microsoft / microsoft/TypeScript
Error when spreading a union of tuples in a call
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@sandersn is already working on this.
Since Apr 27, 2021.
Bug
Domain: check: Type Inference
Rescheduled
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Description
Bug Report
🔎 Search Terms
destructure array typescript union
🕗 Version & Regression Information
I used the playground to test different versions and it looks like this has always occured.
- This is the behavior in every version I tried, and I reviewed the FAQ for entries about "Type Systems behavior", "Type Guards", "Functions".
⏯ Playground Link
Playground link with relevant code
💻 Code
const t = [4,20] as const
const t2 = [4, 20, 30] as const
const t3 = [10, 10] as [number, number] | [number, number, number]
// Works
new Date().setHours(...t)
new Date().setHours(...t2)
// Error: Expected 1-4 arguments, but got 0 or more.
new Date().setHours(...t3)
🙁 Actual behavior
Error: Expected 1-4 arguments, but got 0 or more.
The array type passed as a length of 2 or 3 so the message "got 0 arguments" is wrong.
🙂 Expected behavior
I expect the compiler should be able to recognize that the array type can only have length 2 or 3 and would not throw an error.
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Assessment
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