Pipe operator cannot infer return type as ConnectableObservable

RxJS version: 5.5.0

Code to reproduce:

const obs = Observable.of(5);
const connectableObs = obs.pipe(
    publishReplay(1)
);

Expected behavior: The inferred type of connectableObs is ConnectableObservable<number>.

Actual behavior: The inferred type of connectableObs is Observable<number>.

Additional information:

TypeScript version: 2.5.3

My current workaround is to manually downcast the return value:

const obs = Observable.of(5);
const connectableObs = obs.pipe(
    publishReplay(1)
) as ConnectableObservable<number>;

Happy to send a PR, but not sure how should I fix this properly.

[Dynalon]

This issue still exists in rxjs 6.0 final. Reproduce:

const connectableObservable = from([1, 2, 3]).pipe(publish());
connectableObservable.connect()

tsc will fail, saying error TS2339: Property 'connect' does not exist on type 'Observable<any>'.. Casting the connectableObservable to any and calling .connect() works as expected.

Edit: Used latest typescript 2.8.3.

[cartant]

Actually, if the overload signatures for pipe are written like this:

pipe<A, OA extends Observable<A>>(op1: UnaryFunction<Observable<T>, OA>): OA;
pipe<A, B, OB extends Observable<B>>(op1: OperatorFunction<T, A>, op2: UnaryFunction<Observable<A>, OB>): OB;
// etc.

The problem can be solved without specific reference to ConnectableObservable.

This seems to be okay with the version of TypeScript (2.0) that RxJS uses, but I’ve not investigated this thoroughly.