {
}
/** @type {[A, B, C, D]} */
var t = [1,2,3,4]
Expected behavior:
All of A, B, C, and D are type aliases for number.
Actual behavior:
Cannot find name 'C' and 'D'.
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 JavaScript snippet and tracing how JSDoc typedef tags are bound on variable statements, expression statements, empty statements, and if statements. The fix is complete when A, B, C, and D all resolve as number aliases in the shown type annotation, with regression coverage for these statement forms.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- javascript, typescript
- Domain
- compilers
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 45/100