Spread operator allows invalid return type in record data types

Nadie ha tomado este issue todavía.

### 🔎 Search Terms

spread operator, return type mismatch on record of functions

### 🕗 Version & Regression Information

- This is the behavior in every version I tried, and I reviewed the FAQ for entries. Nothing related was mentioned.
I've tried 3.3, 4.0, 5.0 and 5.8.3 and got the same result.

### ⏯ Playground Link

https://www.typescriptlang.org/play/?ts=5.8.3#code/C4TwDgpgBAYgdgHgJIBooHkB8UC8UDeUokAXFAEQBmc5A3FNWQBQCWcYArsGUgJS7Z0UAL60AUGOLR4AJQgBjAPYAnACbI0WXFDlK1CAM7BlbAOZp4GjNgA+UDnFURKbCKszixlB-OAtFcESKsgoq6qjWTGJQUACGvv5wBmS6YYbGZmis7Fw8-DiCUHYOTi5wbphivGQheuGa2PjRRAAWyooA7lDlXQCiyu3KTLziwhJKScBENXCp+gBuiiyqaHAcALYARhDK2HhNMbFkhFJkVDRojFDDAlAATCJoAPRPUAgAtFBK6+sQcH5wUxQRRcVosAxQAA2rigyggBg4kOAELYcUCO0GUFRwBa0Gh5Sg20hnWaADpycBgrNQmomIRNsx8thyABmcgiXgoMSiMRAA

### 💻 Code

```ts
type Fn = { type: "fn"; fn: (input: I) => O };

type FnRecord = Record | undefined>;

function toFnRecord(
actions: Record O | undefined>
): FnRecord {
throw new Error();
}

const t: FnRecord = {
a: { type: "fn", fn: () => 2 }, // <- commenting out this line results in an error in the line below
...toFnRecord({ b: () => "3" }),
}
```

### 🙁 Actual behavior

No error was reported

### 🙂 Expected behavior

Expect the following type mismatch error message. This is reported if I **comment out** the entry without spread operator (`a: { type: "fn", fn: () => 2 },`)
```
Type '{ [x: string]: Fn | undefined; }' is not assignable to type 'FnRecord'.
'string' index signatures are incompatible.
Type 'Fn | undefined' is not assignable to type 'Fn | undefined'.
Type 'Fn' is not assignable to type 'Fn'.
Type 'string' is not assignable to type 'number'.(2322)
```

### Additional information about the issue

Similar to #61754, but this example does not involve any explicit generic subtyping constraints (`extends`).

I'm not sure if this is related to #10727.

I'd like to know any workaround that can prevent this type error happening at runtime. I've run into this multiple times with the same pattern used in my codebase and got very surprised each time.

Comienza con la reproducción enlazada en TypeScript Playground y compara los diagnósticos con y sin la entrada sin spread. Investiga cómo se comprueba el resultado del spread contra FnRecord; el trabajo está terminado cuando el tipo de retorno string no válido produce el error de incompatibilidad esperado, mientras que los valores de record válidos siguen siendo aceptados.

Escrito por el modelo de indexación a partir del texto del issue.