Error on updating file with interface+class with event parameter that's inside class

Tried updating BouncerService.cs:
```csharp
public interface IBouncerService {
event Action Bounced;
// ..
}

public class BouncerService : IBouncerService {
public struct Case { /* .. */ }
public event Action Bounced = delegate { };
// ..
}
```
Got following SourceCodeCombined.cs:
```csharp
public interface IBouncerService__Patched_{
event Action Bounced;
// ..
}

public class BouncerService__Patched_: IBouncerService {
public struct Case { /* .. */ }
public event Action Bounced = delegate { };
// ..
}
```
With following error:
```
error CS0738: 'BouncerService__Patched_' does not implement interface member 'IBouncerService.Bounced'. 'BouncerService__Patched_.Bounced' cannot implement 'IBouncerService.Bounced' because it does not have the matching return type of 'Action'.
```

Start with the BouncerService.cs example and inspect the generated SourceCodeCombined.cs output, focusing on how the interface and class are renamed. Reproduce the compiler error and trace the hot-reload transformation that produces the renamed types. Done means the transformed example compiles without CS0738 and the event still matches the interface member.

Written by the indexing model from the issue text.