Compiler hangs

[s-panferov]

Try to compile this code with tsc:

declare module Bacon {
    interface Event<T> {
    }
    interface Error<T> extends Event<T> {
    }
    interface Observable<T> {
        zip<U, V>(other: EventStream<U>, f: (a: T, b: U) => V): EventStream<V>;
        slidingWindow(max: number, min?: number): Property<T[]>;
        log(): Observable<T>;
        combine<U, V>(other: Observable<U>, f: (a: T, b: U) => V): Property<V>;
        withStateMachine<U, V>(initState: U, f: (state: U, event: Event<T>) => StateValue<U, V>): EventStream<V>;
        decode(mapping: Object): Property<any>;
        awaiting<U>(other: Observable<U>): Property<boolean>;
        endOnError(f?: (value: T) => boolean): Observable<T>;
        withHandler(f: (event: Event<T>) => any): Observable<T>;
        name(name: string): Observable<T>;
        withDescription(...args: any[]): Observable<T>;
    }
    interface Property<T> extends Observable<T> {
    }
    interface EventStream<T> extends Observable<T> {
    }
    interface Bus<T> extends EventStream<T> {
    }
    var Bus: new <T>() => Bus<T>;
}

var stuck: Bacon.Bus<number> = new Bacon.Bus();

Compiler hangs and you never get result. This repeats on tsc master too.

> tsc --version
message TS6029: Version 1.3.0.0

[s-panferov]

NOTE: It hangs only with primitive types like bool and number. It successfully compiles if you specify any or some complex type.

[s-panferov]

This one looks very similar to #1002.

[saschanaz]

Smaller code to cause hang:

declare module Bacon {
    interface Observable<T> {
        slidingWindow(): Observable<T[]>;
    }
    interface Bus<T> extends Observable<T> {
    }
    var Bus: new <T>() => Bus<T>;
}

var stuck: Bacon.Bus<number> = new Bacon.Bus();

[RyanCavanaugh]

@saschanaz this seems to be fixed in master (probably by the fix in #1002)

Trying to simplify the first repro posted as it does seem to hang in master

[RyanCavanaugh]

Isolated the exponential behavior (good news -- your program might finish compiling within our lifetimes 😄)

interface Observable<T> {
    // This member can't be of type T, Property<T>, or Observable<anything but T>
    needThisOne: Observable<T>;
    // Add more to make it slower
    expo1: Property<T[]>; //  0.31 seconds in check
    expo2: Property<T[]>; //  3.11 seconds
    expo3: Property<T[]>; // 82.28 seconds
}
interface Property<T> extends Observable<T> { }

var p: Observable<{}>;
var stuck: Property<number> = p;

Tagging @JsonFreeman