Property is not assignable to the same property in generic base type

### 🔎 Search Terms

Property is not assignable to the same property in generic base type

### 🕗 Version & Regression Information

-This is the behavior in every version I tried, and I reviewed

### ⏯ Playground Link

https://www.typescriptlang.org/zh/play/?ts=5.8.3#code/IYIwzgLgTsDGEAJYBthjAgSgCwPYIG8AoBBUSGeBABwEsATAc1oDswAeAMQH0BRBAKYAPCAJb0MLAK4BbEAKgAaBDwBSAPgAUIKFLABHKQMgAuFd1UIAPud4BKM2uu2A3EQC+RFGgwAhZFIAZoEKgiJiElh4hCQ0DMxsXHxhouKSsvJK5hraugZGptnOPPaOFsXJscSkpFACEFJQLKQ6eobGEG6knp5AA

### 💻 Code

```ts
abstract class Rho {
abstract pidgins(brusquest: F_J | F_E): F_J | F_E;
}
class Bluffer extends Rho {
pidgins(brusquest: F_J | F_E): F_J | F_E
{
return brusquest;
}
}

```

### 🙁 Actual behavior

Property 'pidgins' in type 'Bluffer' is not assignable to the same property in base type 'Rho'.
Type '(brusquest: F_E | F_J) => F_E | F_J' is not assignable to type '(brusquest: F_E | F_J) => F_E | F_J'. Two different types with this name exist, but they are unrelated.
Type 'number | F_E | F_J' is not assignable to type 'F_E | F_J'.
Type 'number' is not assignable to type 'F_E | F_J'.(2416)

### 🙂 Expected behavior

No error

### Additional information about the issue

The following works with no error:
```
abstract class Rho {
abstract pidgins(brusquest: F_J | F_E): F_J | F_E;
abstract pidgins(brusquest: F_J | F_E): F_J | F_E;
}
class Bluffer extends Rho {
pidgins(brusquest: F_J | F_E): F_J | F_E
{
return brusquest;
}
}

```

Start by reproducing the example from the linked TypeScript Playground and compare the generic method in Rho with the implementation in Bluffer. Trace the type-checking path for generic method compatibility; done means the reproduction reports no error without breaking related assignability behavior.

Written by the indexing model from the issue text.