Super slow compilation in rare cases when mixing explicit typing, generics and type-inference

[choeller]

TypeScript Version:

1.8.7

Code

Having three classes like this:

import {Subject} from 'rxjs/Rx';
import {Task} from '../../models/task'
import {TaskStore} from "../task-store/task-store";

export class TaskService {
  //foo = "bar";   // -> commenting in solves slow compilation
  tasks: Subject<Task[]>;
}

import {Task} from "../../models/task";
import {BehaviorSubject} from "rxjs/Rx";

export class TaskStore {
  tasks =  new BehaviorSubject([]);
  //tasks = new BehaviorSubject<Task[]>([]); // -> change above line withis this one solves slow compilation
  //_tasks =  new BehaviorSubject([]);  // -> change above line withis this one solves slow compilation
}

import {bootstrap} from 'angular2/platform/browser';
import {TaskStore} from "./app/services/task-store/task-store";
import {TaskService} from './app/services/task-service/task-service';

class TestClass {
}

bootstrap(TestClass, [
    TaskService,
    TaskStore,
]);

leads to super slow compilation. Commenting in any of the lines above makes the compilation about 6 times faster.

See this repositiory as a reference for the problem:

https://github.com/choeller/slow-ts-compiler-demo/

[sandersn]

This looks like a dupe of #7082 or the other problems with compiling RxJs. @vladima can you take a look?

[sandersn]

As a quick overview of the problem, caching is broken for class this types and RxJs is a commonly used project that relies on caching common base types to be able to compile fast enough.

[vladima]

I would keep this open, fix for this types does not make this issue completely go away - compilation time is dropped from 8-9 to ~6 seconds but still it is kind of slow. Crux of the problem - rxjs-5.0.0.beta2 exposes a number of types that look similar and quite complicated in structure and doing a full structural comparison of them takes a lot of time

Simplified repro: https://github.com/vladima/rxjs-issue - majority of time is spent doing subtype reduction.

[vladima]

closing as fix to RxJS was already merged