BugDomain: check: Type CircularityEffort: ModerateHelp Wanted
Repository-Metriken
- Stars
- (48.455 Stars)
- PR-Merge-Metriken
- (Durchschn. Merge 6T 17h) (9 gemergte PRs in 30 T)
Beschreibung
Bug Report
🔎 Search Terms
site:github.com inurl:/microsoft/TypeScript/issues/ Array [] normalization syntactic sugar
🕗 Version & Regression Information
This works in 3.9.7, broke in 4.0.5, and remains broken in Nightly.
- This changed between versions 3.9.7 and 4.0.5
⏯ Playground Link
Playground link with relevant code
💻 Code
type R<C> = [C, ...R<C>[]] | number; // works, as expected
type S<C> = [C, ...Array<S<C>>] | number; // fails unexpectedly - should work identically
const r: R<"add"> = ["add", 2, 1];
const s: S<"add"> = ["add", 2, 1];
🙁 Actual behavior
The A[] form in the first line works, but the otherwise-identical Array<…> form on the second line breaks with the warning Type alias 'S' circularly references itself.(2456).
🙂 Expected behavior
Both of these should work, and behave identically, as they are merely syntactic sugar for each other.