microsoft / microsoft/TypeScript
Issue better errors for `?.` and `!.`in type-space
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Domain: Error Messages
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Description
🔎 Search Terms
typeof optional chain type error
🕗 Version & Regression Information
current
⏯ Playground Link
No response
💻 Code
type Q1 = A?.B
type Q2 = A!.B
type Q3 = typeof A?.B
type Q4 = typeof A!.B
🙁 Actual behavior
Bad error.
🙂 Expected behavior
Optional chains are not allowed in entity names. or Non-null assertions are not allowed in entity names.
Additional information about the issue
Productions like type Q = A?.B or type Q = A!.B produce a pretty bad , expected type error today. This is probably a common error - we should improve it.
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 four examples in the issue, including the type and typeof forms, and inspect the diagnostics they produce. Done means optional chains and non-null assertions in entity names report the corresponding specific error instead of the current , expected error.
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
- 45/100