Annotated parameters are not used for inferring rest parameters

🔎 Search Terms

annotated, "rest parameter"

🕗 Version & Regression Information

• This is the behavior in every version I tried

⏯ Playground Link

https://www.typescriptlang.org/play/#code/GYVwdgxgLglg9mABAWwNYEFrzAHgJJgAOIUiApgB5RlgAmAzogIZgCeA2gLoB8AFE1gQAuRAG8AUIimJgARiG8AdMor0hBYlACUiALzdEANzgxaAGknTgAJgXLFq9URI79Rk+fEBfHaK-jxNExYBF4JaRlZXgoheigAJxgwAHMzRFYhMBBkACMyeN8vC0spG2i01kKLCIB6GsQKZjp05niyRCTgfLbaZkYAIhZWfurpOvJDGkQoAAs4EGSZmWsOxk7usl6mAeiROMSUipEs3PzXA2NTfu8tAG5xIA

💻 Code

function mkAction<Input extends any[]>(action: {
    f1:(...xs:Input) => void,
    f2:(...xs:Input) => void,
}) {}

mkAction({
    f1(x:string, y:number) {},

    f2(x, y) {},
    // x and y are inferred as "any",
    // even though f2 is inferred as "(x: string, y: number) => void"
});

🙁 Actual behavior

Arguments "x" and "y" are inferred as "any", even though "f2" has the correct type (x: string, y: number) => void

🙂 Expected behavior

I would expect inference of x: string and y: number for the arguments of "f2".

Additional information about the issue

No response

まず、issue にある注釈付き rest パラメーターの例を、リンク先の TypeScript Playground で再現します。コンパイラーがコンテキスト関数型から f2 の注釈なしパラメーターをどのように推論するかを追跡し、次に期待される string と number の推論のカバレッジを追加して、既存の動作が維持されていることを確認します。