How to type hint Google Types in Google Scripts Library?

Question

I asked a question and through the answer found I had not asked the right question!

Say LibraryFoo is a library and if I use that elsewhere as a library, I get type completion. For example, if I have

/**
 *  Lorem ipsum
 *
 *  @return {Object[]}
 *
 */
function bar() {}

in LibraryFoo and if in the other Google Script I type LibraryFoo.bar(). I get suggestions for an array like forEach and map. However, if instead I have

/**
 *  Lorem ipsum
 *
 *  @return {Sheet}
 *
 */
function barring() {}

and I type LibraryFoo.barring(). I do not get suggestions like getRange or getMaxColumns. I know that using clasp and local IDE might make more sense, but one of two seems to be the case:

1. I am using the wrong name/reference (though when Google's own functions are typed, they simply say "Sheet". Is the source code for e.g. SpreadsheetApp available? That would maybe be a hint, or not be in proper GAS).
2. This is not possible, because Google have done something I/we cannot do.

Regardless, despite searching and trying different ways to namespace the Sheet reference, I have not found out whether it is 1. or 2. (or something else!).

[EDIT: I have made a feature request to Google, still unsure which of 1./2./something else it is]

Answer 1

This is supported in the new editor, and an example of the syntax is as follows:

/**
 *  Returns price list data from the Stock tab/sheet
 *
 *  @param {number} index 
 *  @return {SpreadsheetApp.Range}
 *
 */
function getRange() {
  return SpreadsheetApp.getActiveRange();
}

function foo() {
  getRange().
}

and you will get completion after the . in getRange(). for a Range object.

This works as well if the function comes from a library.