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

Start by reproducing the annotated-parameter example in the linked TypeScript Playground and compare the actual and expected inferred types. The issue names no repository file or regression test, so the relevant reverse mapped type inference implementation and a suitable compiler test will need to be located; done means the example infers c as number while a and b remain unknown.