Unexpected `any[]` spreading `string` into `unknown[]`-constrained argument position

[RyanCavanaugh]

Bug Report

🔎 Search Terms

any spread string

🕗 Version & Regression Information

• This changed between versions 3.9 and 4.0

⏯ Playground Link

Playground link with relevant code

💻 Code

declare function foo<T extends unknown[]>(...args: T): T;
// p: any[], expected string[]
const p = foo(..."hello");
// @ts-expect-error
p[0].blah

🙁 Actual behavior

p is any[]

🙂 Expected behavior

p is string[]

[typescript-bot]

The change between origin/release-3.9 and origin/release-4.0 occurred at d479206.

[typescript-bot]

👋 Hi, I'm the Repro bot. I can help narrow down and track compiler bugs across releases! This comment reflects the current state of the repro in the issue body running against the nightly TypeScript.

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Issue body code block by @RyanCavanaugh

❌ Failed: -

• Unused '@ts-expect-error' directive.

Historical Information

Version	Reproduction Outputs
4.5.2, 4.6.2, 4.7.2, 4.8.2, 4.9.3	❌ Failed: - Unused '@ts-expect-error' directive.

[Andarist]