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

Beginne damit, das annotierte Restparameter-Beispiel aus dem Issue im verknüpften TypeScript Playground zu reproduzieren. Verfolge, wie der Compiler die nicht annotierten Parameter von f2 aus dem kontextuellen Funktionstyp ableitet, füge dann Abdeckung für die erwartete Inferenz von string und number hinzu und überprüfe, dass das bestehende Verhalten intakt bleibt.