microsoft / microsoft/TypeScript
Cast to "<any[]>" not possible within "<" comparison
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Nobody has claimed this yet.
Bug
Domain: Parser
- Dominant language
- Go
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- Avg merge
- 2d 4h
- Merged PRs (30d)
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Description
This code does not work:
for (let i = 0; i < (<any[]>(<any>res).Data).length; i++) { }
if I'll refactor to this:
let ln = (<any[]>(<any>res).Data).length;
for (let i = 0; i < ln; i++) { }
it works.
is this intended?
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 two loop forms from the issue and comparing the compiler diagnostics and emitted behavior. Trace how the cast and the '<' comparison are parsed or checked, then add a regression test for the failing form and confirm that both examples behave consistently.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- typescript
- Domain
- compilers
- Issue type
- Bug
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100