Type definition complains for some operators with union type

[kwonoj]

For example, signature of Observable.of is defined as below

Rx.Observable.of(value, [scheduler])

and declaration is like below, accepts value or scheduler with union type definition.

static of<T>(...array: (T | Scheduler)[]): Observable<T>

which makes eventually type inference confusions like

since array now contains value:T and scheduler:Scheduler both.

While this doesn't hurt functionality at all, would be better to have way to suppress these type of complains.

[kwonoj]

I will prepare PR resolves this issue partially as starting point.