Flow losing types when importing function which returns classes.

[y-sitbon]

Hello!

Flow types works correctly with the code below:

/* @flow */
const movable = (Base): Class<*> => {
  return class extends Base {
    move() {
      console.log('move');
    }
  }
}

class Person {
  firstName: string;

  constructor(firstName: string) {
    this.firstName = firstName;
  }
}

const MovablePerson = movable(Person);
const p = new MovablePerson('John');

p.firstName = 1;
// Flow =>
// 22: p.firstName = 1;
//                  ^ number. This type is incompatible with
// 12:   firstName: string;
//                  ^ string

But the same code splitted into multiple .js files don't:

// Movable.js
export const movable = (Base): Class<*> => {
  return class extends Base {
    move() {
      console.log('move');
    }
  }
}

// Main.js
import {movable} from './Movable.js';

class Person {
  firstName: string;

  constructor(firstName: string) {
    this.firstName = firstName;
  }
}

const MovablePerson = movable(Person);
const p = new MovablePerson('John');

p.firstName = 1;
// Flow doesn't complain anymore but should

Hope that will help

[SamChou19815]

These import related issues should be resolved a long time ago since types first