Empty rest parameter type inferred from candidate function with no rest parameters when "best match" contains a contextually typed argument

Bug Report

🔎 Search Terms

Rest parameter inference contextual

🕗 Version & Regression Information

• This is the behavior in every version I tried, and I reviewed the FAQ for entries about type inference

⏯ Playground Link

Playground link with relevant code

💻 Code

const doSomething = <Args extends unknown[]>(
    fn1: (aNumber: number, ...rest: Args) => void,
    fn2: (aNumber: number, ...rest: Args) => void,
) => {}

// OK, no contextual types
doSomething(
    (explicit: number, rest: string) => {}, // Args = [string]
    () => {},
)

// OK (both contain contextually typed arg)
doSomething(
    (contextual, rest: string) => {}, // Args = [string]
    (contextual) => {},
)

// Contextually type only fn1 - Not ok
doSomething(
    (contextual, rest: string) => {}, // ERROR
    () => {}, // Args = []
)
doSomething(
    (contextual, rest: string) => {}, // ERROR
    (explicit: number) => {}, // Args = []
)

🙁 Actual behavior

When fn1 (and only fn1) contains a contextually typed argument, it is ignored in favour of fn2

🙂 Expected behavior

In all of the examples, fn2 specifies no rest parameters at all.

I would expect functions that do not specify any rest parameters to always be the least preferable candidate (lowest weight?) for rest parameter inference, since "no rest parameters" can always be assigned to any rest parameter type.

Start with the linked TypeScript Playground reproduction and reduce the three doSomething calls to isolate how contextual typing affects rest-parameter inference. Trace the type-checking path that chooses inference candidates, then add a regression test for the shown cases; done when fn1's [string] rest type is not replaced by [] from fn2.