Microsoft/TypeScript
Voir sur GitHubNo type inferrence of callback arguments inside a tuple union type
Open
#55 632 ouverte le 5 sept. 2023
BugDomain: check: Type InferenceHelp Wanted
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- Métriques de merge PR
- (Merge moyen 6j 17h) (9 PRs mergées en 30 j)
Description
🔎 Search Terms
- discriminated union inference
- union argument inference
🕗 Version & Regression Information
- This is a compilation error in
tsserver 3.3.2
⏯ Playground Link
💻 Code
type InferArg =
| [1, (a: number) => void]
| [2, (b: string) => void];
const arg: InferArg = [1, (a) => { }];
🙁 Actual behavior
I get a compilation error:
Parameter 'a' implicitly has an 'any' type.(7006)
🙂 Expected behavior
a should be inferred to be a number because I already passed 1 as the first tuple element. Type inference should be identical to this code:
type InferArg = [1, (a: number) => void];
const arg: InferArg = [1, (a) => { }];
Additional information about the issue
No response