How to describe classes with statics in a return type

[KimlikDAO-bot]

Say I want a factory which returns a class with certain static members. How can I write the return type? The constructor shape can be described by function(new: Type, args), but what if we also want to specify some static members?

To demonstrate, we'll define an interface for 2d Points. makeHorizontalLine() will return a Point class, with a static member Intercept.

/** @interface */
class Point { /** @type {number} */ x; /** @type {number} */ y; }

/**
 * @param {number} y
 * @return {typeof PointShape}
 */
function makeHorizontalLine(y) {
  return /** @type {typeof PointShape} */(
    /** @implements {Point} */
    class {
      /** @param {number} x */
      constructor(x) {
        this.x = x;
        this.y = y;
      }
      static Intercept = new this(0);
    }
  )
}

class PointShape {
  /** @param {number} x */
  constructor(x) { }
  /** @type {Point} */
  static Intercept; // where this line intersects the x=0 line
}

This one seems to work but it's quite indirect, requires a cast and I'm not sure if it's sound for property mangling. In typescript an interface containing a constructor type (function(new: Type, args)) is understood as describing the shape of the class, not the instances. What options are there in Google Closure?

[dandov]

Hello! We don't currently support this feature in our type system and we don't have plans on adding new features to it.