Reverse mapped type inference fails to infer from annotated parameters in partially-inferrable object types

🔎 Search Terms

reverse mapped inference annotated parameters partially inferrable noninferrable object context sensitive

🕗 Version & Regression Information

• This is the behavior in every version I tried

⏯ Playground Link

https://www.typescriptlang.org/play?ts=5.5.0-dev.20240315#code/CYUwxgNghgTiAEAzArgOzAFwJYHtXwGcQNkAHAHgBUBxZWYAgPgAoB9ALngG8AoeeAOZ0YDTr378A2gGl4WfAGsQATxyJ4NYQwC6nZpgAenNAtQ4A7qgA08UrCgBbAp030CM7QEp4AXkbwAIxwcCBAoVABuPngAXyiYzxdaNyieMDwCDEEtAl9CYjJmcWy3MWj+KD1vP3gMGGQQK3LAvVYbOxhHAmr-OoamiXgwVvb7J05UZAcAkBge2vrG6JimhNShNx4Aei34AD0AfiA

💻 Code

declare function setup<TGuards>(_: {
  guards: {
    [K in keyof TGuards]: (ctx: unknown, params: TGuards[K]) => boolean;
  };
}): TGuards;

const guards = setup({
  guards: {
    a: () => true,
    b: (_, params) => true,
    c: (_, params: number) => true,
  },
});

guards
// ^? const guards: { a: unknown; b: unknown; c: unknown; }

🙁 Actual behavior

It infers { a: unknown; b: unknown; c: unknown; }

🙂 Expected behavior

I'd expect { a: unknown; b: unknown; c: number; } to get inferred here

Additional information about the issue

No response

Commencez par reproduire l’exemple de paramètre annoté dans le TypeScript Playground lié et comparez les types effectivement inférés avec ceux attendus. L’issue ne mentionne aucun fichier du dépôt ni aucun test de régression ; il faudra donc localiser l’implémentation pertinente de l’inférence des reverse mapped types ainsi qu’un test approprié du compilateur ; la tâche sera terminée lorsque l’exemple inférera c comme number tandis que a et b resteront unknown.