Spreading a get accessor property results in false positive "overwritten" error

[Dionysusnu]

Bug Report

🔎 Search Terms

spread, get, accessor, class

🕗 Version & Regression Information

• This changed between versions 3.8.3 and 3.9.7

⏯ Playground Link

Playground link with relevant code

💻 Code

class A {
    get bar() {
        return "Overwritten by getter";
    }
}

const foo = new A()
const a = {
    // False-positive error because `bar` will not be overwritten by a get accessor
    bar: "Was not overwritten",
    ...foo,
}
// `bar` is correctly not in `b`'s type, because it's from a get accessor
const b = {
    ...foo,
}

// logs `{"bar": "Was not overwritten"}`
console.log(a)
// logs `{}`
console.log(b)

🙁 Actual behavior

An error is thrown on line 10, reporting that bar is overwritten. However, get accessors do not overwrite properties during spread behaviour.

🙂 Expected behavior

The error should not be reported, because bar is not actually overwritten. This is already recognised, as the type of b shows the bar property is excluded when not specified in the literal.

[RyanCavanaugh]

See #9726 - enumerability is not tracked

[typescript-bot]

This issue has been marked as a 'Duplicate' and has seen no recent activity. It has been automatically closed for house-keeping purposes.

[Dionysusnu]

It's kind of a separate bug though, isn't it? The type of b shows clearly that the enumerability is tracked in some way. It seems odd that that would then not be used for the overwriting diagnostic.

[Dionysusnu]

For example, 47078 also added similar checks related to spreads.