Our code currently uses the `IConstructorSignature` types in a two main ways:
- As argument types in functions that take a service constructor.
- As return types or property types when we expose a service constructor in the API
This first usage is not valid with strict function types. The reason is that the `IConstructorSignature` types takes a rest array of `...services: BrandedService[]` , while the concrete constructors you pass in use actual services. With strict function types, you cannot convert the concrete constructor type to an `IConstructorSignature` because this would drop important type information that the implementation needs. As an example
```ts
class Foo {
constructor(@ILogService service: ILogService) {}
}
registerFoo(Foo);
// The type of `ctor` inlines `IConstructorSignature0`
function registerFoo(ctor: { new(....serivces: BrandedService[]): Foo}) {
// When registerFoo(Foo) is called, the implementation here would need to know that
// ctor needs to be invoked with exactly one `ILogService`. However the type of `IConstructorSignature0`
// does not express this. Strict function types therefore disallows this conversion
}
```
To fix this, I have converted a few places were we were taking `IConstructorSignature` arguments so that they preserve the full type of the constructor. This fixed over half of our 900 strict function type errors. Unfortunatly I can not figure out a more elegant way to express this besides inlining the types
However, even after this change, we still need to figure out how to deal with:
- Places in the code where `IConstructorSignature` is exposed as a return type or object property
- How to deal with all of our descriptor types (such as `SyncActionDescriptor`)
