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

Empieza reproduciendo el ejemplo de parámetro rest anotado del issue en el TypeScript Playground enlazado. Sigue cómo el compilador infiere los parámetros sin anotación de f2 a partir del tipo de función contextual, añade después cobertura para la inferencia esperada de string y number y verifica que el comportamiento existente se mantiene intacto.